NATIONAL MARINE FISHERIES SERVICE 

ENDANGERED SPECIES ACT .	 . 

BIOLOGICAL OPINION 

Agency:	 Anny Corps of Engineers (ACOE), Philadelphia District 

Activity Considered:	 Deepening ofthe Delaware River Federal Naviglltion Channel
 

(ReiJ)itiation) .
 

FINERJ2011100574 

Conducted by: 

Date Issued: 

Approved by: . 

. Table of Contents . < 

1.0 rnTRODUCTION 4
 

2'.0 PROJECT HISTORy , ; , : 4
 

2.1 Delaware River Channel	 4
 

2.2 ESA Consultation on ACOE Maintenance of the Existing Channel	 5
 

2.3 Channel Deepening Proposal andConsultation History	 : 8
 

3.0 DESCRIPTION OF THE PROPOSED ACTION :	 ,.. 10
 

3.1 Action Area	 · i .. 10

3.2 Proposed Deepening Project .i 	 . , 11 . 

3.3 Dredged Material Disposal · , : 16
 

·3.4 Maintenance Dredging · : ; 19
 

4.0 STATUS OF LISTED SPECIES IN THE ACTION AREA.	 19
 

4.1 Overview of Status of Sea Turtles	 20
 

4.2 l'Jorthwest Atlantic DPS of loggerhead sea turtle :	 21
 

4.3 Status of Kemp's Ridley Sea Turtles	 34
 

4.4 Status of Green Sea Turtles ,	 38 / 

4.5 Status of Leatherback Sea Turtles :..;	 42
 

4.6 Shortnose Sturgeon	 \ : 50
 

4.7	 Status of Atlantic sturgeon ; ,' ;.; 64
 

J,.
 
2

Status and Distribution of Shortnose Sturgeon in the Delaware River ................. 58

4.7 Status of Atlantic sturgeon ............................................ 64

4.8 Gulf of Maine DPS of Atlantic sturgeon ................................... 73

4.9 New York Bight DPS of Atlantic sturgeon ................................. 77

4.10 Chesapeake Bay DPS of Atlantic sturgeon ................................. 79

4.11 Carolina DPS of Atlantic sturgeon....................................... 81

4.12 South Atlantic DPS of Atlantic sturgeon................................... 86

4.13 Summary of Available Information on Use of Action Area by Listed Species ......... 91

5.0 ENVIRONMENTAL BASELINE ......................................... 101

5.2 State or Private Actions in the Action Area................................ 106

5.3 Other Impacts of Human Activities in the Action Area ....................... 109

6.0 CLIMATE CHANGE ................................................... 112

6.1 Background Information on Global climate change.......................... 112

6.2 Species Specific Information on Climate Change Effects ...................... 114

6.3 Effects of Climate Change in the Action Area .............................. 119

6.4 Effects of Climate Change in the Action Area to Atlantic and shortnose sturgeon ..... 120

6.5 Effects of Climate Change in the Action Area on Sea Turtles ................... 122

7.0 EFFECTS OF THE ACTION ............................................ 123

7.1 Hopper Dredge ................................................... 124

7.2 Hydraulic Cutterhead Dredge......................................... 140

7.3 Dredged Material Disposal ........................................... 145

7.4 Blasting and Mechanical Dredging ..................................... 146

7.5 Maintenance Dredging.............................................. 151

7.6 Effects on Benthic Resources and Foraging ............................... 152

7.7 Dredge and Disposal Vessel Traffic ..................................... 154

7.8 Effects of Deepening on Substrate/Habitat Type ............................ 156

7.9 Effects of Deepening on Salinity ....................................... 157

7.10 Effects of Deepening on Dissolved Oxygen ................................ 162

7.11 Effects to Atlantic sturgeon spawning ................................... 163

7.12 Increased Use of Channel by Vessels .................................... 164

8.0 CUMULATIVE EFFECTS ............................................. 165

9.0 INTEGRATION AND SYNTHESIS OF EFFECTS ............................. 167

9.1 Shortnose sturgeon ................................................ 168

9.2 Atlantic sturgeon.................................................. 172
3

9.2.1 Determination of DPS Composition ................................... 172

9.2.2 Gulf of Maine DPS ............................................... 172

9.2.3 New York Bight DPS ............................................. 175

9.2.4 Chesapeake Bay DPS ............................................. 179

9.2.5 South Atlantic DPS .............................................. 182

9.2.6 Carolina DPS................................................... 185

9.3 Green sea turtles .................................................. 185

9.4 Leatherback sea turtles ............................................. 185

9.5 Kemp’s ridley sea turtles ............................................ 185

9.6 Northwest Atlantic DPS of Loggerhead sea turtles .......................... 188

10.0 CONCLUSION ..................................................... 193

11.0 INCIDENTAL TAKE STATEMENT....................................... 193

11.1 Amount or Extent of Incidental Take.................................... 194

11.2 Reasonable and prudent measures...................................... 195

11.3 Terms and conditions............................................... 197

12.0 CONSERVATION RECOMMENDATIONS ................................. 203

13.0 REINITIATION OF CONSULTATION ..................................... 204

14.0 LITERATURE CITED ................................................ 205

APPENDIX A. .......................................................... 247

APPENDIX B............................................................ 253

Appendix C............................................................. 256

APPENDIX D ........................................................... 258

APPENDIX E ........................................................... 263

Appendix F. ............................................................ 264
4

1.0 INTRODUCTION 

This constitutes the biological opinion (Opinion) of NOAA’s National Marine Fisheries Service 

(NMFS) issued pursuant to Section 7 of the Endangered Species Act (ESA) of 1973, as amended, 

on the effects of the U.S. Army Corps of Engineers ongoing deepening of the Delaware River 

Federal navigation channel from Philadelphia to the Sea. This Opinion is based on information 

provided in the Biological Assessment (BA) dated January 2009; a supplement to the BA dated 

February 9, 2009; a further supplement dated March 2011; an Environmental Assessment (EA) 

dated April 2009; a supplement to the EA dated September 2011; NMFS October 25, 1996 Opinion

on dredging in the Philadelphia District of the Army Corps of Engineers (ACOE); a May 25, 1999 

supplement to the 1996 Opinion; the February 2, 2001 Opinion on the Delaware River Main 

Channel Blasting Project; our July 2009 Opinion on the deepening project; and, scientific papers 

and other sources of information as cited in this Opinion. A complete administrative record of this 

consultation will be kept at the NMFS Northeast Regional Office. 

2.0 PROJECT HISTORY

2.1 Delaware River Channel 

The existing Delaware River Philadelphia to the Sea Federal navigation project was authorized by 

Congress in 1910 and modified in 1930, ’35, ’38, ’45, ’54 and ’58. This 96.5 mile long channel is 

authorized for depths of 37 to 40 feet. The existing project provides for a channel from deep water 

in Delaware Bay to a point in the Bay, near Ship John Light, 40 feet deep1and 1,000 feet wide; 

thence to the Philadelphia Naval Base, 40 feet deep and 800 feet wide, with a 1,200-foot width at 

Bulkhead Bar and a 1,000-foot width at other channel bends; thence to Allegheny Avenue 

Philadelphia, PA; 40 feet deep and 500 feet wide through Horseshoe Bend and 40 feet deep and 400 

feet wide through Philadelphia Harbor along the west side of the channel. The east side of the 

channel in Philadelphia Harbor has a depth of 37 feet and a width of 600 feet. The 40-foot channel 

from the former Naval Base to the sea was completed in 1942. The channel from the former Naval 

Base to Allegheny Avenue was completed in 1962. There are 19 anchorages on the Delaware 

River. The Mantua Creek, Marcus Hook, Deepwater Point, Reedy Point, Gloucester and Port 

Richmond anchorages are authorized under the Philadelphia to the Sea project. The remaining 13 

are natural, deep-water anchorages. The authorized anchorage dimensions are as follows: Mantua 

Creek: 40’ x 2,300’ x 11,500’ (mean); Marcus Hook: 40’ x 2,300’ x 13,650’ (mean); Deepwater 

Point: 40’ x 2,300’ x 5,200’ (mean); Reedy Point: 40’ x 2,300’ x 8,000’ (mean); Port Richmond: 

37’ x 500’ (mean) x 6,400’; and, Gloucester: 30’ x 400’ (mean) x 3,500’. Mantua Creek anchorage 

is currently maintained to about 60% of the authorized width and a 37-foot depth. The Marcus 

Hook anchorage, enlarged in 1964, is maintained to the authorized dimensions. The anchorage at 

Port Richmond is about 35 feet deep, as are the Reedy Point and Deepwater Point anchorages. The 

Gloucester anchorage requires no dredging and is currently deeper than authorized. See Figure 1 

for map of the project location. 

The existing authorized channel is maintained by the ACOE at 40 feet and is routinely dredged. 

There are wide variations in the amount of dredging required to maintain the Philadelphia to the Sea 

project. Some ranges are nearly self-maintaining and others experience rapid shoaling. The 40-foot 

 

1 All depths refer to mean low water.
5

channel requires annual maintenance dredging in the amount of approximately 3,455,000 cubic 

yards. Of this amount, the majority of material is removed from the Marcus Hook (44%), 

Deepwater Point (18%) and New Castle (23%) ranges. The remaining 15 percent of material is 

spread throughout the other 37 channel ranges. The historic annual maintenance quantities for the 

Marcus Hook and Mantua Creek anchorages are 487,000 and 157,000 cubic yards, respectively.

There are currently seven upland sites in the riverine portion of the project and one open-water site, 

located in Delaware Bay, that are used for dredged material disposal. The seven confined upland 

sites are National Park, Oldmans, Pedricktown North, Pedricktown South, Penns Neck, Killcohook 

and Artificial Island. The open water site in Delaware Bay is located in the vicinity of Buoy 10. 

This site is only approved for placement of sand and is only used for disposal of material removed 

from the Bay (reaches D and E).

2.2 ESA Consultation on ACOE Maintenance of the Existing Channel 

In September 1986, the Philadelphia District initiated formal consultation under Section 7 of the 

ESA, with regard to maintenance dredging of Delaware River Federal Navigation Projects from 

Trenton to the Sea, and potential impacts to the Federally endangered shortnose sturgeon (Acipenser 

brevirostrum). “A Biological Assessment of Shortnose Sturgeon (Acipenser brevirostrum) 

Population in the Upper Tidal Delaware River: Potential Impacts of Maintenance Dredging” was 

provided to NMFS with the initiation request. It was determined by the ACOE that maintenance 

dredging activities in the southern reaches of the Delaware River, specifically from Philadelphia to 

the Sea, were not likely to adversely affect shortnose sturgeon. In a letter dated June 17, 1994 we

provided concurrence with this determination. 

In September 1995, consultation was reinitiated regarding potential impacts associated with 

dredging projects permitted, funded or conducted by the Philadelphia District. This batched 

consultation was to consider effects of the following actions on NMFS listed species: maintenance 

of the Philadelphia to Trenton Federal navigation channel, maintenance of the Philadelphia to the 

Sea Federal navigation channel, several beach nourishment projects which used sand dredged from 

Delaware Bay and authorized borrow areas located along the New Jersey and Delaware coasts, and 

dredging projects conducted by private applicants and authorized by the ACOE through their 

regulatory authority under Section 10 of the Rivers and Harbors Act. “A Biological Assessment of 

Federally Listed Threatened and Endangered Species of Sea Turtles, Whales, and the Shortnose 

Sturgeon within Philadelphia District Boundaries: Potential Impacts of Dredging Activities” was 

provided to us for review. An Opinion was issued by us on November 26, 1996 which considered 

effects of all projects conducted or authorized by the ACOE in the Philadelphia District. The 

Opinion concluded that the District’s dredging program, including maintenance of the Philadelphia 

to the Sea and Philadelphia to Trenton navigation projects, may adversely affect sea turtles and 

shortnose sturgeon, but was not likely to jeopardize the continued existence of any threatened or 

endangered species under our jurisdiction. The Opinion included an Incidental Take Statement 

(ITS) which exempted the annual take by injury or mortality of three shortnose sturgeon. This 

Opinion was amended with a revised ITS on May 25, 1999. The amended take statement issued on 

May 25, 1999 exempts the annual take of up to four shortnose sturgeon and four loggerhead sea 

turtles or one Kemp’s ridley or one green sea turtle. 
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'DELAWARE'RIVER'tMIN' . 

c:HANNE~DEEP~NjNG 'P~OiECT

Dredged'Mafeital.Plilcement:Plan. 

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DELAWARE RIVERMAIN CHANNEL DEEPENING 

DREDGING CO~TS',,:

leem..ct No, 2 

_s· 

155+000 to 178+000.;. Pedricktown Sou1h . 

. lH.~~~f~I~~'I~'FH+h~I~~~r+t-+-frFf''Ff~~l'"rH+1~I~~~'~fl· t 1:I~l~rjl~T"JI'.' rfT~fJl~~r~fRlrff+l~~.sl~' 1.95-·' ,-t,051,564I .. · HVD .". 

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IContract No.3 

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Reach A' ';7 

2.BS­

( . 994.0001 HYO 

32+75610 90+000~ PedridctOwn Ncirtti" '8.10'; < . '. 1.666.6001 . HOP

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.., ContnIct Total " 

1.6504.800 

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. ".871,400' 

1098+000 to 124..-000· PedricktOwn NarttI·, .:. 2.89!••

124+000 to 137+000 ~Pedfk:kt0Vl'l SouIt1;. ·::;:0.45" 

137-tOoo to 155+000"; PedricktOwn SOOth:. '. 0.13''!'' 

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. MllIClJ3HookAndlorag8"';-~ .•~. ' :.,.O.!9fr; 

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Berth ~penlngs

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Berth Oeepen/flgs eso R:ehandlng WP; . I ,,, 

Tat.! Berth DeepeninG.' 4tU---;437 

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'\~HYD :.:,: CUTTER SUCTlON DREDGE 

.;:-: .", l.:ANDSIDE CONSTRUcnON" 

•..1:MEC:,.. ClAMSHEll DREDGE 

.. 'SLA"; DRILl80AT.(8tASTIN~r

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',1.', 

·,i 

IRewlaed February 2012 

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( 

( 
8

2.3 Channel Deepening Proposal and Consultation History 

In 1983, the Philadelphia district was directed by Congress to begin feasibility studies regarding 

modifying the existing 40-foot Delaware River main shipping channel. In 1992, a final feasibility

report recommended that the channel be deepened to 45 feet. Congress authorized the deepening 

project for construction in 1992. The project would involve deepening the main channel of the 

Delaware River from 40 to 45 feet from Philadelphia Harbor, PA and the Joseph A. Balzano Marine 

Terminal (formerly the Beckett Street Terminal), Camden, NJ to the mouth of the Delaware Bay as 

well as the widening of 12 of the 16 bends in the channel and deepening the Marcus Hook 

Anchorage. It was anticipated that the project would result in the removal of approximately 26 

million cubic yards (CY) of material. 

An Environmental Impact Statement (EIS) for this project was issued in 1992, a supplemental EIS 

was issued in 1997 and a Record of Decision (ROD) was signed in 1998. We provided comments 

to the ACOE on the EIS and SEIS in letters dated March 1, 1995, February 14, 1997 and September 

29, 1997. 

In May 2000, the Philadelphia District submitted a BA and request for consultation considering the 

effects of proposed rock blasting in the Marcus Hook range of the main channel deepening project

on shortnose sturgeon. On January 31, 2001, we issued an Opinion which concluded that rock 

blasting conducted from December 1 to March 15 may adversely affect, but is not likely to 

jeopardize the continued existence of shortnose sturgeon. The Opinion included an ITS that 

exempts the lethal take of 2 shortnose sturgeon and an unquantifiable amount of non-lethal take. 

The ITS included reasonable and prudent measures and terms and conditions including a time of 

year restriction, reporting requirements, and other measures to minimize the potential for injury or 

mortality of shortnose sturgeon during blasting operations. 

Planning for the deepening project was suspended in 2002 as a result of a review by the 

Government Accountability Office (GAO) regarding the economic benefits of the project and the 

environmental impacts. In May 2007, the Philadelphia Regional Port Authority (PRPA) took over 

sponsorship of this project from the Delaware River Port Authority. In June 2008, the ACOE and 

the PRPA executed a Project Partnership Agreement for construction of the Delaware Main Stem 

and Channel Deepening Project from 40 feet to 45 feet. In December 2008, we were notified that 

the project was reactivated. A Public Notice was posted on the Philadelphia District's (District) 

website on December 18, 2008, announcing that the District would conduct an environmental 

review of all applicable, existing and new information generated subsequent to the 1997 SEIS. We

commented on that notice in a letter dated December 30, 2008. Also in this letter, we indicated that 

upon review of the project materials, it appeared that reinitiation of the 1996 and 2001 consultations

was appropriate. 

Reinitiation of consultation is required if: “(a) the amount or extent of taking specified in the ITS is 

exceeded; (b) new information reveals effects of these actions that may affect listed species or 

critical habitat in a manner or to an extent not previously considered; (c) any of the identified 

actions are subsequently modified in a manner that causes an effect to the listed species that was not 

considered in the BO; or (d) a new species is listed or critical habitat designated that may be 

affected by the identified actions” (50 CFR 402.16). 
9

As noted above, on November 26, 1996, we issued a Biological Opinion to the Philadelphia 

District, which concluded that maintenance dredging operations within the Philadelphia District 

were not likely to jeopardize the continued existence of any threatened or endangered species listed 

under NMFS’ jurisdiction. Following the exceedence of the ITS in 1998, on May 25, 1999, in 

response to the authorized take level being exceeded, consultation was reinitiated and we amended 

the existing consultation with a revised ITS. Consultation on the blasting portion of the project had 

been completed in February 2001. As noted in our December 2008 letter, there was new 

information that indicated that the proposed deepening may have effects to listed species in a 

manner or to an extent not previously considered. This information included new information on 

the distribution and seasonal movements of shortnose sturgeon in the Delaware River as well as 

new information on the vulnerability of the species to capture in mechanical dredges and 

entrainment in hydraulic hopper dredges. Additionally, the project had been modified from the 

proposal outlined in the 1992 EIS and 1997 SEIS. Modifications included changes to the amount of 

material to be removed in the initial dredge cycle as well as in maintenance dredging, plans for 

beneficial reuse of the material, and the anticipated schedule for completion. 

On January 26, 2009, we received a letter from the ACOE requesting the initiation of consultation 

regarding the effects of the proposed deepening on listed species. Supplemental information was 

provided by the ACOE on February 9, 2009. Also sent in February 2009 was a letter from the 

ACOE clarifying that the scope of the proposed action under consultation was the initial dredge 

cycle necessary to deepen the channel to 45 feet, including blasting at Marcus Hook, collectively 

referred to as the “construction” phase of the project, and 10 years of ACOE planned maintenance 

dredging. On March 12, 2009, a revised project schedule was provided to us by the ACOE and on 

April 3, 2009 a final Environmental Assessment (EA) was distributed by the ACOE. Consultation 

was initiated on February 9, 2009. 

A Biological Opinion was signed by NMFS on July 17, 2009. In this Opinion, NMFS considered 

the effects of the proposed deepening project, including blasting and dredging, on listed sea turtles 

and shortnose sturgeon. By issuing the 2009 Opinion, we withdrew the 2001 Opinion on blasting. 

The first phase of the deepening, in Reach C, occurred from March – September 2010. No 

interactions with any NMFS listed species were observed. 

In October 2010, we published two proposed rules to list five Distinct Population Segments (DPS) 

of Atlantic sturgeon. During the winter of 2010-2011, we discussed potential impacts of the 

deepening project on Atlantic sturgeon with the ACOE. In March 2011, ACOE completed a 

supplemental BA considering effects of the deepening on the proposed New York Bight DPS of 

Atlantic sturgeon. This BA was transmitted to us along with a request to conduct a conference to 

consider the effects of the proposed deepening on Atlantic sturgeon. In June 2011, the ACOE 

published a draft supplemental EA. In an August 15, 2011, letter we provide the ACOE with 

technical assistance regarding upcoming dredging of Reach B. The ACOE published a final EA in 

September 2011. Dredging in reach B was carried out in November and December 2011, with no 

observations of interactions with any NMFS listed species. In March 2012, we received ACOE 

reports on the tracking of tagged Atlantic and shortnose sturgeon during the dredging as well as a 

report on pre- and post-dredge substrate sampling. 

On April 6, 2012, NMFS published two final rules listing five DPSs of Atlantic sturgeon as 
10

threatened or endangered. As described in a letter dated May 3, 2012, we reinitiated the 2009

consultation to consider effects of the deepening project on Atlantic sturgeon. Consultation was 

reinitiated on April 6, 2012. 

We provided a draft of this Opinion to the ACOE on June 22, 2012. Comments were received on 

July 2 and July 3, 2012. These comments have been addressed as appropriate. By issuing this 

Opinion, we withdraw the Opinion dated July 17, 2009. 

3.0 DESCRIPTION OF THE PROPOSED ACTION

3.1 Action Area

The action area is defined in 50 CFR 402.02 as “all areas to be affected directly or indirectly by the 

Federal action and not merely the immediate area involved in the action.” The action area for this 

consultation includes the area affected by dredging and disposal activities as well as the area 

transited by project vessels. The action area, therefore, includes the entirety of the Philadelphia to 

the Sea Federal navigation channel, including the authorized anchorages and bends to be widened. 

Additionally, the action area includes the beneficial use disposal areas at Kelly Island and Broadkill 

Beach. Further, the action area includes the areas where project vessels will transit to offload 

dredged material at the upland disposal areas, which is limited to the navigation channel and 

adjacent berthing areas. The action area will also encompass the underwater area where dredging 

will result in increased suspended sediment and where sound pressure waves associated with 

blasting will be experienced. The size of the sediment plume will vary depending on the type of 

dredge used and is detailed below. Effects of blasting are expected to be limited to an area with a 

radius of 500 feet around the detonation site. The action area is illustrated in Figure 1, and is 

largely consistent with the Philadelphia to the Sea navigation channel. 

3.1.1 Physical Characteristics of the Action Area 

The Delaware River Estuary is 132 miles long and extends from Cape May and Cape Henlopen to 

Trenton, New Jersey. The region of the estuary that is referred to as Delaware Bay is 45 miles long 

and extends from the Capes to a line between stone markers located at Liston Point, Delaware and 

Hope Creek, New Jersey (Polis et al. 1973). The estuary varies in width from 11 miles at the 

Capes; to 27 miles at its widest point (near Miah Maull Shoal). Water depth in the bay is less than 

30 feet deep in 80 percent of the bay and is less than 10 feet deep in much of the tidal river area. 

Artificial Island is located approximately two miles upstream of the hypothetical line demarking the 

head of Delaware Bay. The tidal river in this area narrows upstream of Artificial Island and makes 

a bend of nearly 60 degrees. Both the narrowing and bend are accentuated by the presence of 

Artificial Island. More than half of the typical river width in this area is relatively shallow, less than 

18 feet (5.5 meters), while the deeper part, including the dredged channel has depths of up to 40 feet 

(12.1 meters). The Delaware River between the fall line at Trenton (RM 138 (rkm 222)) and 

Philadelphia (RM 100 (rkm 161)) is tidal freshwater with semidiurnal tides. Mean tidal range at 

Philadelphia 5.9 ft (1.8 m) (U.S. Army Engineer District, 1975); water pH generally is about 6-8.

Tidal flow as measured near the Delaware Memorial Bridge (RM 67 (rkm 108)), 20 miles above 

Artificial Island, was measured at 399,710 cfs (11,320 cubic meters per second) (USGS, 1966). 

Tidal flow of this magnitude is 17 times as great as the total average freshwater flow rate into the 
11

estuary. Proceeding toward the mouth of the estuary, tidal flow increasingly dominates freshwater 

downstream flow; proceeding upstream from the Delaware Memorial Bridge, the ratio of tidal flow 

to net downstream flow becomes smaller as tidal influence decreases.

3.2 Proposed Deepening Project 

The deepening project as authorized by Congress (shown on Figure 1) provides for modifying the 

existing Delaware River Federal Navigation channel Philadelphia to the Sea Project from 40 to 45 

feet at Mean Low Water with an allowable dredging overdepth of one foot, following the existing 

channel alignment from Delaware Bay to Philadelphia Harbor, Pennsylvania and the Joseph A. 

Balzano Terminal, Camden, New Jersey. The channel side slopes are 3 horizontal to 1 vertical. 

The project also includes deepening of an existing Federal access channel at a 45-foot depth to the 

Joseph A. Balzano Terminal, Camden, New Jersey. The channel is divided into six reaches as 

shown in Table 1. The lowermost end of reach E is located approximately 5 miles (8 km) from the 

theoretical line between Cape Henlopen and Cape May Point. 

Reach River Miles River Kilometers

AA 102-97.1 164-156.3

A 97-85.1 156.2-137.1

B 85-67.1 137-108.1

C 67-55.1 108-88.6

D 55-41.1 88.5-66.1

E 41-5 66-8

Table 1. Description of Delaware River Channel Reaches 

The existing channel is maintained at a depth of 40 feet deep at mean low water. Only portions of 

the channel that are currently between 40 feet and 45 feet at mean low water will be dredged for the 

deepening project. The surface area of the Delaware estuary from the Ben Franklin Bridge to the 

capes (excluding tidal tributaries) is approximately 700 square miles. The Philadelphia to the Sea 

Federal navigation channel has a surface area of 15.3 square miles, or approximately 2.2 percent of 

the total estuary surface area. For the 45-foot deepening project, 8.5 square miles would be 

dredged; this is 1.2 percent of the total estuary surface area and 55 percent of the existing channel. 

The remaining 6.8 square miles of the existing channel is already 45 feet deep or deeper. See Table 

2 (below) for a description of the amount of material to be removed from each channel range. 

The channel width (same as the existing 40-foot project) is 400 feet in Philadelphia Harbor (length 

of 2.5 miles); 800 feet from the Philadelphia Navy Yard to Bombay Hook (length of 55.7 miles); 

and 1,000 feet from Bombay Hook to the mouth of Delaware Bay (length of 44.3 miles). The 

project includes 12 bend widenings at various ranges as listed below as well as provision of a two 

space anchorage to a depth of 45 feet at Marcus Hook, Pennsylvania. The existing turning basin 

adjacent to the former Philadelphia Naval Shipyard will not be deepened as part of the 45 foot 

project.

Also included as part of the Federal project is the relocation and addition of navigation buoys at the 

12 modified channel bends. Ten new buoys are proposed: Philadelphia Harbor (2), Tinicum Range 
12

(1), Eddystone Range (1), Bellevue Range (3), Cherry Island Range (1), Bulkhead Bar Range (1), 

and Liston Range (1).

The following channel bends will be modified:

1. LISTON-BAKER: Maximum width increase on the east edge of 250 feet, over a distance of 

4,500 feet south of the apex, and extending 3,900 feet north from the apex (BW2 – channel 

station 275 + 057);

2. MIAH MAULL-CROSS LEDGE: 200 foot width increase at the apex of the west side of the 

bend;

3. BAKER-REEDY ISLAND: 100-foot width increase at the west edge apex of the bend over 

a distance of 3500 feet both north of and south of the apex (BW3 - channel station 265 + 

035);

4. REEDY ISLAND-NEW CASTLE: Maximum widening of 400 feet at the west apex of the 

bend, tapering to zero over a distance of 3,200 feet south of the apex and to zero over a 

distance of 4,000 feet north of the apex (BW4 - channel station 238 +982);

5. NEW CASTLE-BULKHEAD BAR AND BULKHEAD BAR-DEEPWATER: The west 

edge of Bulkhead Bar range is extended by 300 feet to the south and 300 feet to the north; 

the widening tapers to zero at a distance of approximately 3,000 feet south of the south end 

of Bulkhead Bar and 3,000 feet north of the north end of Bulkhead bar (BW5 - channel 

station 212 + 592 and 209 + 201);

6. DEEPWATER-CHERRY ISLAND: A maximum channel widening of 375 feet is required 

at the western apex of the bend. The widening tapers to zero at a distance of about 2,000 feet 

both north and south of the apex (BW6 - channel station 186 + 331);

7. BELLEVUE-MARCUS HOOK: The east apex of the bend requires a 150 foot widening 

over existing conditions, along a total length of approximately 4,000 feet (BW7 - channel 

station 141 + 459);

8. CHESTER-EDDYSTONE: The southwest apex of the bend requires a maximum 225 foot 

widening, with a transition to zero at the northeast end of Eddystone range, over a linear 

distance of approximately 6,000 feet (BW8 - channel station 104 + 545);

9. EDDYSTONE-TINICUM: The northeast apex of this bend requires a 200 foot widening, 

with a transition to zero at a distance of about 1,200 feet northeast and southwest of the bend 

apex (BW9 - channel station 97 + 983);

10. TINICUM-BILLINGSPORT: The north channel edge of Billingsport was widened by 200 

feet. At the northern apex of the Tinicum-Billingsport bend, this results in a maximum 

widening of approximately 400 feet, with a transition to zero at a distance of about 2,000 

feet west of the apex (BW10 - channel station 79 + 567 );

11. BILLINGSPORT-MIFFLIN: The south apex of the bend was widened a maximum of 200 

feet to the south, and transitioned to zero at a distance of approximately 3,000 feet northeast 

of the apex (BW11 - channel station 72 + 574);
13

12. EAGLE POINT-HORSESHOE BEND: The northwest edge of Horseshoe Bend requires a 

maximum widening of 490 feet to the north. The widening transitions to zero at a distance 

of approximately 4,000 lineal feet west of the west end of Horseshoe Bend, and at a distance 

of 1,500 lineal feet north of the north end of the bend (BW12 - channel station 44 + 820 to 

41 + 217).

The current dredged material disposal plan for the riverine portion of the project will utilize the 

existing upland Federal disposal sites (National Park, Oldmans, Pedricktown North, Pedricktown 

South, Killcohook, Reedy Point South, and Artificial Island). In Delaware Bay, material will be 

used for beneficial use projects at Kelly Island and Broadkill Beach. 

3.2.1 Initial Dredging Cycle 

For the initial deepening, approximately 16 million cubic yards (cy) of material would be dredged 

and placed by hydraulic cutter-suction (pipeline) and hopper dredges in confined upland disposal 

facilities in the Delaware River portion of the project area and for beneficial uses in Delaware Bay 

(See Table 1). In addition, approximately 77,000 cubic yards of rock would be removed in the 

vicinity of Marcus Hook, Pennsylvania and placed in the Fort Mifflin confined disposal facility in 

Philadelphia. Blasting would be used in this area, followed by removal of rocky material with a 

mechanical dredge. 

Initial construction began in March 2010. Initial construction is currently scheduled to continue 

through January 2017. To date, the first and the second phase of dredging has been completed

(Reach C and a portion of Reach B). A summary of the proposed dredging remaining to be 

completed is shown in Table 2. As noted in Table 2, several different types of dredges will be used 

for deepening activities. The “Type of Dredge” column indicates the type of dredge (or dredges) 

most likely to be used for each contract; however, with few exceptions, the actual type of dredge 

used for each contract will be determined by the dredging contractor.

Table 2. Summary of initial dredging quantities (remaining work as of May 2012)

Channel Reach

River 

Mile

Duration 

(Months)

Volume 

(CY)

Type of 

Dredge

Scheduled 

Dates2

Contract 3 – Reach A

97-

84.42 6.1 1,666,600

Cutterhead, 

hopper or 

mechanical 

August 2012 – February 

2013

Contract 4 - Reach D 

57.71-

41.57 5.78 2,051,100

Cutterhead

or

hopper

December 2012 – June 

2013

Contract 5 - Reach E 

(Broadkill Beach) 15.6 3.00 1,598,700 hopper (2)

September – December 

2013 

Contract 6 – Reach AA 

99.3-

97.1 2.88 994,000

Cutterhead, 

hopper or 

mechanical August – November 2014

Contact 7 – Rock 76.4 - 77,000 Mechanical December 2014 –

 

2

Schedule is subject to change based on available funding.
14

Removal: Blasting and 

Clean Up Dredging

84.6 February 2015

Contract 8 - Reach E 

(Kelly Island)

30.8-

36.4 4.50 2,483,000 hopper (2) April - August 2015

Contract 9 - Reach B 85-67 0.89 3,485,469 cutterhead

August 2016 – January 

2017

Reach E is considered to be in Delaware Bay. Figure 2 shows the currently proposed construction 

schedule and the type of dredge that would be used for different sections of the river for the 

Deepening Project as provided by the ACOE. The ACOE has indicated that the dredging plan was, 

to the extent practicable, developed to be in compliance with the Delaware River Basin Fish and 

Wildlife Management Cooperative recommended dredging restrictions for protection of fishery 

resources in the Delaware River and Bay. Time periods shaded grey are the recommended periods 

for hopper dredging, cutterhead pipeline dredging, bucket dredging, sand placement and blasting. 

Self-Propelled Hopper Dredges

Hopper dredges are typically self-propelled seagoing vessels. They are equipped with propulsion 

machinery, sediment containers (i.e., hoppers), dredge pumps, and other specialized equipment 

required to excavate sediments from the channel bottom. Hopper dredges have propulsion power 

adequate for required free-running speed and dredging against strong currents. 

A hopper dredge removes material from the bottom of the channel in thin layers, usually 2-12 

inches, depending on the density and cohesiveness of the dredged material (Taylor, 1990). Pumps 

within the hull, but sometimes mounted on the dragarm, create a region of low pressure around the 

dragheads; this forces water and sediment up the dragarm and into the hopper. The more closely 

the draghead is maintained in contact with the sediment, the more efficient the dredging (i.e., the 

greater the concentration of sediment pumped into the hopper). In the hopper, the slurry mixture of 

sediment and water is managed to settle out the dredged material solids and overflow the 

supernatant water. When a full load is achieved, the vessel suspends dredging, the dragarms are 

heaved aboard, and the dredge travels to the placement site where dredged material is disposed of. 

A hopper dredge is likely to be used in reaches A, D and E but could also be used in Reach AA. 

Bucket Dredges

The bucket dredge is a mechanical device that utilizes a bucket to excavate the material to be 

dredged. The dredged material is placed in scows or hopper barges that are towed or pushed to the 

placement site. Bucket dredges include the clamshell, orange-peel, and dragline types. The crane 

that operates the bucket can be mounted on a flat-bottomed barge, on fixed-shore installations, or on 

a crawler mount. In most cases, spuds, or anchors and spuds are used to position the plant. Because 

the bucket dredge loads scows or hopper barges, work is suspended when a fully loaded barge is 

moved away and replaced with another empty scow or barge. Spuds are typically employed to 

maintain the position of a floating bucket dredge plant. A mechanical dredge will be used to 

remove debris following blasting in reach B. The ACOE has also indicated that a bucket dredge 

may be used in Reach AA due to the presence of rocky substrate. 
15

Hydraulic Cutterhead Pipeline Dredges

The cutterhead dredge is essentially a barge hull with a moveable rotating cutter apparatus 

surrounding the intake of a suction pipe (Taylor, 1990). By combining the mechanical cutting 

action with the hydraulic suction, the hydraulic cutterhead has the capability of efficiently dredging 

a wide range of material, including clay, silt, sand, and gravel.

The largest hydraulic cutterhead dredges have 30 to 42 inch diameter pumps with 15,000 to 20,000 

horsepower. The dredge used for this project is expected to have a pump and pipeline with 

approximately 30” diameter. These dredges are capable of pumping certain types of material 

through as much as 5-6 miles of pipeline, though up to 3 miles is more typical. The cutterhead 

pipeline plant employs spuds and anchors in a manner similar to floating mechanical dredges. A 

cutterhead dredge is likely to be used in reaches AA, A, B, C, and D. 

Rock Blasting

Approximately 77,000 cubic yards of bedrock from 18 acres in reach B near Marcus Hook, PA (RM 

76.4 to 84.6) would be removed to deepen the navigation channel to a depth of 45 feet below mean 

lower low water. Rock will be placed in the Fort Mifflin dredged material disposal site located in 

Philadelphia. In order to remove the rock by blasting, holes drilled into the rock will be packed 

with explosive at the bottom of the holes and the remainder of the drill-hole filled with inert 

stemming material to the surface in order to direct the force of the blast into the rock. The depth 

and placement of the holes along with the size and blast timing delays of the charges will be 

carefully controlled so that the amount of rock that is broken and energy levels released during the 

blasting operations is limited to the level required to break up the bedrock. The project would be 

conducted by repeatedly drilling, blasting, and excavating relatively small areas until the required 

cross section of bedrock is removed. Blasting operations will occur between December 1 and 

March 15, with approximately 2 to 6 blasts conducted per day. The broken and pulverized rock 

along with overlying sands and silts will be removed by a mechanical dredge. Blasting is scheduled 

to occur in the winter of 2014-2015. 

The ACOE has built several measures into the proposed action designed to minimize the effects of 

blasting on fish. These include plans to: 

 Minimize the size of explosive charges per delay (time lag during detonation) and the number of 

days of explosive exposure;

 Subdivide the explosives deployment, using suitable detonating caps with delays or delay 

connectors for detonation cord, to reduce the seismic energy and total pressure changes induced 

by the blasting;

 Use decking (explosives separated by delays) in drill holes to reduce total pressure changes; 

 Use angular stemming material in the blasting holes above the explosive charges (specifically 

sized angular rock fragments backfilled in the drill holes to contain the explosive energy and 

reducing the unwanted effects of a pressure waves emanating from the blast and flyrock) ; 

 Use scare charges for each blast; and,

 Monitor impacts to fish from blasting.

Specifically, for each blast, the ACOE proposes to monitor an area with a radius of 500 feet 

surrounding the detonation site with sonar or other imaging techniques designed to document fish in 

this area. Surveys will begin 20 minutes prior to the blast and if any fish are observed in the 
16

monitoring zone, blasting will be delayed until the fish leave the area. Additionally, two scare 

charges shall be used at each blast. The scare charges shall be detonated in close proximity to each 

blast. Each individual scare charge shall not exceed a TNT-equivalent weight of 0.1 lb. The 

detonation of the first scare charge will be 45 seconds prior to the blast, with the second scare 

charge detonated 30 seconds prior to the blast. The ACOE will also monitor blast pressures and 

upper limits will be imposed on each series of 5 blasts so that average peak pressure shall not 

exceed 70 pounds per square inch (psi) at a distance of 140 feet and maximum peak pressure shall 

not exceed 120 psi at a distance of 140 feet. The ACOE is also considering the use of trawlers to 

relocate fish away from the blasting site. 

3.3 Dredged Material Disposal 

As stated above, it is anticipated that approximately 16 million y3of material will be removed from 

the channel over a five year period during initial construction. All material removed from reaches 

AA, A, B, C, and D, regardless of dredge type, will be disposed of at an upland location. Material 

removed from reach E will be used at a beneficial use site (see below). Approximately 4 million y3

of suitable material removed from the channel in reach E will be used for wetland restoration or 

beach nourishment. Descriptions of the proposed beneficial use sites are provided below.

3.3.1 Kelly Island (Delaware) 

As stated by the ACOE, the main purposes of the Kelly Island wetland restoration project are to 

restore intertidal wetlands using dredged sediment from the deepening of the Delaware River 

navigation channel, stem erosion of the Kelly Island shoreline estimated at 20 feet per year, provide 

extensive sandy beach for spawning horseshoe crabs, and provide continued protection to the 

entrance of the Mahon River.

The site will be constructed as an impoundment and remain as such until the sediments consolidate 

and vegetation becomes established. At that time, the State of Delaware will decide whether to 

open the site up to unregulated tidal inundation. The option to convert back to an impoundment 

will be maintained. Following construction, the site will be monitored to insure that the goals of the 

project are met and that no adverse impacts occur, particularly impacts to oyster beds.

Features of the project include:

• Sixty acres of wetlands where the substrate will consist of an estimated 55,000 cubic yards 

of silt and 645,000 cubic yards of sand.

• An offshore containment dike made of 1.7 million cubic yards of sand that will provide up 

to 5,000 linear feet of sandy beach. The crest of the dike will be at +10 ft MLW providing 

substantial spawning habitat for horseshoe crabs.

• A geotextile tube within the core of the offshore dike that provides overwash protection and 

contingency protection against breaching.

• Timber groins to limit sand transport along the beach.

• Option for water level control or free tidal exchange with the bay.

Construction of the sand dikes will begin at the south end gaining access to the site from the Mahon 

River channel. Once the dikes are constructed, the interior will be filled. Filling will take 

approximately 4 months. The total time to construct Kelly Island is 6 months with construction 

scheduled to occur between April and September. 
17

Once the containment area/beach is constructed, fine-grained sediment will be placed first followed 

by placement of sand. The volume of sediment to be placed in the site will ultimately achieve a 

surface elevation of +5 feet MLW which is at the upper part of the tidal range. After construction, 

and possibly for several years, the water levels in the site will be controlled. The offshore dike will 

have a crest elevation of +10 feet MLW. This elevation is coincident with the water level for a 

return interval between 10 and 25 years. It is only during rare events that this sand dike will be 

overtopped. As noted in the BA, the dike is expected to provide up to 5,000 linear feet of spawning 

habitat for horseshoe crabs.

The crest width of the dike will be 200 feet at its narrowest and 350 feet at its widest. The volume 

of sand in the cross section of the dike will be constant, i.e. 845 cubic yards per linear yard. 

Therefore, the crest width of the dike in shallow water will be greater than in deeper water. The 

total volume of sand required for the offshore dike is 1.7 million cubic yards (which includes a 

quantity sufficient to offset an estimated one foot of settlement). The offshore slope of the dike is 

estimated to be initially 1:20, and after the first year of “weathering” it should equilibrate to a 

milder 1:40 slope.

The southern end of the offshore dike will terminate on the island. The elevation of the crest of the 

dike will transition from +10 feet MLW to the +7 feet MLW (approximate) elevation of the existing 

marsh. The dike will extend onto the island far enough to prevent southerly waves at high water 

levels from damaging any portion of the interior of the project. The dike will also extend beyond its 

connection with the landward dike.

The northern end of the offshore dike will extend approximately 300 feet beyond Deepwater Point 

roughly parallel to the shoreline. The outlet works for the project will be placed at Deepwater 

Point, and so the offshore dike will protect that location. A geotextile tube will be placed within the 

offshore dike as a factor of safety against a breach in the dike due to an extreme event and 

overwash. The crest of the tube will be placed to a crest elevation of +7 feet MLW. The tube will 

then be buried under an additional three feet of sand bringing the crest of the dike up to elevation 

+10 feet MLW. The protection that the tube provides should allow time for maintenance or repair 

work to be planned and executed if a breach should develop due to overwash.

A landward dike will be constructed along the edge of the existing marsh with a crest elevation of 

+8 feet MLW. The dike crest width will be 20-30 feet. The dike will prevent dredged material 

from flowing across or settling in the existing marsh. The dike will be built-up by trucking sand 

from the larger offshore dike to the landward dike during construction. The dike will not be 

constructed by hydraulic placement of sand. The dike will be left in place after construction to 

impound the site. In the future, if the State of Delaware decides that the site should function with 

unregulated tidal exchange with the bay, the landward dike may be removed. However, if the 

capability to impound the site at some future date is necessary, then the landward dike should not be 

removed.

Sheetpile groins made of either timber or vinyl will be placed along the perimeter of the offshore 

dike to help limit longshore transport. Although the cross-section of the dike is designed to sustain 

sediment losses for many years without losing any of its function, groins will increase the longevity 
18

of the project, reduce potential maintenance, and add a factor of safety against the risk that sand will 

be transported south along the project into the Mahon River entrance. The groins will extend 

seaward from the crest of the dike about 240 feet. They will extend landward from the crest of the 

dike about 50 feet. Therefore, their total length is 290 feet. The groins will follow the initial profile 

of the dike having a 1:20 slope from the crest of the berm to MLW. The crests of the groins will be 

nominally about 2 feet above the sand berm initial cross-section. The groins will be spaced about 

750 feet apart. At both ends of the project, terminal timber sheet-pile groins will be constructed that 

are 450 feet long. The groins will be constructed after the sand berm is constructed.

The outlet works for the marsh will be placed through a cross-shore sand dike at the north end of the 

project extending from the tip of Deepwater Point to the offshore dike. The elevation of the crest of 

the cross-shore dike will be +8 feet MLW which is sufficient to prevent even the annual highest 

high tide from overtopping the dike. This elevation also provides sufficient freeboard so that water 

levels in the site can be held high if needed. The cross-shore dike does not need additional 

elevation to prevent wave overtopping because it is protected from waves by the offshore dike. A 

geotextile tube like the one described for the offshore sand dike will be placed in the core of the 

cross-shore dike. The flows through the outlet works during dredging depend mainly on the depth 

of water above the weir crests.

The outlet works will have outflow pipes that pass through the core of the cross-shore dike. The 

cross-section of the cross-shore dike will be held to a minimum to minimize the length of outlet 

pipe required. The actual crest width of the dike will depend on the stability of the foundation upon 

which the dike is built. The dike will be filled until a stable cross-section is achieved. The dike will 

be constructed by moving sand from the offshore dike with heavy equipment so that steeper side 

slopes can be achieved which will minimize the dike cross-section.

The outlet works provided at the north end of the project will control release of water during 

dredging. Several drop inlets are planned. The capacity of the outlet works will depend on the size 

of the dredge pump and discharge line, the frequency of hopper discharges (cycle time), and water 

control requirements for post-construction marsh management. But the potential to release water at 

a rate as high as 75-100 cfs may be required.

An outlet works at the southern end of the project will not be necessary for dredging purposes. 

However, tidal connection to the southern end of the site may be desired after the marsh develops 

and natural flow patterns emerge. Any additional tidal connection will be achieved, for example, 

through small tidal guts through the existing marsh to the Mahon River and not through the offshore 

dike. 

3.3.2 Broadkill Beach (Delaware) 

The Delaware Bay Coastline, DE & NJ – Broadkill Beach, DE project was authorized for 

construction by Title I, Section 101 (a) (11) of the Water Resources Development Act of 1999. The 

Delaware Department of Natural Resources and Environmental Control is the non-Federal project 

sponsor. The project area is located along the Delaware Bay Coastline at Broadkill Beach, Sussex 

County, Delaware. The authorized plan for this project has the following components:

 A berm extending seaward 100 feet from the design line at an elevation of +8 ft NGVD. The 

beachfill extends from Alaska Avenue southward for 13,100 linear feet. Tapers of 1,000 feet 
19

extending from the northern project limit and 500 feet extending from the southern project 

limit brings the total project length to 14,600 linear feet.

 On top of the berm lies a dune with a top elevation of +16 ft NGVD and a top width of 25 

feet.

 A total initial volume of 1,598,700 cubic yards of sand fill would be placed along the area. 

This fill volume includes initial design fill requirements and advanced nourishment.

 Periodic nourishment of 358,400 cubic yards of sand fill would be placed every 5 years.

 Planting of 174,800 square yards of dune grass and 21,800 linear feet of sand fence are 

included for dune stability.

 Vehicular access to the beach would be provided at Route 16 in the center of Broadkill 

Beach. Sand fence would be used to create a path 12 feet wide along both sides of the dune 

at a skewed angle to the dune alignment. This would allow vehicles to climb along the side 

of the dune at a flatter slope than 5H:1V.

 Pedestrian access paths would be located at each street end in a similar fashion as the 

vehicular access. However, the access paths would be smaller in width and at a somewhat 

steeper slope.

Dredging and disposal at Broadkill Beach will be executed as Contract 5 and scheduled for 

September – December 2013. Beach grading will be done by bulldozer and is expected to take six 

months to complete during the fall and winter.

3.4 Maintenance Dredging 

The required maintenance dredging of the 45-foot channel will increase by 862,000 cubic yards per 

year (cy/yr) from the current 3,455,000 average cy/yr for the 40-foot channel for a total of 

4,317,000 cy/yr. Only areas shallower than 45 feet will be dredged during maintenance activities. 

Maintenance dredging in the river (Reaches AA – C) usually takes place over an approximately 2 

month period between August and December primarily using a hydraulic cutterhead dredge; 

however, a hopper dredge may occasionally be used for this work. Approximately 3,845,000 cy of 

material will be removed from the river annually, with the majority of material removed from the 

Marcus Hook, Deepwater and New Castle ranges. All material excavated from the river portion of 

the project will continue to be placed in existing approved upland disposal areas. The timing and 

duration of maintenance dredging in the bay varies but typically occurs in the summer and fall. On 

average, approximately 472,000 cy of material will be removed from the bay annually. Dredging in 

this area is done using a hopper dredge with open water disposal (at Buoy 10). As explained above, 

the proposed action under consideration in this consultation includes 10 years of annual 

maintenance dredging (through 2027). 

4.0 STATUS OF LISTED SPECIES IN THE ACTION AREA

Several species listed under NMFS’ jurisdiction occur in the action area for this consultation. 

While listed whales occur seasonally off the Atlantic coast of Delaware and occasional transient 

right and humpback whales have been documented near the mouth of Delaware Bay, no listed 

whales are known to occur in the action area. As such, no whale species will be further discussed in 

this Opinion. 

NMFS has determined that the action being considered in this biological opinion may affect the 
20

following endangered or threatened species under NMFS’ jurisdiction:

Sea Turtles

Northwest Atlantic DPS of Loggerhead sea turtle (Caretta caretta) Threatened

Leatherback sea turtle (Dermochelys coriacea) Endangered

Kemp’s ridley sea turtle (Lepidochelys kempi) Endangered

Green sea turtle (Chelonia mydas) Endangered/Threatened3

Fish

Shortnose sturgeon (Acipenser brevirostrum) Endangered

Gulf of Maine DPS of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) Threatened

New York Bight DPS of Atlantic sturgeon Endangered

Chesapeake Bay DPS of Atlantic sturgeon Endangered

South Atlantic DPS of Atlantic sturgeon Endangered

Carolina DPS of Atlantic sturgeon Endangered 

This section will focus on the status of the various species within the action area, summarizing 

information necessary to establish the environmental baseline and to assess the effects of the 

proposed action. 

4.1 Overview of Status of Sea Turtles

With the exception of loggerheads, sea turtles are listed under the ESA at the species level rather 

than as subspecies or distinct population segments (DPS). Therefore, information on the rangewide status of leatherback, Kemp’s ridley and green sea turtles is included to provide the status of 

each species overall. Information on the status of loggerheads will only be presented for the DPS 

affected by this action. Additional background information on the range-wide status of these 

species can be found in a number of published documents, including sea turtle status reviews and 

biological reports (NMFS and USFWS 1995; Hirth 1997; Marine Turtle Expert Working Group 

[TEWG] 1998, 2000, 2007, 2009; NMFS and USFWS 2007a, 2007b, 2007c, 2007d; Conant et al. 

2009), and recovery plans for the loggerhead sea turtle (NMFS and USFWS 2008), Kemp’s ridley 

sea turtle (NMFS et al. 2011), leatherback sea turtle (NMFS and USFWS 1992, 1998a), Kemp’s 

ridley sea turtle (NMFS et al. 2011) and green sea turtle (NMFS and USFWS 1991, 1998b). 

2010 BP Deepwater Horizon Oil Spill

The April 20, 2010, explosion of the Deepwater Horizon oil rig affected sea turtles in the Gulf of 

Mexico. There is an on-going assessment of the long-term effects of the spill on Gulf of Mexico 

marine life, including sea turtle populations. Following the spill, juvenile Kemp’s ridley, green, and 

loggerhead sea turtles were found in Sargassum algae mats in the convergence zones, where 

currents meet and oil collected. Sea turtles found in these areas were often coated in oil and/or had 

ingested oil. Approximately 536 live adult and juvenile sea turtles were recovered from the Gulf 

 

3 Pursuant to NMFS regulations at 50 CFR 223.205, the prohibitions of Section 9 of the Endangered Species Act apply 

to all green turtles, whether endangered or threatened.
21

and brought into rehabilitation centers; of these, 456 were visibly oiled (these and the following 

numbers were obtained from http://www.nmfs.noaa.gov/pr/health/oilspill/). To date, 469 of the live 

recovered sea turtles have been successfully returned to the wild, 25 died during rehabilitation, and 

42 are still in care but will hopefully be returned to the wild eventually. During the clean-up 

period, 613 dead sea turtles were recovered in coastal waters or on beaches in Mississippi, 

Alabama, Louisiana, and the Florida Panhandle. As of February 2011, 478 of these dead turtles had 

been examined. Many of the examined sea turtles showed indications that they had died as a result 

of interactions with trawl gear, most likely used in the shrimp fishery, and not as a result of 

exposure to or ingestion of oil. 

During the spring and summer of 2010, nearly 300 sea turtle nests were relocated from the northern 

Gulf to the east coast of Florida with the goal of preventing hatchlings from entering the oiled 

waters of the northern Gulf. From these relocated nests, 14,676 sea turtles, including 14,235 

loggerheads, 125 Kemp’s ridleys, and 316 greens, were ultimately released from Florida beaches. 

A thorough assessment of the long-term effects of the spill on sea turtles has not yet been 

completed. However, the spill resulted in the direct mortality of many sea turtles and may have had 

sublethal effects or caused environmental damage that will impact other sea turtles into the future. 

The population level effects of the spill and associated response activity are likely to remain 

unknown for some period into the future. 

4.2 Northwest Atlantic DPS of loggerhead sea turtle 

The loggerhead is the most abundant species of sea turtle in U.S. waters. Loggerhead sea turtles are 

found in temperate and subtropical waters and occupy a range of habitats including offshore waters, 

continental shelves, bays, estuaries, and lagoons. They are also exposed to a variety of natural and 

anthropogenic threats in the terrestrial and marine environment. 

Listing History 

Loggerhead sea turtles were listed as threatened throughout their global range on July 28, 1978. 

Since that time, several status reviews have been conducted to review the status of the species and 

make recommendations regarding its ESA listing status. Based on a 2007 5-year status review of 

the species, which discussed a variety of threats to loggerheads including climate change, NMFS 

and FWS determined that loggerhead sea turtles should not be delisted or reclassified as 

endangered. However, it was also determined that an analysis and review of the species should be 

conducted in the future to determine whether DPSs should be identified for the loggerhead (NMFS 

and USFWS 2007a). Genetic differences exist between loggerhead sea turtles that nest and forage 

in the different ocean basins (Bowen 2003; Bowen and Karl 2007). Differences in the maternally 

inherited mitochondrial DNA also exist between loggerhead nesting groups that occur within the 

same ocean basin (TEWG 2000; Pearce 2001; Bowen 2003; Bowen et al. 2005; Shamblin 2007; 

TEWG 2009; NMFS and USFWS 2008). Site fidelity of females to one or more nesting beaches in 

an area is believed to account for these genetic differences (TEWG 2000; Bowen 2003).

In part to evaluate those genetic differences, in 2008, NMFS and FWS established a Loggerhead 

Biological Review Team (BRT) to assess the global loggerhead population structure to determine 

whether DPSs exist and, if so, the status of each DPS. The BRT evaluated genetic data, tagging and 

telemetry data, demographic information, oceanographic features, and geographic barriers to 
22

determine whether population segments exist. The BRT report was completed in August 2009 

(Conant et al. 2009). In this report, the BRT identified the following nine DPSs as being discrete 

from other conspecific population segments and significant to the species: (1) North Pacific Ocean, 

(2) South Pacific Ocean, (3) North Indian Ocean, (4) Southeast Indo-Pacific Ocean, (5) Southwest 

Indian Ocean, (6) Northwest Atlantic Ocean, (7) Northeast Atlantic Ocean, (8) Mediterranean Sea, 

and (9) South Atlantic Ocean. 

The BRT concluded that although some DPSs are indicating increasing trends at nesting beaches 

(Southwest Indian Ocean and South Atlantic Ocean), available information about anthropogenic 

threats to juveniles and adults in neritic and oceanic environments indicate possible unsustainable 

additional mortalities. According to an analysis using expert opinion in a matrix model framework, 

the BRT report stated that all loggerhead DPSs have the potential to decline in the foreseeable 

future. Based on the threat matrix analysis, the potential for future decline was reported as greatest 

for the North Indian Ocean, Northwest Atlantic Ocean, Northeast Atlantic Ocean, Mediterranean 

Sea, and South Atlantic Ocean DPSs (Conant et al. 2009). The BRT concluded that the North 

Pacific Ocean, South Pacific Ocean, North Indian Ocean, Southeast Indo-Pacific Ocean, Northwest 

Atlantic Ocean, Northeast Atlantic Ocean, and Mediterranean Sea DPSs were at risk of extinction. 

The BRT concluded that although the Southwest Indian Ocean and South Atlantic Ocean DPSs 

were likely not currently at immediate risk of extinction, the extinction risk was likely to increase in 

the foreseeable future.

On March 16, 2010, NMFS and USFWS published a proposed rule (75 FR 12598) to divide the 

worldwide population of loggerhead sea turtles into nine DPSs, as described in the 2009 Status 

Review. Two of the DPSs were proposed to be listed as threatened and seven of the DPSs, 

including the Northwest Atlantic Ocean DPS, were proposed to be listed as endangered. NMFS and 

the USFWS accepted comments on the proposed rule through September 13, 2010 (75 FR 30769, 

June 2, 2010). On March 22, 2011 (76 FR 15932), NMFS and USFWS extended the date by which 

a final determination on the listing action will be made to no later than September 16, 2011. This 

action was taken to address the interpretation of the existing data on status and trends and its 

relevance to the assessment of risk of extinction for the Northwest Atlantic Ocean DPS, as well as 

the magnitude and immediacy of the fisheries bycatch threat and measures to reduce this threat. 

New information or analyses to help clarify these issues were requested by April 11, 2011. 

On September 22, 2011, NMFS and USFWS issued a final rule (76 FR 58868), determining that the 

loggerhead sea turtle is composed of nine DPSs (as defined in Conant et al., 2009) that constitute 

species that may be listed as threatened or endangered under the ESA. Five DPSs were listed as 

endangered (North Pacific Ocean, South Pacific Ocean, North Indian Ocean, Northeast Atlantic 

Ocean, and Mediterranean Sea), and four DPSs were listed as threatened (Northwest Atlantic 

Ocean, South Atlantic Ocean, Southeast Indo-Pacific Ocean, and Southwest Indian Ocean). Note 

that the Northwest Atlantic Ocean (NWA) DPS and the Southeast Indo-Pacific Ocean DPS were 

originally proposed as endangered. The NWA DPS was determined to be threatened based on 

review of nesting data available after the proposed rule was published, information provided in 

public comments on the proposed rule, and further discussions within the agencies. The two 

primary factors considered were population abundance and population trend. NMFS and USFWS 

found that an endangered status for the NWA DPS was not warranted given the large size of the 

nesting population, the overall nesting population remains widespread, the trend for the nesting 
23

population appears to be stabilizing, and substantial conservation efforts are underway to address 

threats. This final listing rule became effective on October 24, 2011. 

The September 2011 final rule also noted that critical habitat for the two DPSs occurring within the 

U.S. (NWA DPS and North Pacific DPS) will be designated in a future rulemaking. Information 

from the public related to the identification of critical habitat, essential physical or biological 

features for this species, and other relevant impacts of a critical habitat designation was solicited. 

Currently, no critical habitat is designated for any DPS of loggerhead sea turtles, and therefore, no 

critical habitat for any DPS occurs in the action area. 

Presence of Loggerhead Sea Turtles in the Action Area 

The effects of this proposed action are only experienced within the Atlantic Ocean. NMFS has 

considered the available information on the distribution of the 9 DPSs to determine the origin of any 

loggerhead sea turtles that may occur in the action area. As noted in Conant et al. (2009), the range 

of the four DPSs occurring in the Atlantic Ocean are as follows: NWA DPS – north of the equator, 

south of 60° N latitude, and west of 40° W longitude; Northeast Atlantic Ocean (NEA) DPS – north 

of the equator, south of 60° N latitude, east of 40° W longitude, and west of 5° 36’ W longitude; 

South Atlantic DPS – south of the equator, north of 60° S latitude, west of 20° E longitude, and east 

of 60° W longitude; Mediterranean DPS – the Mediterranean Sea east of 5° 36’ W longitude. These 

boundaries were determined based on oceanographic features, loggerhead sightings, thermal 

tolerance, fishery bycatch data, and information on loggerhead distribution from satellite telemetry 

and flipper tagging studies. While adults are highly structured with no overlap, there may be some 

degree of overlap by juveniles of the NWA, NEA, and Mediterranean DPSs on oceanic foraging 

grounds (Laurent et al. 1993, 1998; Bolten et al. 1998; LaCasella et al. 2005; Carreras et al. 2006, 

Monzón-Argüello et al. 2006; Revelles et al. 2007). Previous literature (Bowen et al. 2004) has 

suggested that there is the potential, albeit small, for some juveniles from the Mediterranean DPS to 

be present in U.S. Atlantic coastal foraging grounds. These conclusions must be interpreted with 

caution however, as they may be representing a shared common haplotype and lack of 

representative sampling at Eastern Atlantic rookeries rather than an actual presence of 

Mediterranean DPS turtles in US Atlantic coastal waters. A re-analysis of the data by the Atlantic 

loggerhead Turtle Expert Working Group has found that that it is unlikely that U.S. fishing fleets 

are interacting with either the Northeast Atlantic loggerhead DPS or the Mediterranean loggerhead 

DPS (Peter Dutton, NMFS, Marine Turtle Genetics Program, Program Leader, personal 

communication, September 10, 2011). Given that the action area is a subset of the area fished by 

US fleets, it is reasonable to assume that based on this new analysis, no individuals from the 

Mediterranean DPS or Northeast Atlantic DPS would be present in the action area. Sea turtles of 

the South Atlantic DPS do not inhabit the action area of this consultation (Conant et al. 2009). As 

such, the remainder of this consultation will only focus on the NWA DPS, listed as threatened. 

Distribution and Life History 

Ehrhart et al. (2003) provided a summary of the literature identifying known nesting habitats and 

foraging areas for loggerheads within the Atlantic Ocean. Detailed information is also provided in 

the 5-year status review for loggerheads (NMFS and USFWS 2007a), the TEWG report (2009), and 

the final revised recovery plan for loggerheads in the Northwest Atlantic Ocean (NMFS and 

USFWS 2008), which is a second revision to the original recovery plan that was approved in 1984 

and subsequently revised in 1991. 
24

In the western Atlantic, waters as far north as 41 N to 42 N latitude are used for foraging by 

juveniles, as well as adults (Shoop 1987; Shoop and Kenney 1992; Ehrhart et al. 2003; Mitchell et 

al. 2003). In U.S. Atlantic waters, loggerheads commonly occur throughout the inner continental 

shelf from Florida to Cape Cod, Massachusetts and in the Gulf of Mexico from Florida to Texas, 

although their presence varies with the seasons due to changes in water temperature (Shoop and 

Kenney 1992; Epperly et al. 1995a, 1995b; Braun and Epperly 1996; Braun-McNeill et al. 2008; 

Mitchell et al. 2003). Loggerheads have been observed in waters with surface temperatures of 7C 

to 30C, but water temperatures ≥11C are most favorable (Shoop and Kenney 1992; Epperly et al. 

1995b). The presence of loggerhead sea turtles in U.S. Atlantic waters is also influenced by water 

depth. Aerial surveys of continental shelf waters north of Cape Hatteras, North Carolina indicated 

that loggerhead sea turtles were most commonly sighted in waters with bottom depths ranging from 

22 m to 49 m deep (Shoop and Kenney 1992). However, more recent survey and satellite tracking 

data support that they occur in waters from the beach to beyond the continental shelf (Mitchell et al. 

2003; Braun-McNeill and Epperly 2004; Mansfield 2006; Blumenthal et al. 2006; Hawkes et al. 

2006; McClellan and Read 2007; Mansfield et al. 2009). 

Loggerhead sea turtles occur year round in ocean waters off North Carolina, South Carolina, 

Georgia, and Florida. In these areas of the South Atlantic Bight, water temperature is influenced by 

the proximity of the Gulf Stream. As coastal water temperatures warm in the spring, loggerheads 

begin to migrate to inshore waters of the Southeast United States (e.g., Pamlico and Core Sounds) 

and also move up the U.S. Atlantic coast (Epperly et al. 1995a, 1995b, 1995c; Braun-McNeill and 

Epperly 2004), occurring in Virginia foraging areas as early as April/May and on the most northern 

foraging grounds in the Gulf of Maine in June (Shoop and Kenney 1992). The trend is reversed in 

the fall as water temperatures cool. The large majority leave the Gulf of Maine by mid-September 

but some turtles may remain in Mid-Atlantic and Northeast areas until late fall. By December, 

loggerheads have migrated from inshore and more northern coastal waters to waters offshore of 

North Carolina, particularly off of Cape Hatteras, and waters further south where the influence of 

the Gulf Stream provides temperatures favorable to sea turtles (Shoop and Kenney 1992; Epperly et 

al. 1995b). 

Recent studies have established that the loggerhead’s life history is more complex than previously 

believed. Rather than making discrete developmental shifts from oceanic to neritic environments, 

research is showing that both adults and (presumed) neritic stage juveniles continue to use the 

oceanic environment and will move back and forth between the two habitats (Witzell 2002; 

Blumenthal et al. 2006; Hawkes et al. 2006; McClellan and Read 2007; Mansfield et al. 2009). 

One of the studies tracked the movements of adult post-nesting females and found that differences 

in habitat use were related to body size with larger adults staying in coastal waters and smaller 

adults traveling to oceanic waters (Hawkes et al. 2006). A tracking study of large juveniles found 

that the habitat preferences of this life stage were also diverse with some remaining in neritic waters 

and others moving off into oceanic waters (McClellan and Read 2007). However, unlike the 

Hawkes et al. (2006) study, there was no significant difference in the body size of turtles that 

remained in neritic waters versus oceanic waters (McClellan and Read 2007).

Pelagic and benthic juveniles are omnivorous and forage on crabs, mollusks, jellyfish, and 
25

vegetation at or near the surface (Dodd 1988; NMFS and USFWS 2008). Sub-adult and adult 

loggerheads are primarily coastal dwelling and typically prey on benthic invertebrates such as 

mollusks and decapod crustaceans in hard bottom habitats (NMFS and USFWS 2008). 

As presented below, Table 3 from the 2008 loggerhead recovery plan (Table 3 in this Opinion) 

highlights the key life history parameters for loggerheads nesting in the United States. 
26

Population Dynamics and Status

By far, the majority of Atlantic nesting occurs on beaches of the southeastern United States (NMFS 

and USFWS 2007a). For the past decade or so, the scientific literature has recognized five distinct 

nesting groups, or subpopulations, of loggerhead sea turtles in the Northwest Atlantic, divided 

geographically as follows: (1) a northern group of nesting females that nest from North Carolina to 

northeast Florida at about 29 N latitude; (2) a south Florida group of nesting females that nest from 

29 N latitude on the east coast to Sarasota on the west coast; (3) a Florida Panhandle group of 

nesting females that nest around Eglin Air Force Base and the beaches near Panama City, Florida; 

(4) a Yucatán group of nesting females that nest on beaches of the eastern Yucatán Peninsula, 

Mexico; and (5) a Dry Tortugas group that nests on beaches of the islands of the Dry Tortugas, near 

Key West, Florida and on Cal Sal Bank (TEWG 2009). Genetic analyses of mitochondrial DNA, 

which a sea turtle inherits from its mother, indicate that there are genetic differences between 

loggerheads that nest at and originate from the beaches used by each of the five identified nesting 

groups of females (TEWG 2009). However, analyses of microsatellite loci from nuclear DNA, 

which represents the genetic contribution from both parents, indicates little to no genetic differences 

between loggerheads originating from nesting beaches of the five Northwest Atlantic nesting groups 

(Pearce and Bowen 2001; Bowen 2003; Bowen et al. 2005; Shamblin 2007). These results suggest 

that female loggerheads have site fidelity to nesting beaches within a particular area, while males 

provide an avenue of gene flow between nesting groups by mating with females that originate from 

different nesting groups (Bowen 2003; Bowen et al. 2005). The extent of such gene flow, however, 

is unclear (Shamblin 2007). 

The lack of genetic structure makes it difficult to designate specific boundaries for the nesting 

subpopulations based on genetic differences alone. Therefore, the Loggerhead Recovery Team 

recently used a combination of geographic distribution of nesting densities, geographic separation, 

and geopolitical boundaries, in addition to genetic differences, to reassess the designation of these 

subpopulations to identify recovery units in the 2008 recovery plan. 

In the 2008 recovery plan, the Loggerhead Recovery Team designated five recovery units for the 

Northwest Atlantic population of loggerhead sea turtles based on the aforementioned nesting groups 

and inclusive of a few other nesting areas not mentioned above. The first four of these recovery 

units represent nesting assemblages located in the Southeast United States. The fifth recovery unit 

is composed of all other nesting assemblages of loggerheads within the Greater Caribbean, outside 

the United States, but which occur within U.S. waters during some portion of their lives. The five 

recovery units representing nesting assemblages are: (1) the Northern Recovery Unit (NRU: 

Florida/Georgia border through southern Virginia), (2) the Peninsular Florida Recovery Unit 

(PFRU: Florida/Georgia border through Pinellas County, Florida), (3) the Dry Tortugas Recovery 

Unit (DTRU: islands located west of Key West, Florida), (4) the Northern Gulf of Mexico Recovery 

Unit (NGMRU: Franklin County, Florida through Texas), and (5) the Greater Caribbean Recovery 

Unit (GCRU: Mexico through French Guiana, Bahamas, Lesser Antilles, and Greater Antilles). 

The Recovery Team evaluated the status and trends of the Northwest Atlantic loggerhead 

population for each of the five recovery units, using nesting data available as of October 2008 

(NMFS and USFWS 2008). The level and consistency of nesting coverage varies among recovery 

units, with coverage in Florida generally being the most consistent and thorough over time. Since 
27

1989, nest count surveys in Florida have occurred in the form of statewide surveys (a near complete 

census of entire Florida nesting) and index beach surveys (Witherington et al. 2009). Index beaches 

were established to standardize data collection methods and maintain a constant level of effort on 

key nesting beaches over time. 

Note that NMFS and USFWS (2008), Witherington et al. (2009), and TEWG (2009) analyzed the 

status of the nesting assemblages within the NWA DPS using standardized data collected over 

periods ranging from 10-23 years. These analyses used different analytical approaches, but found 

the same finding that there had been a significant, overall nesting decline within the NWA DPS. 

However, with the addition of nesting data from 2008-2010, the trend line changes showing a very 

slight negative trend, but the rate of decline is not statistically different from zero (76 FR 58868, 

September 22, 2011). The nesting data presented in the Recovery Plan (through 2008) is described 

below, with updated trend information through 2010 for two recovery units.

From the beginning of standardized index surveys in 1989 until 1998, the PFRU, the largest nesting 

assemblage in the Northwest Atlantic by an order of magnitude, had a significant increase in the 

number of nests. However, from 1998 through 2008, there was a 41% decrease in annual nest 

counts from index beaches, which represent an average of 70% of the statewide nesting activity 

(NMFS and USFWS 2008). From 1989-2008, the PFRU had an overall declining nesting trend of 

26% (95% CI: -42% to -5%; NMFS and USFWS 2008). With the addition of nesting data through 

2010, the nesting trend for the PFRU does not show a nesting decline statistically different from 

zero (76 FR 58868, September 22, 2011). The NRU, the second largest nesting assemblage of 

loggerheads in the United States, has been declining at a rate of 1.3% annually since 1983 (NMFS 

and USFWS 2008). The NRU dataset included 11 beaches with an uninterrupted time series of 

coverage of at least 20 years; these beaches represent approximately 27% of NRU nesting (in 2008). 

Through 2008, there was strong statistical data to suggest the NRU has experienced a long-term 

decline, but with the inclusion of nesting data through 2010, nesting for the NRU is showing 

possible signs of stabilizing (76 FR 58868, September 22, 2011). Evaluation of long-term nesting 

trends for the NGMRU is difficult because of changed and expanded beach coverage. However, the 

NGMRU has shown a significant declining trend of 4.7% annually since index nesting beach 

surveys were initiated in 1997 (NMFS and USFWS 2008). No statistical trends in nesting 

abundance can be determined for the DTRU because of the lack of long-term data. Similarly, 

statistically valid analyses of long-term nesting trends for the entire GCRU are not available 

because there are few long-term standardized nesting surveys representative of the region. 

Additionally, changing survey effort at monitored beaches and scattered and low-level nesting by 

loggerheads at many locations currently precludes comprehensive analyses (NMFS and USFWS 

2008). 

Sea turtle census nesting surveys are important in that they provide information on the relative 

abundance of nesting each year, and the contribution of each nesting group to total nesting of the 

species. Nest counts can also be used to estimate the number of reproductively mature females 

nesting annually. The 2008 recovery plan compiled information on mean number of loggerhead 

nests and the approximated counts of nesting females per year for four of the five identified 

recovery units (i.e., nesting groups). They are: (1) for the NRU, a mean of 5,215 loggerhead nests 

per year (from 1989-2008) with approximately 1,272 females nesting per year; (2) for the PFRU, a 

mean of 64,513 nests per year (from 1989-2007) with approximately 15,735 females nesting per 
28

year; (3) for the DTRU, a mean of 246 nests per year (from 1995-2004, excluding 2002) with 

approximately 60 females nesting per year; and (4) for the NGMRU, a mean of 906 nests per year 

(from 1995-2007) with approximately 221 females nesting per year. For the GCRU, the only 

estimate available for the number of loggerhead nests per year is from Quintana Roo, Yucatán, 

Mexico, where a range of 903-2,331 nests per year was estimated from 1987-2001 (NMFS and 

USFWS 2007a). There are no annual nest estimates available for the Yucatán since 2001 or for any 

other regions in the GCRU, nor are there any estimates of the number of nesting females per year 

for any nesting assemblage in this recovery unit. Note that the above values for average nesting 

females per year were based upon 4.1 nests per female per Murphy and Hopkins (1984). 

Genetic studies of juvenile and a few adult loggerhead sea turtles collected from Northwest Atlantic 

foraging areas (beach strandings, a power plant in Florida, and North Carolina fisheries) show that 

the loggerheads that occupy East Coast U.S. waters originate from these Northwest Atlantic nesting 

groups; primarily from the nearby nesting beaches of southern Florida, as well as the northern 

Florida to North Carolina beaches, and finally from the beaches of the Yucatán Peninsula, Mexico 

(Rankin-Baransky et al. 2001; Witzell et al. 2002; Bass et al. 2004; Bowen et al. 2004). The 

contribution of these three nesting assemblages varies somewhat among the foraging habitats and 

age classes surveyed along the east coast. The distribution is not random and bears a significant 

relationship to the proximity and size of adjacent nesting colonies (Bowen et al. 2004). Bass et al. 

(2004) attribute the variety in the proportions of sea turtles from loggerhead turtle nesting 

assemblages documented in different east coast foraging habitats to a complex interplay of currents 

and the relative size and proximity of nesting beaches.

Unlike nesting surveys, in-water studies of sea turtles typically sample both sexes and multiple age 

classes. In-water studies have been conducted in some areas of the Northwest Atlantic and provide 

data by which to assess the relative abundance of loggerhead sea turtles and changes in abundance 

over time (Maier et al. 2004; Morreale et al. 2005; Mansfield 2006; Ehrhart et al. 2007; Epperly et 

al. 2007). The TEWG (2009) used raw data from six in-water study sites to conduct trend analyses. 

They identified an increasing trend in the abundance of loggerheads from three of the four sites 

located in the Southeast United States, one site showed no discernible trend, and the two sites 

located in the northeast United States showed a decreasing trend in abundance of loggerheads. The 

2008 loggerhead recovery plan also includes a full discussion of in-water population studies for 

which trend data have been reported, and a brief summary will be provided here. 

Maier et al. (2004) used fishery-independent trawl data to establish a regional index of loggerhead 

abundance for the southeast coast of the United States (Winyah Bay, South Carolina to St. 

Augustine, Florida) during the period 2000-2003. A comparison of loggerhead catch data from this 

study with historical values suggested that in-water populations of loggerhead sea turtles along the 

southeast U.S. coast appear to be larger, possibly an order of magnitude higher than they were 25 

years ago, but the authors caution a direct comparison between the two studies given differences in 

sampling methodology (Maier et al. 2004). A comparison of catch rates for sea turtles in pound net 

gear fished in the Pamlico-Albemarle Estuarine Complex of North Carolina between the years 

1995-1997 and 2001-2003 found a significant increase in catch rates for loggerhead sea turtles for 

the latter period (Epperly et al. 2007). A long-term, on-going study of loggerhead abundance in the 

Indian River Lagoon System of Florida found a significant increase in the relative abundance of 

loggerheads over the last 4 years of the study (Ehrhart et al. 2007). However, there was no 
29

discernible trend in loggerhead abundance during the 24-year time period of the study (1982-2006) 

(Ehrhart et al. 2007). At St. Lucie Power Plant, data collected from 1977-2004 show an increasing 

trend of loggerheads at the power plant intake structures (FPL and Quantum Resources 2005). 

In contrast to these studies, Morreale et al. (2005) observed a decline in the percentage and relative 

numbers of loggerhead sea turtles incidentally captured in pound net gear fished around Long 

Island, New York during the period 2002-2004 in comparison to the period 1987-1992, with only 

two loggerheads (of a total 54 turtles) observed captured in pound net gear during the period 2002-

2004. This is in contrast to the previous decade’s study where numbers of individual loggerheads 

ranged from 11 to 28 per year (Morreale et al. 2005). No additional loggerheads were reported 

captured in pound net gear in New York through 2007, although two were found cold-stunned on 

Long Island bay beaches in the fall of 2007 (Memo to the File, L. Lankshear, December 2007). 

Potential explanations for this decline include major shifts in loggerhead foraging areas and/or 

increased mortality in pelagic or early benthic stage/age classes (Morreale et al. 2005). Using aerial 

surveys, Mansfield (2006) also found a decline in the densities of loggerhead sea turtles in 

Chesapeake Bay over the period 2001-2004 compared to aerial survey data collected in the 1980s. 

Significantly fewer loggerheads (p<0.05) were observed in both the spring (May-June) and the 

summer (July-August) of 2001-2004 compared to those observed during aerial surveys in the 1980s 

(Mansfield 2006). A comparison of median densities from the 1980s to the 2000s suggested that 

there had been a 63.2% reduction in densities during the spring residency period and a 74.9% 

reduction in densities during the summer residency period (Mansfield 2006). The decline in 

observed loggerhead populations in Chesapeake Bay may be related to a significant decline in prey, 

namely horseshoe crabs and blue crabs, with loggerheads redistributing outside of Bay waters 

(NMFS and USFWS 2008). 

As with other turtle species, population estimates for loggerhead sea turtles are difficult to 

determine, largely given their life history characteristics. However, a recent loggerhead assessment 

using a demographic matrix model estimated that the loggerhead adult female population in the 

western North Atlantic ranges from 16,847 to 89,649, with a median size of 30,050 (NMFS SEFSC 

2009). The model results for population trajectory suggest that the population is most likely 

declining, but this result was very sensitive to the choice of the position of the parameters within 

their range and hypothesized distributions. The pelagic stage survival parameter had the largest 

effect on the model results. As a result of the large uncertainty in our knowledge of loggerhead life 

history, at this point predicting the future populations or population trajectories of loggerhead sea 

turtles with precision is very uncertain. It should also be noted that additional analyses are 

underway which will incorporate any newly available information. 

As part of the Atlantic Marine Assessment Program for Protected Species (AMAPPS), line transect 

aerial abundance surveys and turtle telemetry studies were conducted along the Atlantic coast in the 

summer of 2010. AMAPPS is a multi-agency initiative to assess marine mammal, sea turtle, and

seabird abundance and distribution in the Atlantic. Aerial surveys were conducted from Cape 

Canaveral, Florida to the Gulf of St. Lawrence, Canada. Satellite tags on juvenile loggerheads 

were deployed in two locations – off the coasts of northern Florida to South Carolina (n=30) and off 

the New Jersey and Delaware coasts (n=14). As presented in NMFS NEFSC (2011), the 2010 

survey found a preliminary total surface abundance estimate within the entire study area of about 

60,000 loggerheads (CV=0.13) or 85,000 if a portion of unidentified hard-shelled sea turtles were 
30

included (CV=0.10). Surfacing times were generated from the satellite tag data collected during the 

aerial survey period, resulting in a 7% (5%-11% inter-quartile range) median surface time in the 

South Atlantic area and a 67% (57%-77% inter-quartile range) median surface time to the north. 

The calculated preliminary regional abundance estimate is about 588,000 loggerheads along the 

U.S. Atlantic coast, with an inter-quartile range of 382,000-817,000 (NMFS NEFSC 2011). The 

estimate increases to approximately 801,000 (inter-quartile range of 521,000-1,111,000) when based 

on known loggerheads and a portion of unidentified turtle sightings. The density of loggerheads 

was generally lower in the north than the south; based on number of turtle groups detected, 64% 

were seen south of Cape Hatteras, North Carolina, 30% in the southern Mid-Atlantic Bight, and 6% 

in the northern Mid-Atlantic Bight. Although they have been seen farther north in previous studies 

(e.g., Shoop and Kenney 1992), no loggerheads were observed during the aerial surveys conducted 

in the summer of 2010 in the more northern zone encompassing Georges Bank, Cape Cod Bay, and 

the Gulf of Maine. These estimates of loggerhead abundance over the U.S. Atlantic continental 

shelf are considered very preliminary. A more thorough analysis will be completed pending the 

results of further studies related to improving estimates of regional and seasonal variation in 

loggerhead surface time (by increasing the sample size and geographical area of tagging) and other 

information needed to improve the biases inherent in aerial surveys of sea turtles (e.g., research on 

depth of detection and species misidentification rate). This survey effort represents the most 

comprehensive assessment of sea turtle abundance and distribution in many years. Additional aerial 

surveys and research to improve the abundance estimates are anticipated in 2011-2014, depending 

on available funds.

Threats

The diversity of a sea turtle’s life history leaves them susceptible to many natural and human 

impacts, including impacts while they are on land, in the neritic environment, and in the oceanic 

environment. The 5-year status review and 2008 recovery plan provide a summary of natural as 

well as anthropogenic threats to loggerhead sea turtles (NMFS and USFWS 2007a, 2008). 

Amongst those of natural origin, hurricanes are known to be destructive to sea turtle nests. Sand 

accretion, rainfall, and wave action that result from these storms can appreciably reduce hatchling 

success. Other sources of natural mortality include cold-stunning, biotoxin exposure, and native 

species predation. 

Anthropogenic factors that impact hatchlings and adult females on land, or the success of nesting 

and hatching include: beach erosion, beach armoring, and nourishment; artificial lighting; beach 

cleaning; beach pollution; increased human presence; recreational beach equipment; vehicular and 

pedestrian traffic; coastal development/construction; exotic dune and beach vegetation; removal of 

native vegetation; and poaching. An increased human presence at some nesting beaches or close to 

nesting beaches has led to secondary threats such as the introduction of exotic fire ants, feral hogs, 

dogs, and an increased presence of native species (e.g., raccoons, armadillos, and opossums), which 

raid nests and feed on turtle eggs (NMFS and USFWS 2007a, 2008). Although sea turtle nesting 

beaches are protected along large expanses of the Northwest Atlantic coast (in areas like Merritt 

Island, Archie Carr, and Hobe Sound National Wildlife Refuges), other areas along these coasts 

have limited or no protection. Sea turtle nesting and hatching success on unprotected high density 

East Florida nesting beaches from Indian River to Broward County are affected by all of the above 

threats. 
31

Loggerheads are affected by a completely different set of anthropogenic threats in the marine 

environment. These include oil and gas exploration, coastal development, and transportation; 

marine pollution; underwater explosions; hopper dredging; offshore artificial lighting; power plant 

entrainment and/or impingement; entanglement in debris; ingestion of marine debris; marina and 

dock construction and operation; boat collisions; poaching; and fishery interactions. 

A 1990 National Research Council (NRC) report concluded that for juveniles, subadults, and 

breeding adults in coastal waters, the most important source of human caused mortality in U.S. 

Atlantic waters was fishery interactions. The sizes and reproductive values of sea turtles taken by 

fisheries vary significantly, depending on the location and season of the fishery, and size-selectivity 

resulting from gear characteristics. Therefore, it is possible for fisheries that interact with fewer, 

more reproductively valuable turtles to have a greater detrimental effect on the population than one 

that takes greater numbers of less reproductively valuable turtles (Wallace et al. 2008). The 

Loggerhead Biological Review Team determined that the greatest threats to the NWA DPS of 

loggerheads result from cumulative fishery bycatch in neritic and oceanic habitats (Conant et al. 

2009). Attaining a more thorough understanding of the characteristics, as well as the quantity of sea 

turtle bycatch across all fisheries is of great importance.

Finkbeiner et al. (2011) compiled cumulative sea turtle bycatch information in U.S. fisheries from 

1990 through 2007, before and after implementation of bycatch mitigation measures. Information 

was obtained from peer reviewed publications and NMFS documents (e.g., Biological Opinions and 

bycatch reports). In the Atlantic, a mean estimate of 137,700 bycatch interactions, of which 4,500 

were mortalities, occurred annually (since implementation of bycatch mitigation measures). 

Kemp’s ridleys interacted with fisheries most frequently, with the highest level of mean annual 

mortality (2,700), followed by loggerheads (1,400), greens (300), and leatherbacks (40). The 

Southeast/Gulf of Mexico shrimp trawl fishery was responsible for the vast majority of U.S. 

interactions (up to 98%) and mortalities (more than 80%). While this provides an initial cumulative 

bycatch assessment, there are a number of caveats that should be considered when interpreting this 

information, such as sampling inconsistencies and limitations.

Of the many fisheries known to adversely affect loggerheads, the U.S. South Atlantic and Gulf of 

Mexico shrimp fisheries were considered to pose the greatest threat of mortality to neritic juvenile 

and adult age classes of loggerheads (NRC 1990, Finkbeiner et al. 2011). Significant changes to the 

South Atlantic and Gulf of Mexico shrimp fisheries have occurred since 1990, and the effects of 

these shrimp fisheries on ESA-listed species, including loggerhead sea turtles, have been assessed 

several times through section 7 consultation. There is also a lengthy regulatory history with regard 

to the use of Turtle Excluder Devices (TEDs) in the U.S. South Atlantic and Gulf of Mexico shrimp 

fisheries (Epperly and Teas 2002; NMFS 2002a; Lewison et al. 2003). The current section 7 

consultation on the U.S. South Atlantic and Gulf of Mexico shrimp fisheries was completed in 2002 

and estimated the total annual level of take for loggerhead sea turtles to be 163,160 interactions (the 

total number of turtles that enter a shrimp trawl, which may then escape through the TED or fail to 

escape and be captured) with 3,948 of those takes being lethal (NMFS 2002a). 

In addition to improvements in TED designs and TED enforcement, interactions between 

loggerheads and the shrimp fishery have also been declining because of reductions in fishing effort 

unrelated to fisheries management actions. The 2002 Opinion take estimates are based in part on 
32

fishery effort levels. In recent years, low shrimp prices, rising fuel costs, competition with imported 

products, and the impacts of recent hurricanes in the Gulf of Mexico have all impacted the shrimp 

fleets; in some cases reducing fishing effort by as much as 50% for offshore waters of the Gulf of 

Mexico (GMFMC 2007). As a result, loggerhead interactions and mortalities in the Gulf of Mexico 

have been substantially less than projected in the 2002 Opinion. Currently, the estimated annual 

number of interactions between loggerheads and shrimp trawls in the Gulf of Mexico shrimp fishery 

is 23,336, with 647 (2.8%) of those interactions resulting in mortality (Memo from Dr. B. Ponwith, 

Southeast Fisheries Science Center to Dr. R. Crabtree, Southeast Region, PRD, December 2008). 

Section 7 consultation on the Shrimp FMP has recently been reinitiated and a new Biological 

Opinion is forthcoming.

Loggerhead sea turtles are also known to interact with non-shrimp trawl, gillnet, longline, dredge, 

pound net, pot/trap, and hook and line fisheries. The NRC (1990) report stated that other U.S. 

Atlantic fisheries collectively accounted for 500 to 5,000 loggerhead deaths each year, but 

recognized that there was considerable uncertainty in the estimate. The reduction of sea turtle 

captures in fishing operations is identified in recovery plans and 5-year status reviews as a priority 

for the recovery of all sea turtle species. In the threats analysis of the loggerhead recovery plan, 

trawl bycatch is identified as the greatest source of mortality. While loggerhead bycatch in U.S. 

Mid-Atlantic bottom otter trawl gear was previously estimated for the period 1996-2004 (Murray 

2006, 2008), a recent bycatch analysis estimated the number of loggerhead sea turtle interactions 

with U.S. Mid-Atlantic bottom trawl gear from 2005-2008 (Warden 2011a). Northeast Fisheries 

Observer Program data from 1994-2008 were used to develop a model of interaction rates and those 

predicted rates were applied to 2005-2008 commercial fishing data to estimate the number of 

interactions for the trawl fleet. The number of predicted average annual loggerhead interactions for 

2005-2008 was 292 (CV=0.13, 95% CI=221-369), with an additional 61 loggerheads (CV=0.17, 

95% CI=41-83) interacting with trawls but being released through a TED. Of the 292 average 

annual observable loggerhead interactions, approximately 44 of those were adult equivalents. 

Warden (2011b) found that latitude, depth and SST were associated with the interaction rate, with 

the rates being highest south of 37°N latitude in waters < 50 m deep and SST > 15°C. This estimate 

is a decrease from the average annual loggerhead bycatch in bottom otter trawls during 1996-2004, 

estimated to be 616 sea turtles (CV=0.23, 95% CI over the 9-year period: 367-890) (Murray 2006, 

2008). 

There have been several published estimates of the number of loggerheads taken annually as a result 

of the dredge fishery for Atlantic sea scallops, ranging from a low of zero in 2005 (Murray 2007) to 

a high of 749 in 2003 (Murray 2004). Murray (2011) recently re-evaluated loggerhead sea turtle 

interactions in scallop dredge gear from 2001-2008. In that paper, the average number of annual 

observable interactions of hard-shelled sea turtles in the Mid-Atlantic scallop dredge fishery prior to 

the implementation of chain mats (January 1, 2001 through September 25, 2006) was estimated to 

be 288 turtles (CV = 0.14, 95% CI: 209-363) [equivalent to 49 adults], 218 of which were 

loggerheads [equivalent to 37 adults]. After the implementation of chain mats, the average annual 

number of observable interactions was estimated to be 20 hard-shelled sea turtles (CV = 0.48, 95% 

CI: 3-42), 19 of which were loggerheads. If the rate of observable interactions from dredges 

without chain mats had been applied to trips with chain mats, the estimated number of observable 

and inferred interactions of hard-shelled sea turtles after chain mats were implemented would have 

been 125 turtles per year (CV = 0.15, 95% CI: 88-163) [equivalent to 22 adults], 95 of which were 
33

loggerheads [equivalent to 16 adults]. Interaction rates of hard-shelled turtles were correlated with 

sea surface temperature, depth, and use of a chain mat. Results from this recent analysis suggest that 

chain mats and fishing effort reductions have contributed to the decline in estimated loggerhead sea 

turtle interactions with scallop dredge gear after 2006 (Murray 2011). 

An estimate of the number of loggerheads taken annually in U.S. Mid-Atlantic gillnet fisheries has 

also recently been published (Murray 2009a, b). From 1995-2006, the annual bycatch of 

loggerheads in U.S. Mid-Atlantic gillnet gear was estimated to average 350 turtles (CV=0.20, 95% 

CI over the 12-year period: 234 to 504). Bycatch rates were correlated with latitude, sea surface 

temperature, and mesh size. The highest predicted bycatch rates occurred in warm waters of the 

southern Mid-Atlantic in large-mesh gillnets (Murray 2009a). 

The U.S. tuna and swordfish longline fisheries that are managed under the Highly Migratory 

Species (HMS) FMP are estimated to capture 1,905 loggerheads (no more than 339 mortalities) for 

each 3-year period starting in 2007 (NMFS 2004a). NMFS has mandated gear changes for the 

HMS fishery to reduce sea turtle bycatch and the likelihood of death from those incidental takes that 

would still occur (Garrison and Stokes 2010). In 2010, there were 40 observed interactions between 

loggerhead sea turtles and longline gear used in the HMS fishery (Garrison and Stokes 2011a, 

2011b). All of the loggerheads were released alive, with the vast majority released with all gear 

removed. While 2010 total estimates are not yet available, in 2009, 242.9 (95% CI: 167.9-351.2) 

loggerhead sea turtles are estimated to have been taken in the longline fisheries managed under the 

HMS FMP based on the observed takes (Garrison and Stokes 2010). The 2009 estimate is 

considerably lower than those in 2006 and 2007 and is consistent with historical averages since 

2001 (Garrison and Stokes 2010). This fishery represents just one of several longline fisheries 

operating in the Atlantic Ocean. Lewison et al. (2004) estimated that 150,000-200,000 loggerheads 

were taken in all Atlantic longline fisheries in 2000 (including the U.S. Atlantic tuna and swordfish 

longline fisheries as well as others). 

Documented takes also occur in other fishery gear types and by non-fishery mortality sources (e.g., 

hopper dredges, power plants, vessel collisions), but quantitative estimates are unavailable. Past 

and future impacts of global climate change are considered in Section 6.0 below. 

Summary of Status for Loggerhead Sea Turtles

Loggerheads are a long-lived species and reach sexual maturity relatively late at around 32-35 years 

in the Northwest Atlantic (NMFS and USFWS 2008). The species continues to be affected by 

many factors occurring on nesting beaches and in the water. These include poaching, habitat loss, 

and nesting predation that affects eggs, hatchlings, and nesting females on land, as well as fishery 

interactions, vessel interactions, marine pollution, and non-fishery (e.g., dredging) operations 

affecting all sexes and age classes in the water (NRC 1990; NMFS and USFWS 2007a, 2008). As a 

result, loggerheads still face many of the original threats that were the cause of their listing under 

the ESA. 

As mentioned previously, a final revised recovery plan for loggerhead sea turtles in the Northwest 

Atlantic was recently published by NMFS and FWS in December 2008. The revised recovery plan 

is significant in that it identifies five unique recovery units, which comprise the population of 

loggerheads in the Northwest Atlantic, and describes specific recovery criteria for each recovery 
34

unit. The recovery plan noted a decline in annual nest counts for three of the five recovery units for 

loggerheads in the Northwest Atlantic, including the PFRU, which is the largest (in terms of number 

of nests laid) in the Atlantic Ocean. The nesting trends for the other two recovery units could not be 

determined due to an absence of long term data. 

NMFS convened a new Loggerhead Turtle Expert Working Group (TEWG) to review all available 

information on Atlantic loggerheads in order to evaluate the status of this species in the Atlantic. A 

final report from the Loggerhead TEWG was published in July 2009. In this report, the TEWG 

indicated that it could not determine whether the decreasing annual numbers of nests among the 

Northwest Atlantic loggerhead subpopulations were due to stochastic processes resulting in fewer 

nests, a decreasing average reproductive output of adult females, decreasing numbers of adult 

females, or a combination of these factors. Many factors are responsible for past or present 

loggerhead mortality that could impact current nest numbers; however, no single mortality factor 

stands out as a likely primary factor. It is likely that several factors compound to create the current 

decline, including incidental capture (in fisheries, power plant intakes, and dredging operations), 

lower adult female survival rates, increases in the proportion of first-time nesters, continued 

directed harvest, and increases in mortality due to disease. Regardless, the TEWG stated that “it is 

clear that the current levels of hatchling output will result in depressed recruitment to subsequent 

life stages over the coming decades” (TEWG 2009). However, the report does not provide 

information on the rate or amount of expected decrease in recruitment but goes on to state that the 

ability to assess the current status of loggerhead subpopulations is limited due to a lack of 

fundamental life history information and specific census and mortality data. 

While several documents reported the decline in nesting numbers in the NWA DPS (NMFS and 

USFWS 2008, TEWG 2009), when nest counts through 2010 are analyzed, the nesting trends from 

1989-2010 are not significantly different than zero for all recovery units within the NWA DPS for 

which there are enough data to analyze (76 FR 58868, September 22, 2011). The SEFSC (2009) 

estimated the number of adult females in the NWA DPS at 30,000, and if a 1:1 adult sex ratio is 

assumed, the result is 60,000 adults in this DPS. Based on the reviews of nesting data, as well as 

information on population abundance and trends, NMFS and USFWS determined in the September 

2011 listing rule that the NWA DPS should be listed as threatened. They found that an endangered 

status for the NWA DPS was not warranted given the large size of the nesting population, the 

overall nesting population remains widespread, the trend for the nesting population appears to be 

stabilizing, and substantial conservation efforts are underway to address threats. 

4.3 Status of Kemp’s Ridley Sea Turtles

Distribution and Life History 

The Kemp’s ridley is one of the least abundant of the world’s sea turtle species. In contrast to 

loggerhead, leatherback, and green sea turtles, which are found in multiple oceans of the world, 

Kemp’s ridleys typically occur only in the Gulf of Mexico and the northwestern Atlantic Ocean 

(NMFS et al. 2011). 

Kemp’s ridleys mature at 10-17 years (Caillouet et al. 1995; Schmid and Witzell 1997; Snover et al. 

2007; NMFS and USFWS 2007c). Nesting occurs from April through July each year with 

hatchlings emerging after 45-58 days (NMFS et al. 2011). Females lay an average of 2.5 clutches 
35

within a season (TEWG 1998, 2000) and the mean remigration interval for adult females is 2 years 

(Marquez et al. 1982; TEWG 1998, 2000). 

Once they leave the nesting beach, hatchlings presumably enter the Gulf of Mexico where they feed 

on available Sargassum and associated infauna or other epipelagic species (NMFS et al. 2011). The 

presence of juvenile turtles along both the U.S. Atlantic and Gulf of Mexico coasts, where they are 

recruited to the coastal benthic environment, indicates that post-hatchlings are distributed in both 

the Gulf of Mexico and Atlantic Ocean (TEWG 2000). 

The location and size classes of dead turtles recovered by the STSSN suggests that benthic 

immature developmental areas occur along the U.S. coast and that these areas may change given 

resource quality and quantity (TEWG 2000). Developmental habitats are defined by several 

characteristics, including coastal areas sheltered from high winds and waves such as embayments 

and estuaries, and nearshore temperate waters shallower than 50 m (NMFS and USFWS 2007c). 

The suitability of these habitats depends on resource availability, with optimal environments 

providing rich sources of crabs and other invertebrates. Kemp’s ridleys consume a variety of crab 

species, including Callinectes, Ovalipes, Libinia, and Cancer species. Mollusks, shrimp, and fish 

are consumed less frequently (Bjorndal 1997). A wide variety of substrates have been documented 

to provide good foraging habitat, including seagrass beds, oyster reefs, sandy and mud bottoms, and 

rock outcroppings (NMFS and USFWS 2007c). 

Foraging areas documented along the U.S. Atlantic coast include Charleston Harbor, Pamlico 

Sound (Epperly et al. 1995c), Chesapeake Bay (Musick and Limpus 1997), Delaware Bay (Stetzar 

2002), and Long Island Sound (Morreale and Standora 1993; Morreale et al. 2005). For instance, in 

the Chesapeake Bay, Kemp’s ridleys frequently forage in submerged aquatic grass beds for crabs 

(Musick and Limpus 1997). Upon leaving Chesapeake Bay in autumn, juvenile Kemp’s ridleys 

migrate down the coast, passing Cape Hatteras in December and January (Musick and Limpus 

1997). These larger juveniles are joined by juveniles of the same size from North Carolina sounds 

and smaller juveniles from New York and New England to form one of the densest concentrations 

of Kemp’s ridleys outside of the Gulf of Mexico (Epperly et al. 1995a, 1995b; Musick and Limpus 

1997). 

Adult Kemp’s ridleys are found in the coastal regions of the Gulf of Mexico and southeastern 

United States, but are typically rare in the northeastern U.S. waters of the Atlantic (TEWG 2000). 

Adults are primarily found in nearshore waters of 37 m or less that are rich in crabs and have a 

sandy or muddy bottom (NMFS and USFWS 2007c). 

Population Dynamics and Status

The majority of Kemp’s ridleys nest along a single stretch of beach near Rancho Nuevo, 

Tamaulipas, Mexico (Carr 1963; NMFS and USFWS 2007c; NMFS et al. 2011). There is a limited 

amount of scattered nesting to the north and south of the primary nesting beach (NMFS and 

USFWS 2007c). Nesting often occurs in synchronized emergences termed arribadas. The number 

of recorded nests reached an estimated low of 702 nests in 1985, corresponding to fewer than 300 

adult females nesting in that season (TEWG 2000; NMFS and USFWS 2007c; NMFS et al. 2011). 

Conservation efforts by Mexican and U.S. agencies have aided this species by eliminating egg 

harvest, protecting eggs and hatchlings, and reducing at-sea mortality through fishing regulations 
36

(TEWG 2000). Since the mid-1980s, the number of nests observed at Rancho Nuevo and nearby 

beaches has increased 14-16% per year (Heppell et al. 2005), allowing cautious optimism that the 

population is on its way to recovery. An estimated 5,500 females nested in the State of Tamaulipas 

over a 3-day period in May 2007 and over 4,000 of those nested at Rancho Nuevo (NMFS and 

USFWS 2007c). In 2008, 17,882 nests were documented on Mexican nesting beaches (NMFS 

2011). There is limited nesting in the United States, most of which is located in South Texas. 

While six nests were documented in 1996, a record 195 nests were found in 2008 (NMFS 2011). 

Threats 

Kemp’s ridleys face many of the same natural threats as loggerheads, including destruction of 

nesting habitat from storm events, predators, and oceanographic-related events such as coldstunning. Although cold-stunning can occur throughout the range of the species, it may be a greater 

risk for sea turtles that utilize the more northern habitats of Cape Cod Bay and Long Island Sound. 

In the last five years (2006-2010), the number of cold-stunned turtles on Cape Cod beaches 

averaged 115 Kemp’s ridleys, 7 loggerheads, and 7 greens (NMFS unpublished data). The numbers 

ranged from a low in 2007 of 27 Kemp's ridleys, 5 loggerheads, and 5 greens to a high in 2010 of 

213 Kemp's ridleys, 4 loggerheads, and 14 greens. Annual cold stun events vary in magnitude; the 

extent of episodic major cold stun events may be associated with numbers of turtles utilizing 

Northeast U.S. waters in a given year, oceanographic conditions, and/or the occurrence of storm 

events in the late fall. Although many cold-stunned turtles can survive if they are found early 

enough, these events represent a significant source of natural mortality for Kemp’s ridleys. 

Like other sea turtle species, the severe decline in the Kemp’s ridley population appears to have 

been heavily influenced by a combination of exploitation of eggs and impacts from fishery 

interactions. From the 1940s through the early 1960s, nests from Ranch Nuevo were heavily 

exploited, but beach protection in 1967 helped to curtail this activity (NMFS et al. 2011). 

Following World War II, there was a substantial increase in the number of trawl vessels, 

particularly shrimp trawlers, in the Gulf of Mexico where adult Kemp’s ridley sea turtles occur. 

Information from fisheries observers helped to demonstrate the high number of turtles taken in these 

shrimp trawls (USFWS and NMFS 1992). Subsequently, NMFS has worked with the industry to 

reduce sea turtle takes in shrimp trawls and other trawl fisheries, including the development and use 

of turtle excluder devices (TEDs). As described above, there is lengthy regulatory history with 

regard to the use of TEDs in the U.S. South Atlantic and Gulf of Mexico shrimp fisheries (NMFS 

2002a; Epperly 2003; Lewison et al. 2003). The 2002 Biological Opinion on shrimp trawling in the 

southeastern United States concluded that 155,503 Kemp’s ridley sea turtles would be taken 

annually in the fishery with 4,208 of the takes resulting in mortality (NMFS 2002a). 

Although modifications to shrimp trawls have helped to reduce mortality of Kemp’s ridleys, a 

recent assessment found that the Southeast/Gulf of Mexico shrimp trawl fishery remained 

responsible for the vast majority of U.S. fishery interactions (up to 98%) and mortalities (more than 

80%). Finkbeiner et al. (2011) compiled cumulative sea turtle bycatch information in U.S. fisheries 

from 1990 through 2007, before and after implementation of bycatch mitigation measures. 

Information was obtained from peer reviewed publications and NMFS documents (e.g., Biological 

Opinions and bycatch reports). In the Atlantic, a mean estimate of 137,700 bycatch interactions, of 

which 4,500 were mortalities, occurred annually (since implementation of bycatch mitigation 

measures). Kemp’s ridleys interacted with fisheries most frequently, with the highest level of mean 
37

annual mortality (2,700), followed by loggerheads (1,400), greens (300), and leatherbacks (40). 

While this provides an initial cumulative bycatch assessment, there are a number of caveats that 

should be considered when interpreting this information, such as sampling inconsistencies and 

limitations.

This species is also affected by other sources of anthropogenic impact (fishery and non-fishery 

related), similar to those discussed above. Three Kemp’s ridley captures in Mid-Atlantic trawl

fisheries were documented by NMFS observers between 1994 and 2008 (Warden and Bisack 2010), 

and eight Kemp’s ridleys were documented by NMFS observers in mid-Atlantic sink gillnet 

fisheries between 1995 and 2006 (Murray 2009a). Additionally, in the spring of 2000, a total of 

five Kemp’s ridley carcasses were recovered from the same North Carolina beaches where 275 

loggerhead carcasses were found. The cause of death for most of the turtles recovered was 

unknown, but the mass mortality event was suspected by NMFS to have been from a large-mesh 

gillnet fishery for monkfish and dogfish operating offshore in the preceding weeks (67 FR 71895, 

December 3, 2002). The five Kemp’s ridley carcasses that were found are likely to have been only 

a minimum count of the number of Kemp’s ridleys that were killed or seriously injured as a result 

of the fishery interaction, since it is unlikely that all of the carcasses washed ashore. The NMFS 

Northeast Fisheries Science Center also documented 14 Kemp’s ridleys entangled in or impinged on 

Virginia pound net leaders from 2002-2005. Note that bycatch estimates for Kemp’s ridleys in 

various fishing gear types (e.g., trawl, gillnet, dredge) are not available at this time, largely due to 

the low number of observed interactions precluding a robust estimate. Kemp’s ridley interactions in 

non-fisheries have also been observed; for example, the Oyster Creek Nuclear Generating Station in 

Barnegat Bay, New Jersey, recorded a total of 27 Kemp’s ridleys (15 of which were found alive) 

impinged or captured on their intake screens from 1992-2006 (NMFS 2006). 

Summary of Status for Kemp’s Ridley Sea Turtles

The majority of Kemp’s ridleys nest along a single stretch of beach near Rancho Nuevo, 

Tamaulipas, Mexico (Carr 1963; NMFS and USFWS 2007c; NMFS et al. 2011). The number of 

nesting females in the Kemp’s ridley population declined dramatically from the late 1940s through 

the mid-1980s, with an estimated 40,000 nesting females in a single arribada in 1947 and fewer 

than 300 nesting females in the entire 1985 nesting season (TEWG 2000; NMFS et al. 2011). 

However, the total annual number of nests at Rancho Nuevo gradually began to increase in the 

1990s (NMFS and USFWS 2007c). Based on the number of nests laid in 2006 and the remigration 

interval for Kemp’s ridley sea turtles (1.8-2 years), there were an estimated 7,000-8,000 adult 

female Kemp’s ridley sea turtles in 2006 (NMFS and USFWS 2007c). The number of adult males 

in the population is unknown, but sex ratios of hatchlings and immature Kemp’s ridleys suggest that 

the population is female-biased, suggesting that the number of adult males is less than the number 

of adult females (NMFS and USFWS 2007c). While there is cautious optimism for recovery, 

events such as the Deepwater Horizon oil release, and stranding events associated increased 

skimmer trawl use and poor TED compliance in the northern Gulf of Mexico may dampen recent 

population growth.

As with the other sea turtle species, fishery mortality accounts for a large proportion of annual 

human-caused mortality outside the nesting beaches, while other activities like dredging, pollution,

and habitat destruction account for an unknown level of other mortality. Based on their 5-year 

status review of the species, NMFS and USFWS (2007c) determined that Kemp’s ridley sea turtles 
38

should not be reclassified as threatened under the ESA. A revised bi-national recovery plan was 

published for public comment in 2010, and in September 2011, NMFS, USFWS, and the Services 

and the Secretary of Environment and Natural Resources, Mexico (SEMARNAT) released the 

second revision to the Kemp’s ridley recovery plan.

4.4 Status of Green Sea Turtles

Green sea turtles are distributed circumglobally, and can be found in the Pacific, Indian, and 

Atlantic Oceans as well as the Mediterranean Sea (NMFS and USFWS 1991, 2007d; Seminoff 

2004). In 1978, the Atlantic population of the green sea turtle was listed as threatened under the 

ESA, except for the breeding populations in Florida and on the Pacific coast of Mexico, which were 

listed as endangered. As it is difficult to differentiate between breeding populations away from the 

nesting beaches, all green sea turtles in the water are considered endangered. 

Pacific Ocean

Green sea turtles occur in the western, central, and eastern Pacific. Foraging areas are also found 

throughout the Pacific and along the southwestern U.S. coast (NMFS and USFWS 1998b). In the 

western Pacific, major nesting rookeries at four sites including Heron Island (Australia), Raine 

Island (Australia), Guam, and Japan were evaluated and determined to be increasing in abundance, 

with the exception of Guam which appears stable (NMFS and USFWS 2007d). In the central 

Pacific, nesting occurs on French Frigate Shoals, Hawaii, which has also been reported as 

increasing with a mean of 400 nesting females annually from 2002-2006 (NMFS and USFWS 

2007d). The main nesting sites for the green sea turtle in the eastern Pacific are located in 

Michoacan, Mexico and in the Galapagos Islands, Ecuador (NMFS and USFWS 2007d). The 

number of nesting females per year exceeds 1,000 females at each site (NMFS and USFWS 2007d). 

However, historically, greater than 20,000 females per year are believed to have nested in 

Michoacan alone (Cliffton et al. 1982; NMFS and USFWS 2007d). The Pacific Mexico green turtle 

nesting population (also called the black turtle) is considered endangered. 

Historically, green sea turtles were used in many areas of the Pacific for food. They were also 

commercially exploited, which, coupled with habitat degradation, led to their decline in the Pacific 

(NMFS and USFWS 1998b). Green sea turtles in the Pacific continue to be affected by poaching, 

habitat loss or degradation, fishing gear interactions, and fibropapillomatosis, which is a viral 

disease that causes tumors in affected turtles (NMFS and USFWS 1998b; NMFS 2004b). 

Indian Ocean 

There are numerous nesting sites for green sea turtles in the Indian Ocean. One of the largest 

nesting sites for green sea turtles worldwide occurs on the beaches of Oman where an estimated 

20,000 green sea turtles nest annually (Hirth 1997; Ferreira et al. 2003). Based on a review of the 

32 Index Sites used to monitor green sea turtle nesting worldwide, Seminoff (2004) concluded that 

declines in green sea turtle nesting were evident for many of the Indian Ocean Index Sites. While 

several of these had not demonstrated further declines in the more recent past, only the Comoros 

Island Index Site in the western Indian Ocean showed evidence of increased nesting (Seminoff 

2004). 
39

Mediterranean Sea

There are four nesting concentrations of green sea turtles in the Mediterranean from which data are 

available – Turkey, Cyprus, Israel, and Syria. Currently, approximately 300-400 females nest each 

year, about two-thirds of which nest in Turkey and one-third in Cyprus. Although green sea turtles 

are depleted from historic levels in the Mediterranean Sea (Kasparek et al. 2001), nesting data 

gathered since the early 1990s in Turkey, Cyprus, and Israel show no apparent trend in any 

direction. However, a declining trend is apparent along the coast of Palestine/Israel, where 300-350 

nests were deposited each year in the 1950s (Sella 1982) compared to a mean of 6 nests per year 

from 1993-2004 (Kuller 1999; Y. Levy, Israeli Sea Turtle Rescue Center, unpublished data). A 

recent discovery of green sea turtle nesting in Syria adds roughly 100 nests per year to green sea 

turtle nesting activity in the Mediterranean (Rees et al. 2005). That such a major nesting 

concentration could have gone unnoticed until recently (the Syria coast was surveyed in 1991, but 

nesting activity was attributed to loggerheads) bodes well for the ongoing speculation that the 

unsurveyed coast of Libya may also host substantial nesting. 

Atlantic Ocean 

Distribution and Life History

As has occurred in other oceans of its range, green sea turtles were once the target of directed 

fisheries in the United States and throughout the Caribbean. In 1890, over one million pounds of 

green sea turtles were taken in a directed fishery in the Gulf of Mexico (Doughty 1984). However, 

declines in the turtle fishery throughout the Gulf of Mexico were evident by 1902 (Doughty 1984).

In the western Atlantic, large juvenile and adult green sea turtles are largely herbivorous, occurring 

in habitats containing benthic algae and seagrasses from Massachusetts to Argentina, including the 

Gulf of Mexico and Caribbean (Wynne and Schwartz 1999). Green sea turtles occur seasonally in 

Mid-Atlantic and Northeast waters such as Chesapeake Bay and Long Island Sound (Musick and 

Limpus 1997; Morreale and Standora 1998; Morreale et al. 2005), which serve as foraging and 

developmental habitats. 

Some of the principal feeding areas in the western Atlantic Ocean include the upper west coast of 

Florida, the Florida Keys, and the northwestern coast of the Yucatán Peninsula. Additional 

important foraging areas in the western Atlantic include the Mosquito and Indian River Lagoon 

systems and nearshore wormrock reefs between Sebastian and Ft. Pierce Inlets in Florida, Florida 

Bay, the Culebra archipelago and other Puerto Rico coastal waters, the south coast of Cuba, the 

Mosquito Coast of Nicaragua, the Caribbean coast of Panama, and scattered areas along Colombia 

and Brazil (Hirth 1971). The waters surrounding the island of Culebra, Puerto Rico, and its 

outlying keys are designated critical habitat for the green sea turtle.

Age at maturity for green sea turtles is estimated to be 20-50 years (Balazs 1982; Frazer and Ehrhart 

1985; Seminoff 2004). As is the case with the other sea turtle species described above, adult 

females may nest multiple times in a season (average 3 nests/season with approximately 100 

eggs/nest) and typically do not nest in successive years (NMFS and USFWS 1991; Hirth 1997). 

Population Dynamics and Status

Like other sea turtle species, nest count information for green sea turtles provides information on 

the relative abundance of nesting, and the contribution of each nesting group to total nesting of the 
40

species. Nest counts can also be used to estimate the number of reproductively mature females 

nesting annually. The 5-year status review for the species identified eight geographic areas 

considered to be primary sites for threatened green sea turtle nesting in the Atlantic/Caribbean, and 

reviewed the trend in nest count data for each (NMFS and USFWS 2007d). These include: (1) 

Yucatán Peninsula, Mexico, (2) Tortuguero, Costa Rica, (3) Aves Island, Venezuela, (4) Galibi 

Reserve, Suriname, (5) Isla Trindade, Brazil, (6) Ascension Island, United Kingdom, (7) Bioko 

Island, Equatorial Guinea, and (8) Bijagos Achipelago, Guinea-Bissau (NMFS and USFWS 2007d). 

Nesting at all of these sites is considered to be stable or increasing with the exception of Bioko 

Island, which may be declining. However, the lack of sufficient data precludes a meaningful trend 

assessment for this site (NMFS and USFWS 2007d). 

Seminoff (2004) reviewed green sea turtle nesting data for eight sites in the western, eastern, and 

central Atlantic, including all of the above threatened nesting sites with the exception that nesting in 

Florida was reviewed in place of Isla Trindade, Brazil. He concluded that all sites in the central and 

western Atlantic showed increased nesting with the exception of nesting at Aves Island, Venezuela, 

while both sites in the eastern Atlantic demonstrated decreased nesting. These sites are not 

inclusive of all green sea turtle nesting in the Atlantic Ocean. However, other sites are not believed 

to support nesting levels high enough that would change the overall status of the species in the 

Atlantic (NMFS and USFWS 2007d). 

By far, the most important nesting concentration for green sea turtles in the western Atlantic is in 

Tortuguero, Costa Rica (NMFS and USFWS 2007d). Nesting in the area has increased 

considerably since the 1970s and nest count data from 1999-2003 suggest nesting by 17,402-37,290 

females per year (NMFS and USFWS 2007d). The number of females nesting per year on beaches 

in the Yucatán, at Aves Island, Galibi Reserve, and Isla Trindade number in the hundreds to low 

thousands, depending on the site (NMFS and USFWS 2007d). 

The status of the endangered Florida breeding population was also evaluated in the 5-year review 

(NMFS and USFWS 2007d). The pattern of green sea turtle nesting shows biennial peaks in 

abundance, with a generally positive trend since establishment of the Florida index beach surveys in 

1989. This trend is perhaps due to increased protective legislation throughout the Caribbean 

(Meylan et al. 1995), as well as protections in Florida and throughout the United States (NMFS and 

USFWS 2007d). 

The statewide Florida surveys (2000-2006) have shown that a mean of approximately 5,600 nests 

are laid annually in Florida, with a low of 581 in 2001 to a high of 9,644 in 2005 (NMFS and 

USFWS 2007d). Most nesting occurs along the east coast of Florida, but occasional nesting has 

been documented along the Gulf coast of Florida, at Southwest Florida beaches, as well as the 

beaches in the Florida Panhandle (Meylan et al. 1995). More recently, green sea turtle nesting 

occurred on Bald Head Island, North Carolina (just east of the mouth of the Cape Fear River), 

Onslow Island, and Cape Hatteras National Seashore. One green sea turtle nested on a beach in 

Delaware in 2011, although its occurrence was considered very rare. 

Threats 

Green sea turtles face many of the same natural threats as loggerhead and Kemp’s ridley sea turtles. 

In addition, green sea turtles appear to be particularly susceptible to fibropapillomatosis, an 
41

epizootic disease producing lobe-shaped tumors on the soft portion of a turtle’s body. Juveniles 

appear to be most affected in that they have the highest incidence of disease and the most extensive 

lesions, whereas lesions in nesting adults are rare. Also, green sea turtles frequenting nearshore 

waters, areas adjacent to large human populations, and areas with low water turnover, such as 

lagoons, have a higher incidence of the disease than individuals in deeper, more remote waters. The 

occurrence of fibropapilloma tumors may result in impaired foraging, breathing, or swimming 

ability, leading potentially to death (George 1997). 

As with the other sea turtle species, incidental fishery mortality accounts for a large proportion of 

annual human-caused mortality outside the nesting beaches. Witherington et al. (2009) observes 

that because green sea turtles spend a shorter time in oceanic waters and as older juveniles occur on 

shallow seagrass pastures (where benthic trawling is unlikely), they avoid high mortalities in 

pelagic longline and benthic trawl fisheries. Although the relatively low number of observed green 

sea turtle captures makes it difficult to estimate bycatch rates and annual take levels, green sea 

turtles have been observed captured in the pelagic driftnet, pelagic longline, southeast shrimp trawl, 

and mid-Atlantic trawl and gillnet fisheries. Murray (2009a) also lists five observed captures of 

green turtle in Mid-Atlantic sink gillnet gear between 1995 and 2006. 

Finkbeiner et al. (2011) compiled cumulative sea turtle bycatch information in U.S. fisheries from 

1990 through 2007, before and after implementation of bycatch mitigation measures. Information 

was obtained from peer reviewed publications and NMFS documents (e.g., Biological Opinions and 

bycatch reports). In the Atlantic, a mean estimate of 137,700 bycatch interactions, of which 4,500 

were mortalities, occurred annually (since implementation of bycatch mitigation measures). 

Kemp’s ridleys interacted with fisheries most frequently, with the highest level of mean annual 

mortality (2,700), followed by loggerheads (1,400), greens (300), and leatherbacks (40). The 

Southeast/Gulf of Mexico shrimp trawl fishery was responsible for the vast majority of U.S. 

interactions (up to 98%) and mortalities (more than 80%). While this provides an initial cumulative 

bycatch assessment, there are a number of caveats that should be considered when interpreting this 

information, such as sampling inconsistencies and limitations.

Other activities like channel dredging, marine debris, pollution, vessel strikes, power plant 

impingement, and habitat destruction account for an unquantifiable level of other mortality. 

Stranding reports indicate that between 200-400 green sea turtles strand annually along the eastern 

U.S. coast from a variety of causes most of which are unknown (STSSN database). 

Summary of Status of Green Sea Turtles

A review of 32 Index Sites4distributed globally revealed a 48-67% decline in the number of mature 

females nesting annually over the last three generations5(Seminoff 2004). An evaluation of green 

sea turtle nesting sites was also conducted as part of the 5-year status review of the species (NMFS 

 

4

The 32 Index Sites include all of the major known nesting areas as well as many of the lesser nesting areas for which 

quantitative data are available. 

5 Generation times ranged from 35.5 years to 49.5 years for the assessment depending on the Index Beach site 
42

and USFWS 2007d). Of the 23 threatened nesting groups assessed in that report for which nesting 

abundance trends could be determined, ten were considered to be increasing, nine were considered 

stable, and four were considered to be decreasing (NMFS and USFWS 2007d). Nesting groups 

were considered to be doing relatively well (the number of sites with increasing nesting were 

greater than the number of sites with decreasing nesting) in the Pacific, western Atlantic, and central 

Atlantic (NMFS and USFWS 2007d). However, nesting populations were determined to be doing 

relatively poorly in Southeast Asia, eastern Indian Ocean, and perhaps the Mediterranean. Overall, 

based on mean annual reproductive effort, the report estimated that 108,761 to 150,521 females nest 

each year among the 46 threatened and endangered nesting sites included in the evaluation (NMFS 

and USFWS 2007d). However, given the late age to maturity for green sea turtles, caution is urged 

regarding the status for any of the nesting groups since no area has a dataset spanning a full green 

sea turtle generation (NMFS and USFWS 2007d). 

Seminoff (2004) and NMFS and USFWS (2007d) made comparable conclusions with regard to 

nesting for four nesting sites in the western Atlantic that indicate sea turtle abundance is increasing 

in the Atlantic Ocean. Each also concluded that nesting at Tortuguero, Costa Rica represented the 

most important nesting area for green sea turtles in the western Atlantic and that nesting had 

increased markedly since the 1970s (Seminoff 2004; NMFS and USFWS 2007d). 

However, the 5-year review also noted that the Tortuguero nesting stock continued to be affected by 

ongoing directed take at their primary foraging area in Nicaragua (NMFS and USFWS 2007d). The 

endangered breeding population in Florida appears to be increasing based upon index nesting data 

from 1989-2010 (NMFS 2011).

As with the other sea turtle species, fishery mortality accounts for a large proportion of annual 

human-caused mortality outside the nesting beaches, while other activities like hopper dredging, 

pollution, and habitat destruction account for an unknown level of other mortality. Based on its 5-

year status review of the species, NMFS and USFWS (2007d) determined that the listing 

classification for green sea turtles should not be changed. However, it was also determined that an 

analysis and review of the species should be conducted in the future to determine whether DPSs 

should be identified (NMFS and USFWS 2007d).

4.5 Status of Leatherback Sea Turtles

Leatherback sea turtles are widely distributed throughout the oceans of the world, including the 

Atlantic, Pacific, and Indian Oceans, and the Mediterranean Sea (Ernst and Barbour 1972). 

Leatherbacks are the largest living turtles and range farther than any other sea turtle species. Their 

large size and tolerance of relatively low water temperatures allows them to occur in boreal waters 

such as those off Labrador and in the Barents Sea (NMFS and USFWS 1995). 

In 1980, the leatherback population was estimated at approximately 115,000 adult females globally 

(Pritchard 1982). By 1995, this global population of adult females was estimated to have declined 

to 34,500 (Spotila et al. 1996). The most recent population size estimate for the North Atlantic 

alone is a range of 34,000-94,000 adult leatherbacks (TEWG 2007). Thus, there is substantial 

uncertainty with respect to global population estimates of leatherback sea turtles. 
43

Pacific Ocean

Leatherback nesting has been declining at all major Pacific basin nesting beaches for the last two 

decades (Spotila et al. 1996, 2000; NMFS and USFWS 1998a, 2007b; Sarti et al. 2000). In the 

western Pacific, major nesting beaches occur in Papua New Guinea, Indonesia, Solomon Islands, 

and Vanuatu, with an approximate 2,700-4,500 total breeding females, estimated from nest counts 

(Dutton et al. 2007). While there appears to be overall long term population decline, the Indonesian 

nesting aggregation at Jamursba-Medi is currently stable (since 1999), although there is evidence to 

suggest a significant and continued decline in leatherback nesting in Papua New Guinea and 

Solomon Islands over the past 30 years (NMFS 2011). Leatherback sea turtles disappeared from 

India before 1930, have been virtually extinct in Sri Lanka since 1994, and appear to be 

approaching extinction in Malaysia (Spotila et al. 2000). In Fiji, Thailand, and Australia, 

leatherback sea turtles have only been known to nest in low densities and scattered sites. 

The largest, extant leatherback nesting group in the Indo-Pacific lies on the North Vogelkop coast 

of West Papua, Indonesia, with 3,000-5,000 nests reported annually in the 1990s (Suárez et al. 

2000). However, in 1999, local villagers started reporting dramatic declines in sea turtles near their 

villages (Suárez 1999). Declines in nesting groups have been reported throughout the western 

Pacific region where observers report that nesting groups are well below abundance levels that were 

observed several decades ago (e.g., Suárez 1999). 

Leatherback sea turtles in the western Pacific are threatened by poaching of eggs, killing of nesting 

females, human encroachment on nesting beaches, incidental capture in fishing gear, beach erosion, 

and egg predation by animals. 

In the eastern Pacific Ocean, major leatherback nesting beaches are located in Mexico and Costa 

Rica, where nest numbers have been declining. According to reports from the late 1970s and early 

1980s, beaches located on the Mexican Pacific coasts of Michoacán, Guerrero, and Oaxaca 

sustained a large portion, perhaps 50%, of all global nesting by leatherbacks (Sarti et al. 1996). A 

dramatic decline has been seen on nesting beaches in Pacific Mexico, where aerial survey data was 

used to estimate that tens of thousands of leatherback nests were laid on the beaches in the 1980s 

(Pritchard 1982), but a total of only 120 nests on the four primary index beaches (combined) were 

counted in the 2003-2004 season (Sarti Martinez et al. 2007). Since the early 1980s, the Mexican 

Pacific population of adult female leatherback turtles has declined to slightly more than 200 during 

1998-1999 and 1999-2000 (Sarti et al. 2000). Spotila et al. (2000) reported the decline of the 

leatherback nesting at Playa Grande, Costa Rica, which had been the fourth largest nesting group in 

the world and the most important nesting beach in the Pacific. Between 1988 and 1999, the nesting 

group declined from 1,367 to 117 female leatherback sea turtles. Based on their models, Spotila et 

al. (2000) estimated that the group could fall to less than 50 females by 2003-2004. Another, more 

recent, analysis of the Costa Rican nesting beaches indicates a decline in nesting during 15 years of 

monitoring (1989-2004) with approximately 1,504 females nesting in 1988-1989 to an average of 

188 females nesting in 2000-2001 and 2003-2004 (NMFS and USFWS 2007b), indicating that the 

reductions in nesting females were not as extreme as the reductions predicted by Spotila et al. 

(2000). 

On September 26, 2007, NMFS received a petition to revise the critical habitat designation for 

leatherback sea turtles to include waters along the U.S. West Coast. On December 28, 2007, NMFS 
44

published a positive 90-day finding on the petition and convened a critical habitat review team. On 

January 26, 2012, NMFS published a final rule to revise the critical habitat designation to include 

three particular areas of marine habitat. The designation includes approximately 16,910 square 

miles along the California coast from Point Arena to Point Arguello east of the 3,000 meter depth 

contour, and 25,004 square miles from Cape Flattery, Washington to Cape Blanco, Oregon east of 

the 2,000 meter depth contour. The areas comprise approximately 41,914 square miles of marine 

habitat and include waters from the ocean surface down to a maximum depth of 262 feet. The 

designated critical habitat areas contain the physical or biological feature essential to the 

conservation of the species that may require special management conservation or protection. In 

particular, the team identified one Primary Constituent Element: the occurrence of prey species, 

primarily scyphomedusae of the order Semaeostomeae, of sufficient condition, distribution, 

diversity, abundance and density necessary to support individual as well as population growth, 

reproduction, and development of leatherbacks. 

Leatherbacks in the eastern Pacific face a number of threats to their survival. For example, 

commercial and artisanal swordfish fisheries off Chile, Columbia, Ecuador, and Peru; purse seine 

fisheries for tuna in the eastern tropical Pacific Ocean; and California/Oregon drift gillnet fisheries 

are known to capture, injure, or kill leatherbacks in the eastern Pacific Ocean. Given the declines in 

leatherback nesting in the Pacific, some researchers have concluded that the leatherback is on the 

verge of extinction in the Pacific Ocean (e.g., Spotila et al. 1996, 2000). 

Indian Ocean

Leatherbacks nest in several areas around the Indian Ocean. These sites include Tongaland, South 

Africa (Pritchard 2002) and the Andaman and Nicobar Islands (Andrews et al. 2002). Intensive 

survey and tagging work in 2001 provided new information on the level of nesting in the Andaman 

and Nicobar Islands (Andrews et al. 2002). Based on the survey and tagging work, it was estimated 

that 400-500 female leatherbacks nest annually on Great Nicobar Island (Andrews et al. 2002). The 

number of nesting females using the Andaman and Nicobar Islands combined was estimated around 

1,000 (Andrews and Shanker 2002). Some nesting also occurs along the coast of Sri Lanka, 

although in much smaller numbers than in the past (Pritchard 2002). 

Mediterranean Sea

Casale et al. (2003) reviewed the distribution of leatherback sea turtles in the Mediterranean. 

Among the 411 individual records of leatherback sightings in the Mediterranean, there were no 

nesting records. Nesting in the Mediterranean is believed to be extremely rare if it occurs at all. 

Leatherbacks found in Mediterranean waters originate from the Atlantic Ocean (P. Dutton, NMFS, 

unpublished data). 

Atlantic Ocean

Distribution and Life History

Evidence from tag returns and strandings in the western Atlantic suggests that adult leatherback sea 

turtles engage in routine migrations between northern temperate and tropical waters (NMFS and 

USFWS 1992). Leatherbacks are frequently thought of as a pelagic species that feed on jellyfish 

(e.g., Stomolophus, Chryaora, and Aurelia species) and tunicates (e.g., salps, pyrosomas) (Rebel 

1974; Davenport and Balazs 1991). However, leatherbacks are also known to use coastal waters of 
45

the U.S. continental shelf (James et al. 2005a; Eckert et al. 2006; Murphy et al. 2006), as well as the 

European continental shelf on a seasonal basis (Witt et al. 2007). 

Tagging and satellite telemetry data indicate that leatherbacks from the western North Atlantic 

nesting beaches use the entire North Atlantic Ocean (TEWG 2007). For example, leatherbacks 

tagged at nesting beaches in Costa Rica have been found in Texas, Florida, South Carolina, 

Delaware, and New York (STSSN database). Leatherback sea turtles tagged in Puerto Rico, 

Trinidad, and the Virgin Islands have also been subsequently found on U.S. beaches of southern, 

Mid-Atlantic, and northern states (STSSN database). Leatherbacks from the South Atlantic nesting 

assemblages (West Africa, South Africa, and Brazil) have not been re-sighted in the western North 

Atlantic (TEWG 2007). 

The CETAP aerial survey of the outer Continental Shelf from Cape Hatteras, North Carolina to 

Cape Sable, Nova Scotia conducted between 1978 and 1982 showed leatherbacks to be present 

throughout the area with the most numerous sightings made from the Gulf of Maine south to Long 

Island. Leatherbacks were sighted in water depths ranging from 1 to 4,151 m, but 84.4% of 

sightings were in waters less than 180 m (Shoop and Kenney 1992). Leatherbacks were sighted in 

waters within a sea surface temperature range similar to that observed for loggerheads; from 7°-

27.2°C (Shoop and Kenney 1992). However, leatherbacks appear to have a greater tolerance for 

colder waters in comparison to loggerhead sea turtles since more leatherbacks were found at the 

lower temperatures (Shoop and Kenney 1992). Studies of satellite tagged leatherbacks suggest that 

they spend 10%-41% of their time at the surface, depending on the phase of their migratory cycle 

(James et al. 2005b). The greatest amount of surface time (up to 41%) was recorded when 

leatherbacks occurred in continental shelf and slope waters north of 38°N (James et al. 2005b). 

In 1979, the waters adjacent to Sandy Point, St. Croix, U.S. Virgin Islands were designated as 

critical habitat for the leatherback sea turtle. On February 2, 2010, NMFS received a petition to 

revise the critical habitat designation for leatherback sea turtles to include waters adjacent to a 

major nesting beach in Puerto Rico. NMFS published a 90-day finding on the petition on July 16, 

2010, which found that the petition did not present substantial scientific information indicating that 

the petitioned revision was warranted. The original petitioners submitted a second petition on 

November 2, 2010 to revise the critical habitat designation to again include waters adjacent to a 

major nesting beach in Puerto Rico, including additional information on the usage of the 

waters. NMFS determined on May 5, 2011, that a revision to critical habitat off Puerto Rico may be 

warranted, and an analysis is underway. Note that on August 4, 2011, FWS issued a determination 

that revision to critical habitat along Puerto Rico should be made and will be addressed during the 

future planned status review.

Leatherbacks are a long lived species (>30 years). They were originally believed to mature at a 

younger age than loggerhead sea turtles, with a previous estimated age at sexual maturity of about 

13-14 years for females with 9 years reported as a likely minimum (Zug and Parham 1996) and 19 

years as a likely maximum (NMFS SEFSC 2001). However, new sophisticated analyses suggest 

that leatherbacks in the Northwest Atlantic may reach maturity at 24.5-29 years of age (Avens et al. 

2009). In the United States and Caribbean, female leatherbacks nest from March through July. In 

the Atlantic, most nesting females average between 150-160 cm curved carapace length (CCL), 

although smaller (<145 cm CCL) and larger nesters are observed (Stewart et al. 2007, TEWG 
46

2007). They nest frequently (up to seven nests per year) during a nesting season and nest about 

every 2-3 years. They produce 100 eggs or more in each clutch and can produce 700 eggs or more 

per nesting season (Schultz 1975). However, a significant portion (up to approximately 30%) of the 

eggs can be infertile. Therefore, the actual proportion of eggs that can result in hatchlings is less 

than the total number of eggs produced per season. As is the case with other sea turtle species, 

leatherback hatchlings enter the water soon after hatching. Based on a review of all sightings of 

leatherback sea turtles of <145 cm CCL, Eckert (1999) found that leatherback juveniles remain in 

waters warmer than 26°C until they exceed 100 cm CCL. 

Population Dynamics and Status

As described earlier, sea turtle nesting survey data is important in that it provides information on the 

relative abundance of nesting, and the contribution of each population/subpopulation to total nesting 

of the species. Nest counts can also be used to estimate the number of reproductively mature 

females nesting annually, and as an indicator of the trend in the number of nesting females in the 

nesting group. The 5-year review for leatherback sea turtles (NMFS and USFWS 2007b) compiled 

the most recent information on mean number of leatherback nests per year for each of the seven 

leatherback populations or groups of populations that were identified by the Leatherback TEWG as 

occurring within the Atlantic. These are: Florida, North Caribbean, Western Caribbean, Southern 

Caribbean, West Africa, South Africa, and Brazil (TEWG 2007). 

In the United States, the Florida Statewide Nesting Beach Survey program has documented an 

increase in leatherback nesting numbers from 98 nests in 1988 to between 800 and 900 nests in the 

early 2000s (NMFS and USFWS 2007b). Stewart et al. (2011) evaluated nest counts from 68 

Florida beaches over 30 years (1979-2008) and found that nesting increased at all beaches with 

trends ranging from 3.1%-16.3% per year, with an overall increase of 10.2% per year. An analysis 

of Florida’s index nesting beach sites from 1989-2006 shows a substantial increase in leatherback 

nesting in Florida during this time, with an annual growth rate of approximately 1.17 (TEWG 

2007). The TEWG reports an increasing or stable nesting trend for all of the seven populations or 

groups of populations with the exception of the Western Caribbean and West Africa. The 

leatherback rookery along the northern coast of South America in French Guiana and Suriname 

supports the majority of leatherback nesting in the western Atlantic (TEWG 2007), and represents 

more than half of total nesting by leatherback sea turtles worldwide (Hilterman and Goverse 2004). 

Nest numbers in Suriname have shown an increase and the long-term trend for the Suriname and 

French Guiana nesting group seems to show an increase (Hilterman and Goverse 2004). In 2001, 

the number of nests for Suriname and French Guiana combined was 60,000, one of the highest 

numbers observed for this region in 35 years (Hilterman and Goverse 2004). The TEWG (2007) 

report indicates that using nest numbers from 1967-2005, a positive population growth rate was 

found over the 39-year period for French Guinea and Suriname, with a 95% probability that the 

population was growing. Given the magnitude of leatherback nesting in this area compared to other 

nest sites, negative impacts in leatherback sea turtles in this area could have profound impacts on 

the entire species. 

The CETAP aerial survey conducted from 1978-1982 estimated the summer leatherback population 

for the northeastern United States at approximately 300-600 animals (from near Nova Scotia, 

Canada to Cape Hatteras, North Carolina) (Shoop and Kenney 1992). However, the estimate was 

based on turtles visible at the surface and does not include those that were below the surface out of 
47

view. Therefore, it likely underestimated the leatherback population for the northeastern United 

States at the time of the survey. Estimates of leatherback abundance of 1,052 turtles (C.V. = 0.38) 

and 1,174 turtles (C.V. = 0.52) were obtained from surveys conducted from Virginia to the Gulf of 

St. Lawrence in 1995 and 1998, respectively (Palka 2000). However, since these estimates were 

also based on sightings of leatherbacks at the surface, the author considered the estimates to be 

negatively biased and the true abundance of leatherbacks may be 4.27 times higher (Palka 2000). 

Threats

The 5-year status review (NMFS and USFWS 2007b) and TEWG (2007) report provide summaries 

of natural as well as anthropogenic threats to leatherback sea turtles. Of the Atlantic sea turtle 

species, leatherbacks seem to be the most vulnerable to entanglement in fishing gear, trap/pot gear 

in particular. This susceptibility may be the result of their body type (large size, long pectoral 

flippers, and lack of a hard shell), their diving and foraging behavior, their distributional overlap 

with the gear, their possible attraction to gelatinous organisms and algae that collect on buoys and 

buoy lines at or near the surface, and perhaps to the lightsticks used to attract target species in 

longline fisheries. Leatherbacks entangled in fishing gear generally have a reduced ability to feed, 

dive, surface to breathe, or perform any other behavior essential to survival (Balazs 1985). In 

addition to drowning from forced submergence, they may be more susceptible to boat strikes if 

forced to remain at the surface, and entangling lines can constrict blood flow resulting in tissue 

necrosis. The long-term impacts of entanglement on leatherback health remain unclear. Innis et al. 

(2010) conducted a health evaluation of leatherback sea turtles during direct capture (n=12) and 

disentanglement (n=7). They found no significant difference in many of the measured health 

parameters between entangled and directly captured turtles. However, blood parameters, including 

but not limited to sodium, chloride, and blood urea nitrogen, for entangled turtles showed several 

key differences that were most likely due to reduced foraging and associated seawater ingestion, as 

well as a general stress response. 

Finkbeiner et al. (2011) compiled cumulative sea turtle bycatch information in U.S. fisheries from 

1990 through 2007, before and after implementation of bycatch mitigation measures. Information 

was obtained from peer reviewed publications and NMFS documents (e.g., Biological Opinions and 

bycatch reports). In the Atlantic, a mean estimate of 137,700 bycatch interactions, of which 4,500 

were mortalities, occurred annually (since implementation of bycatch mitigation measures). 

Kemp’s ridleys interacted with fisheries most frequently, with the highest level of mean annual 

mortality (2,700), followed by loggerheads (1,400), greens (300), and leatherbacks (40). The 

Southeast/Gulf of Mexico shrimp trawl fishery was responsible for the vast majority of U.S. 

interactions (up to 98%) and mortalities (more than 80%). While this provides an initial cumulative 

bycatch assessment, there are a number of caveats that should be considered when interpreting this 

information, such as sampling inconsistencies and limitations.

Leatherbacks have been documented interacting with longline, trap/pot, trawl, and gillnet fishing 

gear. For instance, an estimated 6,363 leatherback sea turtles were documented as caught by the 

U.S. Atlantic tuna and swordfish longline fisheries between 1992-1999 (NMFS SEFSC 2001). 

Currently, the U.S. tuna and swordfish longline fisheries managed under the HMS FMP are 

estimated to capture 1,764 leatherbacks (no more than 252 mortalities) for each 3-year period 

starting in 2007 (NMFS 2004a). In 2010, there were 26 observed interactions between leatherback 

sea turtles and longline gear used in the HMS fishery (Garrison and Stokes 2011a, 2011b). All 
48

leatherbacks were released alive, with all gear removed for the majority of captures. While 2010 

total estimates are not yet available, in 2009, 285.8 (95% CI: 209.6-389.7) leatherback sea turtles 

are estimated to have been taken in the longline fisheries managed under the HMS FMP based on 

the observed takes (Garrison and Stokes 2010). The 2009 estimate continues a downward trend 

since 2007 and remains well below the average prior to implementation of gear regulations 

(Garrison and Stokes 2010). Since the U.S. fleet accounts for only 5%-8% of the longline hooks 

fished in the Atlantic Ocean, adding up the under-represented observed takes of the other 23 

countries actively fishing in the area would likely result in annual take estimates of thousands of 

leatherbacks over different life stages (NMFS SEFSC 2001). Lewison et al. (2004) estimated that 

30,000-60,000 leatherbacks were taken in all Atlantic longline fisheries in 2000 (including the U.S. 

Atlantic tuna and swordfish longline fisheries, as well as others). 

Leatherbacks are susceptible to entanglement in the lines associated with trap/pot gear used in 

several fisheries. From 1990-2000, 92 entangled leatherbacks were reported from New York 

through Maine (Dwyer et al. 2002). Additional leatherbacks stranded wrapped in line of unknown 

origin or with evidence of a past entanglement (Dwyer et al. 2002). More recently, from 2002 to 

2010, NMFS received 137 reports of sea turtles entangled in vertical lines from Maine to Virginia, 

with 128 events confirmed (verified by photo documentation or response by a trained responder; 

NMFS 2008a). Of the 128 confirmed events during this period, 117 events involved leatherbacks. 

NMFS identified the gear type and fishery for 72 of the 117 confirmed events, which included 

lobster (426), whelk/conch (15), black sea bass (10), crab (2), and research pot gear (1). A review of 

leatherback mortality documented by the STSSN in Massachusetts suggests that vessel strikes and 

entanglement in fixed gear (primarily lobster pots and whelk pots) are the principal sources of this 

mortality (Dwyer et al. 2002). 

Leatherback interactions with the U.S. South Atlantic and Gulf of Mexico shrimp fisheries are also 

known to occur (NMFS 2002). Leatherbacks are likely to encounter shrimp trawls working in the 

coastal waters off the U.S. Atlantic coast (from Cape Canaveral, Florida through North Carolina) as 

they make their annual spring migration north. For many years, TEDs that were required for use in 

the U.S. South Atlantic and Gulf of Mexico shrimp fisheries were less effective for leatherbacks as 

compared to the smaller, hard-shelled turtle species, because the TED openings were too small to 

allow leatherbacks to escape. To address this problem, NMFS issued a final rule on February 21, 

2003, to amend the TED regulations (68 FR 8456, February 21, 2003). Modifications to the design 

of TEDs are now required in order to exclude leatherbacks as well as large benthic immature and 

sexually mature loggerhead and green sea turtles. Given those modifications, Epperly et al. (2002) 

anticipated an average of 80 leatherback mortalities a year in shrimp gear interactions, dropping to 

an estimate of 26 leatherback mortalities in 2009 due to effort reduction in the Southeast shrimp 

fishery (Memo from Dr. B. Ponwith, SEFSC, to Dr. R. Crabtree, SERO, January 5, 2011).

Other trawl fisheries are also known to interact with leatherback sea turtles although on a much 

smaller scale. In October 2001, for example, a NMFS fisheries observer documented the take of a 

leatherback in a bottom otter trawl fishing for Loligo squid off of Delaware. TEDs are not currently 

 

6 One case involved both lobster and whelk/conch gear.
49

required in this fishery. In November 2007, fisheries observers reported the capture of a 

leatherback sea turtle in bottom otter trawl gear fishing for summer flounder. 

Gillnet fisheries operating in the waters of the Mid-Atlantic states are also known to capture, injure, 

and/or kill leatherbacks when these fisheries and leatherbacks co-occur. Data collected by the 

NEFSC Fisheries Observer Program from 1994-1998 (excluding 1997) indicate that a total of 37 

leatherbacks were incidentally captured (16 lethally) in drift gillnets set in offshore waters from 

Maine to Florida during this period. Observer coverage for this period ranged from 54%-92%. In 

North Carolina, six additional leatherbacks were reported captured in gillnet sets in the spring 

(NMFS SEFSC 2001). In addition to these, in September 1995, two dead leatherbacks were 

removed from an 11-inch (28.2-cm) monofilament shark gillnet set in the nearshore waters off of 

Cape Hatteras (STSSN unpublished data reported in NMFS SEFSC 2001). Lastly, Murray (2009a) 

reports five observed leatherback captures in Mid-Atlantic sink gillnet fisheries between 1994 and 

2008. 

Fishing gear interactions can occur throughout the range of leatherbacks. Entanglements occur in 

Canadian waters where Goff and Lien (1988) reported that 14 of 20 leatherbacks encountered off 

the coast of Newfoundland/Labrador were entangled in fishing gear including salmon net, herring 

net, gillnet, trawl line, and crab pot line. Leatherbacks are known to drown in fish nets set in coastal 

waters of Sao Tome, West Africa (Castroviejo et al. 1994; Graff 1995). Gillnets are one of the 

suspected causes for the decline in the leatherback sea turtle population in French Guiana 

(Chevalier et al. 1999), and gillnets targeting green and hawksbill sea turtles in the waters of coastal 

Nicaragua also incidentally catch leatherback sea turtles (Lagueux et al.1998). Observers on shrimp 

trawlers operating in the northeastern region of Venezuela documented the capture of six 

leatherbacks from 13,600 trawls (Marcano and Alio-M. 2000). An estimated 1,000 mature female 

leatherback sea turtles are caught annually in fishing nets off of Trinidad and Tobago with mortality 

estimated to be between 50%-95% (Eckert and Lien 1999). Many of the sea turtles do not die as a 

result of drowning, but rather because the fishermen cut them out of their nets (NMFS SEFSC 

2001). 

Leatherbacks may be more susceptible to marine debris ingestion than other sea turtle species due to 

the tendency of floating debris to concentrate in convergence zones that juveniles and adults use for 

feeding (Shoop and Kenney 1992; Lutcavage et al. 1997). Investigations of the necropsy results of 

leatherback sea turtles revealed that a substantial percentage (34% of the 408 leatherback 

necropsies’ recorded between 1885 and 2007) reported plastic within the turtles’ stomach contents, 

and in some cases (8.7% of those cases in which plastic was reported), blockage of the gut was 

found in a manner that may have caused the mortality (Mrosovsky et al. 2009). An increase in 

reports of plastic ingestion was evident in leatherback necropsies conducted after the late 1960s 

(Mrosovsky et al. 2009). Along the coast of Peru, intestinal contents of 19 of 140 (13%) 

leatherback carcasses were found to contain plastic bags and film (Fritts 1982). The presence of 

plastic debris in the digestive tract suggests that leatherbacks might not be able to distinguish 

between prey items (e.g., jellyfish) and plastic debris (Mrosovsky 1981). Balazs (1985) speculated 

that plastic objects may resemble food items by their shape, color, size, or even movements as they 

drift about, and induce a feeding response in leatherbacks. 
50

Summary of Status for Leatherback Sea Turtles

In the Pacific Ocean, the abundance of leatherback sea turtles on nesting beaches has declined 

dramatically over the past 10 to 20 years. Nesting groups throughout the eastern and western 

Pacific Ocean have been reduced to a fraction of their former abundance by the combined effects of 

human activities that have reduced the number of nesting females and reduced the reproductive 

success of females that manage to nest (for example, egg poaching) (NMFS and USFWS 2007b). 

No reliable long term trend data for the Indian Ocean populations are currently available. While 

leatherbacks are known to occur in the Mediterranean Sea, nesting in this region is not known to 

occur (NMFS and USFWS 2007b). 

Nest counts in many areas of the Atlantic Ocean show increasing trends, including for beaches in 

Suriname and French Guiana which support the majority of leatherback nesting (NMFS and 

USFWS 2007b). The species as a whole continues to face numerous threats in nesting and marine 

habitats. As with the other sea turtle species, fishery mortality accounts for a large proportion of 

annual human-caused mortality outside the nesting beaches, while other activities like pollution and 

habitat destruction account for an unknown level of other mortality. The long term recovery 

potential of this species may be further threatened by observed low genetic diversity, even in the 

largest nesting groups like French Guiana and Suriname (NMFS and USFWS 2007b). 

Based on its 5-year status review of the species, NMFS and USFWS (2007b) determined that 

endangered leatherback sea turtles should not be delisted or reclassified. However, it was also 

determined that an analysis and review of the species should be conducted in the future to determine 

whether DPSs should be identified (NMFS and USFWS 2007b). 

4.6 Shortnose Sturgeon

Shortnose sturgeon life history

Shortnose sturgeon are benthic fish that mainly occupy the deep channel sections of large rivers. 

They feed on a variety of benthic and epibenthic invertebrates including mollusks, crustaceans 

(amphipods, chironomids, isopods), and oligochaete worms (Vladykov and Greeley 1963; Dadswell 

1979 in NMFS 1998). Shortnose sturgeon have similar lengths at maturity (45-55 cm fork length) 

throughout their range, but, because sturgeon in southern rivers grow faster than those in northern 

rivers, southern sturgeon mature at younger ages (Dadswell et al. 1984). Shortnose sturgeon are 

long-lived (30-40 years) and, particularly in the northern extent of their range, mature at late ages. 

In the north, males reach maturity at 5 to 10 years, while females mature between 7 and 13 years. 

Based on limited data, females spawn every three to five years while males spawn approximately 

every two years. The spawning period is estimated to last from a few days to several weeks. 

Spawning begins from late winter/early spring (southern rivers) to mid to late spring (northern 

rivers)7 when the freshwater temperatures increase to 8-9oC. Several published reports have 

presented the problems facing long-lived species that delay sexual maturity (Crouse et al. 1987; 

Crowder et al. 1994; Crouse 1999). In general, these reports concluded that animals that delay 

sexual maturity and reproduction must have high annual survival as juveniles through adults to 

 

7

For purposes of this consultation, Northern rivers are considered to include tributaries of the Chesapeake Bay 

northward to the St. John River in Canada. Southern rivers are those south of the Chesapeake Bay. 
51

ensure that enough juveniles survive to reproductive maturity and then reproduce enough times to 

maintain stable population sizes. 

Total instantaneous mortality rates (Z) are available for the Saint John River (0.12 - 0.15; ages 14-

55; Dadswell 1979), Upper Connecticut River (0.12; Taubert 1980b), and Pee Dee-Winyah River 

(0.08-0.12; Dadswell et al. 1984). Total instantaneous natural mortality (M) for shortnose sturgeon 

in the lower Connecticut River was estimated to be 0.13 (T. Savoy, Connecticut Department of 

Environmental Protection, personal communication). There is no recruitment information available 

for shortnose sturgeon because there are no commercial fisheries for the species. Estimates of 

annual egg production for this species are difficult to calculate because females do not spawn every 

year (Dadswell et al. 1984). Further, females may abort spawning attempts, possibly due to 

interrupted migrations or unsuitable environmental conditions (NMFS 1998). Thus, annual egg 

production is likely to vary greatly in this species. Fecundity estimates have been made and range 

from 27,000 to 208,000 eggs/female and a mean of 11,568 eggs/kg body weight (Dadswell et al. 

1984). 

At hatching, shortnose sturgeon are blackish-colored, 7-11mm long and resemble tadpoles (Buckley 

and Kynard 1981). In 9-12 days, the yolk sac is absorbed and the sturgeon develops into larvae 

which are about 15mm total length (TL; Buckley and Kynard 1981). Sturgeon larvae are believed 

to begin downstream migrations at about 20mm TL. Dispersal rates differ at least regionally, 

laboratory studies on Connecticut River larvae indicated dispersal peaked 7-12 days after hatching 

in comparison to Savannah River larve that had longer dispersal rates with multiple, prolonged 

peaks, and a low level of downstream movement that continued throughout the entire larval and 

early juvenile period (Parker 2007). Synder (1988) and Parker (2007) considered individuals to be 

juvenile when they reached 57mm TL. Laboratory studies demonstrated that larvae from the 

Connecticut River made this transformation on day 40 while Savannah River fish made this 

transition on day 41 and 42 (Parker 2007). 

The juvenile phase can be subdivided in to young of the year (YOY) and immature/ sub-adults. 

YOY and sub-adult habitat use differs and is believed to be a function of differences in salinity 

tolerances. Little is known about YOY behavior and habitat use, though it is believed that they are 

typically found in channel areas within freshwater habitats upstream of the saltwedge for about one 

year (Dadswell et al. 1984, Kynard 1997). One study on the stomach contents of YOY revealed 

that the prey items found corresponded to organisms that would be found in the channel 

environment (amphipods) (Carlson and Simpson 1987). Sub-adults are typically described as age 

one or older and occupy similar spatio-temporal patterns and habitat-use as adults (Kynard 1997). 

Though there is evidence from the Delaware River that sub-adults may overwinter in different areas 

than adults and no not form dense aggregations like adults (ERC Inc. 2007). Sub-adults feed 

indiscriminately, typical prey items found in stomach contents include aquatic insects, isopods, and 

amphipods along with large amounts of mud, stones, and plant material (Dadswell 1979, Carlson 

and Simpson 1987, Bain 1997). 

In populations that have free access to the total length of a river (e.g., no dams within the species’ 

range in a river: Saint John, Kennebec, Altamaha, Savannah, Delaware and Merrimack Rivers), 

spawning areas are located at the farthest upstream reach of the river (NMFS 1998). In the northern 

extent of their range, shortnose sturgeon exhibit three distinct movement patterns. These migratory 
52

movements are associated with spawning, feeding, and overwintering activities. In spring, as water 

temperatures reach between 7-9.7oC, pre-spawning shortnose sturgeon move from overwintering 

grounds to spawning areas. Spawning occurs from mid/late March to mid/late May depending upon 

location and water temperature. Sturgeon spawn in upper, freshwater areas and feed and overwinter 

in both fresh and saline habitats. Shortnose sturgeon spawning migrations are characterized by 

rapid, directed and often extensive upstream movement (NMFS 1998). 

Shortnose sturgeon are believed to spawn at discrete sites within their natal river (Kieffer and 

Kynard 1996). In the Merrimack River, males returned to only one reach during a four year 

telemetry study (Kieffer and Kynard 1996). Squires (1982) found that during the three years of the 

study in the Androscoggin River, adults returned to a 1-km reach below the Brunswick Dam and 

Kieffer and Kynard (1996) found that adults spawned within a 2-km reach in the Connecticut River 

for three consecutive years. Spawning occurs over channel habitats containing gravel, rubble, or 

rock-cobble substrates (Dadswell et al. 1984; NMFS 1998). Additional environmental conditions 

associated with spawning activity include decreasing river discharge following the peak spring 

freshet, water temperatures ranging from 8 - 15o, and bottom water velocities of 0.4 to 0.8 m/sec 

(Dadswell et al. 1984; Hall et al. 1991, Kieffer and Kynard 1996, NMFS 1998). For northern 

shortnose sturgeon, the temperature range for spawning is 6.5-18.0oC (Kieffer and Kynard in press). 

Eggs are separate when spawned but become adhesive within approximately 20 minutes of 

fertilization (Dadswell et al. 1984). Between 8° and 12°C, eggs generally hatch after approximately 

13 days. The larvae are photonegative, remaining on the bottom for several days. Buckley and 

Kynard (1981) found week old larvae to be photonegative and form aggregations with other larvae 

in concealment.

Adult shortnose sturgeon typically leave the spawning grounds soon after spawning. Non-spawning 

movements include rapid, directed post-spawning movements to downstream feeding areas in 

spring and localized, wandering movements in summer and winter (Dadswell et al. 1984; Buckley 

and Kynard 1985; O’Herron et al. 1993). Kieffer and Kynard (1993) reported that post-spawning 

migrations were correlated with increasing spring water temperature and river discharge. Youngof-the-year shortnose sturgeon are believed to move downstream after hatching (Dovel 1981) but 

remain within freshwater habitats. Older juveniles or sub-adults tend to move downstream in fall 

and winter as water temperatures decline and the salt wedge recedes and move upstream in spring 

and feed mostly in freshwater reaches during summer. 

Juvenile shortnose sturgeon generally move upstream in spring and summer and move back 

downstream in fall and winter; however, these movements usually occur in the region above the 

saltwater/freshwater interface (Dadswell et al. 1984; Hall et al. 1991). Non-spawning movements 

include wandering movements in summer and winter (Dadswell et al. 1984; Buckley and Kynard 

1985; O’Herron et al. 1993). Kieffer and Kynard (1993) reported that post-spawning migrations 

were correlated with increasing spring water temperature and river discharge. Adult sturgeon 

occurring in freshwater or freshwater/tidal reaches of rivers in summer and winter often occupy 

only a few short reaches of the total length (Buckley and Kynard 1985). Summer concentration 

areas in southern rivers are cool, deep, thermal refugia, where adult and juvenile shortnose sturgeon 

congregate (Flourney et al. 1992; Rogers et al. 1994; Rogers and Weber 1995; Weber 1996). 

While shortnose sturgeon do not undertake the significant marine migrations seen in Atlantic 
53

sturgeon, telemetry data indicates that shortnose sturgeon do make localized coastal migrations. 

This is particularly true within certain areas such as the Gulf of Maine (GOM) and among rivers in 

the Southeast. Interbasin movements have been documented among rivers within the GOM and 

between the GOM and the Merrimack, between the Connecticut and Hudson rivers, the Delaware 

River and Chesapeake Bay, and among the rivers in the Southeast. 

The temperature preference for shortnose sturgeon is not known (Dadswell et al. 1984) but 

shortnose sturgeon have been found in waters with temperatures as low as 2 to 3oC (Dadswell et al. 

1984) and as high as 34oC (Heidt and Gilbert 1978). However, temperatures above 28oC are 

thought to adversely affect shortnose sturgeon. In the Altamaha River, temperatures of 28-30oC 

during summer months create unsuitable conditions and shortnose sturgeon are found in deep cool 

water refuges. Dissolved oxygen (DO) also seems to play a role in temperature tolerance, with 

increased stress levels at higher temperatures with low DO versus the ability to withstand higher 

temperatures with elevated DO (Niklitchek 2001). 

Shortnose sturgeon are known to occur at a wide range of depths. A minimum depth of 0.6m is 

necessary for the unimpeded swimming by adults. Shortnose sturgeon are known to occur at depths 

of up to 30m but are generally found in waters less than 20m (Dadswell et al. 1984; Dadswell 

1979). Shortnose sturgeon have also demonstrated tolerance to a wide range of salinities. 

Shortnose sturgeon have been documented in freshwater (Taubert 1980; Taubert and Dadswell 

1980) and in waters with salinity of 30 parts-per-thousand (ppt) (Holland and Yeverton 1973; 

Saunders and Smith 1978). Mcleave et al. (1977) reported adults moving freely through a wide 

range of salinities, crossing waters with differences of up to 10ppt within a two hour period. The 

tolerance of shortnose sturgeon to increasing salinity is thought to increase with age (Kynard 1996). 

Shortnose sturgeon typically occur in the deepest parts of rivers or estuaries where suitable oxygen 

and salinity values are present (Gilbert 1989).

Status and Trends of Shortnose Sturgeon Rangewide 

Shortnose sturgeon were listed as endangered on March 11, 1967 (32 FR 4001), and the species 

remained on the endangered species list with the enactment of the ESA in 1973. Although the 

original listing notice did not cite reasons for listing the species, a 1973 Resource Publication, 

issued by the US Department of the Interior, stated that shortnose sturgeon were “in peril...gone in 

most of the rivers of its former range [but] probably not as yet extinct” (USDOI 1973). Pollution 

and overfishing, including bycatch in the shad fishery, were listed as principal reasons for the 

species’ decline. In the late nineteenth and early twentieth centuries, shortnose sturgeon commonly 

were taken in a commercial fishery for the closely related and commercially valuable Atlantic 

sturgeon (Acipenser oxyrinchus). More than a century of extensive fishing for sturgeon contributed 

to the decline of shortnose sturgeon along the east coast. Heavy industrial development during the 

twentieth century in rivers inhabited by sturgeon impaired water quality and impeded these species’ 

recovery; possibly resulting in substantially reduced abundance of shortnose sturgeon populations 

within portions of the species’ ranges (e.g., southernmost rivers of the species range: Santilla, St. 

Marys and St. Johns Rivers). A shortnose sturgeon recovery plan was published in December 1998 

to promote the conservation and recovery of the species (see NMFS 1998). Shortnose sturgeon are 

listed as “vulnerable” on the IUCN Red List. 

Although shortnose sturgeon are listed as endangered range-wide, in the final recovery plan NMFS 
54

recognized 19 separate populations occurring throughout the range of the species. These 

populations are in New Brunswick Canada (1); Maine (2); Massachusetts (1); Connecticut (1); New 

York (1); New Jersey/Delaware (1); Maryland and Virginia (1); North Carolina (1); South Carolina 

(4); Georgia (4); and Florida (2). NMFS has not formally recognized distinct population segments 

(DPS)8of shortnose sturgeon under the ESA. Although genetic information within and among 

shortnose sturgeon occurring in different river systems is largely unknown, life history studies 

indicate that shortnose sturgeon populations from different river systems are substantially 

reproductively isolated (Kynard 1997) and, therefore, should be considered discrete. The 1998 

Recovery Plan indicates that while genetic information may reveal that interbreeding does not occur

between rivers that drain into a common estuary, at this time, such river systems are considered a 

single population compromised of breeding subpopulations (NMFS 1998). 

Studies conducted since the issuance of the Recovery Plan have provided evidence that suggests 

that years of isolation between populations of shortnose sturgeon have led to morphological and 

genetic variation. Walsh et al. (2001) examined morphological and genetic variation of shortnose 

sturgeon in three rivers (Kennebec, Androscoggin, and Hudson). The study found that the Hudson 

River shortnose sturgeon population differed markedly from the other two rivers for most 

morphological features (total length, fork length, head and snout length, mouth width, interorbital 

width and dorsal scute count, left lateral scute count, right ventral scute count). Significant 

differences were found between fish from Androscoggin and Kennebec rivers for interorbital width 

and lateral scute counts which suggests that even though the Androscoggin and Kennebec rivers 

drain into a common estuary, these rivers support largely discrete populations of shortnose sturgeon. 

The study also found significant genetic differences among all three populations indicating 

substantial reproductive isolation among them and that the observed morphological differences may 

be partly or wholly genetic. 

Grunwald et al. (2002) examined mitochondrial DNA (mtDNA) from shortnose sturgeon in eleven 

river populations. The analysis demonstrated that all shortnose sturgeon populations examined 

showed moderate to high levels of genetic diversity as measured by haplotypic diversity indices. 

The limited sharing of haplotypes and the high number of private haplotypes are indicative of high 

homing fidelity and low gene flow. The researchers determined that glaciation in the Pleistocene 

Era was likely the most significant factor in shaping the phylogeographic pattern of mtDNA 

diversity and population structure of shortnose sturgeon. The Northern glaciated region extended 

south to the Hudson River while the southern non-glaciated region begins with the Delaware River. 

There is a high prevalence of haplotypes restricted to either of these two regions and relatively few 

are shared; this represents a historical subdivision that is tied to an important geological 

phenomenon that reflects historical isolation. Analyses of haplotype frequencies at the level of 

individual rivers showed significant differences among all systems in which reproduction is known 

to occur. This implies that although higher level genetic stock relationships exist (i.e., southern vs. 

 

8 The definition of species under the ESA includes any subspecies of fish, wildlife, or plants, and any distinct population segment of 

any species of vertebrate fish or wildlife which interbreeds when mature. To be considered a DPS, a population segment must meet 

two criteria under NMFS policy. First, it must be discrete, or separated, from other populations of its species or subspecies. Second, it 

must be significant, or essential, to the long-term conservation status of its species or subspecies. This formal legal procedure to 

designate DPSs for shortnose sturgeon has not been undertaken.
55

northern and other regional subdivisions), shortnose sturgeon appear to be discrete stocks, and low 

gene flow exists between the majority of populations. 

Waldman et al. (2002) also conducted mtDNA analysis on shortnose sturgeon from 11 river systems 

and identified 29 haplotypes. Of these haplotypes, 11 were unique to northern, glaciated systems 

and 13 were unique to the southern non-glaciated systems. Only 5 were shared between them. This 

analysis suggests that shortnose sturgeon show high structuring and discreteness and that low gene 

flow rates indicated strong homing fidelity. 

Wirgin et al. (2005), also conducted mtDNA analysis on shortnose sturgeon from 12 rivers (St. 

John, Kennebec, Androscoggin, Upper Connecticut, Lower Connecticut, Hudson, Delaware, 

Chesapeake Bay, Cooper, Peedee, Savannah, Ogeechee and Altamaha). This analysis suggested 

that most population segments are independent and that genetic variation among groups was high. 

The best available information demonstrates differences in life history and habitat preferences 

between northern and southern river systems and given the species’ anadromous breeding habits, 

the rare occurrence of migration between river systems, and the documented genetic differences 

between river populations, it is unlikely that populations in adjacent river systems interbreed with 

any regularity. This likely accounts for the failure of shortnose sturgeon to repopulate river systems 

from which they have been extirpated, despite the geographic closeness of persisting populations. 

This characteristic of shortnose sturgeon also complicates recovery and persistence of this species in 

the future because, if a river population is extirpated in the future, it is unlikely that this river will be 

recolonized. Consequently, this Opinion will treat the nineteen separate populations of shortnose 

sturgeon as subpopulations (one of which occurs in the action area) for the purposes of this analysis.

Historically, shortnose sturgeon are believed to have inhabited nearly all major rivers and estuaries 

along nearly the entire east coast of North America. The range extended from the St John River in 

New Brunswick, Canada to the Indian River in Florida. Today, only 19 populations remain ranging 

from the St. Johns River, Florida (possibly extirpated from this system) to the Saint John River in 

New Brunswick, Canada. Shortnose sturgeon are large, long lived fish species. The present range 

of shortnose sturgeon is disjunct, with northern populations separated from southern populations by 

a distance of about 400 km. Population sizes vary across the species’ range. From available 

estimates, the smallest populations occur in the Cape Fear (~8 adults; Moser and Ross 1995) in the 

south and Merrimack and Penobscot rivers in the north (~ several hundred to several thousand 

adults depending on population estimates used; M. Kieffer, United States Geological Survey, 

personal communication; Dionne 2010), while the largest populations are found in the Saint John 

(~18, 000; Dadswell 1979) and Hudson Rivers (~61,000; Bain et al. 1998). As indicated in Kynard 

1996, adult abundance is less than the minimum estimated viable population abundance of 1000 

adults for 5 of 11 surveyed northern populations and all natural southern populations. Kynard 1996 

indicates that all aspects of the species’ life history indicate that shortnose sturgeon should be 

abundant in most rivers. As such, the expected abundance of adults in northern and north-central 

populations should be thousands to tens of thousands of adults. Expected abundance in southern 

rivers is uncertain, but large rivers should likely have thousands of adults. The only river systems 

likely supporting populations of these sizes are the St John, Hudson and possibly the Delaware and 

the Kennebec, making the continued success of shortnose sturgeon in these rivers critical to the 

species as a whole. While no reliable estimate of the size of either the total species or the shortnose 
56

sturgeon population in the Northeastern United States exists, it is clearly below the size that could 

be supported if the threats to shortnose sturgeon were removed. 

Threats to shortnose sturgeon recovery

The Shortnose Sturgeon Recovery Plan (NMFS 1998) identifies habitat degradation or loss 

(resulting, for example, from dams, bridge construction, channel dredging, and pollutant discharges) 

and mortality (resulting, for example, from impingement on cooling water intake screens, dredging 

and incidental capture in other fisheries) as principal threats to the species’ survival. 

Several natural and anthropogenic factors continue to threaten the recovery of shortnose sturgeon. 

Shortnose sturgeon continue to be taken incidentally in fisheries along the east coast and are 

probably targeted by poachers throughout their range (Dadswell 1979; Dovel et al. 1992; Collins et 

al. 1996). Bridge construction and demolition projects may interfere with normal shortnose 

sturgeon migratory movements and disturb sturgeon concentration areas. Unless appropriate 

precautions are made, internal damage and/or death may result from blasting projects with powerful 

explosives. Hydroelectric dams may affect shortnose sturgeon by restricting habitat, altering river 

flows or temperatures necessary for successful spawning and/or migration and causing mortalities 

to fish that become entrained in turbines. Maintenance dredging of Federal navigation channels and 

other areas can adversely affect or jeopardize shortnose sturgeon populations. Hydraulic dredges 

can lethally take sturgeon by entraining sturgeon in dredge dragarms and impeller pumps. 

Mechanical dredges have also been documented to lethally take shortnose sturgeon. In addition to 

direct effects, dredging operations may also impact shortnose sturgeon by destroying benthic 

feeding areas, disrupting spawning migrations, and filling spawning habitat with resuspended fine 

sediments. Shortnose sturgeon are susceptible to impingement on cooling water intake screens at 

power plants. Electric power and nuclear power generating plants can affect sturgeon by impinging 

larger fish on cooling water intake screens and entraining larval fish. The operation of power plants 

can have unforeseen and extremely detrimental impacts to water quality which can affect shortnose 

sturgeon. For example, the St. Stephen Power Plant near Lake Moultrie, South Carolina was shut 

down for several days in June 1991 when large mats of aquatic plants entered the plant’s intake 

canal and clogged the cooling water intake gates. Decomposing plant material in the tailrace canal 

coupled with the turbine shut down (allowing no flow of water) triggered a low dissolved oxygen 

water condition downstream and a subsequent fish kill. The South Carolina Wildlife and Marine 

Resources Department reported that twenty shortnose sturgeon were killed during this low 

dissolved oxygen event. 

Contaminants, including toxic metals, polychlorinated aromatic hydrocarbons (PAHs), pesticides, 

and polychlorinated biphenyls (PCBs) can have substantial deleterious effects on aquatic life 

including production of acute lesions, growth retardation, and reproductive impairment (Cooper 

1989; Sinderman 1994). Ultimately, toxins introduced to the water column become associated with 

the benthos and can be particularly harmful to benthic organisms (Varanasi 1992) like sturgeon. 

Heavy metals and organochlorine compounds are known to accumulate in fat tissues of sturgeon, 

but their long term effects are not yet known (Ruelle and Henry 1992; Ruelle and Kennlyne 1993). 

Available data suggests that early life stages of fish are more susceptible to environmental and 

pollutant stress than older life stages (Rosenthal and Alderdice 1976).

Although there is scant information available on the levels of contaminants in shortnose sturgeon 
57

tissues, some research on other related species indicates that concern about the effects of 

contaminants on the health of sturgeon populations is warranted. Detectible levels of chlordane, 

DDE (1,1-dichloro-2, 2-bis(p-chlorophenyl)ethylene), DDT (dichlorodiphenyl-trichloroethane), and 

dieldrin, and elevated levels of PCBs, cadmium, mercury, and selenium were found in pallid 

sturgeon tissue from the Missouri River (Ruelle and Henry 1994). These compounds were found in 

high enough levels to suggest they may be causing reproductive failure and/or increased 

physiological stress (Ruelle and Henry 1994). In addition to compiling data on contaminant levels, 

Ruelle and Henry also determined that heavy metals and organochlorine compounds (i.e. PCBs) 

accumulate in fat tissues. Although the long term effects of the accumulation of contaminants in fat 

tissues is not yet known, some speculate that lipophilic toxins could be transferred to eggs and 

potentially inhibit egg viability. In other fish species, reproductive impairment, reduced egg 

viability, and reduced survival of larval fish are associated with elevated levels of environmental 

contaminants including chlorinated hydrocarbons. A strong correlation that has been made between

fish weight, fish fork length, and DDE concentration in pallid sturgeon livers indicates that DDE 

increases proportionally with fish size (NMFS 1998).

Contaminant analysis was conducted on two shortnose sturgeon from the Delaware River in the fall 

of 2002. Muscle, liver, and gonad tissue were analyzed for contaminants (ERC 2002). Sixteen 

metals, two semivolatile compounds, three organochlorine pesticides, one PCB Aroclor, as well as 

polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) were 

detected in one or more of the tissue samples. Levels of aluminum, cadmium, PCDDs, PCDFs, 

PCBs, DDE (an organochlorine pesticide) were detected in the “adverse affect” range. It is of 

particular concern that of the above chemicals, PCDDs, DDE, PCBs and cadmium, were detected as 

these have been identified as endocrine disrupting chemicals. Contaminant analysis conducted in 

2003 on tissues from a shortnose sturgeon from the Kennebec River revealed the presence of 

fourteen metals, one semivolatile compound, one PCB Aroclor, Polychlorinated dibenzo-p-dioxins 

(PCDDs) and polychlorinated dibenzofurans (PCDFs) in one or more of the tissue samples. Of 

these chemicals, cadmium and zinc were detected at concentrations above an adverse effect 

concentration reported for fish in the literature (ERC 2003). While no directed studies of chemical 

contamination in shortnose sturgeon have been undertaken, it is evident that the heavy 

industrialization of the rivers where shortnose sturgeon are found is likely adversely affecting this 

species. 

During summer months, especially in southern areas, shortnose sturgeon must cope with the 

physiological stress of water temperatures that may exceed 28oC. Flourney et al.(1992) suspected 

that, during these periods, shortnose sturgeon congregate in river regions which support conditions 

that relieve physiological stress (i.e., in cool deep thermal refuges). In southern rivers where 

sturgeon movements have been tracked, sturgeon refrain from moving during warm water 

conditions and are often captured at release locations during these periods (Flourney et al.1992; 

Rogers and Weber 1994; Weber 1996). The loss and/or manipulation of these discrete refuge 

habitats may limit or be limiting population survival, especially in southern river systems. 

Pulp mill, silvicultural, agricultural, and sewer discharges, as well as a combination of non-point 

source discharges, which contain elevated temperatures or high biological demand, can reduce 

dissolved oxygen levels. Shortnose sturgeon are known to be adversely affected by dissolved 

oxygen levels below 5 mg/L. Shortnose sturgeon may be less tolerant of low dissolved oxygen 
58

levels in high ambient water temperatures and show signs of stress in water temperatures higher 

than 28oC (Flourney et al. 1992). At these temperatures, concomitant low levels of dissolved 

oxygen may be lethal. 

Status and Distribution of Shortnose Sturgeon in the Delaware River 

Shortnose sturgeon occur in the Delaware River from the lower bay upstream to at least 

Lambertville, New Jersey (river mile 148). Tagging studies by O’Herron et al. (1993) found that 

the most heavily used portion of the river appears to be between river mile 118 below Burlington 

Island and river mile 137 at the Trenton Rapids. Hastings et al. (1987) used Floy T-anchor tags in a 

tag-and-recapture experiment from 1981 to 1984 to estimate the size of the Delaware River 

population in the Trenton to Florence reach. Population sizes by three estimation procedures ranged 

from 6,408 to 14,080 adult sturgeon. These estimates compare favorably with those based upon 

similar methods in similar river systems. The most recent population estimate for the Delaware 

River is 12, 047 (95% CI= 10,757-13,580) and is based on mark recapture data collected from 

January 1999 through March 2003 (ERC Inc. 2006). Comparisons between the population estimate 

by ERC Inc. and the earlier estimate by Hastings et al. (1987) of 12, 796 (95% CI=10,228-16,367) 

suggests that the population is stable, but not increasing. This is the best available information on 

population size, but because the recruitment and migration rates between the population segment 

studied and the total population in the river are unknown, model assumptions may have been 

violated. 

In the Delaware River, movement to the spawning grounds occurs in early spring, typically in late 

March9, with spawning occurring through early May. Movement to the spawning areas is triggered 

in part by water temperature and fish typically arrive at the spawning locations when water 

temperatures are between 8-9oC with most spawning occurring when water temperatures are 

between 10 and 18oC. Until recently, actual spawning (i.e., fertilized eggs or larvae) had not been 

documented in this area; however, the concentrated use of the Scudders Falls region in the spring by 

large numbers of mature male and female shortnose sturgeon indicated that the area between 

Scudders Falls and the Trenton rapids (rkm223-214) is the major spawning area, though shortnose 

sturgeon eggs were collected upstream of Titusville, NJ (rkm 229) in spring 2008 (O’Herron et al. 

1993; ERC 2009). The same area was identified as a likely spawning area based on the collection 

of two ripe females in the spring of 1965 (Hoff 1965). The capture of early life stages (eggs and 

larvae) in this region in the spring of 2008 confirms that this area of the river is used for spawning 

and as a nursery area (ERC 2009).During the spawning period males remain on the spawning 

grounds for approximately a week while females only stay for a few days (O’Herron and Hastings 

1985). After spawning, which typically ceases by the time water temperatures reach 18oC, 

shortnose sturgeon move rapidly downstream to the Philadelphia area. 

Shortnose sturgeon eggs generally hatch after approximately 9-12 days (Buckley and Kynard 1981). 

 

9 Based on US Geological Survey (USGS) water temperature data for the Delaware River at the Trenton gage (USGS 

gage 01463500; the site closest to the Scudders Falls area), for the period 2003-2009, mean daily water temperature 

reached 8°C sometime between March 26 (2006) and April 21 (2007), with temperatures typically reaching 8°C in the 

last few days of March. During this period, mean water temperatures at Trenton reached 10°C between March 28 

(2004) and April 22 (2007) and 15oC between April 15 (2006) and May 4 (2007). There is typically a three to four 

week period with mean daily temperatures between 8 and 15°C. 
59

The larvae are photonegative, remaining on the bottom for several days. Buckley and Kynard 

(1981) found week old larvae to be photonegative and form aggregations with other larvae in 

concealment. Larvae are expected to begin swimming downstream at 9-14 days old (Richmond and 

Kynard 1995). Larvae are expected to be less than 20mm TL at this time (Richmond and Kynard 

1995). This initial downstream migration generally lasts two to three days (Richmond and Kynard 

1995). Studies (Kynard and Horgan 2002) suggest that larvae move approximately 7.5km/day 

during this initial 2 to 3 day migration. Laboratory studies indicate that young sturgeon move 

downstream in a 2-step migration: the initial 2-3 day migration followed by a residency period of 

the Young of the Year (YOY), then a resumption of migration by yearlings in the second summer of 

life (Buckley and Kynard 1981). 

No studies have been conducted on juveniles in the Delaware River. As shortnose sturgeon 

demonstrate nearly identical migration patterns in all rivers, it is likely that juveniles in the 

Delaware River exhibit similar migration patterns to sturgeon in other river systems. As such, it is 

likely that yearlings are concentrated in the upper Delaware River above Philadelphia. 

As noted above, due to limited information on juvenile shortnose sturgeon, it is difficult to ascertain 

their distribution and nursery habitat (O’Herron 2000, pers. comm.). Sub-adults are typically 

described as age one or older and occupy similar spatio-temporal patterns and habitat-use as adults 

(Kynard 1997). In these systems, juveniles moved back and forth in the low salinity portion of the 

salt wedge during summer. In the Delaware River the oligohaline/fresh interface can range from as 

far south as Wilmington, Delaware, north to Philadelphia, Pennsylvania, depending upon 

meteorological conditions such as excessive rainfall or drought. As a result, it is possible that in the 

Delaware River, juveniles could range from Artificial Island (river mile 54) to the Schuylkill River 

(river mile 92) (O’Herron 2000, pers. comm.). The distribution of juveniles in the river is likely 

highly influenced by flow and salinity. In years of high flow (for example, due to excessive rains or 

a significant spring runoff), the salt wedge will be pushed seaward and the low salinity reaches 

preferred by juveniles will extend further downriver. In these years, shortnose sturgeon juveniles 

are likely to be found further downstream in the summer months. In years of low flow, the salt 

wedge will be higher in the river and in these years juveniles are likely to be concentrated further 

upstream. 

O’Herron believes that if juveniles are present within this range they would likely aggregate closer 

to the downstream boundary in the winter when freshwater input is normally greater (O’Herron 

2000, pers. comm.). Research in other river systems indicates that juveniles are typically found 

over silt and sand/mud substrates in deep water of 10-20m. Juveniles feed indiscriminately, typical 

prey items found in stomach contents include aquatic insects, isopods, and amphipods along with 

large amounts of mud, stones, and plant material (Dadswell 1979, Carlson and Simpson 1987, Bain 

1997). Juvenile sturgeon primarily feed in 10 to 20 meter deep river channels, over sand-mud or 

gravel-mud bottoms (Pottle and Dadswell 1979). However, little is known about the specific 

feeding habits of juvenile shortnose sturgeon in the Delaware River.

As noted above, after spawning, adult shortnose sturgeon migrate rapidly downstream to the 

Philadelphia area (RM 100). After adult sturgeon migrate to the area around Philadelphia, many 

adults return upriver to between river mile 127 and 134 within a few weeks, while others gradually 

move to the same area over the course of the summer (O’Herron 1993). By the time water 
60

temperatures have reached 10°C, typically by mid-November10, adult sturgeon have returned to the 

overwintering grounds in the Roebling (rkm 199), Bordentown (rkm 207), or Trenton reaches (rkm 

214). These patterns are generally supported by the movement of radio-tagged fish in the region 

between river mile 125 and river mile 148 as presented by Brundage (1986). Based on water 

temperature data collected at the USGS gage at Philadelphia, in general, shortnose sturgeon are 

expected to be at the overwintering grounds between early December and March. Adult sturgeon 

overwinter in dense sedentary aggregations in the upper tidal reaches of the Delaware between river 

mile 118 and 131. The areas around Duck Island and Newbold Island seem to be regions of intense 

overwintering concentrations. However, unlike sturgeon in other river systems, shortnose sturgeon 

in the Delaware do not appear to remain as stationary during overwintering periods. Overwintering 

fish have been found to be generally active, appearing at the surface and even breaching through the 

skim ice (O’Herron 1993). Due to the relatively active nature of these fish, the use of the river 

during the winter is difficult to predict. However, O’Herron et al. (1993) found that the typical 

overwintering movements are fairly localized and sturgeon appear to remain within 1.24 river miles 

of the aggregation site (O’Herron and Able 1986). Investigations with video equipment by the 

ACOE in March 2005 (Versar 2006) documented two sturgeon of unknown species at Marcus Hook 

and 1 sturgeon of unknown species at Tinicum. Gillnetting in these same areas caught only one 

Atlantic sturgeon and no shortnose sturgeon. Video surveys of the known overwintering area near 

Newbold documented 61 shortnose sturgeon in approximately 1/3 of the survey effort. This study 

supports the conclusion that the vast majority of shortnose sturgeon overwinter near Duck and 

Newbold Island but that a limited number of shortnose sturgeon occur in other downstream areas, 

including Marcus Hook, during the winter months. Preliminary tracking studies of juveniles 

indicate that the entire lower Delaware River from Philadelphia (rkm 161) to below Artificial Island 

(rkm 79) may be utilized as an overwintering area by juvenile shortnose sturgeon (ERC 2007). 

There is also evidence that unlike adults, juveniles do not form dense aggregations and instead are 

more dispersed in overwintering areas (ERC 2007). 

Shortnose sturgeon appear to be strictly benthic feeders (Dadswell 1984). Adults eat mollusks, 

insects, crustaceans and small fish. Juveniles eat crustaceans and insects. While shortnose sturgeon 

forage on a variety of organisms, in the Delaware River, sturgeon primarily feed on the Asiatic river 

clam (Corbicula manilensis). Corbicula is widely distributed at all depths in the upper tidal 

Delaware River, but it is considerably more numerous in the shallows on both sides of the river than 

in the navigation channels. Foraging is heaviest immediately after spawning in the spring and 

during the summer and fall, and lighter in the winter. 

Historically, sturgeon were relatively rare below Philadelphia due to poor water quality. Since the 

1990s, the water quality in the Philadelphia area has improved leading to an increased use of the 

lower river by shortnose sturgeon. Few studies have been conducted to document the use of the 

river below Philadelphia by sturgeon. Brundage and Meadows (1982) have reported incidental 

captures in commercial gillnets in the lower Delaware. During a study focusing on Atlantic 

sturgeon, Shirey et al. (1999) captured 9 shortnose sturgeon in 1998. During the June through 

 

10 Based on information from the USGS gage at Philadelphia (01467200) during the 2003-2008 time period, mean water 

temperatures reached 10°C between October 29 (2005 and 2006) and November 14 (2003). In the spring, mean water 

temperature reached 10°C between April 2 (2006) and April 21 (2009). 
61

September study period, Atlantic and shortnose sturgeon were found to use the area on the west side 

of the shipping channel between Deep Water Point, New Jersey and the Delaware-Pennsylvania 

line. The most frequently utilized areas within this section were off the northern and southern ends 

of Cherry Island Flats in the vicinity of the Marcus Hook Bar. A total of 25 shortnose sturgeon 

have been captured by Shirey in this region of the river from 1992 - 2004, with capture rates 

ranging from 0-10 fish per year (Shirey 2006). Shortnose sturgeon have also been documented on 

the trash racks of the Salem nuclear power plant in Salem, New Jersey at Artificial Island. The 

intakes for this plant are located in Delaware Bay. While the available information does not 

identify the area below Philadelphia as a concentration area for adult shortnose sturgeon, it is 

apparent that this species does occur in the lower Delaware River and upper Delaware Bay. 

In May 2005, a one-year survey for juvenile sturgeon in the Delaware River in the vicinity of the 

proposed Crown Landing LNG project was initiated. The objective of the survey was to obtain 

information on the occurrence and distribution of juvenile shortnose and Atlantic sturgeon near the 

proposed project site to be located near RM 78, approximately 20 miles south of Philadelphia. 

Sampling for juvenile sturgeon was performed using trammel nets and small mesh gill nets. The 

nets were set at three stations, one located adjacent to the project site, one at the upstream end of the 

Marcus Hook anchorage (approximately 2.7 miles upstream of the project site, at RM 81), and one 

near the upstream end of the Cherry Island Flats (at RM 74; approximately 3.8 miles downstream of 

the site). Nets were set within three depth ranges at each station: shallow (<10 feet at MLW), 

intermediate (10-20 feet at MLW) and deep (20-30+ feet at MLW). Each station/depth zone was 

sampled once per month. Nets were fished for at least 4 hours when water temperatures were less 

than 27°C and limited to 2 hours when water temperature was greater than 27°C. The sampling 

from April through August 2005 yielded 3,014 specimens of 22 species, including 3 juvenile 

shortnose sturgeon. Juvenile shortnose sturgeon were collected one each during the June, July and 

August sampling events. Two of the shortnose sturgeon were collected at RM 78 and one was 

taken at the downstream sampling station at RM 74. Total length ranged from 311-367mm. During 

the September – December sampling, one juvenile shortnose sturgeon was caught in September at 

RM 78 and one in November at the same location. One adult shortnose sturgeon was captured in 

October at RM 74. All of the shortnose sturgeon were collected in deep water sets (greater than 20 

feet). These depths are consistent with the preferred depths for foraging shortnose sturgeon 

juveniles reported in the literature (NMFS 1998). The capture of an adult in the Cherry Island Flats 

area (RM 74) is consistent with the capture location of several adult sturgeon reported by Shirey et 

al. 1999 and Shirey 2006. 

Brundage compiled a report presenting an analysis of telemetry data from receivers located at 

Torresdale RM 93, Tinicum RM 86, Bellevue RM 73 and New Castle RM 58 during April through 

December 2003. The objective of the study was to provide information on the occurrence and 

movements of shortnose sturgeon in the general vicinity of the proposed Crown Landing LNG 

facility. A total of 60 shortnose sturgeon had been tagged with ultrasonic transmitters: 30 in fall 

2002, 13 in early summer 2003 and 13 in fall 2003. All fish tagged were adults tagged after 

collection in gill nets in the upper tidal Delaware River, between RM 126-132. Of the 60 tagged 

sturgeon, 39 (65%) were recorded at Torresdale, 22 (36.7%) were recorded at Tinicum, 16 (26.7%) 

at Bellevue and 18 (30%) at New Castle. The number of tagged sturgeon recorded at each location 

varied with date of tagging. Of the 30 sturgeon tagged in fall 2002, 26 were recorded at Torresdale, 

17 at Tinicum, 11 at Bellevue and 13 at New Castle. Only two of the 13 tagged in fall 2003 were 
62

recorded, both at Torresdale only. Brundage concludes that seasonal movement patterns and time 

available for dispersion likely account for this variation, particularly for the fish tagged in fall 2003. 

Eleven of the 30 shortnose sturgeon tagged in fall 2002 and 5 of the 17 fish tagged in summer 2003 

were recorded at all four locations. Some of the fish evidenced rapid movements from one location 

sequentially to the next in upstream and/or downstream direction. These periods of rapid sequential 

movement tended to occur in the spring and fall, and were probably associated with movement to 

summer foraging and overwintering grounds, respectively. As a group, the shortnose sturgeon 

tagged in summer 2003 occurred a high percentage of time within the range of the Torresdale 

receiver. The report concludes that the metrics indicate that the Torresdale Range of the Delaware 

River is utilized by adult shortnose sturgeon more frequently and for greater durations than the other 

three locations. Of the other locations, the New Castle Range appears to be the most utilized 

region. At all ranges, shortnose were detected throughout the study period, with most shortnose 

sturgeon detected in the project area between April and October. The report indicates that most 

adult shortnose sturgeon used the Torresdale to New Castle area as a short-term migratory route 

rather than a long-term concentration or foraging area. Adult sturgeon in this region of the river are 

highly mobile, and as noted above, likely using the area as a migration route. 

Information on the use of the river by juveniles is lacking and the information available is extremely 

limited (i.e., 5 captures). As evidenced by the Crown Landing study, juvenile shortnose sturgeon 

have been documented between RM 81-74 from June – November. Due to the limited geographic 

scope of this study, it is difficult to use these results to predict the occurrence of juvenile shortnose 

sturgeon throughout the action area. However, the April – August time frame is when flows in the 

Delaware River are highest and the time when the action area is likely to experience the low salinity 

levels preferred by juveniles (FERC 2005). Beginning in August, flows decrease and the salt wedge 

begins to move upstream, which may preclude juveniles from occurring in the action area. Based 

on this information, it is likely that juvenile shortnose sturgeon are present in the action area at least 

during the April – August time frame. The capture of juvenile shortnose sturgeon in the RM 81-74 

range in November of 2005 suggests that if water conditions are appropriate, juveniles may also be 

present in this area through the fall. While it is possible, based on habitat characteristics, that this 

area of the river is used as an overwintering site for juveniles, there is currently no evidence to 

support this presumption. 

In 2005, the ACOE conducted investigations to determine the use of the Marcus Hook region by 

sturgeon. Surveys for the presence of Atlantic and shortnose sturgeon were conducted between 

March 4 and March 25, 2005 primarily using a Video Ray®Explorer submersible remotely operated 

vehicle (ROV). The Video Ray® was attached to a 1.0 x 1.0 x 1.5 meter aluminum sled which was 

towed over channel bottom habitats behind a 25-foot research boat. All images captured by the 

underwater camera were transmitted through the unit’s electronic tether and recorded on video 

cassettes. A total of 43 hours of bottom video were collected on 14 separate survey days. Twelve 

days of survey work were conducted at the Marcus Hook, Eddystone, Chester, and Tinicum ranges, 

while two separate days of survey work were conducted up river near Trenton, New Jersey, at an 

area known to have an over wintering population of shortnose sturgeon.

The sled was generally towed on the bottom parallel to the centerline of the channel and into the 

current at 0.8 knots. Tow track logs were maintained throughout the survey and any fish seen on 

the ROV monitor was noted. Boat position during each video tow was recorded every five minutes 
63

with the vessel’s Furuno GPS. The Sony digital recorder recorded a time stamp that could be 

matched with the geographic coordinates taken from the on-board GPS. Digital tapes were 

reviewed in a darkened laboratory at normal or slow speed using a high quality 28-inch television 

screen as a monitor. When a fish image was observed the tape was slowed and advanced frame by 

frame (30 images per second were recorded by the system). The time stamp where an individual 

fish was observed was recorded by the technician. Each fish was identified to the lowest practical 

taxon (usually species) and counted. A staff fishery biologist reviewed questionable images and 

species identifications. Distances traveled by the sled between time stamps were calculated based 

on the GPS coordinates recorded in the field during each tow. Total fish counts between the 

recorded coordinates within a particular tow were converted to observed numbers per 100 meters of 

tow track.

Limited 25-foot otter trawling and gillnet sets were conducted initially to provide density data, and 

later to provide ground truth information on the fish species seen in the video recording. Large 

boulders and other snags that tore the net and hung up the vessel early on in the study prompted 

abandoning this effort for safety reasons given the high degree of tanker traffic in the lower 

Delaware River. The trawl net was a 7.6-m (25-foot) experimental semi-balloon otter trawl with 

44.5-mm stretch mesh body fitted with a 3.2-mm stretch mesh liner in the cod end. Otter trawls 

were generally conducted for five minutes unless a snag or tanker traffic caused a reduction in tow 

time. Experimental gillnets were periodically deployed throughout the survey period in the Marcus 

Hook area. One experimental gillnet was 91.4-m in length and 3-m deep and was composed of six 

15.2-m panels of varying mesh size. Of the six panels in each net, two panels were 50.8-mm stretch 

mesh, 2 panels were 101.6-mm stretch mesh and two panels were 152.4-mm stretch mesh. Another 

gillnet was 100 m in length and consisted of four 25 x 2-m panels of 2.5-10.2-cm stretched 

monofilament mesh in 2.5 cm increments. Gill nets were generally set an hour before slack high or 

low water and allowed to fish for two hours as the nets had to be retrieved before maximum 

currents were reached.

Turbidity in the Marcus Hook region of the Delaware River limited visibility to about 18 inches in 

front of the camera. However, despite the reduced visibility, several different fish species were 

recorded by the system including sturgeon. In general, fish that encountered the sled between the 

leading edge of the sled runners were relatively easy to distinguish. The major fish species seen in 

the video images were confirmed by the trawl and gillnet samples. In the Marcus Hook project 

area, a total of 39 survey miles of bottom habitat were recorded in twelve separate survey days. 

Eight different species were observed on the tapes from a total of 411 fish encountered by the 

camera. White perch, unidentified catfish, and unidentified shiner were the most common taxa 

observed. Three unidentified sturgeon were seen on the tapes, two in the Marcus Hook Range, and 

one in the Tinicum Range. Although it could not be determined if these sturgeon were Atlantic or 

shortnose, gillnetting in the Marcus Hook anchorage produced one juvenile Atlantic sturgeon that 

was 396 mm in total length, 342 mm in fork length, and weighed 250 g.

Water clarity in the Trenton survey area was much greater (about 6 feet ahead of the camera) and 

large numbers of shortnose sturgeon were seen in the video recordings. In a total of 7.9 survey 

miles completed in two separate days of bottom imaging, 61 shortnose sturgeons were observed. 

To provide a comparative measure of project area density (where visibility was limited) to up river 

densities (where visibility was greater), each of the 61 sturgeon images were classified as to 
64

whether the individual fish was observed between the sled runners or whether they were seen ahead 

of the sled. Real time play backs of video recordings in the upriver sites indicated that the sturgeon 

did not react to the approaching sled until the cross bar directly in front of the camera was nearly 

upon it. Thirty of the 61 upstream sturgeon images were captured when the individual fish was 

between the runners. Using this criterion, approximately 10 times more sturgeon were encountered 

in the upriver area relative to the project site near Marcus Hook where three sturgeons were 

observed. Using the number of sturgeon observed per 100 meters of bottom surveyed, the relative 

sturgeon density in the project area was several orders of magnitude less than those observed in the 

Trenton area. As calculated in the report, the relative density of unidentified sturgeon in the Marcus 

Hook area was 0.005 fish per 100 meters while the densities of shortnose sturgeon between the sled 

runners in the upriver area was 0.235 fish per 100 meters.

The results of the video sled survey in the Marcus Hook project area confirmed that sturgeons are 

using the area in the winter months. However, sturgeon relative densities in the project area were 

much lower than those observed near Trenton, New Jersey, even when the upriver counts were 

adjusted for the higher visibility (i.e., between runner sturgeon counts). The sturgeons seen near 

Trenton were very much concentrated in several large aggregations, which were surveyed in 

multiple passes on the two sampling dates devoted to this area. The lack of avoidance of the 

approaching sled seen in the upriver video recordings where water clarity was good suggests that 

little to no avoidance of the sled occurred in the low visibility downriver project area. Video 

surveys in the downriver project area did not encounter large aggregations of sturgeon as was 

observed in the upstream survey area despite having five times more sampling effort than the 

upstream area. This suggests that sturgeons that do occur in the Marcus Hook area during the 

winter are more dispersed and that the overall number of shortnose sturgeon occurring in this area 

in the winter months is low. 

4.7 Status of Atlantic sturgeon 

The section below describes the Atlantic sturgeon listing, provides life history information that is 

relevant to all DPSs of Atlantic sturgeon and then provides information specific to the status of each 

DPS of Atlantic sturgeon. Below, we also provide a description of which Atlantic sturgeon DPSs 

likely occur in the action area and provide information on the use of the action area by Atlantic 

sturgeon. 

The Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) is a subspecies of sturgeon distributed 

along the eastern coast of North America from Hamilton Inlet, Labrador, Canada to Cape 

Canaveral, Florida, USA (Scott and Scott, 1988; ASSRT, 2007; T. Savoy, CT DEP, pers. comm.). 

NMFS has delineated U.S. populations of Atlantic sturgeon into five DPSs11 ( 77 FR 5880 and 77 

FR 5914). These are: the Gulf of Maine, New York Bight, Chesapeake Bay, Carolina, and South 

Atlantic DPSs (see Figure 3). The results of genetic studies suggest that natal origin influences the 

distribution of Atlantic sturgeon in the marine environment (Wirgin and King, 2011). However, 

genetic data as well as tracking and tagging data demonstrate sturgeon from each DPS and Canada 

 

11 To be considered for listing under the ESA, a group of organisms must constitute a “species.” A “species” is defined 

in section 3 of the ESA to include “any subspecies of fish or wildlife or plants, and any distinct population segment of 

any species of vertebrate fish or wildlife which interbreeds when mature.”
65

occur throughout the full range of the subspecies. Therefore, sturgeon originating from any of the 5 

DPSs can be affected by threats in the marine, estuarine and riverine environment that occur far 

from natal spawning rivers.

On February 6, 2012, we published notice in the Federal Register that we were listing the New 

York Bight, Chesapeake Bay, Carolina, and South Atlantic DPSs as “endangered,” and the Gulf of 

Maine DPS as “threatened” (77 FR 5880 and 77 FR 5914). The effective date of the listings was 

April 6, 2012. The DPSs do not include Atlantic sturgeon that are spawned in Canadian rivers. 

Therefore, Canadian spawned fish are not included in the listings.

As described below, individuals originating from the five listed DPSs may occur in the action area. 

Information general to all Atlantic sturgeon as well as information specific to each of the relevant 

DPSs, is provided below. 

Figure 3. Map Depicting the Boundaries of the five Atlantic sturgeon DPSs

4.7.1 Atlantic sturgeon life history 

Atlantic sturgeon are long lived (approximately 60 years), late maturing, estuarine dependent, 
66

anadromous12 fish (Bigelow and Schroeder, 1953; Vladykov and Greeley 1963; Mangin, 1964; 

Pikitch et al., 2005; Dadswell, 2006; ASSRT, 2007). 

The life history of Atlantic sturgeon can be divided up into five general categories as described in 

the table below (adapted from information presented in ASSRT 2007).

Age Class Size Description

Egg 

Fertilized or 

unfertilized

Larvae

Negative phototaxic, nourished by 

yolk sac

Young of Year 

(YOY)

0.3 grams <41 cm 

TL

Fish that are > 3 

months and < one 

year; capable of 

capturing and 

consuming live 

food

Sub-adults 

>41 cm and <150 

cm TL 

Fish that are at 

least age 1 and are 

not sexually mature

Adults >150 cm TL

Sexually mature 

fish

Table 4. Descriptions of Atlantic sturgeon life history stages. 

They are a relatively large fish, even amongst sturgeon species (Pikitch et al., 2005). Atlantic 

sturgeons are bottom feeders that suck food into a ventrally-located protruding mouth (Bigelow and 

Schroeder, 1953). Four barbels in front of the mouth assist the sturgeon in locating prey (Bigelow 

and Schroeder, 1953). Diets of adult and migrant subadult Atlantic sturgeon include mollusks, 

gastropods, amphipods, annelids, decapods, isopods, and fish such as sand lance (Bigelow and 

Schroeder, 1953; ASSRT, 2007; Guilbard et al., 2007; Savoy, 2007). Juvenile Atlantic sturgeon 

feed on aquatic insects, insect larvae, and other invertebrates (Bigelow and Schroeder, 1953; 

ASSRT, 2007; Guilbard et al., 2007). 

Rate of maturation is affected by water temperature and gender. In general: (1) Atlantic sturgeon 

that originate from southern systems grow faster and mature sooner than Atlantic sturgeon that 

 

12 Anadromous refers to a fish that is born in freshwater, spends most of its life in the sea, and returns to freshwater to 

spawn (NEFSC FAQ’s, available at http://www.nefsc.noaa.gov/faq/fishfaq1a.html, modified June 16, 2011) 
67

originate from more northern systems; (2) males grow faster than females; (3) fully mature females 

attain a larger size (i.e. length) than fully mature males; and (4) the length of Atlantic sturgeon 

caught since the mid-late 20th century have typically been less than 3 meters (m) (Smith et al., 1982; 

Smith et al., 1984; Smith, 1985; Scott and Scott, 1988; Young et al., 1998; Collins et al., 2000; 

Caron et al., 2002; Dadswell, 2006; ASSRT, 2007; Kahnle et al., 2007; DFO, 2011). The largest 

recorded Atlantic sturgeon was a female captured in 1924 that measured approximately 4.26 m 

(Vladykov and Greeley, 1963). Dadswell (2006) reported seeing seven fish of comparable size in 

the St. John River estuary from 1973 to 1995. Observations of large-sized sturgeon are particularly 

important given that egg production is correlated with age and body size (Smith et al., 1982; Van 

Eenennaam et al., 1996; Van Eenennaam and Doroshov, 1998; Dadswell, 2006). However, while 

females are prolific with egg production ranging from 400,000 to 4 million eggs per spawning year, 

females spawn at intervals of 2-5 years (Vladykov and Greeley, 1963; Smith et al., 1982; Van 

Eenennaam et al., 1996; Van Eenennaam and Doroshov, 1998; Stevenson and Secor, 1999; 

Dadswell, 2006). Given spawning periodicity and a female’s relatively late age to maturity, the age 

at which 50 percent of the maximum lifetime egg production is achieved is estimated to be 29 years 

(Boreman, 1997). Males exhibit spawning periodicity of 1-5 years (Smith, 1985; Collins et al., 

2000; Caron et al., 2002). While long-lived, Atlantic sturgeon are exposed to a multitude of threats 

prior to achieving maturation and have a limited number of spawning opportunities once mature. 

Water temperature plays a primary role in triggering the timing of spawning migrations (ASMFC, 

2009). Spawning migrations generally occur during February-March in southern systems, AprilMay in Mid-Atlantic systems, and May-July in Canadian systems (Murawski and Pacheco, 1977; 

Smith, 1985; Bain, 1997; Smith and Clugston, 1997; Caron et al., 2002). Male sturgeon begin 

upstream spawning migrations when waters reach approximately 6° C (43° F) (Smith et al., 1982; 

Dovel and Berggren, 1983; Smith, 1985; ASMFC, 2009), and remain on the spawning grounds 

throughout the spawning season (Bain, 1997). Females begin spawning migrations when 

temperatures are closer to 12° C to 13° C (54° to 55° F) (Dovel and Berggren, 1983; Smith, 1985; 

Collins et al., 2000), make rapid spawning migrations upstream, and quickly depart following

spawning (Bain, 1997). 

The spawning areas in most U.S. rivers have not been well defined. However, the habitat 

characteristics of spawning areas have been identified based on historical accounts of where 

fisheries occurred, tracking and tagging studies of spawning sturgeon, and physiological needs of 

early life stages. Spawning is believed to occur in flowing water between the salt front of estuaries 

and the fall line of large rivers, when and where optimal flows are 46-76 cm/s and depths are 3-27 

m (Borodin, 1925; Dees, 1961; Leland, 1968; Scott and Crossman, 1973; Crance, 1987; Shirey et 

al. 1999; Bain et al., 2000; Collins et al., 2000; Caron et al. 2002; Hatin et al. 2002; ASMFC, 

2009). Sturgeon eggs are deposited on hard bottom substrate such as cobble, coarse sand, and 

bedrock (Dees, 1961; Scott and Crossman, 1973; Gilbert, 1989; Smith and Clugston, 1997; Bain et 

al. 2000; Collins et al., 2000; Caron et al., 2002; Hatin et al., 2002; Mohler, 2003; ASMFC, 2009), 

and become adhesive shortly after fertilization (Murawski and Pacheco, 1977; Van den Avyle, 

1983; Mohler, 2003). Incubation time for the eggs increases as water temperature decreases 

(Mohler, 2003). At temperatures of 20° and 18° C, hatching occurs approximately 94 and 140 

hours, respectively, after egg deposition (ASSRT, 2007). 

Larval Atlantic sturgeon (i.e. less than 4 weeks old, with total lengths (TL) less than 30 mm; Van 
68

Eenennaam et al. 1996) are assumed to undertake a demersal existence and inhabit the same 

riverine or estuarine areas where they were spawned (Smith et al., 1980; Bain et al., 2000; Kynard 

and Horgan, 2002; ASMFC, 2009). Studies suggest that age-0 (i.e., young-of-year), age-1, and age2 juvenile Atlantic sturgeon occur in low salinity waters of the natal estuary (Haley, 1999; Hatin et 

al., 2007; McCord et al., 2007; Munro et al., 2007) while older fish are more salt tolerant and occur 

in higher salinity waters as well as low salinity waters (Collins et al., 2000). Atlantic sturgeon 

remain in the natal estuary for months to years before emigrating to open ocean as subadults 

(Holland and Yelverton, 1973; Dovel and Berggen, 1983; Waldman et al., 1996; Dadswell, 2006; 

ASSRT, 2007). 

After emigration from the natal estuary, subadults and adults travel within the marine environment, 

typically in waters less than 50 m in depth, using coastal bays, sounds, and ocean waters (Vladykov 

and Greeley, 1963; Murawski and Pacheco, 1977; Dovel and Berggren, 1983; Smith, 1985; Collins 

and Smith, 1997; Welsh et al., 2002; Savoy and Pacileo, 2003; Stein et al., 2004; USFWS, 2004; 

Laney et al., 2007; Dunton et al., 2010; Erickson et al., 2011; Wirgin and King, 2011). Tracking 

and tagging studies reveal seasonal movements of Atlantic sturgeon along the coast. Satellitetagged adult sturgeon from the Hudson River concentrated in the southern part of the Mid-Atlantic 

Bight at depths greater than 20 m during winter and spring, and in the northern portion of the MidAtlantic Bight at depths less than 20 m in summer and fall (Erickson et al., 2011). Shirey 

(Delaware Department of Fish and Wildlife, unpublished data reviewed in ASMFC, 2009) found a 

similar movement pattern for juvenile Atlantic sturgeon based on recaptures of fish originally 

tagged in the Delaware River. After leaving the Delaware River estuary during the fall, juvenile 

Atlantic sturgeon were recaptured by commercial fishermen in nearshore waters along the Atlantic 

coast as far south as Cape Hatteras, North Carolina from November through early March. In the 

spring, a portion of the tagged fish re-entered the Delaware River estuary. However, many fish 

continued a northerly coastal migration through the Mid-Atlantic as well as into southern New 

England waters where they were recovered throughout the summer months. Movements as far 

north as Maine were documented. A southerly coastal migration was apparent from tag returns 

reported in the fall. The majority of these tag returns were reported from relatively shallow near 

shore fisheries with few fish reported from waters in excess of 25 m (C. Shirey, Delaware 

Department of Fish and Wildlife, unpublished data reviewed in ASMFC, 2009). Areas where 

migratory Atlantic sturgeon commonly aggregate include the Bay of Fundy (e.g., Minas and 

Cumberland Basins), Massachusetts Bay, Connecticut River estuary, Long Island Sound, New York 

Bight, Delaware Bay, Chesapeake Bay, and waters off of North Carolina from the Virginia/North 

Carolina border to Cape Hatteras at depths up to 24 m (Dovel and Berggren, 1983; Dadswell et al., 

1984; Johnson et al., 1997; Rochard et al., 1997; Kynard et al., 2000; Eyler et al., 2004; Stein et al., 

2004; Wehrell, 2005; Dadswell, 2006; ASSRT, 2007; Laney et al., 2007). These sites may be used 

as foraging sites and/or thermal refuge. 

4.7.2 Determination of DPS Composition in the Action Area 

As explained above, the range of all five DPSs overlaps and extends from Canada through Cape 

Canaveral, Florida. We have considered the best available information to determine from which 

DPSs individuals in the action area are likely to have originated. Based on mixed-stock analysis, 

we have determined that Atlantic sturgeon in the action area likely originate from the five DPSs at 

the following frequencies: Gulf of Maine 7%; NYB 58%; Chesapeake Bay 18%; South Atlantic 

17%; and Carolina 0.5%. These percentages are largely based on genetic sampling of individuals 
69

(n=105) sampled in directed research targeting Atlantic sturgeon along the Delaware Coast, just 

south of Delaware Bay. This is the closest sampling effort (geographically) to the action area for 

which mixed stock analysis results are available. Because the genetic composition of the mixed 

stock changes with distance from the rivers of origin, it is appropriate to use mixed stock analysis 

results from the nearest sampling location. Therefore, this represents the best available information 

on the likely genetic makeup of individuals occurring in the action area. We also considered 

information on the genetic makeup of individuals captured within the Delaware River. However, 

we only have information on the assignment of these individuals to the river of origin and do not 

have a mixed stock analysis for these samples. The river assignments are very similar to the mixed 

stock analysis results for the Delaware Coastal sampling, with the Hudson/Delaware accounting for 

55-61% of the fish, James River accounting for 17-18%, South Atlantic 17-18%, and Gulf of Maine 

9-11%. The range in assignments considers the slightly different percentages calculated by treating 

each sample individually versus treating each fish individually (some fish were captured in more 

than one of the years during the three year study). Carolina DPS origin fish have rarely been 

detected in samples taken in the Northeast and are not detected in either the Delaware Coast or inriver samples noted above. However, mixed stock analysis from one sampling effort (i.e., Long 

Island Sound, n=275), indicates that approximately 0.5% of the fish sampled were Carolina DPS 

origin. Additionally, 4% of Atlantic sturgeon captured incidentally in commercial fisheries along 

the U.S. Atlantic coast north of Cape Hatteras and genetically analyzed belong to the Carolina DPS. 

No Carolina DPS fish have been documented in sampling carried out in the Delaware River or 

along the Delaware Coast. However, because any Carolina origin sturgeon that were sampled in 

Long Island Sound could have swam through the action area on their way between Long Island 

Sound and their rivers of origin, it is reasonable to expect that 0.5% of the Atlantic sturgeon 

captured in the action area could originate from the Carolina DPS. The genetic assignments have a 

plus/minus 5% confidence interval; however, for purposes of section 7 consultation we have 

selected the reported values above, which approximate the mid-point of the range, as a reasonable 

indication of the likely genetic makeup of Atlantic sturgeon in the action area. These assignments 

and the data from which they are derived are described in detail in Damon-Randall et al. (2012a).

4.7.3 Distribution and Abundance

Atlantic sturgeon underwent significant range-wide declines from historical abundance levels due to 

overfishing in the mid to late 19th century when a caviar market was established (Scott and 

Crossman, 1973; Taub, 1990; Kennebec River Resource Management Plan, 1993; Smith and 

Clugston, 1997; Dadswell, 2006; ASSRT, 2007). Abundance of spawning-aged females prior to 

this period of exploitation was predicted to be greater than 100,000 for the Delaware, and at least 

10,000 females for other spawning stocks (Secor and Waldman, 1999; Secor, 2002). Historical 

records suggest that Atlantic sturgeon spawned in at least 35 rivers prior to this period. Currently, 

only 16 U.S. rivers are known to support spawning based on available evidence (i.e., presence of 

young-of-year or gravid Atlantic sturgeon documented within the past 15 years) (ASSRT, 2007). 

While there may be other rivers supporting spawning for which definitive evidence has not been 

obtained (e.g., in the Penobscot and York Rivers), the number of rivers supporting spawning of 

Atlantic sturgeon are approximately half of what they were historically. In addition, only four 

rivers (Kennebec, Hudson, Delaware, James) are known to currently support spawning from Maine 

through Virginia where historical records support there used to be fifteen spawning rivers (ASSRT, 

2007). Thus, there are substantial gaps in the range between Atlantic sturgeon spawning rivers 

amongst northern and mid-Atlantic states which could make recolonization of extirpated 
70

populations more difficult. 

There are no current, published population abundance estimates for any of the currently known 

spawning stocks. Therefore, there are no published abundance estimates for any of the five DPSs of 

Atlantic sturgeon. An estimate of 863 mature adults per year (596 males and 267 females) was 

calculated for the Hudson River based on fishery-dependent data collected from 1985-1995 (Kahnle 

et al., 2007). An estimate of 343 spawning adults per year is available for the Altamaha River, GA, 

based on fishery-independent data collected in 2004 and 2005 (Schueller and Peterson, 2006). 

Using the data collected from the Hudson River and Altamaha River to estimate the total number of 

Atlantic sturgeon in either subpopulation is not possible, since mature Atlantic sturgeon may not 

spawn every year (Vladykov and Greeley, 1963; Smith, 1985; Van Eenennaam et al., 1996; 

Stevenson and Secor, 1999; Collins et al. 2000; Caron et al., 2002), the age structure of these 

populations is not well understood, and stage to stage survival is unknown. In other words, the 

information that would allow us to take an estimate of annual spawning adults and expand that 

estimate to an estimate of the total number of individuals (e.g., yearlings, subadults, and adults) in a 

population is lacking. The ASSRT presumed that the Hudson and Altamaha rivers had the most 

robust of the remaining U.S. Atlantic sturgeon spawning populations and concluded that the other 

U.S. spawning populations were likely less than 300 spawning adults per year (ASSRT, 2007). 

It is possible, however, to estimate the total number of adults in some other rivers based on the 

number of mature adults in the Hudson River. We have calculated an estimate of total mature 

adults and a proportion of subadults for four of the five DPSs. The technique used to obtain these 

estimates is explained fully in Damon-Randall 2012(b) and is summarized briefly below. We used 

this method because for these four DPSs, there are: (1) no total population estimates available; (2) 

with the exception of the Hudson River, no estimates of the number of mature adults; and, (3) no 

information from directed population surveys which could be used to generate an estimate of the 

number of spawning adults, total adult population or total DPS population. 

Kahnle et al. (2007) estimated the number of total mature adults per year in the Hudson River using 

data from surveys in the 1980s to mid-1990s and based on mean harvest by sex divided by sex 

specific exploitation rate. While this data is over 20 years old, it is currently the best available data 

on the abundance of Hudson River origin Atlantic sturgeon. The sex ratio of spawners is estimated 

to be approximately 70% males and 30% females. As noted above, Kahnle et al. (2007) estimated a 

mean annual number of mature adults at 596 males and 267 females. 

We were able to use this estimate of the adult population in the Hudson River and the rate at which 

Atlantic sturgeon from the Hudson River are intercepted in certain Northeast commercial fisheries13

to estimate the number of adults in other spawning rivers. As noted above, the method used is 

summarized below and explained fully in Damon-Randall 2012(b). 

Given the geographic scope of commercial fisheries as well as the extensive marine migrations of 

Atlantic sturgeon, fish originating from nearly all spawning rivers are believed to be intercepted by 

 

13 Bycatch information was obtained from a report prepared by NMFS’ Northeast Fisheries Science Center (NEFSC 

2012). 
71

commercial fisheries. An estimate of the number of Atlantic sturgeon captured in certain fisheries 

authorized by NMFS under Federal FMPs in the Northeast is available (NEFSC 2011). This report 

indicates that based on observed interactions with Atlantic sturgeon in sink gillnet and otter trawl 

fisheries from 2006-2010, on average 3,118 Atlantic sturgeon are captured in these fisheries each 

year. Information in the NEFOP database, indicates that 25% of captured Atlantic sturgeon are 

adults (determined as length greater than 150 cm) and 75% are subadults (determined as length less 

than 150cm). By applying the mixed stock genetic analysis of individuals14 sampled by the 

NEFOP and At Sea Monitoring Program (see Damon-Randall et al. 2012a) to the bycatch estimate, 

we can determine an estimate of the number of Hudson River Atlantic sturgeon that are intercepted 

by these fisheries on an annual basis. 

Given the number of observed Hudson River origin Atlantic sturgeon adults taken as bycatch, we 

can calculate what percentage of Hudson River origin Atlantic sturgeon mature adults these 

represent. This provides an interception rate. We assume that fish originating in any river in any 

DPS are equally likely to be intercepted by the observed commercial fisheries; therefore, we can use 

this interception rate to estimate the number of Atlantic sturgeon in the other rivers of origin. This 

type of back calculation allows us to use the information we have for the Hudson River and fill in 

significant data gaps present for the other rivers. Using this method, we have estimated the total 

adult populations for three DPSs (Gulf of Maine, Chesapeake Bay, and South Atlantic) as follows. 

It is important to note that this method likely underestimates the total number of adults in the SA 

DPS because genetic analysis of individuals observed through the NEFOP program indicate that 

only individuals from the Savannah and Ogeechee are being captured in Northeast fisheries 

considered in the NEFSC bycatch report. Spawning is known to occur in other rivers in the SA 

DPS, including the Altamaha (estimate of 343 adult spawners per year). 

We are not able to use this method to calculate an adult population estimate for the Carolina DPS. 

Based on the results of the genetic mixed stock analysis, fish originating from the Carolina DPS 

rarely appear in the NEFOP dataset and based on this, as well as genetics information on fish 

captured in other coastal sampling programs in the Northeast are assumed to be only rarely 

intercepted in Northeast fisheries. 

Given the proportion of adults to subadults in the observer database (ratio of 1:3), we can also 

estimate a number of subadults originating from each DPS. However, this cannot be considered an 

estimate of the total number of subadults because it would only consider those subadults that are of 

a size vulnerable to capture in commercial sink gillnet and otter trawl gear in the marine 

environment and are present in the marine environment. 

Currently, there are an estimated 343 spawning adults in the Altamaha and there are estimated to be 

less than 300 spawning adults (total of both sexes) in each of the other major river systems occupied 

by the South Atlantic DPS. Spawning is thought to occur in six rivers in the SA DPS. Adding 

these estimates together results in a total adult population estimated of less than 1,843 mature 

adults. Our fishery dependent estimate is 390. This is likely an underestimate of the total number 

 

14 Based on the best available information, we expect that 46% of Atlantic sturgeon captured in Northeast commercial 

fisheries originate from the New York Bight DPS and that 91% of those individuals originate from the Hudson River 

(see Damon-Randall et al. 2012a and Wirgin and King 2011). 
72

of adults in the SA DPS because genetic analysis of individuals observed through the NEFOP 

program indicate that only individuals from the Savannah and Ogeechee are being captured in 

Northeast fisheries considered in the NEFSC bycatch report. Because of this, it is difficult to 

compare these two estimates. It may be reasonable to consider the estimate of 390 adults to be an 

estimate of the number of adults in the Savannah and Ogeechee rivers only. This would be 

consistent with the assumption that there are fewer than 300 adults in each of these two rivers. 

While we are unable to calculate a population estimate for the Carolina DPS using the above 

methodology, we do have an estimate of 1500 adult spawners/year (5 spawning rivers x 300 

spawning adults per river) described in the Atlantic sturgeon status review report. As noted above, 

for the South Atlantic DPS, using this method, the estimated number of fish in the South Atlantic 

DPS would be 1800 spawning adults (6 spawning rivers x 300 spawning adults per 

river). Therefore, the Carolina DPS has approximately 17% less fish than the South Atlantic 

DPS. Based on the methodology described above, the estimated number of mean annual mature 

adults for the South Atlantic DPS is 390 fish. Using the proportion of Carolina DPS fish to South 

Atlantic DPS fish, we estimate that the mean number of annual mature adults in the Carolina DPS is 

324 (17% less than 390).

Table 5: Summary of Calculated Population Estimates from NER Fisheries Dependent Data

DPS Estimated Adult Population Estimated Subadults of Size 

vulnerable to capture in 

commercial fisheries 

GOM 215 645

NYB (Hudson River 

and Delaware River)

951 2,853

CB 273 819

SA* 390 972

Carolina* 324 1,170

*see note re. South Atlantic and Carolina population sizes in paragraphs above. 

4.7.4 Threats faced by Atlantic sturgeon throughout their range 

Atlantic sturgeon are susceptible to over exploitation given their life history characteristics (e.g., 

late maturity, dependence on a wide-variety of habitats). Similar to other sturgeon species 

(Vladykov and Greeley, 1963; Pikitch et al., 2005), Atlantic sturgeon experienced range-wide 

declines from historical abundance levels due to overfishing (for caviar and meat) and impacts to 

habitat in the 19th and 20th centuries (Taub, 1990; Smith and Clugston, 1997; Secor and Waldman, 

1999). 

Based on the best available information, NMFS has concluded that unintended catch of Atlantic 

sturgeon in fisheries, vessel strikes, poor water quality, water availability, dams, lack of regulatory 

mechanisms for protecting the fish, and dredging are the most significant threats to Atlantic 

sturgeon (77 FR 5880 and 77 FR 5914; February 6, 2012). While all of the threats are not 

necessarily present in the same area at the same time, given that Atlantic sturgeon subadults and 

adults use ocean waters from the Labrador, Canada to Cape Canaveral, FL, as well as estuaries of 

large rivers along the U.S. East Coast, activities affecting these water bodies are likely to impact 
73

more than one Atlantic sturgeon DPS. In addition, given that Atlantic sturgeon depend on a variety 

of habitats, every life stage is likely affected by one or more of the identified threats. 

 

An ASMFC interstate fishery management plan for sturgeon (Sturgeon FMP) was developed and 

implemented in 1990 (Taub, 1990). In 1998, the remaining Atlantic sturgeon fisheries in U.S. state 

waters were closed per Amendment 1 to the Sturgeon FMP. Complementary regulations were 

implemented by NMFS in 1999 that prohibit fishing for, harvesting, possessing or retaining Atlantic 

sturgeon or its parts in or from the Exclusive Economic Zone in the course of a commercial fishing 

activity. 

Commercial fisheries for Atlantic sturgeon still exist in Canadian waters (DFO, 2011). Sturgeon 

belonging to one or more of the DPSs may be harvested in the Canadian fisheries. In particular, the 

Bay of Fundy fishery in the Saint John estuary may capture sturgeon of U.S. origin given that

sturgeon from the Gulf of Maine and the New York Bight DPSs have been incidentally captured in 

other Bay of Fundy fisheries (DFO, 2010; Wirgin and King, 2011). Because Atlantic sturgeon are 

listed under Appendix II of the Convention on International Trade in Endangered Species (CITES), 

the U.S. and Canada are currently working on a conservation strategy to address the potential for 

captures of U.S. fish in Canadian directed Atlantic sturgeon fisheries and of Canadian fish 

incidentally in U.S. commercial fisheries. At this time, there are no estimates of the number of 

individuals from any of the DPSs that are captured or killed in Canadian fisheries each year. Based 

on geographic distribution, most U.S. Atlantic sturgeon that are intercepted in Canadian fisheries 

are likely to originate from the Gulf of Maine DPS, with a smaller percentage from the New York 

Bight DPS. 

Fisheries bycatch in U.S. waters is the primary threat faced by all 5 DPSs. At this time, we have an 

estimate of the number of Atlantic sturgeon captured and killed in sink gillnet and otter trawl 

fisheries authorized by Federal FMPs (NMFS NEFSC 2011) in the Northeast Region but do not 

have a similar estimate for Southeast fisheries. We also do not have an estimate of the number of 

Atlantic sturgeon captured or killed in state fisheries. At this time, we are not able to quantify the 

effects of other significant threats (e.g., vessel strikes, poor water quality, water availability, dams, 

and dredging) in terms of habitat impacts or loss of individuals. While we have some information 

on the number of mortalities that have occurred in the past in association with certain activities 

(e.g., mortalities in the Delaware and James rivers that are thought to be due to vessel strikes), we 

are not able to use those numbers to extrapolate effects throughout one or more DPS. This is 

because of (1) the small number of data points and, (2) lack of information on the percent of 

incidences that the observed mortalities represent. 

As noted above, the NEFSC prepared an estimate of the number of encounters of Atlantic sturgeon 

in fisheries authorized by Northeast FMPs (NEFSC 2011). The analysis prepared by the NEFSC 

estimates that from 2006 through 2010 there were 2,250 to 3,862 encounters per year in observed 

gillnet and trawl fisheries, with an average of 3,118 encounters. Mortality rates in gillnet gear are 

approximately 20%. Mortality rates in otter trawl gear are believed to be lower at approximately 

5%.

4.8 Gulf of Maine DPS of Atlantic sturgeon 

The Gulf of Maine DPS includes the following: all anadromous Atlantic sturgeons that are spawned 
74

in the watersheds from the Maine/Canadian border and, extending southward, all watersheds 

draining into the Gulf of Maine as far south as Chatham, MA. Within this range, Atlantic sturgeon 

historically spawned in the Androscoggin, Kennebec, Merrimack, Penobscot, and Sheepscot Rivers 

(ASSRT, 2007). Spawning still occurs in the Kennebec and Androscoggin Rivers, and it is possible 

that it still occurs in the Penobscot River as well. Spawning in the Androscoggin River was just 

recently confirmed by the Maine Department of Marine Resources when they captured a larval 

Atlantic sturgeon during the 2011 spawning season below the Brunswick Dam. There is no 

evidence of recent spawning in the remaining rivers. In the 1800s, construction of the Essex Dam 

on the Merrimack River at river kilometer (rkm) 49 blocked access to 58 percent of Atlantic 

sturgeon habitat in the river (Oakley, 2003; ASSRT, 2007). However, the accessible portions of the 

Merrimack seem to be suitable habitat for Atlantic sturgeon spawning and rearing (i.e., nursery 

habitat) (Keiffer and Kynard, 1993). Therefore, the availability of spawning habitat does not appear 

to be the reason for the lack of observed spawning in the Merrimack River. Studies are on-going to 

determine whether Atlantic sturgeon are spawning in these rivers. Atlantic sturgeons that are 

spawned elsewhere continue to use habitats within all of these rivers as part of their overall marine 

range (ASSRT, 2007). The movement of subadult and adult sturgeon between rivers, including to 

and from the Kennebec River and the Penobscot River, demonstrates that coastal and marine 

migrations are key elements of Atlantic sturgeon life history for the Gulf of Maine DPS as well as 

likely throughout the entire range (ASSRT, 2007; Fernandes, et al., 2010).

Bigelow and Schroeder (1953) surmised that Atlantic sturgeon likely spawned in Gulf of Maine 

Rivers in May-July. More recent captures of Atlantic sturgeon in spawning condition within the 

Kennebec River suggest that spawning more likely occurs in June-July (Squiers et al., 1981; 

ASMFC, 1998; NMFS and USFWS, 1998). Evidence for the timing and location of Atlantic 

sturgeon spawning in the Kennebec River includes: (1) the capture of five adult male Atlantic 

sturgeon in spawning condition (i.e., expressing milt) in July 1994 below the (former) Edwards 

Dam; (2) capture of 31 adult Atlantic sturgeon from June 15,1980, through July 26,1980, in a small 

commercial fishery directed at Atlantic sturgeon from the South Gardiner area (above 

Merrymeeting Bay) that included at least 4 ripe males and 1 ripe female captured on July 26,1980; 

and, (3) capture of nine adults during a gillnet survey conducted from 1977-1981, the majority of 

which were captured in July in the area from Merrymeeting Bay and upriver as far as Gardiner, ME 

(NMFS and USFWS, 1998; ASMFC 2007). The low salinity values for waters above 

Merrymeeting Bay are consistent with values found in other rivers where successful Atlantic 

sturgeon spawning is known to occur. 

Several threats play a role in shaping the current status of Gulf of Maine DPS Atlantic sturgeon. 

Historical records provide evidence of commercial fisheries for Atlantic sturgeon in the Kennebec 

and Androscoggin Rivers dating back to the 17th century (Squiers et al., 1979). In 1849, 160 tons of 

sturgeon was caught in the Kennebec River by local fishermen (Squiers et al., 1979). Following the 

1880's, the sturgeon fishery was almost non-existent due to a collapse of the sturgeon stocks. All 

directed Atlantic sturgeon fishing as well as retention of Atlantic sturgeon by catch has been 

prohibited since 1998. Nevertheless, mortalities associated with bycatch in fisheries occurring in 

state and federal waters still occurs. In the marine range, Gulf of Maine DPS Atlantic sturgeon are 

incidentally captured in federal and state managed fisheries, reducing survivorship of subadult and 

adult Atlantic sturgeon (Stein et al., 2004; ASMFC 2007). As explained above, we have estimates 

of the number of subadults and adults that are killed as a result of bycatch in fisheries authorized 
75

under Northeast FMPs. At this time, we are not able to quantify the impacts from other threats or 

estimate the number of individuals killed as a result of other anthropogenic threats. Habitat 

disturbance and direct mortality from anthropogenic sources are the primary concerns. 

Riverine habitat may be impacted by dredging and other in-water activities, disturbing spawning 

habitat and also altering the benthic forage base. Many rivers in the Gulf of Maine DPS have 

navigation channels that are maintained by dredging. Dredging outside of Federal channels and inwater construction occurs throughout the Gulf of Maine DPS. While some dredging projects 

operate with observers present to document fish mortalities, many do not. To date we have not 

received any reports of Atlantic sturgeon killed during dredging projects in the Gulf of Maine 

region; however, as noted above, not all projects are monitored for interactions with fish. At this 

time, we do not have any information to quantify the number of Atlantic sturgeon killed or 

disturbed during dredging or in-water construction projects are also not able to quantify any effects 

to habitat. 

Connectivity is disrupted by the presence of dams on several rivers in the Gulf of Maine region, 

including the Penobscot and Merrimack Rivers. While there are also dams on the Kennebec, 

Androscoggin and Saco Rivers, these dams are near the site of natural falls and likely represent the 

maximum upstream extent of sturgeon occurrence even if the dams were not present. Because no 

Atlantic sturgeon are known to occur upstream of any hydroelectric projects in the Gulf of Maine 

region, passage over hydroelectric dams or through hydroelectric turbines is not a source of injury 

or mortality in this area. While not expected to be killed or injured during passage at a dam, the 

extent that Atlantic sturgeon are affected by the existence of dams and their operations in the Gulf 

of Maine region is currently unknown. The extent that Atlantic sturgeon are affected by operations 

of dams in the Gulf of Maine region is currently unknown; however, the documentation of an 

Atlantic sturgeon larvae downstream of the Brunswick Dam in the Androscoggin River suggests 

that Atlantic sturgeon spawning may be occurring in the vicinity of at least that project and 

therefore, may be affected by project operations. The range of Atlantic sturgeon in the Penobscot 

River is limited by the presence of the Veazie and Great Works Dams. Together these dams 

prevent Atlantic sturgeon from accessing approximately 29 km of habitat, including the presumed 

historical spawning habitat located downstream of Milford Falls, the site of the Milford Dam. 

While removal of the Veazie and Great Works Dams is anticipated to occur in the near future, the 

presence of these dams is currently preventing access to significant habitats within the Penobscot 

River. While Atlantic sturgeon are known to occur in the Penobscot River, it is unknown if 

spawning is currently occurring or whether the presence of the Veazie and Great Works Dams 

affects the likelihood of spawning occurring in this river. The Essex Dam on the Merrimack River 

blocks access to approximately 58% of historically accessible habitat in this river. Atlantic sturgeon 

occur in the Merrimack River but spawning has not been documented. Like the Penobscot, it is 

unknown how the Essex Dam affects the likelihood of spawning occurring in this river. 

Gulf of Maine DPS Atlantic sturgeon may also be affected by degraded water quality. In general, 

water quality has improved in the Gulf of Maine over the past decades (Lichter et al. 2006; EPA, 

2008). Many rivers in Maine, including the Androscoggin River, were heavily polluted in the past 

from industrial discharges from pulp and paper mills. While water quality has improved and most 

discharges are limited through regulations, many pollutants persist in the benthic environment. This 

can be particularly problematic if pollutants are present on spawning and nursery grounds as 
76

developing eggs and larvae are particularly susceptible to exposure to contaminants. 

There are no empirical abundance estimates for the Gulf of Maine DPS. The Atlantic sturgeon SRT 

(2007) presumed that the Gulf of Maine DPS was comprised of less than 300 spawning adults per 

year, based on abundance estimates for the Hudson and Altamaha River riverine populations of 

Atlantic sturgeon. Surveys of the Kennebec River over two time periods, 1977-1981 and 1998-

2000, resulted in the capture of nine adult Atlantic sturgeon (Squiers, 2004). However, since the 

surveys were primarily directed at capture of shortnose sturgeon, the capture gear used may not 

have been selective for the larger-sized, adult Atlantic sturgeon; several hundred subadult Atlantic 

sturgeon were caught in the Kennebec River during these studies. As explained above, we have 

estimated that there is an annual mean of 166 mature adult Atlantic sturgeon in the GOM DPS. 

Summary of the Gulf of Maine DPS

Spawning for the Gulf of Maine DPS is known to occur in two rivers (Kennebec and Androscoggin) 

and possibly in a third. Spawning may be occurring in other rivers, such as the Sheepscot or 

Penobscot, but has not been confirmed. There are indications of increasing abundance of Atlantic 

sturgeon belonging to the Gulf of Maine DPS. Atlantic sturgeon continue to be present in the 

Kennebec River; in addition, they are captured in directed research projects in the Penobscot River, 

and are observed in rivers where they were unknown to occur or had not been observed to occur for 

many years (e.g., the Saco, Presumpscot, and Charles rivers). These observations suggest that 

abundance of the Gulf of Maine DPS of Atlantic sturgeon is sufficient such that recolonization to 

rivers historically suitable for spawning may be occurring. However, despite some positive signs, 

there is not enough information to establish a trend for this DPS. 

Some of the impacts from the threats that contributed to the decline of the Gulf of Maine DPS have 

been removed (e.g., directed fishing), or reduced as a result of improvements in water quality and 

removal of dams (e.g., the Edwards Dam on the Kennebec River in 1999). There are strict 

regulations on the use of fishing gear in Maine state waters that incidentally catch sturgeon. In 

addition, there have been reductions in fishing effort in state and federal waters, which most likely 

would result in a reduction in bycatch mortality of Atlantic sturgeon. A significant amount of 

fishing in the Gulf of Maine is conducted using trawl gear, which is known to have a much lower 

mortality rate for Atlantic sturgeon caught in the gear compared to sink gillnet gear (ASMFC, 

2007). Atlantic sturgeon from the GOM DPS are not commonly taken as bycatch in areas south of 

Chatham, MA, with only 8 percent (e.g., 7 of the 84 fish) of interactions observed in the Mid 

Atlantic/Carolina region being assigned to the Gulf of Maine DPS (Wirgin and King, 2011). 

Tagging results also indicate that Gulf of Maine DPS fish tend to remain within the waters of the 

Gulf of Maine and only occasionally venture to points south. However, data on Atlantic sturgeon 

incidentally caught in trawls and intertidal fish weirs fished in the Minas Basin area of the Bay of 

Fundy.(Canada) indicate that approximately 35 percent originated from the Gulf of Maine DPS 

(Wirgin et al., in draft). 

As noted previously, studies have shown that in order to rebuild, Atlantic sturgeon can only sustain 

low levels of bycatch and other anthropogenic mortality (Boreman, 1997; ASMFC, 2007; Kahnle et 

al., 2007; Brown and Murphy, 2010). NMFS has determined that the Gulf of Maine DPS is at risk 

of becoming endangered in the foreseeable future throughout all of its range (i.e., is a threatened 

species) based on the following: (1) significant declines in population sizes and the protracted 
77

period during which sturgeon populations have been depressed; (2) the limited amount of current 

spawning; and, (3) the impacts and threats that have and will continue to affect recovery. 

4.9 New York Bight DPS of Atlantic sturgeon 

The New York Bight DPS includes the following: all anadromous Atlantic sturgeon spawned in the 

watersheds that drain into coastal waters from Chatham, MA to the Delaware-Maryland border on 

Fenwick Island. Within this range, Atlantic sturgeon historically spawned in the Connecticut, 

Delaware, Hudson, and Taunton Rivers (Murawski and Pacheco, 1977; Secor, 2002; ASSRT, 

2007). Spawning still occurs in the Delaware and Hudson Rivers, but there is no recent evidence 

(within the last 15 years) of spawning in the Connecticut and Taunton Rivers (ASSRT, 2007). 

Atlantic sturgeon that are spawned elsewhere continue to use habitats within the Connecticut and 

Taunton Rivers as part of their overall marine range (ASSRT, 2007; Savoy, 2007; Wirgin and King, 

2011). 

The abundance of the Hudson River Atlantic sturgeon riverine population prior to the onset of 

expanded exploitation in the 1800’s is unknown but, has been conservatively estimated at 10,000 

adult females (Secor, 2002). Current abundance is likely at least one order of magnitude smaller 

than historical levels (Secor, 2002; ASSRT, 2007; Kahnle et al., 2007). As described above, an 

estimate of the mean annual number of mature adults (863 total; 596 males and 267 females) was 

calculated for the Hudson River riverine population based on fishery-dependent data collected from 

1985-1995 (Kahnle et al., 2007). Kahnle et al. (1998; 2007) also showed that the level of fishing 

mortality from the Hudson River Atlantic sturgeon fishery during the period of 1985-1995 exceeded 

the estimated sustainable level of fishing mortality for the riverine population and may have led to 

reduced recruitment. All available data on abundance of juvenile Atlantic sturgeon in the Hudson 

River Estuary indicate a substantial drop in production of young since the mid 1970's (Kahnle et al., 

1998). A decline appeared to occur in the mid to late 1970's followed by a secondary drop in the 

late 1980's (Kahnle et al., 1998; Sweka et al., 2007; ASMFC, 2010). Catch-per-unit-effort data 

suggests that recruitment has remained depressed relative to catches of juvenile Atlantic sturgeon in 

the estuary during the mid-late 1980’s (Sweka et al., 2007; ASMFC, 2010). In examining the CPUE 

data from 1985-2007, there are significant fluctuations during this time. There appears to be a 

decline in the number of juveniles between the late 1980s and early 1990s and while the CPUE is 

generally higher in the 2000s as compared to the 1990s, given the significant annual fluctuation it is 

difficult to discern any trend. Despite the CPUEs from 2000-2007 being generally higher than those 

from 1990-1999, they are low compared to the late 1980s. There is currently not enough 

information regarding any life stage to establish a trend for the Hudson River population. 

There is no abundance estimate for the Delaware River population of Atlantic sturgeon. Harvest 

records from the 1800’s indicate that this was historically a large population with an estimated 

180,000 adult females prior to 1890 (Secor and Waldman, 1999; Secor, 2002). Sampling in 2009 to 

target young-of- the year (YOY) Atlantic sturgeon in the Delaware River (i.e., natal sturgeon) 

resulted in the capture of 34 YOY, ranging in size from 178 to 349 mm TL (Fisher, 2009) and the 

collection of 32 YOY Atlantic sturgeon in a separate study (Brundage and O’Herron in Calvo et al., 

2010). Genetics information collected from 33 of the 2009 year class YOY indicates that at least 3 

females successfully contributed to the 2009 year class (Fisher, 2011). Therefore, while the capture 

of YOY in 2009 provides evidence that successful spawning is still occurring in the Delaware 

River, the relatively low numbers suggest the existing riverine population is limited in size. 
78

Several threats play a role in shaping the current status and trends observed in the Delaware River 

and Estuary. In-river threats include habitat disturbance from dredging, and impacts from historical 

pollution and impaired water quality. A dredged navigation channel extends from Trenton seaward 

through the tidal river (Brundage and O’Herron, 2009), and the river receives significant shipping 

traffic. Vessel strikes have been identified as a threat in the Delaware River; however, at this time 

we do not have information to quantify this threat or its impact to the population or the New York 

Bight DPS. Similar to the Hudson River, there is currently not enough information to determine a 

trend for the Delaware River population. 

Summary of the New York Bight DPS

Atlantic sturgeon originating from the New York Bight DPS spawn in the Hudson and Delaware 

rivers. While genetic testing can differentiate between individuals originating from the Hudson or 

Delaware river the available information suggests that the straying rate is high between these rivers. 

There are no indications of increasing abundance for the New York Bight DPS (ASSRT, 2009; 

2010). Some of the impact from the threats that contributed to the decline of the New York Bight 

DPS have been removed (e.g., directed fishing) or reduced as a result of improvements in water 

quality since passage of the Clean Water Act (CWA). In addition, there have been reductions in 

fishing effort in state and federal waters, which may result in a reduction in bycatch mortality of 

Atlantic sturgeon. Nevertheless, areas with persistent, degraded water quality, habitat impacts from 

dredging, continued bycatch in state and federally-managed fisheries, and vessel strikes remain 

significant threats to the New York Bight DPS. 

In the marine range, New York Bight DPS Atlantic sturgeon are incidentally captured in federal and 

state managed fisheries, reducing survivorship of subadult and adult Atlantic sturgeon (Stein et al., 

2004; ASMFC 2007). As explained above, currently available estimates indicate that at least 4% of 

adults may be killed as a result of bycatch in fisheries authorized under Northeast FMPs. Based on 

mixed stock analysis results presented by Wirgin and King ( 2011), over 40 percent of the Atlantic 

sturgeon bycatch interactions in the Mid Atlantic Bight region were sturgeon from the New York 

Bight DPS. Individual-based assignment and mixed stock analysis of samples collected from 

sturgeon captured in Canadian fisheries in the Bay of Fundy indicated that approximately 1-2% 

were from the New York Bight DPS. At this time, we are not able to quantify the impacts from 

other threats or estimate the number of individuals killed as a result of other anthropogenic threats. 

Riverine habitat may be impacted by dredging and other in-water activities, disturbing spawning 

habitat and also altering the benthic forage base. Both the Hudson and Delaware rivers have 

navigation channels that are maintained by dredging. Dredging is also used to maintain channels in 

the nearshore marine environment. Dredging outside of Federal channels and in-water construction 

occurs throughout the New York Bight region. While some dredging projects operate with 

observers present to document fish mortalities many do not. We have reports of one Atlantic 

sturgeon entrained during hopper dredging operations in Ambrose Channel, New Jersey. At this 

time, we do not have any information to quantify the number of Atlantic sturgeon killed or 

disturbed during dredging or in-water construction projects are also not able to quantify any effects 

to habitat. 

In the Hudson and Delaware Rivers, dams do not block access to historical habitat. The Holyoke 
79

Dam on the Connecticut River blocks further upstream passage; however, the extent that Atlantic 

sturgeon would historically have used habitat upstream of Holyoke is unknown. Connectivity may 

be disrupted by the presence of dams on several smaller rivers in the New York Bight region. 

Because no Atlantic sturgeon occur upstream of any hydroelectric projects in the New York Bight 

region, passage over hydroelectric dams or through hydroelectric turbines is not a source of injury 

or mortality in this area. The extent that Atlantic sturgeon are affected by operations of dams in the 

New York Bight region is currently unknown. 

New York Bight DPS Atlantic sturgeon may also be affected by degraded water quality. In general, 

water quality has improved in the Hudson and Delaware over the past decades (Lichter et al. 2006; 

EPA, 2008). Both the Hudson and Delaware rivers, as well as other rivers in the New York Bight 

region, were heavily polluted in the past from industrial and sanitary sewer discharges. While water 

quality has improved and most discharges are limited through regulations, many pollutants persist 

in the benthic environment. This can be particularly problematic if pollutants are present on 

spawning and nursery grounds as developing eggs and larvae are particularly susceptible to 

exposure to contaminants. 

Vessel strikes occur in the Delaware River. Twenty-nine mortalities believed to be the result of 

vessel strikes were documented in the Delaware River from 2004 to 2008, and at least 13 of these 

fish were large adults. Given the time of year in which the fish were observed (predominantly May 

through July, with two in August), it is likely that many of the adults were migrating through the 

river to the spawning grounds. Because we do not know the percent of total vessel strikes that the 

observed mortalities represent, we are not able to quantify the number of individuals likely killed as 

a result of vessel strikes in the New York Bight DPS. 

Studies have shown that to rebuild, Atlantic sturgeon can only sustain low levels of anthropogenic 

mortality (Boreman, 1997; ASMFC, 2007; Kahnle et al., 2007; Brown and Murphy, 2010). There 

are no empirical abundance estimates of the number of Atlantic sturgeon in the New York Bight 

DPS. As explained above, we have estimated that there are an annual mean total of 950 mature 

adult Atlantic sturgeon in the NYB DPS. NMFS has determined that the New York Bight DPS is 

currently at risk of extinction due to: (1) precipitous declines in population sizes and the protracted 

period in which sturgeon populations have been depressed; (2) the limited amount of current 

spawning; and (3) the impacts and threats that have and will continue to affect population recovery. 

4.10 Chesapeake Bay DPS of Atlantic sturgeon 

The Chesapeake Bay DPS includes the following: all anadromous Atlantic sturgeons that are 

spawned in the watersheds that drain into the Chesapeake Bay and into coastal waters from the 

Delaware-Maryland border on Fenwick Island to Cape Henry, VA. Within this range, Atlantic 

sturgeon historically spawned in the Susquehanna, Potomac, James, York, Rappahannock, and 

Nottoway Rivers (ASSRT, 2007). Based on the review by Oakley (2003), 100 percent of Atlantic 

sturgeon habitat is currently accessible in these rivers since most of the barriers to passage (i.e. 

dams) are located upriver of where spawning is expected to have historically occurred (ASSRT, 

2007). Spawning still occurs in the James River, and the presence of juvenile and adult sturgeon in 

the York River suggests that spawning may occur there as well (Musick et al., 1994; ASSRT, 2007; 

Greene, 2009). However, conclusive evidence of current spawning is only available for the James 

River. Atlantic sturgeon that are spawned elsewhere are known to use the Chesapeake Bay for 
80

other life functions, such as foraging and as juvenile nursery habitat prior to entering the marine 

system as subadults (Vladykov and Greeley, 1963; ASSRT, 2007; Wirgin et al., 2007; Grunwald et 

al., 2008). 

Age to maturity for Chesapeake Bay DPS Atlantic sturgeon is unknown. However, Atlantic 

sturgeon riverine populations exhibit clinal variation with faster growth and earlier age to maturity 

for those that originate from southern waters, and slower growth and later age to maturity for those 

that originate from northern waters (75 FR 61872; October 6, 2010). Age at maturity is 5 to 19 

years for Atlantic sturgeon originating from South Carolina rivers (Smith et al., 1982) and 11 to 21 

years for Atlantic sturgeon originating from the Hudson River (Young et al., 1998). Therefore, age 

at maturity for Atlantic sturgeon of the Chesapeake Bay DPS likely falls within these values. 

Several threats play a role in shaping the current status of Chesapeake Bay DPS Atlantic sturgeon. 

Historical records provide evidence of the large-scale commercial exploitation of Atlantic sturgeon 

from the James River and Chesapeake Bay in the 19th century (Hildebrand and Schroeder, 1928; 

Vladykov and Greeley, 1963; ASMFC, 1998; Secor, 2002; Bushnoe et al., 2005; ASSRT, 2007) as 

well as subsistence fishing and attempts at commercial fisheries as early as the 17th century (Secor, 

2002; Bushnoe et al., 2005; ASSRT, 2007; Balazik et al., 2010). Habitat disturbance caused by inriver work such as dredging for navigational purposes is thought to have reduced available 

spawning habitat in the James River (Holton and Walsh, 1995; Bushnoe et al., 2005; ASSRT, 

2007). At this time, we do not have information to quantify this loss of spawning habitat. 

Decreased water quality also threatens Atlantic sturgeon of the Chesapeake Bay DPS, especially 

since the Chesapeake Bay system is vulnerable to the effects of nutrient enrichment due to a 

relatively low tidal exchange and flushing rate, large surface to volume ratio, and strong 

stratification during the spring and summer months (Pyzik et al., 2004; ASMFC, 1998; ASSRT, 

2007; EPA, 2008). These conditions contribute to reductions in dissolved oxygen levels throughout 

the Bay. The availability of nursery habitat, in particular, may be limited given the recurrent 

hypoxia (low dissolved oxygen) conditions within the Bay (Niklitschek and Secor, 2005; 2010). At 

this time we do not have sufficient information to quantify the extent that degraded water quality 

effects habitat or individuals in the James River or throughout the Chesapeake Bay. 

Vessel strikes have been observed in the James River (ASSRT, 2007). Eleven Atlantic sturgeon 

were reported to have been struck by vessels from 2005 through 2007. Several of these were 

mature individuals. Because we do not know the percent of total vessel strikes that the observed

mortalities represent, we are not able to quantify the number of individuals likely killed as a result 

of vessel strikes in the New York Bight DPS. 

In the marine and coastal range of the Chesapeake Bay DPS from Canada to Florida, fisheries 

bycatch in federally and state managed fisheries poses a threat to the DPS, reducing survivorship of 

subadults and adults and potentially causing an overall reduction in the spawning population (Stein 

et al., 2004; ASMFC, 2007; ASSRT, 2007). 

Summary of the Chesapeake Bay DPS

Spawning for the Chesapeake Bay DPS is known to occur in only the James River. Spawning may 

be occurring in other rivers, such as the York, but has not been confirmed. There are anecdotal 
81

reports of increased sightings and captures of Atlantic sturgeon in the James River. However, this 

information has not been comprehensive enough to develop a population estimate for the James 

River or to provide sufficient evidence to confirm increased abundance. Some of the impact from 

the threats that facilitated the decline of the Chesapeake Bay DPS have been removed (e.g., directed 

fishing) or reduced as a result of improvements in water quality since passage of the Clean Water 

Act (CWA). As explained above, we have estimated that there is an annual mean of 329 mature 

adult Atlantic sturgeon in the Chesapeake Bay DPS. We do not currently have enough information 

about any life stage to establish a trend for this DPS. 

Areas with persistent, degraded water quality, habitat impacts from dredging, continued bycatch in 

U.S. state and federally-managed fisheries, Canadian fisheries and vessel strikes remain significant 

threats to the Chesapeake Bay DPS of Atlantic sturgeon. Studies have shown that Atlantic sturgeon 

can only sustain low levels of bycatch mortality (Boreman, 1997; ASMFC, 2007; Kahnle et al., 

2007). The Chesapeake Bay DPS is currently at risk of extinction given (1) precipitous declines in 

population sizes and the protracted period in which sturgeon populations have been depressed; (2) 

the limited amount of current spawning; and, (3) the impacts and threats that have and will continue 

to affect the potential for population recovery. 

4.11 Carolina DPS of Atlantic sturgeon 

The Carolina DPS includes all Atlantic sturgeon that spawn or are spawned in the watersheds 

(including all rivers and tributaries) from Albemarle Sound southward along the southern Virginia, 

North Carolina, and South Carolina coastal areas to Charleston Harbor. The marine range of 

Atlantic sturgeon from the Carolina DPS extends from the Hamilton Inlet, Labrador, Canada, to 

Cape Canaveral, Florida. Sturgeon are commonly captured 40 miles offshore (D. Fox, DSU, pers. 

comm.). Records providing fishery bycatch data by depth show the vast majority of Atlantic 

sturgeon bycatch via gillnets is observed in waters less than 50 meters deep (Stein et al. 2004, 

ASMFC 2007), but Atlantic sturgeon are recorded as bycatch out to 500 fathoms.

Rivers known to have current spawning populations within the range of the Carolina DPS include 

the Roanoke, Tar-Pamlico, Cape Fear, Waccamaw, and Pee Dee Rivers. We determined spawning 

was occurring if young-of-the-year (YOY) were observed, or mature adults were present, in 

freshwater portions of a system (Table 6). However, in some rivers, spawning by Atlantic sturgeon 

may not be contributing to population growth because of lack of suitable habitat and the presence of 

other stressors on juvenile survival and development. There may also be spawning populations in 

the Neuse, Santee and Cooper Rivers, though it is uncertain. Historically, both the Sampit and 

Ashley Rivers were documented to have spawning populations at one time. However, the spawning 

population in the Sampit River is believed to be extirpated and the current status of the spawning 

population in the Ashley River is unknown. Both rivers may be used as nursery habitat by young 

Atlantic sturgeon originating from other spawning populations. This represents our current 

knowledge of the river systems utilized by the Carolina DPS for specific life functions, such as 

spawning, nursery habitat, and foraging. However, fish from the Carolina DPS likely use other 

river systems than those listed here for their specific life functions. 
82

River/Estuary Spawning 

Population

Data

Roanoke River, VA/NC;

Albemarle Sound, NC 

Yes collection of 15 YOY (1997-

1998); single YOY (2005)

Tar-Pamlico River, NC;

Pamlico Sound

Yes one YOY (2005)

Neuse River, NC; 

Pamlico Sound

Unknown

Cape Fear River, NC Yes upstream migration of adults in 

the fall, carcass of a ripe female 

upstream in mid-September 

(2006)

Waccamaw River, SC; 

Winyah Bay

Yes age-1, potentially YOY (1980s)

Pee Dee River, SC; Winyah 

Bay

Yes running ripe male in Great Pee 

Dee River (2003)

Sampit, SC; Winyah Bay Extirpated

Santee River, SC Unknown

Cooper River, SC Unknown

Ashley River, SC Unknown

Table 6. Major rivers, tributaries, and sounds within the range of the Carolina DPS and currently 

available data on the presence of an Atlantic sturgeon spawning population in each system.

The riverine spawning habitat of the Carolina DPS occurs within the Mid-Atlantic Coastal Plain 

ecoregion (TNC 2002a), which includes bottomland hardwood forests, swamps, and some of the 

world’s most active coastal dunes, sounds, and estuaries. Natural fires, floods, and storms are so 

dominant in this region that the landscape changes very quickly. Rivers routinely change their 

courses and emerge from their banks. The primary threats to biological diversity in the MidAtlantic Coastal Plain, as listed by TNC are: global climate change and rising sea level; altered 

surface hydrology and landform alteration (e.g., flood-control and hydroelectric dams, inter-basin 

transfers of water, drainage ditches, breached levees, artificial levees, dredged inlets and river 

channels, beach renourishment, and spoil deposition banks and piles); a regionally receding water 

table, probably resulting from both over-use and inadequate recharge; fire suppression; land 

fragmentation, mainly by highway development; land-use conversion (e.g., from forests to timber 

plantations, farms, golf courses, housing developments, and resorts); the invasion of exotic plants 

and animals; air and water pollution, mainly from agricultural activities including concentrated 

animal feed operations; and over-harvesting and poaching of species. Many of the Carolina DPS’ 

spawning rivers, located in the Mid-Coastal Plain, originate in areas of marl. Waters draining 

calcareous, impervious surface materials such as marl are: (1) likely to be alkaline; (2) dominated 

by surface run-off; (3) have little groundwater connection; and, (4) are seasonally ephemeral. 

Historical landings data indicate that between 7,000 and 10,500 adult female Atlantic sturgeon were 

present in North Carolina prior to 1890 (Armstrong and Hightower 2002, Secor 2002). Secor 

(2002) estimates that 8,000 adult females were present in South Carolina during that same time-
83

frame. Prior reductions from the commercial fishery and ongoing threats have drastically reduced 

the numbers of Atlantic sturgeon within the Carolina DPS. Currently, the Atlantic sturgeon 

spawning population in at least one river system within the Carolina DPS has been extirpated, with 

a potential extirpation in an additional system. The abundances of the remaining river populations 

within the DPS, each estimated to have fewer than 300 spawning adults, is estimated to be less than 

3 percent of what they were historically (ASSRT 2007). 

Threats

The Carolina DPS was listed as endangered under the ESA as a result of a combination of habitat 

curtailment and modification, overutilization (i.e, being taken as bycatch) in commercial fisheries, 

and the inadequacy of regulatory mechanisms in ameliorating these impacts and threats. 

The modification and curtailment of Atlantic sturgeon habitat resulting from dams, dredging, and 

degraded water quality is contributing to the status of the Carolina DPS. Dams have curtailed 

Atlantic sturgeon spawning and juvenile developmental habitat by blocking over 60 percent of the 

historical sturgeon habitat upstream of the dams in the Cape Fear and Santee-Cooper River systems. 

Water quality (velocity, temperature, and dissolved oxygen (DO)) downstream of these dams, as 

well as on the Roanoke River, has been reduced, which modifies and curtails the extent of spawning 

and nursery habitat for the Carolina DPS. Dredging in spawning and nursery grounds modifies the 

quality of the habitat and is further curtailing the extent of available habitat in the Cape Fear and 

Cooper Rivers, where Atlantic sturgeon habitat has already been modified and curtailed by the 

presence of dams. Reductions in water quality from terrestrial activities have modified habitat 

utilized by the Carolina DPS. In the Pamlico and Neuse systems, nutrient-loading and seasonal

anoxia are occurring, associated in part with concentrated animal feeding operations (CAFOs). 

Heavy industrial development and CAFOs have degraded water quality in the Cape Fear River. 

Water quality in the Waccamaw and Pee Dee rivers have been affected by industrialization and 

riverine sediment samples contain high levels of various toxins, including dioxins. Additional 

stressors arising from water allocation and climate change threaten to exacerbate water quality 

problems that are already present throughout the range of the Carolina DPS. Twenty interbasin 

water transfers in existence prior to 1993, averaging 66.5 million gallons per day (mgd), were 

authorized at their maximum levels without being subjected to an evaluation for certification by 

North Carolina Department of Environmental and Natural Resources or other resource agencies. 

Since the 1993 legislation requiring certificates for transfers, almost 170 mgd of interbasin water 

withdrawals have been authorized, with an additional 60 mgd pending certification. The removal of 

large amounts of water from the system will alter flows, temperature, and DO. Existing water 

allocation issues will likely be compounded by population growth and potentially climate change. 

Climate change is also predicted to elevate water temperatures and exacerbate nutrient-loading, 

pollution inputs, and lower DO, all of which are current stressors to the Carolina DPS.

Overutilization of Atlantic sturgeon from directed fishing caused initial severe declines in Atlantic 

sturgeon populations in the Southeast, from which they have never rebounded. Further, continued 

overutilization of Atlantic sturgeon as bycatch in commercial fisheries is an ongoing impact to the 

Carolina DPS. Atlantic sturgeon are more sensitive to bycatch mortality because they are a longlived species, have an older age at maturity, have lower maximum fecundity values, and a large 

percentage of egg production occurs later in life. Based on these life history traits, Boreman (1997) 

calculated that Atlantic sturgeon can only withstand the annual loss of up to 5 percent of their 
84

population to bycatch mortality without suffering population declines. Mortality rates of Atlantic 

sturgeon taken as bycatch in various types of fishing gear range between 0 and 51 percent, with the 

greatest mortality occurring in sturgeon caught by sink gillnets. Atlantic sturgeon are particularly 

vulnerable to being caught in sink gillnets, therefore fisheries using this type of gear account for a 

high percentage of Atlantic sturgeon bycatch. Little data exists on bycatch in the Southeast and 

high levels of bycatch underreporting are suspected. Further, a total population abundance for the 

DPS is not available, and it is therefore not possible to calculate the percentage of the DPS subject 

to bycatch mortality based on the available bycatch mortality rates for individual fisheries. 

However, fisheries known to incidentally catch Atlantic sturgeon occur throughout the marine range 

of the species and in some riverine waters as well. Because Atlantic sturgeon mix extensively in 

marine waters and may access multiple river systems, they are subject to being caught in multiple 

fisheries throughout their range. In addition, stress or injury to Atlantic sturgeon taken as bycatch 

but released alive may result in increased susceptibility to other threats, such as poor water quality 

(e.g., exposure to toxins and low DO). This may result in reduced ability to perform major life 

functions, such as foraging and spawning, or even post-capture mortality. 

As a wide-ranging anadromous species, Atlantic sturgeon are subject to numerous Federal (U.S. and 

Canadian), state and provincial, and inter-jurisdictional laws, regulations, and agency activities. 

While these mechanisms have addressed impacts to Atlantic sturgeon through directed fisheries, 

there are currently no mechanisms in place to address the significant risk posed to Atlantic sturgeon 

from commercial bycatch. Though statutory and regulatory mechanisms exist that authorize 

reducing the impact of dams on riverine and anadromous species, such as Atlantic sturgeon, and 

their habitat, these mechanisms have proven inadequate for preventing dams from blocking access 

to habitat upstream and degrading habitat downstream. Further, water quality continues to be a 

problem in the Carolina DPS, even with existing controls on some pollution sources. Current 

regulatory regimes are not necessarily effective in controlling water allocation issues (e.g., no 

restrictions on interbasin water transfers in South Carolina, the lack of ability to regulate non-point 

source pollution, etc.) 

The recovery of Atlantic sturgeon along the Atlantic Coast, especially in areas where habitat is 

limited and water quality is severely degraded, will require improvements in the following areas: (1) 

elimination of barriers to spawning habitat either through dam removal, breaching, or installation of 

successful fish passage facilities; (2) operation of water control structures to provide appropriate 

flows, especially during spawning season; (3) imposition of dredging restrictions including seasonal 

moratoriums and avoidance of spawning/nursery habitat; and, (4) mitigation of water quality 

parameters that are restricting sturgeon use of a river (i.e., DO). Additional data regarding sturgeon 

use of riverine and estuarine environments is needed.

The concept of a viable population able to adapt to changing environmental conditions is critical to 

Atlantic sturgeon, and the low population numbers of every river population in the Carolina DPS 

put them in danger of extinction throughout their range; none of the populations are large or stable 

enough to provide with any level of certainty for continued existence of Atlantic sturgeon in this 

part of its range. Although the largest impact that caused the precipitous decline of the species has 

been curtailed (directed fishing), the population sizes within the Carolina DPS have remained 

relatively constant at greatly reduced levels (approximately 3 percent of historical population sizes) 

for 100 years. Small numbers of individuals resulting from drastic reductions in populations, such 
85

as occurred with Atlantic sturgeon due to the commercial fishery, can remove the buffer against 

natural demographic and environmental variability provided by large populations (Berry, 1971; 

Shaffer, 1981; Soulé, 1980). Recovery of depleted populations is an inherently slow process for a 

late-maturing species such as Atlantic sturgeon, and they continue to face a variety of other threats 

that contribute to their risk of extinction. Their late age at maturity provides more opportunities for 

individual Atlantic sturgeon to be removed from the population before reproducing. While a long 

life-span also allows multiple opportunities to contribute to future generations, it also results 

increases the timeframe over which exposure to the multitude of threats facing the Carolina DPS 

can occur. 

The viability of the Carolina DPS depends on having multiple self-sustaining riverine spawning 

populations and maintaining suitable habitat to support the various life functions (spawning, 

feeding, growth) of Atlantic sturgeon sturgeon populations. Because a DPS is a group of 

populations, the stability, viability, and persistence of individual populations affects the persistence

and viability of the larger DPS. The loss of any population within a DPS will result in: (1) a longterm gap in the range of the DPS that is unlikely to be recolonized; (2) loss of reproducing 

individuals; (3) loss of genetic biodiversity; (4) potential loss of unique haplotypes; (5) potential 

loss of adaptive traits; and (6) reduction in total number. The loss of a population will negatively 

impact the persistence and viability of the DPS as a whole, as fewer than two individuals per 

generation spawn outside their natal rivers (Secor and Waldman 1999). The persistence of 

individual populations, and in turn the DPS, depends on successful spawning and rearing within the 

freshwater habitat, the immigration into marine habitats to grow, and then the return of adults to 

natal rivers to spawn. 

Summary of the Status of the Carolina DPS of Atlantic Sturgeon

In summary, the Carolina DPS is estimated to number less than 3 percent of its historic population 

size. There are estimated to be less than 300 spawning adults per year (total of both sexes) in each 

of the major river systems occupied by the DPS in which spawning still occurs, whose freshwater 

range occurs in the watersheds (including all rivers and tributaries) from Albemarle Sound 

southward along the southern Virginia, North Carolina, and South Carolina coastal areas to 

Charleston Harbor. Recovery of depleted populations is an inherently slow process for a latematuring species such as Atlantic sturgeon. Their late age at maturity provides more opportunities 

for individuals to be removed from the population before reproducing. While a long life-span also 

allows multiple opportunities to contribute to future generations, this is hampered within the 

Carolina DPS by habitat alteration and bycatch. This DPS was severely depleted by past directed 

commercial fishing, and faces ongoing impacts and threats from habitat alteration or inaccessibility, 

bycatch, and the inadequacy of existing regulatory mechanisms to address and reduce habitat 

alterations and bycatch that have prevented river populations from rebounding and will prevent their 

recovery. 

The presence of dams has resulted in the loss of over 60 percent of the historical sturgeon habitat on 

the Cape Fear River and in the Santee-Cooper system. Dams are contributing to the status of the 

Carolina DPS by curtailing the extent of available spawning habitat and further modifying the 

remaining habitat downstream by affecting water quality parameters (such as depth, temperature, 

velocity, and DO) that are important to sturgeon. Dredging is also contributing to the status of the 

Carolina DPS by modifying Atlantic sturgeon spawning and nursery habitat. Habitat modifications 
86

through reductions in water quality are contributing to the status of the Carolina DPS due to 

nutrient-loading, seasonal anoxia, and contaminated sediments. Interbasin water transfers and 

climate change threaten to exacerbate existing water quality issues. Bycatch is also a current threat 

to the Carolina DPS that is contributing to its status. Fisheries known to incidentally catch Atlantic 

sturgeon occur throughout the marine range of the species and in some riverine waters as well. 

Because Atlantic sturgeon mix extensively in marine waters and may utilize multiple river systems 

for nursery and foraging habitat in addition to their natal spawning river, they are subject to being 

caught in multiple fisheries throughout their range. In addition to direct mortality, stress or injury to 

Atlantic sturgeon taken as bycatch but released alive may result in increased susceptibility to other 

threats, such as poor water quality (e.g., exposure to toxins). This may result in reduced ability to 

perform major life functions, such as foraging and spawning, or even post-capture mortality. While 

many of the threats to the Carolina DPS have been ameliorated or reduced due to the existing 

regulatory mechanisms, such as the moratorium on directed fisheries for Atlantic sturgeon, bycatch 

is currently not being addressed through existing mechanisms. Further, access to habitat and water 

quality continues to be a problem even with NMFS’ authority under the Federal Power Act to 

recommend fish passsage and existing controls on some pollution sources. The inadequacy of 

regulatory mechanisms to control bycatch and habitat alterations is contributing to the status of the 

Carolina DPS.

4.12 South Atlantic DPS of Atlantic sturgeon 

The South Atlantic DPS includes all Atlantic sturgeon that spawn or are spawned in the watersheds 

(including all rivers and tributaries) of the Ashepoo, Combahee, and Edisto Rivers (ACE) Basin 

southward along the South Carolina, Georgia, and Florida coastal areas to the St. Johns River, 

Florida. The marine range of Atlantic sturgeon from the South Atlantic DPS extends from the 

Hamilton Inlet, Labrador, Canada, to Cape Canaveral, Florida. 

Rivers known to have current spawning populations within the range of the South Atlantic DPS 

include the Combahee, Edisto, Savannah, Ogeechee, Altamaha, and Satilla Rivers. We determined 

spawning was occurring if young-of-the-year (YOY) were observed, or mature adults were present, 

in freshwater portions of a system (Table 7). However, in some rivers, spawning by Atlantic 

sturgeon may not be contributing to population growth because of lack of suitable habitat and the 

presence of other stressors on juvenile survival and development. Historically, both the BroadCoosawatchie and St. Marys Rivers were documented to have spawning populations at one time; 

there is also evidence that spawning may have occurred in the St. Johns River or one of its 

tributaries. However, the spawning population in the St. Marys River, as well as any historical 

spawning population present in the St. Johns, is believed to be extirpated, and the status of the 

spawning population in the Broad-Coosawatchie is unknown. Both the St. Marys and St. Johns 

Rivers are used as nursery habitat by young Atlantic sturgeon originating from other spawning 

populations. The use of the Broad-Coosawatchie by sturgeon from other spawning populations is 

unknown at this time. The presence of historical and current spawning populations in the Ashepoo 

River has not been documented; however, this river may currently be used for nursery habitat by 

young Atlantic sturgeon originating from other spawning populations. This represents our current 

knowledge of the river systems utilized by the South Atlantic DPS for specific life functions, such 

as spawning, nursery habitat, and foraging. However, fish from the South Atlantic DPS likely use 

other river systems than those listed here for their specific life functions. 
87

River/Estuary Spawning 

Population

Data

ACE (Ashepoo, Combahee, and 

Edisto Rivers) Basin, SC;

St. Helena Sound 

Yes 1,331 YOY (1994-2001); 

gravid female and running ripe 

male in the Edisto (1997); 39 

spawning adults (1998)

Broad-Coosawhatchie Rivers, 

SC;

Port Royal Sound

Unknown

Savannah River, SC/GA Yes 22 YOY (1999-2006); running 

ripe male (1997)

Ogeechee River, GA Yes age-1 captures, but high interannual variability (1991-1998); 

17 YOY (2003); 9 YOY (2004)

Altamaha River, GA Yes 74 captured/308 estimated 

spawning adults (2004); 139 

captured/378 estimated 

spawning adults (2005)

Satilla River, GA Yes 4 YOY and spawning adults 

(1995-1996)

St. Marys River, GA/FL Extirpated

St. Johns River, FL Extirpated

Table 7. Major rivers, tributaries, and sounds within the range of the South Atlantic DPS and 

currently available data on the presence of an Atlantic sturgeon spawning population in each 

system.

The riverine spawning habitat of the South Atlantic DPS occurs within the South Atlantic Coastal 

Plain ecoregion (TNC 2002b), which includes fall-line sandhills, rolling longleaf pine uplands, wet 

pine flatwoods, isolated depression wetlands, small streams, large river systems, and estuaries. 

Other ecological systems in the ecoregion include maritime forests on barrier islands, pitcher plant 

seepage bogs and Altamaha grit (sandstone) outcrops. Other ecological systems in the ecoregion 

include maritime forests on barrier islands, pitcher plant seepage bogs and Altamaha grit 

(sandstone) outcrops. The primary threats to biological diversity in the South Atlantic Coastal Plain 

listed by TNC are intensive silvicultural practices, including conversion of natural forests to highly 

managed pine monocultures and the clear-cutting of bottomland hardwood forests. Changes in 

water quality and quantity, caused by hydrologic alterations (impoundments, groundwater 

withdrawal, and ditching), and point and nonpoint pollution, are threatening the aquatic systems. 

Development is a growing threat, especially in coastal areas. Agricultural conversion, fire regime 

alteration, and the introduction of nonnative species are additional threats to the ecoregion’s 

diversity. The South Atlantic DPS’ spawning rivers, located in the South Atlantic Coastal Plain, are 

primarily of two types: brownwater (with headwaters north of the Fall Line, silt-laden) and 

blackwater (with headwaters in the coastal plain, stained by tannic acids). 
88

Secor (2002) estimates that 8,000 adult females were present in South Carolina prior to 1890. Prior 

to the collapse of the fishery in the late 1800s, the sturgeon fishery was the third largest fishery in 

Georgia. Secor (2002) estimated from U.S. Fish Commission landing reports that approximately 

11,000 spawning females were likely present in the state prior to 1890. Reductions from the 

commercial fishery and ongoing threats have drastically reduced the numbers of Atlantic sturgeon 

within the South Atlantic DPS. Currently, the Atlantic sturgeon spawning population in at least two 

river systems within the South Atlantic DPS has been extirpated. The Altamaha River population 

of Atlantic sturgeon, with an estimated 343 adults spawning annually, is believed to be the largest 

population in the Southeast, yet is estimated to be only 6 percent of its historical population size. 

The abundances of the remaining river populations within the DPS, each estimated to have fewer 

than 300 spawning adults, is estimated to be less than 1 percent of what they were historically 

(ASSRT 2007). 

Threats

The South Atlantic DPS was listed as endangered under the ESA as a result of a combination of 

habitat curtailment and modification, overutilization (i.e, being taken as bycatch) in commercial 

fisheries, and the inadequacy of regulatory mechanisms in ameliorating these impacts and threats. 

The modification and curtailment of Atlantic sturgeon habitat resulting from dredging and degraded 

water quality is contributing to the status of the South Atlantic DPS. Dredging is a present threat to 

the South Atlantic DPS and is contributing to their status by modifying the quality and availability 

of Atlantic sturgeon habitat. Maintenance dredging is currently modifying Atlantic sturgeon 

nursery habitat in the Savannah River and modeling indicates that the proposed deepening of the 

navigation channel will result in reduced DO and upriver movement of the salt wedge, curtailing 

spawning habitat. Dredging is also modifying nursery and foraging habitat in the St. Johns Rivers. 

Reductions in water quality from terrestrial activities have modified habitat utilized by the South 

Atlantic DPS. Low DO is modifying sturgeon habitat in the Savannah due to dredging, and nonpoint source inputs are causing low DO in the Ogeechee River and in the St. Marys River, which 

completely eliminates juvenile nursery habitat in summer. Low DO has also been observed in the 

St. Johns River in the summer. Sturgeon are more sensitive to low DO and the negative (metabolic, 

growth, and feeding) effects caused by low DO increase when water temperatures are concurrently 

high, as they are within the range of the South Atlantic DPS. Additional stressors arising from 

water allocation and climate change threaten to exacerbate water quality problems that are already 

present throughout the range of the South Atlantic DPS. Large withdrawals of over 240 million 

gallons per day mgd of water occur in the Savannah River for power generation and municipal uses. 

However, users withdrawing less than 100,000 gallons per day (gpd) are not required to get permits, 

so actual water withdrawals from the Savannah and other rivers within the range of the South 

Atlantic DPS are likely much higher. The removal of large amounts of water from the system will 

alter flows, temperature, and DO. Water shortages and “water wars” are already occurring in the 

rivers occupied by the South Atlantic DPS and will likely be compounded in the future by 

population growth and potentially by climate change. Climate change is also predicted to elevate 

water temperatures and exacerbate nutrient-loading, pollution inputs, and lower DO, all of which 

are current stressors to the South Atlantic DPS.

Overutilization of Atlantic sturgeon from directed fishing caused initial severe declines in Atlantic 

sturgeon populations in the Southeast, from which they have never rebounded. Further, continued 
89

overutilization of Atlantic sturgeon as bycatch in commercial fisheries is an ongoing impact to the 

South Atlantic DPS. The loss of large subadults and adults as a result of bycatch impacts Atlantic 

sturgeon populations because they are a long-lived species, have an older age at maturity, have 

lower maximum fecundity values, and a large percentage of egg production occurs later in life. 

Little data exists on bycatch in the Southeast and high levels of bycatch underreporting are 

suspected. Further, a total population abundance for the DPS is not available, and it is therefore not 

possible to calculate the percentage of the DPS subject to bycatch mortality based on the available 

bycatch mortality rates for individual fisheries. However, fisheries known to incidentally catch 

Atlantic sturgeon occur throughout the marine range of the species and in some riverine waters as 

well. Because Atlantic sturgeon mix extensively in marine waters and may access multiple river 

systems, they are subject to being caught in multiple fisheries throughout their range. In addition, 

stress or injury to Atlantic sturgeon taken as bycatch but released alive may result in increased

susceptibility to other threats, such as poor water quality (e.g., exposure to toxins and low DO). 

This may result in reduced ability to perform major life functions, such as foraging and spawning, 

or even post-capture mortality. 

As a wide-ranging anadromous species, Atlantic sturgeon are subject to numerous Federal (U.S. and 

Canadian), state and provincial, and inter-jurisdictional laws, regulations, and agency activities. 

While these mechanisms have addressed impacts to Atlantic sturgeon through directed fisheries, 

there are currently no mechanisms in place to address the significant risk posed to Atlantic sturgeon 

from commercial bycatch. Though statutory and regulatory mechanisms exist that authorize 

reducing the impact of dams on riverine and anadromous species, such as Atlantic sturgeon, and 

their habitat, these mechanisms have proven inadequate for preventing dams from blocking access 

to habitat upstream and degrading habitat downstream. Further, water quality continues to be a 

problem in the South Atlantic DPS, even with existing controls on some pollution sources. Current 

regulatory regimes are not necessarily effective in controlling water allocation issues (e.g., no 

permit requirements for water withdrawals under 100,000 gpd in Georgia, no restrictions on 

interbasin water transfers in South Carolina, the lack of ability to regulate non-point source 

pollution.) 

The recovery of Atlantic sturgeon along the Atlantic Coast, especially in areas where habitat is 

limited and water quality is severely degraded, will require improvements in the following areas: (1) 

elimination of barriers to spawning habitat either through dam removal, breaching, or installation of 

successful fish passage facilities; (2) operation of water control structures to provide appropriate 

flows, especially during spawning season; (3) imposition of dredging restrictions including seasonal 

moratoriums and avoidance of spawning/nursery habitat; and, (4) mitigation of water quality 

parameters that are restricting sturgeon use of a river (i.e., DO). Additional data regarding sturgeon 

use of riverine and estuarine environments is needed.

A viable population able to adapt to changing environmental conditions is critical to Atlantic 

sturgeon, and the low population numbers of every river population in the South Atlantic DPS put 

them in danger of extinction throughout their range; none of the populations are large or stable 

enough to provide with any level of certainty for continued existence of Atlantic sturgeon in this 

part of its range. Although the largest impact that caused the precipitous decline of the species has 

been curtailed (directed fishing), the population sizes within the South Atlantic DPS have remained 

relatively constant at greatly reduced levels (approximately 6 percent of historical population sizes 
90

in the Altamaha River, and 1 percent of historical population sizes in the remainder of the DPS) for 

100 years. Small numbers of individuals resulting from drastic reductions in populations, such as 

occurred with Atlantic sturgeon due to the commercial fishery, can remove the buffer against 

natural demographic and environmental variability provided by large populations (Berry, 1971; 

Shaffer, 1981; Soulé, 1980). Recovery of depleted populations is an inherently slow process for a 

late-maturing species such as Atlantic sturgeon, and they continue to face a variety of other threats 

that contribute to their risk of extinction. Their late age at maturity provides more opportunities for 

individual Atlantic sturgeon to be removed from the population before reproducing. While a long 

life-span also allows multiple opportunities to contribute to future generations, it also results 

increases the timeframe over which exposure to the multitude of threats facing the South Atlantic 

DPS can occur. 

Summary of the Status of the South Atlantic DPS of Atlantic Sturgeon

The South Atlantic DPS is estimated to number fewer than 6 percent of its historical population 

size, with all river populations except the Altamaha estimated to be less than 1 percent of historical 

abundance. There are an estimated 343 spawning adults per year in the Altamaha and less than 300 

spawning adults per year (total of both sexes) in each of the other major river systems occupied by 

the DPS in which spawning still occurs, whose freshwater range occurs in the watersheds (including 

all rivers and tributaries) of the ACE Basin southward along the South Carolina, Georgia, and 

Florida coastal areas to the St. Johns River, Florida. Recovery of depleted populations is an 

inherently slow process for a late-maturing species such as Atlantic sturgeon. Their late age at 

maturity provides more opportunities for individuals to be removed from the population before 

reproducing. While a long life-span also allows multiple opportunities to contribute to future 

generations, this is hampered within the South Atlantic DPS by habitat alteration, bycatch, and from 

the inadequacy of existing regulatory mechanisms to address and reduce habitat alterations and 

bycatch. 

Dredging is contributing to the status of the South Atlantic DPS by modifying spawning, nursery, 

and foraging habitat. Habitat modifications through reductions in water quality are also 

contributing to the status of the South Atlantic DPS through reductions in DO, particularly during 

times of high water temperatures, which increase the detrimental effects on Atlantic sturgeon 

habitat. Interbasin water transfers and climate change threaten to exacerbate existing water quality 

issues. Bycatch is also a current impact to the South Atlantic DPS that is contributing to its status. 

Fisheries known to incidentally catch Atlantic sturgeon occur throughout the marine range of the 

species and in some riverine waters as well. Because Atlantic sturgeon mix extensively in marine 

waters and may utilize multiple river systems for nursery and foraging habitat in addition to their 

natal spawning river, they are subject to being caught in multiple fisheries throughout their range. 

In addition to direct mortality, stress or injury to Atlantic sturgeon taken as bycatch but released 

alive may result in increased susceptibility to other threats, such as poor water quality (e.g., 

exposure to toxins). This may result in reduced ability to perform major life functions, such as 

foraging and spawning, or even post-capture mortality. While many of the threats to the South 

Atlantic DPS have been ameliorated or reduced due to the existing regulatory mechanisms, such as 

the moratorium on directed fisheries for Atlantic sturgeon, bycatch is currently not being addressed 

through existing mechanisms. Further, access to habitat and water quality continues to be a 

problem even with NMFS’ authority under the Federal Power Act to recommend fish passsage and 

existing controls on some pollution sources. There is a lack of regulation for some large water 
91

withdrawals, which threatens sturgeon habitat. Current regulatory regimes do not require a permit 

for water withdrawals under 100,000 gpd in Georgia and there are no restrictions on interbasin 

water transfers in South Carolina. Data required to evaluate water allocation issues are either very 

weak, in terms of determining the precise amounts of water currently being used, or non-existent, in 

terms of our knowledge of water supplies available for use under historical hydrologic conditions in 

the region. Existing water allocation issues will likely be compounded by population growth, 

drought, and potentially climate change. The inadequacy of regulatory mechanisms to control 

bycatch and habitat alterations is contributing to the status of the South Atlantic DPS. 

4.13 Summary of Available Information on Use of Action Area by Listed Species 

4.13.1 Sea turtles 

Sea turtles are seasonally present in Delaware Bay from May to early November each year, with the 

highest number of individuals present from June to October. Sea turtles occur as far upstream as 

Artificial Island, but are unlikely to be present in reaches further upstream; as such sea turtles are 

only present in Reaches D and E. 

One of the main factors influencing sea turtle presence in northern waters is seasonal temperature 

patterns (Ruben and Morreale 1999). Temperature is correlated with the time of year, with the 

warmer waters in the late spring, summer, and early fall being the most suitable for cold-blooded 

sea turtles. Sea turtles are most likely to occur in the action area between June and October when 

water temperatures are above 11°C and depending on seasonal weather patterns, could be present in 

May and early November. Sea turtles have been documented in the action area by the CETAP 

aerial and boat surveys as well as by surveys conducted by NMFS Northeast Science Center and 

fisheries observers. Additionally, satellite tracked sea turtles have been documented in the action 

area (seaturtle.org tracking database). The majority of sea turtle observations have been of 

loggerhead sea turtles, although all four species of sea turtles have been recorded in the area. 

To some extent, water depth also dictates the number of sea turtles occurring in a particular area. 

The only areas to be dredged have water depths of less than 45 feet. Satellite tracking studies of sea 

turtles in the Northeast found that foraging turtles mainly occurred in areas where the water depth 

was between approximately 16 and 49 ft (Ruben and Morreale 1999). This depth was interpreted 

not to be as much an upper physiological depth limit for turtles, as a natural limiting depth where 

light and food are most suitable for foraging turtles (Morreale and Standora 1990). The areas to be 

dredged and the depths preferred by sea turtles do overlap, suggesting that if suitable forage was 

present, loggerheads and Kemp’s ridleys may be foraging in the channel areas where dredging will 

occur. As there are no SAV beds in any of the channel areas where dredging will occur, green sea 

turtles are not likely to use the areas to be dredged for foraging. 

4.13.2 Shortnose Sturgeon 

Shortnose sturgeon occur in the Delaware River from the lower bay upstream to at least 

Lambertville, New Jersey (river mile 148). Tagging studies by O’Herron et al. (1993) found that 

the most heavily used portion of the river appears to be between river mile 118 below Burlington 

Island and river mile 137 at the Trenton Rapids. Hastings et al. (1987) used Floy T-anchor tags in a 

tag-and-recapture experiment from 1981 to 1984 to estimate the size of the Delaware River 

population in the Trenton to Florence reach. Population sizes by three estimation procedures ranged 
92

from 6,408 to 14,080 adult sturgeon. These estimates compare favorably with those based upon 

similar methods in similar river systems. This is the best available information on population size, 

but because the recruitment and migration rates between the population segment studied and the 

total population in the river are unknown, model assumptions may have been violated. 

In the Delaware River, movement to the spawning grounds occurs in early spring, typically in late 

March15, with spawning occurring through the end of April. Movement to the spawning areas is 

triggered in part by water temperature and fish typically arrive at the spawning locations when 

water temperatures are between 8-9oC with most spawning occurring when water temperatures are 

between 10 and 15oC. Until recently, actual spawning (i.e., fertilized eggs or larvae) had not been 

documented in this area; however, the concentrated use of the Scudders Falls region in the spring by 

large numbers of mature male and female shortnose sturgeon indicated that this is the major 

spawning area (O’Herron et al. 1993). The same area was identified as a likely spawning area 

based on the collection of two ripe females in the spring of 1965 (Hoff 1965). The capture of early 

life stages (eggs and larvae) in this region in the spring of 2008 confirms that this area of the river is 

used for spawning and as a nursery area (ERC 2009). During the spawning period, males remain on 

the spawning grounds for approximately a week while females only stay for a few days (O’Herron 

and Hastings 1985). After spawning, which typically ceases by the time water temperatures reach 

15oC (although sturgeon have been reported on the spawning grounds at water temperatures as high 

as 18oC), shortnose sturgeon move rapidly downstream to the Philadelphia area. 

Shortnose sturgeon eggs generally hatch after approximately 9-12 days (Buckley and Kynard 1981). 

The larvae are photonegative, remaining on the bottom for several days. Buckley and Kynard 

(1981) found week old larvae to be photonegative and form aggregations with other larvae in 

concealment. Larvae are expected to begin swimming downstream at 9-14 days old (Richmond and 

Kynard 1995). Larvae are expected to be less than 20mm TL at this time (Richmond and Kynard 

1995). This initial downstream migration generally lasts two to three days (Richmond and Kynard 

1995). Studies (Kynard and Horgan 2002) suggest that larvae move approximately 7.5km/day 

during this initial 2 to 3 day migration. Laboratory studies indicate that young sturgeon move 

downstream in a 2-step migration: the initial 2-3 day migration followed by a residency period of 

the Young of the Year (YOY), then a resumption of migration by yearlings in the second summer of 

life (Buckley and Kynard 1981). 

No studies have been conducted on juveniles in the Delaware River. As shortnose sturgeon 

demonstrate nearly identical migration patterns in all rivers, it is likely that juveniles in the 

Delaware River exhibit similar migration patterns to sturgeon in other river systems. As such, it is 

likely that yearlings are concentrated in the upper Delaware River above Philadelphia. 

As noted above, due to limited information on juvenile shortnose sturgeon, it is difficult to ascertain 

 

15 Based on US Geological Survey (USGS) water temperature data for the Delaware River at the Trenton gage (USGS 

gage 01463500; the site closest to the Scudders Falls area), for the period 2003-2009, water temperature reached 8°C 

sometime between March 26 (2006) and April 21 (2007), with temperatures typically reaching 8°C in the last few days 

of March. During this period, mean water temperatures at Trenton reached 10°C between March 28 (2004) and April 

22 (2007) and 15oC between April 15 (2006) and April 21 (2003). There is typically a three to four week period with 

mean daily temperatures between 8 and 15°C. 
93

their distribution and nursery habitat (O’Herron 2000, pers. comm.). In other river systems, older 

juveniles (3-10 years old) occur in the saltwater/freshwater interface (NMFS 1998). In these 

systems, juveniles moved back and forth in the low salinity portion of the salt wedge during 

summer. In the Delaware River the oligohaline/fresh interface can range from as far south as 

Wilmington, Delaware, north to Philadelphia, Pennsylvania, depending upon meteorological 

conditions such as excessive rainfall or drought. As a result, it is possible that in the Delaware 

River, juveniles could range from Artificial Island (river mile 54) to the Schuylkill River (river mile 

92) (O’Herron 2000, pers. comm.). The distribution of juveniles in the river is likely highly 

influenced by flow and salinity. In years of high flow (for example, due to excessive rains or a 

significant spring runoff), the salt wedge will be pushed seaward and the low salinity reaches 

preferred by juveniles will extend further downriver. In these years, shortnose sturgeon juveniles 

are likely to be found further downstream in the summer months. In years of low flow, the salt 

wedge will be higher in the river and in these years juveniles are likely to be concentrated further 

upstream. 

O’Herron believes that if juveniles are present within this range they would likely aggregate closer 

to the downstream boundary in the winter when freshwater input is normally greater (O’Herron 

2000, pers. comm.). Research in other river systems indicates that juveniles are typically found 

over silt and sand/mud substrates in deep water of 10-20m. Juvenile sturgeon primarily feed in 10 

to 20 meter deep river channels, over sand-mud or gravel-mud bottoms (Pottle and Dadswell 1979). 

However, little is known about the specific feeding habits of juvenile shortnose sturgeon in the 

Delaware River.

As noted above, after spawning, adult shortnose sturgeon migrate rapidly downstream to the 

Philadelphia area (RM 100). After adult sturgeon migrate to the area around Philadelphia, many 

adults return upriver to between river mile 127 and 134 within a few weeks, while others gradually 

move to the same area over the course of the summer (O’Herron 1993). By the time water 

temperatures have reached 10°C, typically by mid-November16, adult sturgeon have returned to the 

overwintering grounds around Duck Island and Newbold Island. These patterns are generally 

supported by the movement of radio-tagged fish in the region between river mile 125 and river mile 

148 as presented by Brundage (1986). Based on water temperature data collected at the USGS gage 

at Philadelphia, in general, shortnose sturgeon are expected to be at the overwintering grounds 

between early November and mid-April. Adult sturgeon overwinter in dense sedentary 

aggregations in the upper tidal reaches of the Delaware between river mile 118 and 131. The areas 

around Duck Island and Newbold Island seem to be regions of intense overwintering 

concentrations. However, unlike sturgeon in other river systems, shortnose sturgeon in the 

Delaware do not appear to remain as stationary during overwintering periods. Overwintering fish 

have been found to be generally active, appearing at the surface and even breaching through the 

skim ice (O’Herron 1993). Due to the relatively active nature of these fish, the use of the river 

during the winter is difficult to predict. However, O’Herron et al. (1993) found that the typical 

overwintering movements are fairly localized and sturgeon appear to remain within 1.24 river miles 

 

16 Based on information from the USGS gage at Philadelphia (01467200) during the 2003-2008 time period, mean water 

temperatures reached 10°C between October 29 (2005 and 2006) and November 14 (2003). In the spring, mean water 

temperature reached 10°C between April 2 (2006) and April 21 (2009). 
94

of the aggregation site (O’Herron and Able 1986). Investigations with video equipment by the 

ACOE in March 2005 (Versar 2006) documented two sturgeon of unknown species at Marcus Hook 

and 1 sturgeon of unknown species at Tinicum. Gillnetting in these same areas caught only one 

Atlantic sturgeon and no shortnose sturgeon. Video surveys of the known overwintering area near 

Newbold documented 61 shortnose sturgeon in approximately 1/3 of the survey effort. This study 

supports the conclusion that the vast majority of shortnose sturgeon overwinter near Duck and 

Newbold Island but that a limited number of shortnose sturgeon occur in other downstream areas, 

including Marcus Hook, during the winter months. The overwintering location of juvenile 

shortnose sturgeon is not known but believed to be on the freshwater side of the oligohaline/fresh 

water interface (O’Herron 1990). In the Delaware River, the oligohaline/freshwater interface 

occurs in the area between Wilmington, Delaware and Marcus Hook, Pennsylvania (O’Herron 

1990). 

Shortnose sturgeon appear to be strictly benthic feeders (Dadswell 1984). Adults eat mollusks, 

insects, crustaceans and small fish. Juveniles eat crustaceans and insects. While shortnose sturgeon 

forage on a variety of organisms, in the Delaware River, sturgeon primarily feed on the Asiatic river 

clam (Corbicula manilensis). Corbicula is widely distributed at all depths in the upper tidal 

Delaware River, but it is considerably more numerous in the shallows on both sides of the river than 

in the navigation channels. Foraging is heaviest immediately after spawning in the spring and 

during the summer and fall, and lighter in the winter. 

Historically, sturgeon were relatively rare below Philadelphia due to poor water quality. Since the 

1990s, the water quality in the Philadelphia area has improved leading to an increased use of the 

lower river by shortnose sturgeon. Few studies have been conducted to document the use of the 

river below Philadelphia by sturgeon. Brundage and Meadows (1982) have reported incidental 

captures in commercial gillnets in the lower Delaware. During a study focusing on Atlantic 

sturgeon, Shirey et al. (1999) captured 9 shortnose sturgeon in 1998. During the June through 

September study period, Atlantic and shortnose sturgeon were found to use the area on the west side 

of the shipping channel between Deep Water Point, New Jersey and the Delaware-Pennsylvania 

line. The most frequently utilized areas within this section were off the northern and southern ends 

of Cherry Island Flats in the vicinity of the Marcus Hook Bar. A total of 25 shortnose sturgeon 

have been captured by Shirey in this region of the river from 1992 - 2004, with capture rates 

ranging from 0-10 fish per year (Shirey 2006). Shortnose sturgeon have also been documented on 

the trash racks of the Salem nuclear power plant in Salem, New Jersey at Artificial Island. The 

intakes for this plant are located in Delaware Bay. While the available information does not 

identify the area below Philadelphia as a concentration area for adult shortnose sturgeon, it is 

apparent that this species does occur in the lower Delaware River and upper Delaware Bay. 

In May 2005, a one-year survey for juvenile sturgeon in the Delaware River in the vicinity of the 

proposed Crown Landing LNG project was initiated. The objective of the survey was to obtain 

information on the occurrence and distribution of juvenile shortnose and Atlantic sturgeon near the 

proposed project site to be located near RM 78, approximately 20 miles south of Philadelphia. 

Sampling for juvenile sturgeon was performed using trammel nets and small mesh gill nets. The 

nets were set at three stations, one located adjacent to the project site, one at the upstream end of the 

Marcus Hook anchorage (approximately 2.7 miles upstream of the project site, at RM 81), and one 

near the upstream end of the Cherry Island Flats (at RM 74; approximately 3.8 miles downstream of 
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the site). Nets were set within three depth ranges at each station: shallow (<10 feet at MLW), 

intermediate (10-20 feet at MLW) and deep (20-30+ feet at MLW). Each station/depth zone was 

sampled once per month. Nets were fished for at least 4 hours when water temperatures were less 

than 27°C and limited to 2 hours when water temperature was greater than 27°C. The sampling 

from April through August 2005 yielded 3,014 specimens of 22 species, including 3 juvenile 

shortnose sturgeon. Juvenile shortnose sturgeon were collected one each during the June, July and 

August sampling events. Two of the shortnose sturgeon were collected at RM 78 and one was 

taken at the downstream sampling station at RM 74. Total length ranged from 311-367mm. During 

the September – December sampling, one juvenile shortnose sturgeon was caught in September at 

RM 78 and one in November at the same location. One adult shortnose sturgeon was captured in 

October at RM 74. All of the shortnose sturgeon were collected in deep water sets (greater than 20 

feet). These depths are consistent with the preferred depths for foraging shortnose sturgeon 

juveniles reported in the literature (NMFS 1998). The capture of an adult in the Cherry Island Flats 

area (RM 74) is consistent with the capture location of several adult sturgeon reported by Shirey et 

al. 1999 and Shirey 2006. 

Brundage compiled a report presenting an analysis of telemetry data from receivers located at 

Torresdale RM 93, Tinicum RM 86, Bellevue RM 73 and New Castle RM 58 during April through 

December 2003. The objective of the study was to provide information on the occurrence and 

movements of shortnose sturgeon in the general vicinity of the proposed Crown Landing LNG 

facility. A total of 60 shortnose sturgeon had been tagged with ultrasonic transmitters: 30 in fall 

2002, 13 in early summer 2003 and 13 in fall 2003. All fish tagged were adults tagged after 

collection in gill nets in the upper tidal Delaware River, between RM 126-132. Of the 60 tagged 

sturgeon, 39 (65%) were recorded at Torresdale, 22 (36.7%) were recorded at Tinicum, 16 (26.7%) 

at Bellevue and 18 (30%) at New Castle. The number of tagged sturgeon recorded at each location 

varied with date of tagging. Of the 30 sturgeon tagged in fall 2002, 26 were recorded at Torresdale, 

17 at Tinicum, 11 at Bellevue and 13 at New Castle. Only two of the 13 tagged in fall 2003 were 

recorded, both at Torresdale only. Brundage concludes that seasonal movement patterns and time 

available for dispersion likely account for this variation, particularly for the fish tagged in fall 2003. 

Eleven of the 30 shortnose sturgeon tagged in fall 2002 and 5 of the 17 fish tagged in summer 2003 

were recorded at all four locations. Some of the fish evidenced rapid movements from one location 

sequentially to the next in upstream and/or downstream direction. These periods of rapid sequential 

movement tended to occur in the spring and fall, and were probably associated with movement to 

summer foraging and overwintering grounds, respectively. As a group, the shortnose sturgeon 

tagged in summer 2003 occurred a high percentage of time within the range of the Torresdale 

receiver. The report concludes that the metrics indicate that the Torresdale Range of the Delaware 

River is utilized by adult shortnose sturgeon more frequently and for greater durations than the other 

three locations. Of the other locations, the New Castle Range appears to be the most utilized 

region. At all ranges, shortnose were detected throughout the study period, with most shortnose 

sturgeon detected in the project area between April and October. The report indicates that most 

adult shortnose sturgeon used the Torresdale to New Castle area as a short-term migratory route 

rather than a long-term concentration or foraging area. Adult sturgeon in this region of the river are 

highly mobile, and as noted above, likely using the area as a migration route. 

Information on the use of the river by juveniles is lacking and the information available is extremely 

limited (i.e., 5 captures). As evidenced by the Crown Landing study, juvenile shortnose sturgeon 
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have been documented between RM 81-74 from June – November. Due to the limited geographic 

scope of this study, it is difficult to use these results to predict the occurrence of juvenile shortnose 

sturgeon throughout the action area. However, the April – August time frame is when flows in the 

Delaware River are highest and the time when the action area is likely to experience the low salinity 

levels preferred by juveniles (FERC 2005). Beginning in August, flows decrease and the salt wedge 

begins to move upstream, which may preclude juveniles from occurring in the action area. Based 

on this information, it is likely that juvenile shortnose sturgeon are present in the action area at least 

during the April – August time frame. The capture of juvenile shortnose sturgeon in the RM 81-74 

range in November of 2005 suggests that if water conditions are appropriate, juveniles may also be 

present in this area through the fall. While it is possible, based on habitat characteristics, that this 

area of the river is used as an overwintering site for juveniles, there is currently no evidence to 

support this presumption. 

In 2005, the ACOE conducted investigations to determine the use of the Marcus Hook region by 

sturgeon. Surveys for the presence of Atlantic and shortnose sturgeon were conducted between 

March 4 and March 25, 2005 primarily using a Video Ray®Explorer submersible remotely operated 

vehicle (ROV). The Video Ray® was attached to a 1.0 x 1.0 x 1.5 meter aluminum sled which was 

towed over channel bottom habitats behind a 25-foot research boat. All images captured by the 

underwater camera were transmitted through the unit’s electronic tether and recorded on video 

cassettes. A total of 43 hours of bottom video were collected on 14 separate survey days. Twelve 

days of survey work were conducted at the Marcus Hook, Eddystone, Chester, and Tinicum ranges, 

while two separate days of survey work were conducted up river near Trenton, New Jersey, at an 

area known to have an over wintering population of shortnose sturgeon.

The sled was generally towed on the bottom parallel to the centerline of the channel and into the 

current at 0.8 knots. Tow track logs were maintained throughout the survey and any fish seen on 

the ROV monitor was noted. Boat position during each video tow was recorded every five minutes 

with the vessel’s Furuno GPS. The Sony digital recorder recorded a time stamp that could be 

matched with the geographic coordinates taken from the on-board GPS. Digital tapes were 

reviewed in a darkened laboratory at normal or slow speed using a high quality 28-inch television 

screen as a monitor. When a fish image was observed the tape was slowed and advanced frame by 

frame (30 images per second were recorded by the system). The time stamp where an individual 

fish was observed was recorded by the technician. Each fish was identified to the lowest practical 

taxon (usually species) and counted. A staff fishery biologist reviewed questionable images and 

species identifications. Distances traveled by the sled between time stamps were calculated based 

on the GPS coordinates recorded in the field during each tow. Total fish counts between the 

recorded coordinates within a particular tow were converted to observed numbers per 100 meters of 

tow track.

Limited 25-foot otter trawling and gillnet sets were conducted initially to provide density data, and 

later to provide ground truth information on the fish species seen in the video recording. Large 

boulders and other snags that tore the net and hung up the vessel early on in the study prompted 

abandoning this effort for safety reasons given the high degree of tanker traffic in the lower 

Delaware River. The trawl net was a 7.6-m (25-foot) experimental semi-balloon otter trawl with 

44.5-mm stretch mesh body fitted with a 3.2-mm stretch mesh liner in the cod end. Otter trawls 

were generally conducted for five minutes unless a snag or tanker traffic caused a reduction in tow 
97

time. Experimental gillnets were periodically deployed throughout the survey period in the Marcus 

Hook area. One experimental gillnet was 91.4-m in length and 3-m deep and was composed of six 

15.2-m panels of varying mesh size. Of the six panels in each net, two panels were 50.8-mm stretch 

mesh, 2 panels were 101.6-mm stretch mesh and two panels were 152.4-mm stretch mesh. Another 

gillnet was 100 m in length and consisted of four 25 x 2-m panels of 2.5-10.2-cm stretched 

monofilament mesh in 2.5 cm increments. Gill nets were generally set an hour before slack high or 

low water and allowed to fish for two hours as the nets had to be retrieved before maximum 

currents were reached.

Turbidity in the Marcus Hook region of the Delaware River limited visibility to about 18 inches in 

front of the camera. However, despite the reduced visibility, several different fish species were 

recorded by the system including sturgeon. In general, fish that encountered the sled between the 

leading edge of the sled runners were relatively easy to distinguish. The major fish species seen in 

the video images were confirmed by the trawl and gillnet samples. In the Marcus Hook project 

area, a total of 39 survey miles of bottom habitat were recorded in twelve separate survey days. 

Eight different species were observed on the tapes from a total of 411 fish encountered by the 

camera. White perch, unidentified catfish, and unidentified shiner were the most common taxa 

observed. Three unidentified sturgeon were seen on the tapes, two in the Marcus Hook Range, and 

one in the Tinicum Range. Although it could not be determined if these sturgeon were Atlantic or 

shortnose, gillnetting in the Marcus Hook anchorage produced one juvenile Atlantic sturgeon that 

was 396 mm in total length, 342 mm in fork length, and weighed 250 g.

Water clarity in the Trenton survey area was much greater (about 6 feet ahead of the camera) and 

large numbers of shortnose sturgeon were seen in the video recordings. In a total of 7.9 survey 

miles completed in two separate days of bottom imaging, 61 shortnose sturgeons were observed. 

To provide a comparative measure of project area density (where visibility was limited) to up river 

densities (where visibility was greater), each of the 61 sturgeon images were classified as to 

whether the individual fish was observed between the sled runners or whether they were seen ahead 

of the sled. Real time play backs of video recordings in the upriver sites indicated that the sturgeon 

did not react to the approaching sled until the cross bar directly in front of the camera was nearly 

upon it. Thirty of the 61 upstream sturgeon images were captured when the individual fish was 

between the runners. Using this criterion, approximately 10 times more sturgeon were encountered 

in the upriver area relative to the project site near Marcus Hook where three sturgeons were 

observed. Using the number of sturgeon observed per 100 meters of bottom surveyed, the relative 

sturgeon density in the project area was several orders of magnitude less than those observed in the 

Trenton area. As calculated in the report, the relative density of unidentified sturgeon in the Marcus 

Hook area was 0.005 fish per 100 meters while the densities of shortnose sturgeon between the sled 

runners in the upriver area was 0.235 fish per 100 meters.

The results of the video sled survey in the Marcus Hook project area confirmed that sturgeons are 

using the area in the winter months. However, sturgeon relative densities in the project area were 

much lower than those observed near Trenton, New Jersey, even when the upriver counts were 

adjusted for the higher visibility (i.e., between runner sturgeon counts). The sturgeons seen near 

Trenton were very much concentrated in several large aggregations, which were surveyed in 

multiple passes on the two sampling dates devoted to this area. The lack of avoidance of the 

approaching sled seen in the upriver video recordings where water clarity was good suggests that 
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little to no avoidance of the sled occurred in the low visibility downriver project area. Video 

surveys in the downriver project area did not encounter large aggregations of sturgeon as was 

observed in the upstream survey area despite having five times more sampling effort than the 

upstream area. This suggests that sturgeons that do occur in the Marcus Hook area during the 

winter are more dispersed and that the overall number of shortnose sturgeon occurring in this area 

in the winter months is low. 

As described in the “Description of the Action” section above, dredging will occur in six river 

reaches (see Table 1 and 2). The discussion below will summarize the likely seasonal distribution 

of shortnose sturgeon in these river reaches. Based on the best available information, eggs and 

larvae are not likely to be in the action area. Due to the benthic, adhesive nature of the eggs, they 

only occur in the immediate vicinity of the spawning area, located at least 30 miles upstream of the 

action area. Larvae are also limited to an area close to the spawning grounds, and therefore, not 

likely to occur in the action area. Distribution of adult and juvenile shortnose sturgeon in the action 

area is influenced by seasonal water temperature, the distribution of forage items, and salinity. 

Although they have been documented in waters with salinities as high as 31 parts per thousand 

(ppt), shortnose sturgeon are typically concentrated in areas with salinity levels of less than 3 ppt 

(Dadswell et al. 1984). Jenkins et al. (1993) demonstrated in lab studies that 76 day old shortnose 

sturgeon experienced 100% mortality in salinity greater than 14 ppt. One year old shortnose 

sturgeon were able to tolerate salinity levels as high as 20 ppt for up to 18 hours but experienced 

100% mortality at salinity levels of 30 ppt. A salinity of 9 ppt appeared to be a threshold at which 

significant mortalities began to occur, especially among the youngest fish (Jenkins et al. 1993). The 

distribution of salinity in the Delaware estuary exhibits significant variability on both spatial and 

temporal scales, and at any given time reflects the opposing influences of freshwater inflow from 

tributaries versus saltwater inflow from the Atlantic Ocean. The estuary can be divided into four 

longitudinal salinity zones. Starting at the downstream end, the mouth of the Bay to RM 34 is 

considered polyhaline (18-30ppt), RM 34-44 is mesohaline (5-18ppt), RM 44-79 is oligohaline (0.5-

5ppt), and Marcus Hook (RM 79) to Trenton is considered Fresh (0.0-0.5ppt). Based on this 

information and the known tolerances and preferences of shortnose sturgeon to salinity, shortnose 

sturgeon are most likely to occur upstream of RM 44 (rkm 70) where salinity is typically less than 

5ppt. As tolerance to salinity increases with age and size, large juveniles and adults are likely to be 

present through the mesohaline area extending to RM 34. Due to the typical high salinities 

experienced in the polyhaline zone (below RM 34 (rkm 55)), shortnose sturgeon are likely to be rare 

in this reach of the river; this area covers part of Reach D and all of Reach E. 

Both adult and juvenile shortnose sturgeon are likely to occur in reach AA (RM 102-97 (rkm 164 –

156)) any time water temperatures are greater than 10°C (the trigger for movement to overwintering 

areas); these temperatures are typically experienced between early April and mid-late November17. 

Shortnose sturgeon in this reach are likely to be using it for migration and for opportunistic 

foraging. This reach of the river is not known to be a concentration area for any life stage of 

shortnose sturgeon. Similarly, reach A (RM 97-85) is also likely to be used by migrating shortnose 

 

17 For example, in 2004 temperatures reached 10°C on April 2 and dropped to 10°C on November 13. In 2005 

temperatures were above 10°C between April 11 and November 23. 
99

sturgeon and for opportunistic foraging. This reach of the river includes the Torresdale Range (RM 

93), an area which the 2003-2004 telemetry study noted above suggests may be a relatively high use 

area for shortnose sturgeon in the April – October time frame. The number of shortnose sturgeon 

utilizing the Torresdale area suggests that conditions in Torresdale may support a shortnose 

sturgeon foraging or resting area; however, the tracking data indicates that shortnose sturgeon in 

this reach are highly mobile. Reach B (RM 85-67) encompasses the Cherry Island Flats and Marcus 

Hook Bar areas. The capture of multiple shortnose sturgeon in this reach during the summer 

months (Shirey 1999 and 2006) indicates that shortnose sturgeon are likely to be foraging here in 

this summer and that it may serve as a summer concentration area. Evidence also suggests that at 

least some shortnose sturgeon may overwinter near Marcus Hook, or that at least that some 

shortnose sturgeon are present in this area during the winter (Versar 2006; ERC 2012). As such, 

shortnose sturgeon could be present in Reach B year round, with the highest numbers present when 

water temperatures are above 10°C between April and November. Reach C encompasses the area 

from RM 67-55 and includes the New Castle range where the 2003-2004 telemetry studies indicated 

was an area frequented by shortnose sturgeon. This area also includes the outlet of the ChesapeakeDelaware canal which has been documented to be used by shortnose sturgeon moving between the 

upper Chesapeake Bay and the Delaware River. Based on the best available information, shortnose 

sturgeon are likely to be present in this reach of the river when water temperatures are greater than 

10°C (mid April – mid November). Reach D includes RM 55-41 and includes the area near 

Artificial Island. Shortnose sturgeon have occasionally been recorded at the Salem Nuclear 

Generating Facility intakes with at least 10 live sturgeon observed at the trash racks between April 

and early November since 1979. One dead shortnose sturgeon was observed at the intake in 

January 1978 and one in late November 2007. However, due to the level of decomposition 

observed with these fish, it is unlikely that they died at the intakes or that they died during the 

winter months. Shortnose sturgeon are likely to at least occasionally occur in Reach D; however, 

the low number of documented occurrences in this reach combined with the higher salinity levels, 

make this reach less likely to be used than other upstream reaches. Reach E includes RM 41- 5. 

Based on the best available information, including the high salinity levels in this reach, shortnose 

sturgeon are expected to be rare in this reach; however, occasional shortnose sturgeon may occur in 

this reach between late April and mid-November. 

4.13.3 Atlantic sturgeon in the Action Area

In the Delaware River and Estuary, Atlantic sturgeon occur from the mouth of the Delaware Bay to 

the fall line near Trenton, NJ, a distance of 220 km (NMFS and USFWS, 1998; Simpson, 2008). 

All historical Atlantic sturgeon habitats appear to be accessible in the Delaware (NMFS and 

USFWS, 1998; ASSRT, 2007). Recent multi-year studies have provided new information on the 

use of habitats by Atlantic sturgeon within the Delaware River and Estuary (Brundage, 2007; 

Simpson, 2008; Brundage and O’Herron, 2009; Fisher, 2009; Calvo et al., 2010; Fox and Breece, 

2010). 

Historical records from the 1830's indicate Atlantic sturgeon may have spawned as far north as 

Bordentown, just below Trenton, NJ (Pennsylvania Commission of Fisheries, 1897). Cobb (1899) 

and Borden (1925) reported spawning between rkm 77 and 130 (Delaware City, DE to Chester City, 

PA). Based on recent tagging and tracking studies carried out from 2009-2011, Breece (2011) 

reports likely spawning locations at rkm 120-150 and rkm 170-190. The shift from historical 

spawning sites is thought to be at least partially related to changes in the location of the salt line 
100

over time. Mature adults have been tracked in these areas at the time of year when spawning is 

expected to occur and movements have been consistent with what would be expected from 

spawning adults. Based on tagging and tracking studies, Simpson (2008) suggested that spawning 

habitat also exists from Tinicum Island (rkm 136) to the fall line in Trenton, NJ (rkm 211). To date, 

eggs and larvae have not been documented to confirm that actual spawning is occurring in these 

areas. However, as noted below, the recent documented presence of young of the year in the 

Delaware River provides confirmation that spawning is occurring in this river. 

Sampling in 2009 that targeted YOY resulted in the capture of more than 60 YOY in the Marcus 

Hook anchorage (rkm 127) area during late October-late November 2009 (Fisher, 2009; Calvo et 

al., 2010). Twenty of the YOY from one study and six from the second study received acoustic tags 

that provided information on habitat use by this early life stage (Calvo et al., 2010; Fisher, 2011). 

YOY used several areas from Deepwater (rkm 105) to Roebling (rkm 199) during late fall to early 

spring. Some remained in the Marcus Hook area while others moved upstream, exhibiting 

migrations in and out of the area during winter months (Calvo et al., 2010; Fisher, 2011). At least 

one YOY spent some time downstream of Marcus Hook (Calvo et al., 2010; Fisher, 2011). 

Downstream detections from May to August between Philadelphia (rkm 150) and New Castle (rkm 

100) suggest non-use of the upriver locations during the summer months (Fisher, 2011). By 

September 2010, only 3 of 20 individuals tagged by DE DNREC persisted with active tags (Fisher, 

2011). One of these migrated upstream to the Newbold Island and Roebling area (rkm 195), but 

was back down in the lower tidal area within three weeks and was last detected at Tinicum Island 

(rkm 141) when the transmitter expired in October (Fisher, 2011). The other two remained in the 

Cherry Island Flats (rkm 113) and Marcus Hook Anchorage area (rkm130) until their tags 

transmissions also ended in October (Fisher, 2011). 

The Delaware Estuary is known to be a congregation area for sturgeon from multiple DPSs. 

Generally, non-natal late stage juveniles (also referred to as subadults) immigrate into the estuary in 

spring, establish home range in the summer months in the river, and emigrate from the estuary in 

the fall (Fisher, 2011). Subadults tagged and tracked by Simpson (2008) entered the lower Delaware 

Estuary as early as mid-March but, more typically, from mid-April through May. Tracked sturgeon 

remained in the Delaware Estuary through the late fall departing in November (Simpson, 2008). 

Previous studies have found a similar movement pattern of upstream movement in the springsummer and downstream movement to overwintering areas in the lower estuary or nearshore ocean 

in the fall-winter (Brundage and Meadows, 1982; Lazzari et al., 1986; Shirey et al., 1997; 1999; 

Brundage and O’Herron, 2009; Brundage and O’Herron in Calvo et al., 2010). 

Brundage and O’Herron (in Calvo et al. (2010)) tagged 26 juvenile Atlantic sturgeon, including six

young of the year. For non YOY fish, most detections occured in the lower tidal Delaware River 

from the middle Liston Range (rkm 70) to Tinicum Island (rkm 141). For non YOY fish, these 

researchers also detected a relationship between the size of individuals and the movement pattern of 

the fish in the fall. The fork length of fish that made defined movements to the lower bay and ocean 

averaged 815 mm (range 651-970 mm) while those that moved towards the bay but were not 

detected below Liston Range averaged 716 mm (range 505-947 mm), and those that appear to have 

remained in the tidal river into the winter averaged 524 mm (range 485-566 mm) (Calvo et al., 

2010). During the summer months, concentrations of Atlantic sturgeon have been located in the 

Marcus Hook (rkm 123-129) and Cherry Island Flats (rkm 112-118) regions of the river (Simpson, 
101

2008; Calvo et al., 2010) as well as near Artificial Island (Simpson, 2008). Sturgeon have also been 

detected using the Chesapeake and Delaware Canal (Brundage, 2007; Simpson, 2008). 

Adult Atlantic sturgeon captured in marine waters off of Delaware Bay in the spring were tracked in 

an attempt to locate spawning areas in the Delaware River, (Fox and Breece, 2010; Breece 2011). 

Over the period of two sampling seasons (2009-2010) four of the tagged sturgeon were detected in 

the Delaware River. The earliest detection was in mid-April while the latest departure occurred in 

mid-June (Fox and Breece, 2010); supporting the assumption that adults are only present in the river 

during spawning. The sturgeon spent relatively little time in the river each year, generally about 4 

weeks, and used the area from New Castle, DE (rkm 100) to Marcus Hook (rkm 130) (Fox and 

Breece, 2010). A fifth sturgeon tagged in a separate study was also tracked and followed a similar 

timing pattern but traveled farther upstream (to rkm 165) before exiting the river in early June (Fox 

and Breece, 2010). 

Based on mixed-stock analysis, we have determined that Atlantic sturgeon in the action area likely 

originate from the five DPSs at the following frequencies: Gulf of Maine 7%; NYB 58%; 

Chesapeake Bay 18%; South Atlantic 17%; and Carolina 0.5%. In the action area, any eggs, larvae, 

or young of the year (juveniles) would only originate from the New York Bight DPS because these 

life stages are restricted to their natal river. Subadults from any of the five DPSs could be present in 

the action area in the proportions noted above; this life stage is most likely to be in the action area 

from mid-April to mid-November although some subadults may overwinter in the river and be 

present year round. Adults are only likely to be present in the river for approximately a four week 

period from mid-April to mid-June, dependent on annual water temperature. Nearly all adults in the 

river are likely to originate from the New York Bight DPS, but tracking indicates that occasionally 

adults are present in rivers outside their DPS of origin. 

Atlantic sturgeon are well distributed throughout the Delaware River and Bay and could be present 

year round in all of the river reaches; however, because of low tolerance to salinity, juveniles are 

restricted to waters above the salt line, which moves seasonally. Juveniles are only likely to be 

present in Reaches AA, A, B and upper portions of C. Based on the likely spawning sites at rkm 

120-150 and 170-190, eggs are only likely to be present seasonally in reach B and upstream of 

reach AA. Larvae and YOY can also be present in Reaches AA, A, B and upper portions of reach 

C. Subadults and adults could be present in any of the reaches. 

5.0 ENVIRONMENTAL BASELINE

Environmental baselines for biological opinions include the past and present impacts of all state, 

federal or private actions and other human activities in the action area, the anticipated impacts of all 

proposed federal projects in the action area that have already undergone formal or early Section 7 

consultation, and the impact of state or private actions that are contemporaneous with the 

consultation in process (50 CFR 402.02). The environmental baseline for this Opinion includes the 

effects of several activities that may affect the survival and recovery of the listed species in the 

action area. The activities that shape the environmental baseline in the action area of this 

consultation generally include: dredging operations, water quality, scientific research, shipping and 

other vessel traffic and fisheries, and recovery activities associated with reducing those impacts. 
102

5.1 Federal Actions that have Undergone Formal or Early Section 7 Consultation 

NMFS has undertaken several ESA section 7 consultations to address the effects of actions 

authorized, funded or carried out by Federal agencies. Each of those consultations sought to 

develop ways of reducing the probability of adverse impacts of the action on listed species. 

Consultations are detailed below. 

5.1.1 Delaware River – Philadelphia to Trenton Federal Navigation Project – Dredging 

The Delaware River Philadelphia to Trenton Federal Navigation Channel is maintained by the 

ACOE. As explained in the Consultation History section above, a batched consultation was 

completed in 1996 between NMFS and the ACOE on the effects of the ACOE’s authorization and 

completion of several Federal navigation projects, including the Philadelphia to Trenton project, as 

well as their regulatory dredging program. The Opinion was reinitiated in 1998 with an amendment 

issued in 1999. The amended Opinion included an Incidental Take Statement exempting the annual 

take (entrainment and mortality) of four shortnose sturgeon, 4 loggerhead, 1 Kemp’s ridley, and 1 

green sea turtle. This take applies to the Philadelphia to Trenton project, maintenance of the 40-

foot Philadelphia to the Sea channel, and the ACOE regulatory program where private dredging 

activities are authorized. 

Dredging in the Philadelphia to Trenton project has caused shortnose sturgeon mortality and may 

have affected shortnose sturgeon distribution and foraging habitat. In mid-March 1996, three 

subadult shortnose sturgeon were found in a dredge discharge pool on Money Island, near Newbold 

Island. The dead sturgeon were found on the side of the spill area into which the hydraulic pipeline 

dredge was pumping, and the presence of large amounts of roe in two specimens and minimal 

decomposition indicates that the fish were alive and in good condition prior to entrainment. In 

January 1998, three shortnose sturgeon were discovered in the hydraulic maintenance dredge spoil 

in the Florence to Trenton section of the upper Delaware River. These fish also appeared to have 

been alive and in good condition prior to entrainment. 

Dredging was being conducted in the Kinkora and Florence ranges when takes occurred; this area is 

overlaps with where shortnose sturgeon are known to overwinter in large aggregations. Since 

dredging involves removing the bottom material down to a specified depth, the benthic environment 

could be severely impacted by dredging operations. As shortnose sturgeon are benthic species, the 

alteration of the benthic habitat could have affected sturgeon prey distribution and/or foraging 

ability. Since 1998 the ACOE has been avoiding dredging in the overwintering area during the time 

of year when shortnose sturgeon are present. Habitats affected by the Philadelphia to Trenton 

project include foraging, overwintering and nursery habitats. Since 1998, no sturgeon mortalities 

have been observed. 

5.1.2 Delaware River – Philadelphia to the Sea Federal Navigation Project 

As noted in the Consultation History section, the existing 40 foot Philadelphia to the Sea navigation 

project is maintained with hopper and cutterhead dredges annually. As noted above, an Opinion 

was issued in 1996 and amended in 1999 that considered the effects of the maintenance of this 

project on shortnose sturgeon and sea turtles. The Philadelphia District Endangered Species 

Monitoring Program began in August 1992. Since that time, all hopper dredge operations 

conducted downstream of the Delaware Memorial Bridge between May and November have used 

endangered species observers to monitor for interactions with sea turtles. No shortnose or Atlantic 
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sturgeon have been observed during any hopper dredging event. Several sea turtles have been 

entrained during hopper dredging operations including two loggerheads in August 1993 and one

loggerhead on June 22, 1994. Relocation trawling was conducted in 1994, and eight loggerheads 

were captured and relocated away from the channel. On November 13, 1995 one loggerhead was 

entrained by a hopper dredge working in the channel. On July 27, 2005, fresh loggerhead parts 

were observed in the hopper basket during two different loads. Outside of the disposal site 

inspectors working at upland disposal areas, no endangered species observers have been used 

during any cutterhead dredging operations for this project or at any hopper dredge operation 

upstream of the Delaware Memorial Bridge. 

The deepening project began in March 2010. Between March and September, 2010, approximately 

3 million cy of material was removed via cutterhead dredge from reach C. The disposal site was 

inspected daily for evidence of entrained sturgeon. No shortnose sturgeon or their parts were 

observed during the dredging operations. Dredging to execute contract 2, Reach B began in 

November 2011 and was completed in December 2011 with approximately 1 million cy of material 

removed. No sturgeon or their parts have been observed at the disposal site. 

5.1.3 Crown Landing LNG Project

On May 23, 2006 NMFS issued an Opinion to the Federal Energy Regulatory Commission (FERC) 

and the ACOE regarding the effects of the issuance of an Order by FERC) to British 

Petroleum/Crown Landing LLC (Crown Landing) to site, construct and operate a Liquefied Natural 

Gas (LNG) import terminal on the banks of Delaware River and the effects of the US Army Corps 

of Engineers (ACOE) issuing two permits to Crown Landing for the construction of this facility. 

The Opinion included an ITS exempting the take (lethal entrainment in cutterhead dredge) of up to 

3 shortnose sturgeon during the initial dredging needed to create the berthing area and the death of 

up to an additional 3 shortnose sturgeon over the first ten years of maintenance dredging permitted 

by the ACOE. As explained in the “Effects of the Action” section of this Opinion, only transient 

shortnose sturgeon are likely to occur in the project area and all other effects on shortnose sturgeon 

and their habitat are likely to be insignificant or discountable. The Opinion also concluded that the 

project is not likely to alter the Delaware River in a way that would make the action area unsuitable 

for use as a migratory pathway for any life stage of shortnose sturgeon. In the Opinion, NMFS 

concluded that the proposed action was not likely to adversely affect listed sea turtles. To date, the 

proposed project has not been constructed. Due to issues related to Coastal Zone Management Act 

consistency determinations, it is currently unknown whether the project will move forward as 

planned or whether it will be surrendered or modified. 

5.1.4 Salem and Hope Creek Nuclear Generating Stations 

PSEG Nuclear operates two nuclear power plants pursuant to licenses issued by the US Nuclear 

Regulatory Commission (NRC). These facilities are the Salem and Hope Creek Generating Stations 

(Salem and HCGS), which are located on adjacent sites within a 740-acre parcel of property at the 

southern end of Artificial Island in Lower Alloways Creek Township, Salem County, New Jersey. 

Salem Unit 1 will cease operations in 2036 and Salem Unit 2 will cease operations in 2040. Hope 

Creek is authorized to operate until 2046. 

Consultation pursuant to Section 7 of the ESA between NRC and NMFS on the effects of the 

operation of these facilities has been ongoing since 1979. A Biological Opinion was issued by 
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NMFS in April 1980 in which NMFS concluded that the ongoing operation of the facilities was not 

likely to jeopardize the continued existence of shortnose sturgeon. Consultation was reinitiated in 

1988 due to the documentation of impingement of sea turtles at the Salem facility. An Opinion was 

issued on January 2, 1991 in which NMFS concluded that the ongoing operation was not likely to 

jeopardize shortnose sturgeon, Kemp’s ridley, green or loggerhead sea turtles. Consultation was 

reinitiated in 1992 due to the number of sea turtle impingements at the Salem intake exceeding the 

number exempted in the 1991 Incidental Take Statement. A new Opinion was issued on August 4, 

1992. Consultation was again reinitiated in January 1993 when the number of sea turtle 

impingements exceeded the 1992 ITS with an Opinion issued on May 14, 1993. In 1998 the NRC 

requested that NMFS modify the Reasonable and Prudent Measures and Terms and Conditions of 

the ITS, and, specifically, remove a sea turtle study requirement. NMFS responded to this request 

in a letter dated January 21, 1999. Accompanying this letter was a revised ITS which served to 

amend the May 14, 1993 Opinion. The 1999 ITS exempts the annual take (capture at intake with 

injury or mortality) of 5 shortnose sturgeon, 30 loggerhead sea turtles, 5 green sea turtles, and 5 

Kemp’s ridleys. With the exception of 1991 and 1992, when 23 and 10 sea turtles were captured at 

the intakes, the actual level of take has been far lower than the exempted level. Inclusive of 1991 

and 1992, for the period between 1979 and 1992, a total of 2 green, 23 Kemp’s ridley and 60 

loggerheads have been captured at the intakes. Since monitoring of the intakes was initiated in 

1978, 18 shortnose sturgeon have been recovered from the Salem intakes. No shortnose sturgeon or 

sea turtles have been observed at the Hope Creek intakes. No sea turtles have been captured at 

Salem since 2001. Two Atlantic sturgeon, both previously dead, have been observed at the Salem 

intakes; none have been observed at the Hope Creek intakes. Consultation was reinitiated in 2011; 

we are currently in the process of preparing an updated Biological Opinion considering effects of 

ongoing operations on sea turtles, shortnose sturgeon and Atlantic sturgeon. 

5.1.5 Emergency Clean-Up Actions associated with the M/V Athos I Spill

On November 26, 2004, during docking operations at the Citgo facility in Paulsboro, New Jersey 

(RM 90), the hull of the tank vessel M/V Athos I was punctured by a submerged object causing the 

discharge of approximately 473,000 gallons of crude oil (low aromatic, sweet, product code: 1267) 

into the Delaware River. The emergency cleanup action was initiated under US Coast Guard 

(USCG) oversight. Pursuant to the emergency consultation procedures outlined in Section 7 of the 

ESA, the USCG initiated emergency consultation on the effects of the cleanup action on shortnose 

sturgeon. In a letter dated January 20, 2006, NMFS concluded that “while it is likely that the spill 

itself negatively impacted shortnose sturgeon in the Delaware River, likely by introducing 

contaminants into the environment and by altering normal behaviors, there is no evidence that 

suggests that the cleanup and response activities had an adverse affect on shortnose sturgeon. The 

removal of oil by mechanical means and the removal of oiled wildlife likely beneficially affected 

shortnose sturgeon as it minimized, to the extent possible, the potential for shortnose sturgeon to 

come into contact with the oil or to be contaminated by toxins through the food chain.” In this letter 

NMFS concurred with the determination made by the USCG that the response activities associated 

with the November 26, 2004 spill of the M/V Athos I did not adversely affect shortnose sturgeon. 

No oiled sturgeon or sea turtles were documented during the spill or during clean up activities. 

5.1.6 Scientific Studies 

There are currently four scientific research permits issued pursuant to Section 10(a)(1)(A) of the 

ESA, that authorize research on sturgeon in the Delaware River. The activities authorized under 
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these permits are presented below. 

Hal Brundage of Environmental Research and Consulting, Inc. holds a scientific research permit 

(#14604, which replaces his previously held permit #1486) authorizing research on relative 

abundance, reproduction, juvenile recruitment, temporal and spatial distributions, and reproductive 

health of shortnose sturgeon. Methods would include capturing up to 1,000 adult and juvenile 

shortnose sturgeon annually via gill net, trammel net, and trawl net; measure; weigh; scan (for tags); 

PIT and Floy T-bar tag; and sample tissue for genetic analysis. A subset of 30 adults and 30 

juveniles annually will be tagged with acoustic transmitters. Another subset of 24 adults annually 

will be examined internally using laparoscopic techniques, blood drawn for analysis, and a biopsy 

of the gonads taken. Up to 500 eggs and larvae will be collected by artificial substrate, D-frame 

ichthyoplankton net, and/or epibenthic sled. The unintentional mortality of one adult or juvenile 

shortnose sturgeon is anticipated over the five year life of the permit. This permit expires on April 

19, 2015. 

Mr. Brundage also holds a scientific research permit (#16438) authorizing research on Atlantic 

sturgeon. Mr. Brundage is authorized to capture and tag 384 juvenile, subadult and adult Atlantic 

sturgeon as well as 500 Atlantic sturgeon eggs or larvae. The unintentional mortality of one adult 

or juvenile shortnose sturgeon is anticipated over the five year life of the permit. This permit 

expires on April 5, 2017. 

Dr. Dewayne Fox of Delaware State University holds a scientific research permit (#16507) 

authorizing research on Atlantic and shortnose sturgeon. Dr. Fox is authorized to capture and tag 

510 Atlantic sturgeon and 100 shortnose sturgeon as well as 300 Atlantic sturgeon eggs. This 

permit expires on April 5, 2017. No mortality is authorized by this permit. 

The Delaware Department of Natural Resources and Environmental Control (DNREC) holds a 

scientific research permit (#14396) authorizing research on shortnose sturgeon. DNREC is 

authorized to capture, handle and tag 215 shortnose sturgeon. The unintentional mortality of one 

adult or juvenile shortnose sturgeon is anticipated over the five year life of the permit. This permit 

expires on December 13, 2014. 

5.1.7 Vessel Operations 

Potential adverse effects from federal vessel operations in the action area of this consultation 

include operations of the US Navy (USN) and the US Coast Guard (USCG), which maintain the 

largest federal vessel fleets, the EPA, the National Oceanic and Atmospheric Administration 

(NOAA), and the ACOE. NMFS has conducted formal consultations with the USCG, the USN, 

EPA and NOAA on their vessel operations. In addition to operation of ACOE vessels, NMFS has 

consulted with the ACOE to provide recommended permit restrictions for operations of contract or 

private vessels around whales. Through the section 7 process, where applicable, NMFS has and 

will continue to establish conservation measures for all these agency vessel operations to avoid 

adverse effects to listed species. Refer to the biological opinions for the USCG (September 15, 

1995; July 22, 1996; and June 8, 1998) and the USN (May 15, 1997) for detail on the scope of 

vessel operations for these agencies and conservation measures being implemented as standard 

operating procedures. No interactions with sturgeon or sea turtles have been reported with any of 

the vessels considered in these Opinions. 
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5.1.8 Other Federally Authorized Actions

We have completed several informal consultations on effects of in-water construction activities in 

the Delaware River permitted by the ACOE. This includes several dock, pier and bank stabilization 

projects. No interactions with shortnose or Atlantic sturgeon have been reported in association 

with any of these projects. 

We have also completed several informal consultations on effects of private dredging projects 

permitted by the ACOE. All of the dredging was with a mechanical or cutterhead dredge. No 

interactions with shortnose or Atlantic sturgeon have been reported in association with any of these 

projects. 

5.2 State or Private Actions in the Action Area 

5.2.1 State Authorized Fisheries

Atlantic and shortnose sturgeon, and sea turtles may be vulnerable to capture, injury and mortality 

in fisheries occurring in state waters. The action area includes portions of Pennsylvania, New 

Jersey and Delaware state waters within the Delaware River and Delaware Bay. Information on the 

number of sturgeon captured or killed in state fisheries is extremely limited and as such, efforts are 

currently underway to obtain more information on the numbers of sturgeon captured and killed in 

state water fisheries. We are currently working with the Atlantic States Marine Fisheries 

Commission (ASMFC) and the coastal states to assess the impacts of state authorized fisheries on 

sturgeon. We anticipate that some states are likely to apply for ESA section 10(a)(1)(B) Incidental 

Take Permits to cover their fisheries; however, to date, no applications have been submitted. 

Below, we discuss the different fisheries authorized by the states and any available information on 

interactions between these fisheries and sturgeon. 

American Eel

American eel (Anguilla rostrata) is exploited in fresh, brackish and coastal waters from the southern 

tip of Greenland to northeastern South America. American eel fisheries are conducted primarily in 

tidal and inland waters. Eels are typically caught with hook and line or with eel traps and may also 

be caught with fyke nets. Sturgeon and sea turtles are not known to interact with the eel fishery. 

Atlantic croaker

Atlantic croaker (Micropogonias undulates) occur in coastal waters from the Gulf of Maine to 

Argentina, and are one of the most abundant inshore bottom-dwelling fish along the U.S. Atlantic 

coast. Atlantic croaker are managed under an ASMFC ISFMP (including Amendment 1 in 2005 

and Addendum 1 in 2010), but no specific management measures are required. Atlantic croaker are 

seasonally present in Delaware Bay; fishing occurs for this species in the Bay but not in the river. 

Recreational fisheries for Atlantic croaker are likely to use hook and line; commercial fisheries 

targeting croaker primarily use otter trawls. The average annual bycatch of loggerhead sea turtles in 

bottom otter trawl gear used in the Atlantic croaker fishery was estimated to be 70 loggerhead sea 

turtles (Warden 2011). Additional information on sea turtle interactions with gillnet gear, including 

gillnet gear used in the Atlantic croaker fishery, has also been recently published by Murray (2009a, 

2009b). The average annual bycatch of loggerhead sea turtles in gillnet gear used in the Atlantic 
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croaker fishery, based on VTR data from 2002-2006, was estimated to be 11 per year with a 95% CI 

of 3-20 (Murray 2009b). A quantitative assessment of the number of Atlantic sturgeon captured in 

the croaker fishery is not available. Mortality rates of Atlantic sturgeon in commercial trawls has 

been estimated at 5%. A review of the NEFOP database indicates that from 2006-2010, 60 Atlantic 

sturgeon (out of a total of 726 observed interactions) were captured during observed trips where the 

trip target was identified as croaker. This represents a minimum number of Atlantic sturgeon 

captured in the croaker fishery during this time period as it only considers observed trips for boats 

with federal permits only. Because of the area where the fishery occurs, we do not anticipate any 

interactions with shortnose sturgeon. 

Horseshoe crabs

ASMFC manages horseshoe crabs through an Interstate Fisheries Management Plan that sets state 

quotas, and allows states to set closed seasons. Horseshoe crabs are present in Delaware Bay. In 

New Jersey, there is currently a moratorium on the harvest of horseshoe crabs and horseshoe crab 

eggs for an indeterminate period of time. The law also prohibits the possession of horseshoe crabs 

and horseshoe crab eggs except for those individuals in possession of a scientific collecting permit, 

allowing them to possess horseshoe crabs or horseshoe crab eggs for research or educational 

purposes only, and those fishermen utilizing horseshoe crabs as bait must provide adequate 

documentation that the horseshoe crabs in their possession were not harvested in New Jersey. In 

Delaware, limited harvest of horseshoe crabs is allowed. Delaware’s annual quota allocation is 

100,000 male-only horseshoe crabs; with an open season of June 8 – December 31. Stein et al.

(2004) examined bycatch of Atlantic sturgeon using the NMFS sea-sampling/observer database 

(1989-2000) and found that the bycatch rate for horseshoe crabs was very low, at 0.05%. Few 

Atlantic sturgeon are expected to be caught in the horeshoe crab fishery in the action area. Sea 

turtles are not known to be captured during horseshoe crab fishing. Shortnose sturgeon are unlikely 

to be captured in gear targeting horseshoe crabs given the location of fishing effort in the lower 

Bay. 

Shad and River herring

Shad and river herring (blueback herring (Alosa aestivalis) and alewives (Alosa pseudoharengus)) 

are managed under an ASMFC Interstate Fishery Management Plan. In the action area, fishing for 

river herring is prohibited. Limited fishing effort for shad continues to occur. Recreational shad 

fishing is currently allowed within the Delaware River with hook and line only; commercial fishing 

for shad occurs with gill nets, but only in Delaware Bay. In the past, it was estimated that over 100 

shortnose sturgeon were captured annually in shad fisheries in the Delaware River, with an 

unknown mortality rate (O’Herron and Able 1985). Nearly all captures occurred in the upper 

Delaware River, upstream of the action area. No recent estimates of captures or mortality of 

shortnose or Atlantic sturgeon are available. In 2012, only one commercial fishing license was 

granted for shad in New Jersey. Shortnose and Atlantic sturgeon continue be exposed to the risk of 

interactions with this fishery; however, because increased controls have been placed on the shad 

fishery, impacts to shortnose and Atlantic sturgeon are likely less than they were in the past. 

Striped bass

Striped bass are managed by ASMFC through Amendment 6 to the Interstate FMP, which requires 

minimum sizes for the commercial and recreational fisheries, possession limits for the recreational 
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fishery, and state quotas for the commercial fishery (ASMFC 2003). Under Addendum 2, the 

coastwide striped bass quota remains the same, at 70% of historical levels. Data from the Atlantic 

Coast Sturgeon Tagging Database (2000-2004) shows that the striped bass fishery accounted for 

43% of Atlantic sturgeon recaptures; however, no information on the total number of Atlantic 

sturgeon caught by fishermen targeting striped bass or the mortality rate is available. 

Weakfish

The weakfish fishery occurs in both state and federal waters but the majority of commercially and 

recreationally caught weakfish are caught in state waters (ASMFC 2002). The dominant 

commercial gears include gill nets, pound nets, haul seines, and trawls, with the majority of

landings occurring in the fall and winter months (ASMFC 2002). Fishing for weakfish occurs in 

Delaware Bay. 

As described in section 3.1.1, sea turtle bycatch in the weakfish fishery has occurred (Warden 2011; 

Murray 2009a, 2009b). The average annual bycatch of loggerhead sea turtles in bottom otter trawl 

gear used in the weakfish fishery was estimated to be 1 loggerhead sea turtle (Warden 2011). 

Additional information on sea turtle interactions with gillnet gear, including gillnet gear used in the 

weakfish fishery, has also been recently published by Murray (2009a, 2009b). The average annual 

bycatch of loggerhead sea turtles in gillnet gear used in the weakfish fishery, based on VTR data 

from 2002-2006, was estimated to be one (1) per year with a 95% CI of 0-1 (Murray 2009b). 

A quantitative assessment of the number of Atlantic sturgeon captured in the weakfish fishery is not 

available. A review of the NEFOP database indicates that from 2006-2010, 36 Atlantic sturgeon 

(out of a total of 726 observed interactions) were captured during observed trips where the trip 

target was identified as weakfish. This represents a minimum number of Atlantic sturgeon captured 

in the weakfish fishery during this time period as it only considers observed trips, and most inshore 

fisheries are not observed. An earlier review of bycatch rates and landings for the weakfish fishery 

reported that the weakfish-striped bass fishery had an Atlantic sturgeon bycatch rate of 16% from 

1989-2000; the weakfish-Atlantic croaker fishery had an Atlantic sturgeon bycatch rate of 0.02%, 

and the weakfish fishery had an Atlantic sturgeon bycatch rate of 1.0% (ASSRT 2007).

American lobster trap fishery 

An American lobster trap fishery also occurs in Delaware Bay. This fishery is managed under the 

ASMFC’s ISFMP. This fishery has also been identified as a source of gear causing injuries to and 

mortality of loggerhead and leatherback sea turtles as a result of entanglement in vertical buoy lines 

of the pot/trap gear. Between 2002 and 2008, the lobster trap fishery in state waters was verified as 

the fishery involved in at least 27 leatherback entanglements in the Northeast Region. All 

entanglements involved the vertical line of the gear. These verified/confirmed entanglements 

occurred in Maine, Massachusetts, and Rhode Island state waters from June through October 

(Northeast Region STDN database). While no entanglements in lobster gear have been reported for 

Delaware Bay, the potential for future entanglement exists. Atlantic and shortnose sturgeon are not 

known to interact with lobster trap gear. 
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5.3 Other Impacts of Human Activities in the Action Area 

5.3.1 Contaminants and Water Quality

Historically, shortnose sturgeon were rare in the area below Philadelphia, likely as a result of poor 

water quality precluding migration further downstream. However, in the past 20 to 30 years, the 

water quality has improved and sturgeon have been found farther downstream. It is likely that 

contaminants remain in the water and in the action area, albeit to reduced levels. 

Point source discharges (i.e., municipal wastewater, industrial or power plant cooling water or waste 

water) and compounds associated with discharges (i.e., metals, dioxins, dissolved solids, phenols, 

and hydrocarbons) contribute to poor water quality and may also impact the health of sturgeon 

populations. The compounds associated with discharges can alter the pH or receiving waters, which 

may lead to mortality, changes in fish behavior, deformations, and reduced egg production and 

survival.

Sources of contamination in the action area include atmospheric loading of pollutants, stormwater 

runoff from coastal development, groundwater discharges, and industrial development. Chemical 

contaminants may also have an effect on sea turtle reproduction and survival. While the effects of 

contaminants on turtles is relatively unclear, pollution may be linked to the fibropapilloma virus that 

kills many turtles each year (NMFS 1997). If pollution is not the causal agent, it may make sea 

turtles more susceptible to disease by weakening their immune systems. 

Contaminants have been detected in Delaware River fish. PCBs have been detected in elevated 

levels in several species of fish. Large portions of the Delaware River is bordered by highly 

industrialized waterfront development. Sewage treatment facilities, refineries, manufacturing plants 

and power generating facilities all intake and discharge water directly from the Delaware River. 

This results in large temperature variations, heavy metals, dioxin, dissolved solids, phenols and 

hydrocarbons which may alter the pH of the water eventually leading to fish mortality. 

Industrialized development, especially the presence of refineries, has also resulted in storage and 

leakage of hazardous material into the Delaware River. Presently 13 Superfund sites have been 

identified in Marcus Hook and one dumpsite has yet to be labeled as a Superfund site, but does 

contain hazardous waste. It is possible that the presence of contaminants in the action area may 

have adversely affected shortnose sturgeon abundance, reproductive success and survival. 

Several characteristics of shortnose sturgeon life history including long life span, extended 

residence in estuarine habitats, and being a benthic omnivore, predispose this species to long term, 

repeated exposure to environmental contaminants and bioaccumulation of toxicants (Dadswell 

1979). Toxins introduced to the water column become associated with the benthos and can be 

particularly harmful to benthic organisms (Varanasi 1992) like sturgeon. Heavy metals and 

organochlorine compounds are known to accumulate in fat tissues of sturgeon, but their long term 

effects are not yet known (Ruelle and Henry 1992; Ruelle and Keenlyne 1993). Available data 

suggest that early life stages of fish are more susceptible to environmental and pollutant stress than 

older life stages (Rosenthal and Alderdice 1976). Although there have not been any studies to 

assess the impact of contaminants on shortnose sturgeon, elevated levels of environmental 

contaminants, including chlorinated hydrocarbons, in several other fish species are associated with 

reproductive impairment (Cameron et al. 1992; Longwell et al. 1992), reduced egg viability (Von 
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Westernhagen et al. 1981; Hansen 1985; Mac and Edsall 1991), and reduced survival of larval fish 

(Berlin et al. 1981; Giesy et al. 1986). Some researchers have speculated that PCBs may reduce the 

shortnose sturgeon’s resistance to fin rot (Dovel et al. 1992). 

Although there is scant information available on levels of contaminants in shortnose sturgeon 

tissues, some research on other, related species indicates that concern about effects of contaminants 

on the health of sturgeon populations is warranted. Detectable levels of chlordane, DDE, DDT, and 

dieldrin, and elevated levels of PCBs, cadmium, mercury, and selenium were found in pallid 

sturgeon tissue from the Missouri River (US Fish and Wildlife Service 1993). These compounds 

may affect physiological processes and impede a fish’s ability to withstand stress. PCBs are 

believed to adversely affect reproduction in pallid sturgeon (Ruelle and Keenlyne 1993). Ruelle 

and Henry (1992) found a strong correlation between fish weight r = 0.91, p < 0.01), fish fork 

length r = 0.91, p < 0.01), and DDE concentration in pallid sturgeon livers, indicating that DDE 

concentration increases proportionally with fish size.

Contaminant analysis was conducted on two shortnose sturgeon from the Delaware River in the fall 

of 2002. Muscle, liver, and gonad tissue were analyzed for contaminants (ERC 2002). Sixteen 

metals, two semivolatile compounds, three organochlorine pesticides, one PCB Aroclor, as well as 

polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) were 

detected in one or more of the tissue samples. Levels of aluminum, cadmium, PCDDs, PCDFs, 

PCBs and DDE (an organochlorine pesticide) were detected in the “adverse effect” range. It is of 

particular concern that of the above chemicals, PCDDs, DDE, PCBs and cadmium, were detected as 

these have been identified as endocrine disrupting chemicals. While no directed studies of chemical 

contamination in shortnose sturgeon in the Delaware River have been undertaken, it is evident that 

the heavy industrialization of the Delaware River is likely adversely affecting this population. 

Excessive turbidity due to coastal development and/or construction sites could influence sea turtle 

foraging ability. Turtles are not very easily affected by changes in water quality or increased 

suspended sediments, but if these alterations make habitat less suitable for turtles and hinder their 

capability to forage, eventually they would tend to leave or avoid these less desirable areas (Ruben 

and Morreale 1999).

Marine debris (e.g., discarded fishing line or lines from boats) can entangle turtles in the water and 

drown them. Turtles commonly ingest plastic or mistake debris for food. Chemical contaminants 

may also have an effect on sea turtle reproduction and survival. Excessive turbidity due to coastal 

development and/or construction sites could influence sea turtle foraging ability. As mentioned 

previously, turtles are not very easily affected by changes in water quality or increased suspended 

sediments, but if these alterations make habitat less suitable for turtles and hinder their capability to 

forage, eventually they would tend to leave or avoid these less desirable areas (Ruben and Morreale 

1999). Noise pollution has been raised, primarily, as a concern for marine mammals but may be a 

concern for other marine organisms, including sea turtles. 

5.3.2 Private and Commercial Vessel Operations

Private and commercial vessels, including fishing vessels, operating in the action area of this 

consultation also have the potential to interact with sea turtles. Approximately 3,000 cargo vessels 

transit the Delaware River annually as well as numerous smaller commercial and recreational 
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vessels. The effects of fishing vessels, recreational vessels, or other types of commercial vessels on 

listed species may involve disturbance or injury/mortality due to collisions or entanglement in 

anchor lines. Sea turtles are known to be vulnerable to vessel strikes; however no estimate of the 

number of vessel strikes in the action area is available. 

There is limited information on the effects of vessel operations on shortnose sturgeon. It is 

generally assumed that as shortnose sturgeon are benthic species, that their movements are limited 

to the bottom of the water column and that vessels operating with sufficient navigational clearance 

would not pose a risk of ship strike. Shortnose sturgeon may not be as susceptible due to their 

smaller size in comparison to Atlantic sturgeon that are larger and for which ship strikes have been 

documented more frequently. However, anecdotal evidence suggests that shortnose sturgeon at 

least occasionally interact with vessels, as evidence by wounds that appear to be caused by 

propellers. There has been only one confirmed incidence of a ship strike on a shortnose sturgeon 

and 2 suspected ship strike mortalities. On November 5, 2008, in the Kennebec River, Maine, 

Maine Department of Marine Resources (MEDMR) staff observed a small (<20) ft boat transiting a 

known shortnose sturgeon overwintering area at high speeds. When MEDMR approached the area 

after the vessel had passed, a fresh dead shortnose sturgeon was discovered. The fish was collected 

for necropsy, which later confirmed that the mortality was the result of a propeller wound to the 

right side of the mouth and gills. The other two suspected ship strike mortalities occurred in the 

Delaware River. On June 8, 2008, a shortnose was collected near Philadelphia. The fish was 

necropsied and found to have suffered from blunt force trauma; though there was no ability to 

confirm whether the source of the trauma resulted from a vessel interaction. Lastly, on November 

28, 2007, a shortnose sturgeon was collected on the trash racks of the Salem Nuclear Generating 

Facility. The fish was not necropsied, however, a pattern of lacerations on the carcass suggested a 

possible vessel interaction. Aside from these incidents, no information on the characteristics of 

vessels that are most likely to interact with shortnose sturgeon is available and there is no 

information on the rate of interactions, however it is assumed to be low. 

As noted in the 2007 Status Review and the final listing rules, vessel strikes have been identified as 

a threat to Atlantic sturgeon. While the exact number of Atlantic sturgeon killed as a result of being 

struck by boat hulls or propellers is unknown, it is an area of concern. Brown and Murphy (2010) 

examined twenty-eight dead Atlantic sturgeon observed in the Delaware River from 2005-

2008. Fifty-percent of the mortalities resulted from apparent vessel strikes and 71% of these (10 of 

14) had injuries consistent with being struck by a large vessel (Brown and Murphy 2010). Eight of 

the fourteen vessel-struck sturgeon were adult-sized fish (Brown and Murphy 2010). Given the 

time of year in which the fish were observed (predominantly May through July; Brown and Murphy 

2010), it is likely that many of the adults were migrating through the river to or from the spawning 

grounds. 

The factors relevant to determining the risk to Atlantic sturgeon from vessel strikes are currently 

unknown, but they may be related to size and speed of the vessels, navigational clearance (i.e., 

depth of water and draft of the vessel) in the area where the vessel is operating, and the behavior of 

Atlantic sturgeon in the area (e.g., foraging, migrating, etc.). It is unknown to what extent the 

mortalities documented by Brown and Murphy (2010) accurately characterize the extent of vessel 

strikes in the Delaware River, but as it is unlikely that all Atlantic sturgeon that died in the time 

period of the study were observed by the authors, it is likely that there are other undocumented 
112

mortalities resulting from vessel strikes as well as from other sources. Vessel interactions are 

thought to cause the death of several Atlantic sturgeon in the Delaware River each year. 

6.0 CLIMATE CHANGE

The discussion below presents background information on global climate change and information 

on past and predicted future effects of global climate change throughout the range of the listed 

species considered here. Additionally, we present the available information on predicted effects of 

climate change in the action area (i.e., the Delaware River and estuary) and how listed sea turtles 

and sturgeon may be affected by those predicted environmental changes over the life of the 

proposed action (i.e., between now and 2027). Generally speaking, climate change may be relevant 

to the Status of the Species, Environmental Baseline and Cumulative Effects sections of an Opinion; 

rather than include partial discussion in several sections of this Opinion, we are synthesizing this 

information into one discussion. Effects of the proposed action that are relevant to climate change 

are included in the Effects of the Action section below (section 7.0 below). 

6.1 Background Information on Global climate change 

The global mean temperature has risen 0.76oC (1.36°F) over the last 150 years, and the linear trend 

over the last 50 years is nearly twice that for the last 100 years (IPCC 2007a) and precipitation has

increased nationally by 5%-10%, mostly due to an increase in heavy downpours (NAST 2000). 

There is a high confidence, based on substantial new evidence, that observed changes in marine 

systems are associated with rising water temperatures, as well as related changes in ice cover, 

salinity, oxygen levels, and circulation. Ocean acidification resulting from massive amounts of 

carbon dioxide and other pollutants released into the air can have major adverse impacts on the 

calcium balance in the oceans. Changes to the marine ecosystem due to climate change include 

shifts in ranges and changes in algal, plankton, and fish abundance (IPCC 2007b); these trends are 

most apparent over the past few decades. Information on future impacts of climate change in the 

action area is discussed below. 

Climate model projections exhibit a wide range of plausible scenarios for both temperature and 

precipitation over the next century. Both of the principal climate models used by the National 

Assessment Synthesis Team (NAST) project warming in the southeast by the 2090s, but at different 

rates (NAST 2000): the Canadian model scenario shows the southeast U.S. experiencing a high 

degree of warming, which translates into lower soil moisture as higher temperatures increase 

evaporation; the Hadley model scenario projects less warming and a significant increase in 

precipitation (about 20%). The scenarios examined, which assume no major interventions to reduce 

continued growth of world greenhouse gases (GHG), indicate that temperatures in the U.S. will rise 

by about 3o-5

oC (5o

-9

o

F) on average in the next 100 years which is more than the projected global 

increase (NAST 2000). A warming of about 0.2oC (0.4°F) per decade is projected for the next two 

decades over a range of emission scenarios (IPCC 2007). This temperature increase will very likely 

be associated with more extreme precipitation and faster evaporation of water, leading to greater 

frequency of both very wet and very dry conditions. Climate warming has resulted in increased 

precipitation, river discharge, and glacial and sea-ice melting (Greene et al. 2008). 

The past three decades have witnessed major changes in ocean circulation patterns in the Arctic, 

and these were accompanied by climate associated changes as well (Greene et al. 2008). Shifts in 

atmospheric conditions have altered Arctic Ocean circulation patterns and the export of freshwater 
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to the North Atlantic (Greene et al. 2008, IPCC 2006). With respect specifically to the North 

Atlantic Oscillation (NAO), changes in salinity and temperature are thought to be the result of 

changes in the earth’s atmosphere caused by anthropogenic forces (IPCC 2006). The NAO impacts 

climate variability throughout the northern hemisphere (IPCC 2006). Data from the 1960s through

the present show that the NAO index has increased from minimum values in the 1960s to strongly 

positive index values in the 1990s and somewhat declined since (IPCC 2006). This warming 

extends over 1000m (0.62 miles) deep and is deeper than anywhere in the world oceans and is 

particularly evident under the Gulf Stream/ North Atlantic Current system (IPCC 2006). On a 

global scale, large discharges of freshwater into the North Atlantic subarctic seas can lead to intense 

stratification of the upper water column and a disruption of North Atlantic Deepwater (NADW) 

formation (Greene et al. 2008, IPCC 2006). There is evidence that the NADW has already 

freshened significantly (IPCC 2006). This in turn can lead to a slowing down of the global ocean 

thermohaline (large-scale circulation in the ocean that transforms low-density upper ocean waters to 

higher density intermediate and deep waters and returns those waters back to the upper ocean), 

which can have climatic ramifications for the whole earth system (Greene et al. 2008). 

While predictions are available regarding potential effects of climate change globally, it is more 

difficult to assess the potential effects of climate change over the next few decades on coastal and 

marine resources on smaller geographic scales, such as the Delaware River, especially as climate 

variability is a dominant factor in shaping coastal and marine systems. The effects of future change 

will vary greatly in diverse coastal regions for the U.S. Warming is very likely to continue in the 

U.S. over the next 25 to 50 years regardless of reduction in GHGs, due to emissions that have 

already occurred (NAST 2000). It is very likely that the magnitude and frequency of ecosystem 

changes will continue to increase in the next 25 to 50 years, and it is possible that the rate of change

will accelerate. Climate change can cause or exacerbate direct stress on ecosystems through high 

temperatures, a reduction in water availability, and altered frequency of extreme events and severe 

storms. Water temperatures in streams and rivers are likely to increase as the climate warms and 

are very likely to have both direct and indirect effects on aquatic ecosystems. Changes in 

temperature will be most evident during low flow periods when they are of greatest concern (NAST 

2000). In some marine and freshwater systems, shifts in geographic ranges and changes in algal, 

plankton, and fish abundance are associated with high confidence with rising water temperatures, as 

well as related changes in ice cover, salinity, oxygen levels and circulation (IPCC 2007). 

A warmer and drier climate is expected to result in reductions in stream flows and increases in 

water temperatures. Expected consequences could be a decrease in the amount of dissolved oxygen 

in surface waters and an increase in the concentration of nutrients and toxic chemicals due to 

reduced flushing rate (Murdoch et al. 2000). Because many rivers are already under a great deal of 

stress due to excessive water withdrawal or land development, and this stress may be exacerbated 

by changes in climate, anticipating and planning adaptive strategies may be critical (Hulme 2005). 

A warmer-wetter climate could ameliorate poor water quality conditions in places where humancaused concentrations of nutrients and pollutants other than heat currently degrade water quality 

(Murdoch et al. 2000). Increases in water temperature and changes in seasonal patterns of runoff 

will very likely disturb fish habitat and affect recreational uses of lakes, streams, and wetlands. 

Surface water resources in the southeast are intensively managed with dams and channels and 

almost all are affected by human activities; in some systems water quality is either below 

recommended levels or nearly so. A global analysis of the potential effects of climate change on 
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river basins indicates that due to changes in discharge and water stress, the area of large river basins 

in need of reactive or proactive management interventions in response to climate change will be 

much higher for basins impacted by dams than for basins with free-flowing rivers (Palmer et al.

2008). Human-induced disturbances also influence coastal and marine systems, often reducing the 

ability of the systems to adapt so that systems that might ordinarily be capable of responding to 

variability and change are less able to do so. Because stresses on water quality are associated with 

many activities, the impacts of the existing stresses are likely to be exacerbated by climate change. 

Within 50 years, river basins that are impacted by dams or by extensive development may 

experience greater changes in discharge and water stress than unimpacted, free-flowing rivers 

(Palmer et al. 2008). 

While debated, researchers anticipate: 1) the frequency and intensity of droughts and floods will 

change across the nation; 2) a warming of about 0.2oC (0.4°F) per decade; and 3) a rise in sea level 

(NAST 2000). A warmer and drier climate will reduce stream flows and increase water temperature 

resulting in a decrease of DO and an increase in the concentration of nutrients and toxic chemicals 

due to reduced flushing. Sea level is expected to continue rising: during the 20th century global sea 

level has increased 15 to 20 cm (6-8 inches). 

6.2 Species Specific Information on Climate Change Effects

6.2.1 Loggerhead Sea Turtles 

The most recent Recovery Plan for loggerhead sea turtles as well as the 2009 Status Review Report 

identifies global climate change as a threat to loggerhead sea turtles. However, trying to assess the 

likely effects of climate change on loggerhead sea turtles is extremely difficult given the uncertainty 

in all climate change models and the difficulty in determining the likely rate of temperature 

increases and the scope and scale of any accompanying habitat effects. Additionally, no significant 

climate change-related impacts to loggerhead sea turtle populations have been observed to date. 

Over the long-term, climate change related impacts are expected to influence biological trajectories 

on a century scale (Parmesan and Yohe 2003). As noted in the 2009 Status Review (Conant et al. 

2009), impacts from global climate change induced by human activities are likely to become more 

apparent in future years (Intergovernmental Panel on Climate Change (IPCC) 2007). Climate 

change related increasing temperatures, sea level rise, changes in ocean productivity, and increased 

frequency of storm events may affect loggerhead sea turtles. 

Increasing temperatures are expected to result in rising sea levels (Titus and Narayanan 1995 in 

Conant et al. 2009), which could result in increased erosion rates along nesting beaches. Sea level 

rise could result in the inundation of nesting sites and decrease available nesting habitat (Daniels et 

al. 1993; Fish et al. 2005; Baker et al. 2006). The BRT noted that the loss of habitat as a result of 

climate change could be accelerated due to a combination of other environmental and 

oceanographic changes such as an increase in the frequency of storms and/or changes in prevailing 

currents, both of which could lead to increased beach loss via erosion (Antonelis et al. 2006; Baker 

et al. 2006; both in Conant et al. 2009). Along developed coastlines, and especially in areas where 

erosion control structures have been constructed to limit shoreline movement, rising sea levels may 

cause severe effects on nesting females and their eggs as nesting females may deposit eggs seaward 

of the erosion control structures potentially subjecting them to repeated tidal inundation. However, 

if global temperatures increase and there is a range shift northwards, beaches not currently used for 
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nesting may become available for loggerhead sea turtles, which may offset some loss of 

accessibility to beaches in the southern portions of the range. 

Climate change has the potential to result in changes at nesting beaches that may affect loggerhead 

sex ratios. Loggerhead sea turtles exhibit temperature-dependent sex determination. Rapidly 

increasing global temperatures may result in warmer incubation temperatures and highly femalebiased sex ratios (e.g., Glen and Mrosovsky 2004; Hawkes et al. 2009); however, to the extent that 

nesting can occur at beaches further north where sand temperatures are not as warm, these effects 

may be partially offset. The BRT specifically identified climate change as a threat to loggerhead 

sea turtles in the neritic/oceanic zone where climate change may result in future trophic changes, 

thus impacting loggerhead prey abundance and/or distribution. In the threats matrix analysis, 

climate change was considered for oceanic juveniles and adults and eggs/hatchlings. The report 

states that for oceanic juveniles and adults, “although the effect of trophic level change 

from...climate change...is unknown it is believed to be very low.” For eggs/hatchlings the report 

states that total mortality from anthropogenic causes, including sea level rise resulting from climate 

change, is believed to be low relative to the entire life stage. However, only limited data are 

available on past trends related to climate effects on loggerhead sea turtles; current scientific 

methods are not able to reliably predict the future magnitude of climate change, associated impacts, 

whether and to what extent some impacts will offset others, or the adaptive capacity of this species. 

However, Van Houtan and Halley (2011) recently developed climate forcing models to investigate 

loggerhead nesting (considering juvenile recruitment and breeding remigration) in the North Pacific 

and Northwest Atlantic. These models found that climate conditions/oceanographic influences 

explain loggerhead nesting variability, with climate models alone explaining an average 60% (range 

18%-88%) of the observed nesting changes over the past several decades. In terms of future nesting 

projections, modeled climate data show a future positive trend for Florida nesting, with increases 

through 2040 as a result of the Atlantic Multidecadal Oscillation signal. 

6.2.2 Kemp’s Ridley Sea Turtles

The recovery plan for Kemp’s ridley sea turtles (NMFS et al. 2011) identifies climate change as a 

threat; however, as with the other species discussed above, no significant climate change-related 

impacts to Kemp’s ridley sea turtles have been observed to date. Atmospheric warming could cause 

habitat alteration which may change food resources such as crabs and other invertebrates. It may 

increase hurricane activity, leading to an increase in debris in nearshore and offshore waters, which 

may result in an increase in entanglement, ingestion, or drowning. In addition, increased hurricane 

activity may cause damage to nesting beaches or inundate nests with sea water. Atmospheric 

warming may change convergence zones, currents and other oceanographic features that are 

relevant to Kemp's ridleys, as well as change rain regimes and levels of nearshore runoff.

Considering that the Kemp’s ridley has temperature-dependent sex determination (Wibbels 2003) 

and the vast majority of the nesting range is restricted to the State of Tamaulipas, Mexico, global 

warming could potentially shift population sex ratios towards females and thus change the 

reproductive ecology of this species. A female bias is presumed to increase egg production 

(assuming that the availability of males does not become a limiting factor) (Coyne and Landry 

2007) and increase the rate of recovery; however, it is unknown at what point the percentage of 
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males may become insufficient to facilitate maximum fertilization rates in a population. If males 

become a limiting factor in the reproductive ecology of the Kemp's ridley, then reproductive output 

in the population could decrease (Coyne 2000). Low numbers of males could also result in the loss 

of genetic diversity within a population; however, there is currently no evidence that this is a 

problem in the Kemp's ridley population (NMFS et al. 2011). Models (Davenport 1997, Hulin and 

Guillon 2007, Hawkes et al. 2007, all referenced in NMFS et al. 2011) predict very long-term 

reductions in fertility in sea turtles due to climate change, but due to the relatively long life cycle of 

sea turtles, reductions may not be seen until 30 to 50 years in the future. 

Another potential impact from global climate change is sea level rise, which may result in increased 

beach erosion at nesting sites. Beach erosion may be accelerated due to a combination of other 

environmental and oceanographic changes such as an increase in the frequency of storms and/or 

changes in prevailing currents. In the case of the Kemp’s ridley where most of the critical nesting 

beaches are undeveloped, beaches may shift landward and still be available for nesting. The Padre 

Island National Seashore (PAIS) shoreline is accreting, unlike much of the Texas coast, and with 

nesting increasing and the sand temperatures slightly cooler than at Rancho Nuevo, PAIS could 

become an increasingly important source of males for the population. 

6.2.3 Green Sea Turtles 

The five year status review for green sea turtles (NMFS and USFWS 2007d) notes that global 

climate change is affecting green sea turtles and is likely to continue to be a threat. There is an 

increasing female bias in the sex ratio of green turtle hatchlings. While this is partly attributable to 

imperfect egg hatchery practices, global climate change is also implicated as a likely cause. This is 

because warmer sand temperatures at nesting beaches are likely to result in the production of more 

female embryos. At least one nesting site, Ascension Island, has had an increase in mean sand 

temperature in recent years (Hays et al. 2003 in NMFS and USFWS 2007d). Climate change may 

also affect nesting beaches through sea level rise, which may reduce the availability of nesting 

habitat and increase the risk of nest inundation. Loss of appropriate nesting habitat may also be 

accelerated by a combination of other environmental and oceanographic changes, such as an 

increase in the frequency of storms and/or changes in prevailing currents, both of which could lead 

to increased beach loss via erosion. Oceanic changes related to rising water temperatures could 

result in changes in the abundance and distribution of the primary food sources of green sea turtles, 

which in turn could result in changes in behavior and distribution of this species. Seagrass habitats 

may suffer from decreased productivity and/or increased stress due to sea level rise, as well as 

salinity and temperature changes (Short and Neckles 1999; Duarte 2002). 

As noted above, the increasing female bias in green sea turtle hatchlings is thought to be at least 

partially linked to increases in temperatures at nesting beaches. However, at this time, we do not 

know how much of this bias is due to hatchery practice and how much is due to increased sand 

temperature. Because we do not have information to predict the extent and rate to which sand 

temperatures at the nesting beaches used by green sea turtles may increase in the short-term future, 

we cannot predict the extent of any future bias. Also, we do not know to what extent to which 

green sea turtles may be able to cope with this change by selecting cooler areas of the beach or 

shifting their nesting distribution to other beaches at which increases in sand temperature may not 

be experienced. 
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6.2.4 Leatherback sea turtles 

Global climate change has been identified as a factor that may affect leatherback habitat and 

biology (NMFS and USFWS 2007b); however, no significant climate change related impacts to 

leatherback sea turtle populations have been observed to date. Over the long term, climate change 

related impacts will likely influence biological trajectories in the future on a century scale 

(Parmesan and Yohe 2003). Changes in marine systems associated with rising water temperatures, 

changes in ice cover, salinity, oxygen levels and circulation including shifts in ranges and changes 

in algal, plankton, and fish abundance could affect leatherback prey distribution and abundance. 

Climate change is expected to expand foraging habitats into higher latitude waters and some 

concern has been noted that increasing temperatures may increase the female:male sex ratio of 

hatchlings on some beaches (Morosovsky et al. 1984 and Hawkes et al. 2007 in NMFS and USFWS 

2007b). However, due to the tendency of leatherbacks to have individual nest placement 

preferences and deposit some clutches in the cooler tide zone of beaches, the effects of long-term 

climate on sex ratios may be mitigated (Kamel and Mrosovsky 2004 in NMFS and USFWS 2007b). 

Additional potential effects of climate change on leatherbacks include range expansion and changes 

in migration routes as increasing ocean temperatures shift range-limiting isotherms north (Robinson 

et al. 2008). Leatherbacks have expanded their range in the Atlantic north by 330 km in the last 17 

years as warming has caused the northerly migration of the 15°C sea surface temperature (SST) 

isotherm, the lower limit of thermal tolerance for leatherbacks (McMahon and Hays 2006). 

Leatherbacks are speculated to be the best able to cope with climate change of all the sea turtle 

species due to their wide geographic distribution and relatively weak beach fidelity. Leatherback 

sea turtles may be most affected by any changes in the distribution of their primary jellyfish prey, 

which may affect leatherback distribution and foraging behavior (NMFS and USFWS 2007b). 

Jellyfish populations may increase due to ocean warming and other factors (Brodeur et al. 1999; 

Attrill et al. 2007; Richardson et al. 2009). However, any increase in jellyfish populations may or 

may not impact leatherbacks as there is no evidence that any leatherback populations are currently

food-limited.

Increasing temperatures are expected to result in rising sea levels (Titus and Narayanan 1995 in 

Conant et al. 2009), which could result in increased erosion rates along nesting beaches. Sea level 

rise could result in the inundation of nesting sites and decrease available nesting habitat (Fish et al. 

2005). This effect would potentially be accelerated due to a combination of other environmental 

and oceanographic changes such as an increase in the frequency of storms and/or changes in 

prevailing currents. While there is a reasonable degree of certainty that climate change related 

effects will be experienced globally (e.g., rising temperatures and changes in precipitation patterns), 

due to a lack of scientific data, the specific effects of climate change on this species are not 

quantifiable at this time (Hawkes et al. 2009). 

6.2.5 Shortnose sturgeon 

Global climate change may affect shortnose sturgeon in the future. Rising sea level may result in 

the salt wedge moving upstream in affected rivers. Shortnose sturgeon spawning occurs in fresh 

water reaches of rivers because early life stages have little to no tolerance for salinity. Similarly, 

juvenile shortnose sturgeon have limited tolerance to salinity and remain in waters with little to no 

salinity. If the salt wedge moves further upstream, shortnose sturgeon spawning and rearing habitat 
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could be restricted. In river systems with dams or natural falls that are impassable by sturgeon, the 

extent that spawning or rearing may be shifted upstream to compensate for the shift in the 

movement of the saltwedge would be limited. While there is an indication that an increase in sea 

level rise would result in a shift in the location of the salt wedge, for most spawning rivers there are 

no predictions on the timing or extent of any shifts that may occur; thus, it is not possible to predict 

any future loss in spawning or rearing habitat. However, in all river systems, spawning occurs 

miles upstream of the saltwedge. It is unlikely that shifts in the location of the saltwedge would 

eliminate freshwater spawning or rearing habitat. If habitat was severely restricted, productivity or 

survivability may decrease. 

The increased rainfall predicted by some models in some areas may increase runoff and scour 

spawning areas and flooding events could cause temporary water quality issues. Rising 

temperatures predicted for all of the U.S. could exacerbate existing water quality problems with DO 

and temperature. While this occurs primarily in rivers in the southeast U.S. and the Chesapeake 

Bay, it may start to occur more commonly in the northern rivers. Shortnose sturgeon are tolerant to 

water temperatures up to approximately 28°C (82.4°F); these temperatures are experienced 

naturally in some areas of rivers during the summer months. If river temperatures rise and 

temperatures above 28°C are experienced in larger areas, sturgeon may be excluded from some 

habitats. 

Increased droughts (and water withdrawal for human use) predicted by some models in some areas 

may cause loss of habitat including loss of access to spawning habitat. Drought conditions in the 

spring may also expose eggs and larvae in rearing habitats. If a river becomes too shallow or flows 

become intermittent, all shortnose sturgeon life stages, including adults, may become susceptible to 

strandings. Low flow and drought conditions are also expected to cause additional water quality 

issues. Any of the conditions associated with climate change are likely to disrupt river ecology 

causing shifts in community structure and the type and abundance of prey. Additionally, cues for 

spawning migration and spawning could occur earlier in the season causing a mismatch in prey that 

are currently available to developing shortnose sturgeon in rearing habitat; however, this would be 

mitigated if prey species also had a shift in distribution or if developing sturgeon were able to shift 

their diets to other species. 

6.2.6 Atlantic sturgeon 

Global climate change may affect all DPSs of Atlantic sturgeon in the future; however, effects of 

increased water temperature and decreased water availability are most likely to effect the South 

Atlantic and Carolina DPSs. Rising sea level may result in the salt wedge moving upstream in 

affected rivers. Atlantic sturgeon spawning occurs in fresh water reaches of rivers because early 

life stages have little to no tolerance for salinity. Similarly, juvenile Atlantic sturgeon have limited 

tolerance to salinity and remain in waters with little to no salinity. If the salt wedge moves further 

upstream, shortnose sturgeon spawning and rearing habitat could be restricted. In river systems 

with dams or natural falls that are impassable by sturgeon, the extent that spawning or rearing may 

be shifted upstream to compensate for the shift in the movement of the saltwedge would be limited. 

While there is an indication that an increase in sea level rise would result in a shift in the location of 

the salt wedge, at this time there are no predictions on the timing or extent of any shifts that may 

occur; thus, it is not possible to predict any future loss in spawning or rearing habitat. However, in 

all river systems, spawning occurs miles upstream of the saltwedge. It is unlikely that shifts in the 
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location of the saltwedge would eliminate freshwater spawning or rearing habitat. If habitat was 

severely restricted, productivity or survivability may decrease. 

The increased rainfall predicted by some models in some areas may increase runoff and scour 

spawning areas and flooding events could cause temporary water quality issues. Rising 

temperatures predicted for all of the U.S. could exacerbate existing water quality problems with DO 

and temperature. While this occurs primarily in rivers in the southeast U.S. and the Chesapeake 

Bay, it may start to occur more commonly in the northern rivers. Atlantic sturgeon prefer water 

temperatures up to approximately 28°C (82.4°F); these temperatures are experienced naturally in 

some areas of rivers during the summer months. If river temperatures rise and temperatures above 

28°C are experienced in larger areas, sturgeon may be excluded from some habitats. 

Increased droughts (and water withdrawal for human use) predicted by some models in some areas 

may cause loss of habitat including loss of access to spawning habitat. Drought conditions in the 

spring may also expose eggs and larvae in rearing habitats. If a river becomes too shallow or flows 

become intermittent, all Atlantic sturgeon life stages, including adults, may become susceptible to 

strandings or habitat restriction. Low flow and drought conditions are also expected to cause 

additional water quality issues. Any of the conditions associated with climate change are likely to 

disrupt river ecology causing shifts in community structure and the type and abundance of prey. 

Additionally, cues for spawning migration and spawning could occur earlier in the season causing a 

mismatch in prey that are currently available to developing sturgeon in rearing habitat. 

6.3 Effects of Climate Change in the Action Area 

Available information on climate change related effects for the Delaware River largely focuses on 

effects that rising water levels may have on the human environment (Barnett et al. 2009) and the 

availability of water for human use (e.g., Ayers et al. 1994). Documents prepared by ACOE for the 

deepening project have considered climate change (ACOE 2009, 2011), with a focus on sea level 

rise and a change in the location of the salt line. 

Kreeger et al. (2010) considers effects of climate change on the Delaware Estuary. Using the 

average of 14 models, an air temperature increase of 1.9-3.7°C over this century is anticipated, with 

the amount dependent on emissions scenarios. No predictions related to increases in river water 

temperature are provided. There is also a 7-9% increase in precipitation predicted as well as an 

increase in the frequency of short term drought, a decline in the number of frost days, and an 

increase in growing season length predicted by 2100. 

The report notes that the Mid-Atlantic States are anticipated to experience sealevel rise greater than 

the global average (GCRP, 2009). While the global sea level rise is largely attributed to melting ice 

sheets and expanding water as it warms, there is regional variation because of gravitational forces, 

wind, and water circulation patterns. In the Mid-Atlantic region, changing water circulation 

patterns are expected to increase sea-level by approximately 10 cm over this century (Yin et al., 

2009 in Kreeger et al. 2010). Subsidence and sediment accretion also influence sea level rise in the 

Mid-Atlantic, including in the Delaware estuary. As described by Kreeger, postglacial settling of 

the land masses has occurred in the Delaware system since the last Ice Age. This settling causes a 

steady loss of elevation, which is called subsidence. Through the next century, subsidence is 

estimated to hold at an average 1-2 mm of land elevation loss per year (Engelhart et al., 2009 in 
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Kreeger et al. 2010). Rates of subsidence and accretion vary in different areas around the Delaware 

Estuary, but the greatest loss of shoreline habitat is expected to occur where subsidence is naturally 

high in areas that cannot accrete more sediments to compensate for elevation loss plus absolute sealevel rise. The net increase in sea-level compared to the change in land elevation is referred to as the 

rate of relative sea-level rise (RSRL). Kreeger states that the best estimate for RSLR by the end of 

the century is 0.8 to 1.7 m in the Delaware Estuary. 

Sea level rise combined with more frequent droughts and increased human demand for water are 

predicted to result in a northward movement of the salt wedge in the Delaware River (Collier 2011). 

Currently, the normal average location of the salt wedge is at approximately river mile 71. Collier 

predicts that without mitigation (e.g., increased release of flows into downstream areas of the river), 

at high tide in the peak of the summer during extreme drought conditions, the salt line could be as 

far upstream as river mile 114 (rkm 183) in 2050 and 117 (rkm 188) in 2100. The farthest north the 

salt line has historically been documented was approximately river mile 103 during a period of 

severe drought in 1965; thus, he predicts that over time, during certain extreme conditions, the salt 

line could shift up to 11 miles further upstream by 2050 and 14 miles further upstream by 2100. 

A hydrologic model for the Delaware River, incorporating predicted changes in temperature and 

precipitation was compiled by Hassell and Miller (1999). The model results indicate that when only 

the temperature increase is input to the hydrologic model, the mean annual streamflow decreased, 

the winter flows increased due to increased snowmelt, and the mean position of the salt front moved 

upstream. When only the precipitation increase was input to the hydrologic model, the mean annual 

streamflow increased, and the mean position of the salt front moved further downstream. However, 

when both the temperature and precipitation increase were input to the hydrologic model the mean 

annual streamflow changed very little, with a small increase during the first four months of the year.

Water temperature in the Delaware River varies seasonally. A 2007 examination of long-term 

trends in Delaware River water temperature shows no indication of any long-term trends in these 

seasonal changes (BBL Sciences 2007). Monthly mean temperature in 2001 compares almost 

identically to long-term monthly mean temperatures for the period from 1964 to 2000, with lowest 

temperatures recorded in April (10–11°C) and peak temperatures observed in August 

(approximately 26–27°C). While water temperature rises have been observed in other mid-Atlantic 

rivers (e.g., a 2°C increase in the Hudson River from the 1960s to 2000s (Pisces 2008)), a similar 

trend does not currently appear in the Delaware River. 

6.4 Effects of Climate Change in the Action Area to Atlantic and shortnose sturgeon 

As there is significant uncertainty in the rate and timing of change as well as the effect of any 

changes that may be experienced in the action area due to climate change, it is difficult to predict 

the impact of these changes on shortnose and Atlantic sturgeon; however, we have considered the 

available information to consider likely impacts to sturgeon in the action area. The proposed action 

under consideration of the continuation of the deepening project through January 2017 and 10 years 

of maintenance dredging; thus, we consider here, likely effects of climate change during the period 

from now until 2027. 

Over time, the most likely effect to shortnose and Atlantic sturgeon would be if sea level rise was 

great enough to consistently shift the salt wedge far enough north which would restrict the range of 
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juvenile sturgeon and may affect the development of these life stages. Upstream shifts in spawning 

or rearing habitat in the Delaware River are not limited by any impassable falls or manmade 

barriers. Habitat that is suitable for spawning is known to be present upstream of the areas that are 

thought to be used by shortnose and Atlantic sturgeon suggesting that there may be some capacity 

for spawning to shift further upstream to remain ahead of the saltwedge. Based on predicted upriver 

shifts in the saltwedge, areas where Atlantic sturgeon currently spawn could, over time, become too 

saline to support spawning and rearing. Modeling conducted by the ACOE indicates that this is 

unlikely to occur before 2040 but modeling conducted by Collier (2011) suggests that by 2100 areas

where spawning is thought to occur (rkm 120-150 and 170-190), may be too salty and spanwing 

would need to shift further north. Given the availability of spawning habitat in the river, it is 

unlikely that the saltwedge would shift far enough upstream to result in a significant restriction of 

spawning or nursery habitat. The available habitat for juvenile sturgeon could decrease over time; 

however, even if the saltwedge shifted several miles upstream, it seems unlikely that the decrease in 

available habitat would have a significant effect on juvenile sturgeon. 

In the action area, it is possible that changing seasonal temperature regimes could result in changes 

in the timing of seasonal migrations through the area as sturgeon move throughout the river. There 

could be shifts in the timing of spawning; presumably, if water temperatures warm earlier in the 

spring, and water temperature is a primary spawning cue, spawning migrations and spawning events 

could occur earlier in the year. However, because spawning is not triggered solely by water 

temperature, but also by day length (which would not be affected by climate change) and river flow 

(which could be affected by climate change), it is not possible to predict how any change in water 

temperature or river flow alone will affect the seasonal movements of sturgeon through the action 

area. However, it seems most likely that spawning would shift earlier in the year. 

Any forage species that are temperature dependent may also shift in distribution as water 

temperatures warm. However, because we do not know the adaptive capacity of these individuals 

or how much of a change in temperature would be necessary to cause a shift in distribution, it is not 

possible to predict how these changes may affect foraging sturgeon. If sturgeon distribution shifted 

along with prey distribution, it is likely that there would be minimal, if any, impact on the 

availability of food. Similarly, if sturgeon shifted to areas where different forage was available and 

sturgeon were able to obtain sufficient nutrition from that new source of forage, any effect would be 

minimal. The greatest potential for effect to forage resources would be if sturgeon shifted to an area 

or time where insufficient forage was available; however, the likelihood of this happening seems 

low because sturgeon feed on a wide variety of species and in a wide variety of habitats.

Limited information on the thermal tolerances of Atlantic and shortnose sturgeon is available. 

Atlantic sturgeon have been observed in water temperatures above 30°C in the south (see DamonRandall et al. 2010); in the wild, shortnose sturgeon are typically found in waters less than 28°C. In 

the laboratory, juvenile Atlantic sturgeon showed negative behavioral and bioenergetics responses 

(related to food consumption and metabolism) after prolonged exposure to temperatures greater 

than 28°C (82.4°F) (Niklitschek 2001). Tolerance to temperatures is thought to increase with age 

and body size (Ziegweid et al. 2008 and Jenkins et al. 1993), however, no information on the lethal 

thermal maximum or stressful temperatures for subadult or adult Atlantic sturgeon is available. 

Shortnose sturgeon, have been documented in the lab to experience mortality at temperatures of 

33.7°C (92.66°F) or greater and are thought to experience stress at temperatures above 28°C. For 
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purposes of considering thermal tolerances, we consider Atlantic sturgeon to be a reasonable 

surrogate for shortnose sturgeon given similar geographic distribution and known biological 

similarities.

Mean monthly ambient temperatures in the Delaware estuary range from 11-27°C from April –

November, with temperatures lower than 11°C from December-March. No estimates of a predicted 

rise in water temperatures for the Delaware River is available. A predicted increase in water 

temperature of 3-4°C within 100 years is predicted in the Hudson River. If we assume that a similar 

rate of change would be experienced in the Delaware River, we would expect an increase of less 

than 1°C between now and 2027. This could result in temperatures approaching the preferred 

temperature of shortnose and Atlantic sturgeon (28°C) on more days and/or in larger areas. This 

could result in shifts in the distribution of sturgeon out of certain areas during the warmer months. 

Information from southern river systems suggests that during peak summer heat, sturgeon are most 

likely to be found in deep water areas where temperatures are coolest. Thus, we could expect that 

over time, sturgeon would shift out of shallow habitats on the warmest days. This could result in 

reduced foraging opportunities if sturgeon were foraging in shallow waters.

As described above, over the long term, global climate change may affect shortnose and Atlantic 

sturgeon by affecting the location of the salt wedge, distribution of prey, water temperature and 

water quality. However, there is significant uncertainty, due to a lack of scientific data, on the 

degree to which these effects may be experienced and the degree to which shortnose or Atlantic 

sturgeon will be able to successfully adapt to any such changes. Any activities occurring within and 

outside the action area that contribute to global climate change are also expected to affect shortnose 

and Atlantic sturgeon in the action area. While we can make some predictions on the likely effects 

of climate change on these species, without modeling and additional scientific data these predictions 

remain speculative. Additionally, these predictions do not take into account the adaptive capacity

of these species which may allow them to deal with change better than predicted. 

6.5 Effects of Climate Change in the Action Area on Sea Turtles

As there is significant uncertainty in the rate and timing of change as well as the effect of any 

changes that may be experienced in the action area due to climate change, it is difficult to predict 

the impact of these changes on sea turtles; however, we have considered the available information 

to consider likely impacts to these species in the action area. The proposed action under 

consideration of the continuation of the deepening project through January 2017 and 10 years of 

maintenance dredging; thus, we consider here, likely effects of climate change during the period 

from now until 2027. Sea turtles are most likely to be affected by climate change due to increasing 

sand temperatures at nesting beaches which in turn would result in increased female:male sex ratio 

among hatchlings, sea level rise which could result in a reduction in available nesting beach habitat, 

increased risk of nest inundation, changes in the abundance and distribution of forage species which 

could result in changes in the foraging behavior and distribution of sea turtle species, and changes in 

water temperature which could possibly lead to a northward shift in their range. 

Over the time period considered in this Opinion, sea surface temperatures are expected to rise less 

than 1°C. It is unknown if that is enough of a change to contribute to shifts in the range or 

distribution of sea turtles. Theoretically we expect that as waters in the action area warm, more sea 

turtles could be present or sea turtles could be present for longer periods of time. However, if 
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temperature affected the distribution of sea turtle forage in a way that decreased forage in the action 

area, sea turtles may be less likely to occur in the action area. It has been speculated that the nesting 

range of some sea turtle species may shift northward. Nesting in the mid-Atlantic generally is 

extremely rare and no nesting has been documented at any beach in the action area. In 2010, one 

green sea turtle came up on the beach in Sea Isle City, New Jersey; however, it did not lay any eggs. 

In August 2011, a loggerhead came up on the beach in Stone Harbor, New Jersey but did not lay 

any eggs. On August 18, 2011, a green sea turtle laid one nest at Cape Henlopen Beach in Lewes 

Delaware near the entrance to Delaware Bay. The nest contained 190 eggs and was transported 

indoors to an incubation facility on October 7. A total of twelve eggs hatched, with eight hatchlings 

surviving. In December, seven of the hatchlings were released in Cape Hatteras, North Carolina. It 

is important to consider that in order for nesting to be successful in the mid-Atlantic, fall and winter 

temperatures need to be warm enough to support the successful rearing of eggs and sea 

temperatures must be warm enough for hatchlings not to die when they enter the water. Predicted 

increases in water temperatures between now and 2027 are not great enough to allow successful 

rearing of sea turtle eggs in the action area. Therefore, it is unlikely that over the time period 

considered here, that there would be an increase in nesting activity in the action area or that 

hatchlings would be present in the action area. 

We have considered whether the disposal of sand at Broadkill Beach and Kelly Island would impact 

sea turtles. As noted above, there is the potential for a northward shift in nesting by sea turtles. 

Given existing nesting locations and the relatively short duration of time considered in this Opinion 

(15 years), it seems extremely unlikely that the range of leatherback or Kemp’s ridley sea turtle 

nesting would shift enough so that nesting would occur on beaches in Delaware Bay. The furthest

north that leatherbacks nest is southeastern Florida. Kemp’s ridleys only nest in Mexico. It is more 

likely that any shift in nesting to Delaware Bay beaches would be from loggerheads (which nest as 

far north as Virginia) and/or green sea turtles (which normally nest as far north as North Carolina. 

The disposal of material at Broadkill Beach and Kelly Island is meant to stabilize and restore

eroding habitats and maintain existing beach. None of the activity is likely to reduce the suitability 

of these beaches for potential future nesting. 

7.0 EFFECTS OF THE ACTION

This section of an Opinion assesses the direct and indirect effects of the proposed action on 

threatened and endangered species or critical habitat, together with the effects of other activities that 

are interrelated or interdependent (50 CFR 402.02). Indirect effects are those that are caused later 

in time, but are still reasonably certain to occur. Interrelated actions are those that are part of a 

larger action and depend upon the larger action for their justification. Interdependent actions are 

those that have no independent utility apart from the action under consideration (50 CFR 402.02). 

We have not identified any interdependent or interrelated actions. This Opinion examines the likely 

effects (direct and indirect) of the proposed action on shortnose sturgeon, five DPSs of Atlantic 

sturgeon, and sea turtles in the action area and their habitat within the context of the species status 

now and projected over the course of the action, the environmental baseline and cumulative effects. 

As explained in the Description of the Action, the action under consideration in this Opinion is the 

ongoing initial dredging cycle needed to deepen the channel which will be conducted through 

January 2017, the disposal of dredged material resulting from this dredging, including beneficial use 

of material at Broadkill Beach and Kelly Island, blasting of rock material at Marcus Hook and 

subsequent removal with a mechanical dredge, as well as 10 years of maintenance dredging. 
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As explained in the Description of the Action section above, both hydraulic cutterhead and hopper 

dredges will be used for the initial deepening. It is also possible that a mechanical dredge could be 

used in Reach AA. Refer to Table 2 and Figure 2 in the “Description of the Action” section for a 

summary of the proposed dredging by reach. The effects of dredging on listed species will be 

different depending on the type of dredge used and the geographical area where dredging will 

occur. As such, the following discussion of effects of dredging will be organized by dredge type. 

Below, the discussion will consider the effects of dredging, including the risk of entrainment or 

capture of Atlantic sturgeon, shortnose sturgeon and sea turtles. We also consider effects of 

dredging and disposal on water quality, including turbidity/suspended sediment and effects of 

dredge vessel traffic. Following, there is a discussion of blasting and associated debris removal 

with a mechanical dredge. Last, there is a discussion of other effects of the project which are not 

specific to the type of equipment used. This includes effects on prey and foraging and changes in 

the characteristics of the river (i.e., sediment type, location of the salt wedge). We also consider 

effects of 10 years of maintenance dredging. 

7.1 Hopper Dredge

A large self-propelled hopper dredge will be used for dredging in Reach E and may also be used in 

Reach AA, A and D. At Reach A, dredging is scheduled over approximately six months from 

August 2012-February 2013 (1,666,600cy to be removed); at this time it is unknown if a cutterhead 

or a hopper dredge will be used. Dredging at Reach E will occur with a hopper dredge, with 

disposal at Broadkill Beach (1,598,700 cy) is scheduled for September – December 2013; dredging 

at Reach E will also occur with disposal at Kelly Island (2,483,000 cy) between April and August 

2015. Dredging at Reach AA will be with a cutterhead or hopper dredge and will remove 994,000 

cy from August – November 2014. Dredging at Reach D is likely to be with a hopper dredge but 

could occur with a cutterhead dredge; dredging will occur from December 2012 – June 2013. 

7.1.1 Entrainment in Hopper Dredges – Sea Turtles 

As outlined above, sea turtles are likely to occur in Delaware Bay from May through midNovember each year with the largest numbers present from June through October of any year 

(Stetzar 2002). The majority of sea turtles in the Delaware Estuary are juvenile loggerheads; 

however, adult loggerheads, juvenile Kemp’s ridley, adult and juvenile leatherback and adult green 

sea turtles have also been documented in the area. The Delaware Estuary is an important foraging 

area for sea turtles and an important developmental habitat for juvenile sea turtles, particularly 

loggerheads. The only dredging operations that are scheduled to occur in the geographic region of 

the action area where sea turtles are likely to occur are deepening and maintenance in Reaches D 

and E. No sea turtles occur in Reach A or AA so no sea turtles will be exposed to effects of hopper 

dredging carried out in Reach A or AA. 

Deepening will remove 2,051,100 cy from Reach D and a total of 4,981,700 cy from Reach E. 

Dredging is scheduled in Reach D from December 2012 – June 2013 and in Reach E from 

September – December 2013 and April – August 2015. Exact scheduling is dependent on funding 

and availability of dredge equipment. 

Loggerhead, Kemp’s ridley and green sea turtles are vulnerable to entrainment in the draghead of 

the hopper dredge. Given their large size, leatherback sea turtles are not vulnerable to entrainment. 
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As reported by ACOE, no leatherback sea turtles have been entrained in hopper dredge operations 

operating along the U.S. Atlantic coast (ACOE Sea Turtle Warehouse, 2012). The areas to be 

dredged in Reaches D and E are part of the summer developmental habitat of juvenile sea turtles 

and are used by turtles for foraging. Sea turtles are likely to be feeding on or near the bottom of the 

water column during the warmer months, with loggerhead and Kemp’s ridley sea turtles being the 

most common species in these waters. Although not expected to be as numerous as loggerheads 

and Kemp’s ridleys, green sea turtles are also likely to occur seasonally in Reach D and E. 

Sea turtles become entrained in hopper dredges as the draghead moves along the bottom. 

Entrainment occurs when sea turtles do not or cannot escape from the suction of the dredge. Sea 

turtles can also be crushed on the bottom by the moving draghead. Mortality most often occurs 

when turtles are sucked into the dredge draghead, pumped through the intake pipe and then killed as 

they cycle through the centrifugal pump and into the hopper. Because entrainment is believed to 

occur primarily while the draghead is operating on the bottom, it is likely that only those species 

feeding or resting on or near the bottom would be vulnerable to entrainment. Turtles can also be

entrained if suction is created in the draghead by current flow while the device is being placed or 

removed, or if the dredge is operating on an uneven or rocky substrate and rises off the bottom. 

Recent information from the ACOE suggests that the risk of entrainment is highest when the bottom 

terrain is uneven or when the dredge is conducting “clean up” operations at the end of a dredge 

cycle when the bottom is trenched and the dredge is working to level out the bottom. In these 

instances, it is difficult for the dredge operator to keep the draghead buried in the sand and sea 

turtles near the bottom may be more vulnerable to entrainment. 

Sea turtles have been found resting in deeper waters, which could increase the likelihood of 

interactions from dredging activities. In 1981, observers documented the take of 71 loggerheads by 

a hopper dredge at the Port Canaveral Ship Channel, Florida (Slay and Richardson 1988). This 

channel is a deep, low productivity environment in the Southeast Atlantic where sea turtles are 

known to rest on the bottom, making them extremely vulnerable to entrainment. The large number 

of turtle mortalities at the Port Canaveral Ship Channel in the early 1980s resulted in part from 

turtles being buried in the soft bottom mud, a behavior known as brumation. Since 1981, 77 

loggerhead sea turtles have been taken by hopper dredge operations in the Port Canaveral Ship 

Channel, Florida. Chelonid turtles have been found to make use of deeper, less productive channels 

as resting areas that afford protection from predators because of the low energy, deep water 

conditions. While sea turtle brumation has not been documented in mid-Atlantic or New England 

waters, it is possible that this phenomenon occurs in these waters. 

7.1.1.1 Background Information on Entrainment of Sea Turtles in Hopper Dredges 

Sea turtles have been killed in hopper dredge operations along the East and Gulf coasts of the US. 

Documented turtle mortalities during dredging operations in the ACOE South Atlantic Division 

(SAD; i.e., south of the Virginia/North Carolina border) are more common than in the ACOE North 

Atlantic Division (NAD; Virginia-Maine) presumably due to the greater abundance of turtles in 

these waters and the greater frequency of hopper dredge operations. For example, in the ACOE 

SAD, over 400 sea turtles have been entrained in hopper dredges since 1980 and in the Gulf Region 

over 160 sea turtles have been killed since 1995. Records of sea turtle entrainment in the ACOE 

NAD began in 1994. Through May 2012, 75 sea turtles deaths (see Table 8) related to hopper 

dredge activities have been recorded in waters north of the North Carolina/Virginia border (USACE 
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Sea Turtle Database18); the majority of these turtles have been entrained in dredges operating in 

Chesapeake Bay. 

Before 1994, endangered species observers were not required on board hopper dredges and dredge 

baskets were not inspected for sea turtles or sea turtle parts. The majority of sea turtle takes in the 

NAD have occurred in the Norfolk district. This is largely a function of the large number of 

loggerhead and Kemp’s ridley sea turtles that occur in the Chesapeake Bay each summer and the 

intense dredging operations that are conducted to maintain the Chesapeake Bay entrance channels 

and for beach nourishment projects at Virginia Beach. Since 1992, the take of 10 sea turtles (all 

loggerheads) has been recorded during hopper dredge operations in the Philadelphia, Baltimore and 

New York Districts. Hopper dredging is relatively rare in New England waters where sea turtles are 

known to occur, with most hopper dredge operations being completed by the specialized 

Government owned dredge Currituck which operates at low suction and has been demonstrated to 

have a very low likelihood of entraining or impinging sea turtles. To date, no hopper dredge 

operations (other than the Currituck) have occurred in the New England District in areas or at times 

when sea turtles are likely to be present. 

Of the 10 sea turtle mortalities attributed to hopper dredge operations outside of the Norfolk 

District, 6 have occurred in the Philadelphia District, 3 in the Baltimore District and 1 in the New 

York District. As explained in the ACOE BA, the Philadelphia District Endangered Species 

Monitoring Program began in 1992. For four hopper dredging projects conducted in 1992 – 1994, 

observers were present to provide approximately 25% coverage (6 hours on, 6 hours off on a 

biweekly basis). No sea turtles were observed during the 8/25-10/13/92 dredging at Bethany Bay, 

DE or the 10/24-11/14/92 dredging at Cape May, NJ. The dredge McFarland worked in the 

Delaware River entrance channel from 6/23 – 7/23/93 with no sea turtle observations. The dredge 

continued in the Brandywine Range from 7/24-8/2 and 8/10-8/19/93. Fresh sea turtle parts were 

observed in the inflow screening on two separate dates three days apart in the Brandywine Range of 

the Delaware Bay. Additionally, three live sea turtles were observed from the bridge during 

dredging operations. Dredging with the McFarland continued in the Delaware Bay entrance 

channel from 6/13-8/10/94. During this dredging cycle, relocation trawling was conducted in an 

attempt to capture sea turtles in the area where dredging was occurring and move them away from 

the dredge. Eight loggerhead sea turtles were captured alive with the trawl and relocated away from 

the dredging site. One loggerhead was taken by the dredge on June 22, 1994. Since this event in 

1994, dredge observer coverage was increased to 50%. On November 3, 1995, one loggerhead was 

taken by a hopper dredge operating in the entrance channel. In 1999, dredging occurred in July at 

the entrance channel. Three decomposed loggerheads were observed at Brandywine Shoal and 

Reedy Island by the dredge observer while the dredge was transiting to the disposal site. There is 

no evidence to suggest that these turtles were killed during dredging operations. On July 27, 2005 

fresh loggerhead parts were observed in two different dredge loads while dredging was being 

conducted in the Miah Maull Range of the channel in Delaware Bay. It is currently unknown 

whether these were parts of the same turtle or two different turtles. 

 

18

 The USACE Sea Turtle Data Warehouse is maintained by the ACOE’s Environmental Laboratory and contains 

information on ACOE dredging projects conducted since 1980 with a focus on information on interactions with sea 

turtles. 
127

In addition to sea turtles observed as entrained, one loggerhead was killed during dredging 

operations off Sea Girt, New Jersey during an ACOE New York District beach renourishment 

project on August 23, 1997. This turtle was closed up in the hinge between the draghead and the 

dragarm as the dragarm lifted off the bottom. 

Table 8. Sea Turtle Takes in USACE NAD Dredging Operations

Project Location Year of 

Operation

Cubic Yardage 

Removed

Observed Takes 

Cape Henry Channel 2012 NA 1 loggerhead 

York Spit 2012 NA 1 Loggerhead

Thimble Shoal 

Channel

2009 NA 3 Loggerheads

York Spit 2007 608,000 1 Kemp’s Ridley 

Cape Henry 2006 NA 3 Loggerheads

Thimble Shoal 

Channel

2006 300,000 1 loggerhead

Delaware Bay 2005 50,000 2 Loggerheads

Thimble Shoal 

Channel

2003 1,828,312 7 Loggerheads

1 Kemp’s ridley

1 unknown

Cape Henry 2002 1,407,814 6 Loggerheads

1 Kemp’s ridley

1 green

VA Beach Hurricane 

Protection Project 

(Cape Henry)

2002 NA 1 Loggerhead

York Spit Channel 2002 911,406 8 Loggerheads

1 Kemp’s ridley

Cape Henry 2001 1,641,140 2 loggerheads

1 Kemp’s ridley

VA Beach Hurricane 

Protection Project 

(Thimble Shoals)

2001 NA 5 loggerheads

1 unknown 

Thimble Shoal 

Channel

2000 831,761 2 loggerheads

1 unknown 

York River Entrance 

Channel

1998 672,536 6 loggerheads

Atlantic Coast of NJ 1997 1,000,000 1 Loggerhead

Thimble Shoal 

Channel

1996 529,301 1 loggerhead

Delaware Bay 1995 218,151 1 Loggerhead
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Cape Henry 1994 552,671 4 loggerheads

1 unknown

York Spit Channel 1994 61,299 4 loggerheads

Delaware Bay 1994 NA 1 Loggerhead

Delaware Bay 1993 NA 2 Loggerheads

Off Ocean City MD 1992 1,592,262 3 Loggerheads

TOTAL = 75 Turtles

It should be noted that the observed takes may not be representative of all the turtles killed during 

dredge operations. Typically, endangered species observers are required to observe a total of 50% 

of the dredge activity (i.e., 6 hours on watch, 6 hours off watch). As such, if the observer was off 

watch or the cage was emptied and not inspected or the dredge company either did not report or was 

unable to identify the turtle incident, there is the possibility that a turtle could be taken by the 

dredge and go unnoticed. Additionally, in older Opinions (i.e., prior to 1995), NMFS frequently 

only required 25% observer coverage and monitoring of the overflows which has since been 

determined to not be as effective as monitoring of the intakes. These conditions may have led to sea 

turtle takes going undetected. 

NMFS raised this issue to the ACOE Norfolk District during the 2002 season, after several turtles 

were taken in the Cape Henry and York Spit Channels, and expressed the need for 100% observer 

coverage. On September 30, 2002, the ACOE informed the dredge contractor that when the 

observer was not present, the cage should not be opened unless it is clogged. This modification was 

to ensure that any sea turtles that were taken and on the intake screen (or in the cage area) would 

remain there until the observer evaluated the load. The ACOE’s letter further stated “Crew 

members will only go into the cage and remove wood, rocks, and man-made debris; any aquatic 

biological material is left in the cage for the observer to document and clear out when they return on 

duty. In addition, the observer is the only one allowed to clean off the overflow screen. This 

practice provides us with 100% observation coverage and shall continue.” Theoretically, all sea 

turtle parts were observed under this scheme, but the frequency of clogging in the cage is unknown 

at this time. The most effective way to ensure that 100% observer coverage is attained is to have a 

NMFS-approved endangered species observer monitoring all loads at all times. This level of 

observer coverage would document all turtle interactions and better quantify the impact of dredging 

on turtle populations. More recently issued Opinions have required 100% observer coverage which 

increases the likelihood of takes being detected and reported. 

It is likely that not all sea turtles killed by dredges are observed onboard the hopper dredge. Several 

sea turtles were stranded on Virginia shores with crushing type injuries from May 25 to October 15, 

2002. The Virginia Marine Science Museum (VMSM) found 10 loggerheads, 2 Kemp’s ridleys, 

and 1 leatherback exhibiting injuries and structural damage consistent with what they have seen in 

animals that were known dredge takes. While it cannot be conclusively determined that these 

strandings were the result of dredge interactions, the link is possible given the location of the 

strandings (e.g., in the southern Chesapeake Bay near ongoing dredging activity), the time of the 

documented strandings in relation to dredge operations, the lack of other ongoing activities which 

may have caused such damage, and the nature of the injuries (e.g., crushed or shattered carapaces 

and/or flipper bones, black mud in mouth). Additionally, in 1992, three dead sea turtles were found 
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on an Ocean City, Maryland beach while dredging operations were ongoing at a borrow area 

located 3 miles offshore. Necropsy results indicate that the deaths of all three turtles were dredge 

related. It is unknown if turtles observed on the beach with these types of injuries were crushed by 

the dredge and subsequently stranded on shore or whether they were entrained in the dredge, 

entered the hopper and then were discharged onto the beach with the dredge spoils. 

A dredge could crush an animal as it was setting the draghead on the bottom, or if the draghead was 

lifting on and off the bottom due to uneven terrain, but the actual cause of these crushing injuries 

cannot be determined at this time. Further analyses need to be conducted to better understand the 

link between crushed strandings and dredging activities, and if those strandings need to be factored 

into an incidental take level. Regardless, it is possible that dredges are taking animals that are not 

observed on the dredge which may result in strandings on nearby beaches.

Due to the nature of interactions between listed species and dredge operations, it is difficult to 

predict the number of interactions that are likely to occur from a particular dredging operation. 

Projects that occur in an identical location with the same equipment year after year may result in 

interactions in some years and none in other years as noted in the examples of sea turtle takes 

above. Dredging operations may go on for months, with sea turtle takes occurring intermittently 

throughout the duration of the action. For example, dredging occurred at Cape Henry over 160 days 

in 2002 with 8 sea turtle takes occurring over 3 separate weeks while dredging at York Spit in 1994 

resulted in 4 sea turtle takes in one week. In Delaware Bay, dredge cycles have been conducted 

during the May-November period with no observed entrainment and as many as two sea turtles have 

been entrained in as little as three weeks. Even in locations where thousands of sea turtles are 

known to be present (i.e., Chesapeake Bay) and where dredges are operating in areas with preferred 

sea turtle depths and forage items (as evidenced by entrainment of these species in the dredge), the 

numbers of sea turtles entrained is an extremely small percentage of the likely number of sea turtles 

in the action area. This is likely due to the distribution of individuals throughout the action area, the 

relatively small area which is affected at any given moment and the ability of some sea turtles to 

avoid the dredge even if they are in the immediate area. 

The number of interactions between dredge equipment and sea turtles seems to be best associated 

with the volume of material removed, which is closely correlated to the length of time dredging 

takes, with a greater number of interactions associated with a greater volume of material removed 

and a longer duration of dredging. The number of interactions is also heavily influenced by the 

time of year dredging occurs (with more interactions correlated to times of year when more sea 

turtles are present in the action area) and the type of dredge plant used (sea turtles are apparently 

capable of avoiding pipeline and mechanical dredges as no takes of sea turtles have been reported 

with these types of dredges). The number of interactions may also be influenced by the terrain in 

the area being dredged, with interactions more likely when the draghead is moving up and off the 

bottom frequently. Interactions are also more likely at times and in areas when sea turtle forage 

items are concentrated in the area being dredged, as sea turtles are more likely to be spending time 

on the bottom while foraging. 

As explained above, since 1992 endangered species observers have worked on all hopper dredge 

operations below the Delaware Memorial Bridge operating between June and November. Prior to 

1995, observers worked one week on, one week off, resulting in approximately 25% observer 
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coverage. Since this date, observers have provided continuous 8-hour on 8-hour off coverage. 

Cages are generally not cleaned without the observer being present, so it is likely that greater than 

50% of material has been observed and that the number of entrainments that go undetected is low. 

Six sea turtles have been entrained in hopper dredges operating in Delaware Bay since 1993. As 

sea turtles have been documented in the action area and suitable habitat and forage items are 

present, it is likely that sea turtles will be present in the action area when dredging takes place. 

We have compiled a dataset representing all of the hopper dredge projects in the Philadelphia 

District that have reported the cubic yardage removed as well as the number of takes observed. 

Records for 12 projects occurring during “sea turtle season” (i.e., May – November 15) in the 

Philadelphia District are available that report the cubic yardage removed during a project. Of these, 

7 projects involved dredging in the Philadelphia to the Sea navigation channel and 5 involved 

dredging off the Atlantic coast of Delaware. The distribution of sea turtles in offshore locations 

such as offshore borrow areas used for beach nourishment is not expected to be comparable to the 

distribution of sea turtles in estuarine foraging areas such as Delaware Bay. Additionally, as 

evidenced in the sea turtle database, very few sea turtles have been entrained in hopper dredges 

operating at any offshore borrow area. This is true even in the southeast, where large numbers of 

sea turtles are present year round. This is likely due to the transitory nature of most sea turtles 

occurring in offshore borrow areas as well as the widely distributed nature of sea turtles in offshore 

waters. As such, we have excluded the five projects involving dredging off the Atlantic coast of 

Delaware from the dataset used to estimate an entrainment rate for sea turtles in hopper dredges 

operating in Delaware Bay (see Table 9 below). 

As explained above, for projects prior to 1995, observers were only present on the dredge for every 

other week of dredging. For dredging undertaken since 1995, observers were present on board the 

dredge full time and worked a 8-hour on, 8-hour off shift. The only time that cages (where sea 

turtle parts are typically observed) were cleaned by anyone other than the observer was when there 

was a clog. If a turtle or turtle part was observed in such an instance, crew were instructed to 

inform the observer, even if off-duty. As such, it is reasonable to expect that even though there was 

only 50% observer coverage, an extremely small amount of biological material went unobserved. 

To make the data from the 1993 and 1994 dredge events when observers were only on board every 

other week, comparable to the 1995-2006 data when observers were on board full time, NMFS has 

assumed that an equal number of turtles were entrained when observers were not present. This 

calculation is reflected in Table 2 as “adjusted entrainment number.” 

Table 9. Sea turtle entrainment in Philadelphia District dredging operations

Project Dates

CY 

Removed

Observed 

Entrainment

Adjusted Entrainment 

Number

Philadelphia to the 

Sea - Miah Maull, 

Brandywine, 

Deepwater and 

Liston ranges

08/08/06 - 08/23/06; 

09/07/06 - 11/16/06

390,000 0 0

Philadelphia to the 

Sea - Brandywine 

and Deepwater 

11/01/2005 -

11/18/2005

167,982 0 0
131

Ranges

Philadelphia to the 

Sea - Miah Maull and 

Brandwine

10/04/05 -

10/22/2005 

162,682 0 0

Philadelphia to the 

Sea - Miah Maull

7/24/05 - 7/27/05 50,000 2 2

Philadelphia to the 

Sea - Miah Maull and 

Brandywine

10/07/95 -11/16/95 218,151 1 1

Philadelphia to the 

Sea - Miah Maul 

McFarland 6/15/94-

8/10/94

2,830,000 1 2

Cape May Inlet 

Beachfill -

Brandywine Range 07/24/93 - 08/19/93 275,000 2 4

TOTAL

4,093,815 6 9

7.1.1.2 Predicted Entrainment in Proposed Hopper Dredging 

Based on the data in Table 9, NMFS has made calculations which indicate that an average of one

sea turtle is killed for approximately every 450,000 cy removed. This calculation has been based on 

a number of assumptions including the following: that sea turtles are evenly distributed throughout 

all channel reaches for which takes have occurred, that all dredges will take an identical number of 

sea turtles, and that sea turtles are equally likely to be encountered throughout the May to 

November time frame. Based on these calculations, we expect that for dredging in Reaches D and 

E of the navigation channel during the time of year when sea turtles are likely to be present, one sea 

turtle is likely to be entrained for every 450,000 cubic yards of material removed by a hopper 

dredge. While this estimate is based on several assumptions, it is reasonable because it uses the best 

available information on entrainment of sea turtles from past dredging operations in the action area, 

including channel reaches that are contained within Reaches D and E, includes multiple projects 

over several years, and all of the projects have had observer coverage. 

With the exception of one green turtle entrained in a hopper dredge operating in Chesapeake Bay, 

all other sea turtles entrained in dredges operating in the ACOE NAD have been loggerheads and 

Kemp’s ridley. Of these 75 sea turtles, 65 have been loggerheads, 5 have been Kemp’s ridleys, 1 

green and 4 unknown. Overall, of those identified to species, approximately 91% of the sea turtles 

entrained in dredges operating in the ACOE North Atlantic Division have been loggerheads. No 

Kemp’s ridleys or greens have been entrained in dredge operations outside of the Chesapeake Bay 

area. The high percentage of loggerheads is likely due to several factors including their tendency to 

forage on the bottom where the dredge is operating and the fact that this species is the most 

numerous of the sea turtle species in Northeast and Mid-Atlantic waters. It is likely that the 

documentation of only one green sea turtle entrainment in Virginia dredging operations is a 

reflection of the low numbers of green sea turtles that occur in waters north of North Carolina. The 

low number of green sea turtles in the action area makes an interaction with a green sea turtle 
132

extremely unlikely to occur. 

Based on the above information, it is reasonable to expect that one sea turtle is likely to be injured 

or killed for approximately every 450,000 cy of material removed from Reach D and E between 

May and November, and that at least 90% will be loggerheads. The ACOE has provided us with a 

schedule that indicates during what months dredging in Reach D and E is expected to occur; 

because sea turtles do not occur in the action area from December – April, we do not expect any 

entrainment during these months. Based on the information outlined above and the volume of 

material estimated to be removed from each reach during the time of year when sea turtles are likely 

to be present, we anticipate the following levels of entrainment:

Reach Scheduled 

Dates

Total Volume May –

November 

Volume

Expected Sea 

turtle 

interactions

D Dec 2012 –

June 2013

2,051,100 586,028 2

E Sept – Dec 

2013

1,598,700 1,200,025 3

E April – Aug 

2015

2,483,000 2,483,000 6

Total: 11

As such, assuming that all three of these reaches are deepened with hopper dredges, we anticipate 

that no more than 11 sea turtles are likely to be entrained in the initial dredge cycle operating on the 

schedule outlined above. We expect that nearly all of the sea turtles will be loggerheads and that 

the entrainment of a Kemp’s ridley during a particular dredge cycle will be rare; however, as 

Kemp’s ridleys have been documented in the action area and have been entrained in hopper 

dredges, it is likely that this species will interact with the dredge over the course of the project life. 

As explained above, approximately 91% of the sea turtles taken in dredges operating in the ACOE 

North Atlantic Division have been loggerheads and all sea turtles entrained in hopper dredges 

operating in Delaware Bay have been loggerheads. Based on the ratio of sea turtle entrainment in 

the ACOE NAD, no more than 1 of the sea turtles likely to be entrained in a hopper dredge will be a 

Kemp’s ridley, with the remainder being loggerheads. As noted above, interactions with green sea 

turtles are extremely unlikely. 

7.1.2 Entrainment – Shortnose Sturgeon

Shortnose sturgeon are also vulnerable to entrainment in hopper dredges. As explained above, since 

1992, endangered species observers have been present for at least a portion of all hopper dredging 

done during the June – November time frame below the Delaware Memorial Bridge (i.e., Reaches 

D and E). No shortnose sturgeon have been documented during any hopper dredge activity in the 

Philadelphia to the Sea channel maintenance. Little is known about the distribution of shortnose 

sturgeon in Delaware Bay. However, shortnose sturgeon have been documented at the Salem 

Nuclear Generating Facility at Artificial Island. The known occurrence of shortnose sturgeon in 

Reaches D and E and the lack of documented occurrence of entrainment of shortnose sturgeon in 

other hopper dredging operations in this area and the extent of the observer coverage (i.e., at least 
133

25% coverage over 7 events over 15 years) leads to the conclusion that it is extremely unlikely that 

a shortnose sturgeon will become entrained in a hopper dredge operating in Reach D or Reach E. 

This is likely due to the low number of shortnose sturgeon in these reaches (due to high salinity). 

Additionally, tracking studies conducted by O’Herron (1985) in the Bay, indicate that sturgeon were 

not typically found in the deepwater channel, but were more common outside the channel and on 

the channel edges. This distribution is likely to reduce the likelihood of an interaction between a 

dredge operating in the Bay and a shortnose sturgeon. Based on this information and the lack of 

interactions with shortnose sturgeon during dredging in this area in the past, no shortnose sturgeon 

are likely to be injured or killed during hopper dredging operations at these reaches. 

A hopper dredge will also be used for deepening at Reach A and Reach AA. Dredging at Reach A 

will remove 1,666,600 cy between August 2012 and February 2013. Dredging in Reach AA will 

remove 994,000 cy between August and November 2014. Shortnose sturgeon are likely to be 

present in these river reaches between April and November. 

Dredging of this reach of the navigation channel has occurred routinely in the past. However, no 

observers have been present on board the dredge. As such, there is no information on any historic 

interactions that may have occurred. Because location specific information is not available, we

have considered information on hopper dredge interactions in other river systems. A hopper dredge 

is used to maintain the Kennebec River Federal Navigation Project (Maine; see Table 10 below). 

Over the past 20 years, dredging in the channel with a hopper dredge has occurred six times. 

Shortnose sturgeon have only been entrained during two of these events, with a total of seven 

sturgeon entrained. Considering the six dredging events that have occurred over the past 20 years, 

an entrainment rate of 1 shortnose sturgeon for every 30,000 cy is calculated for the Kennebec 

River. Hopper dredges are also used to maintain the Hudson River navigation channel in New 

York. However, dredging is timed to minimize the potential for shortnose sturgeon occurrence in 

the area being dredged. No endangered species observers are used and no interactions with 

shortnose sturgeon have been reported to NMFS or the ACOE. 

Table 10. Maintenance dredging of the lower Kennebec River FNP since 1991. 

Location Dates Volume 

Removed (cy)

Observer 

Present?

Interactions 

with Shortnose 

Sturgeon

Doubling Point Fall 1991 69,000 No 2 lethal 

Doubling Point November 1997 22,000 Yes 0

Doubling Point December 2000 20,000 Yes 0

Doubling Point April 2002 25,000 Yes 0

Doubling Point 10/6-10/10/2003 22,310 Yes 3 lethal

2 injured but 

alive upon 

release

Doubling Point August 2011 50,000 No 0
134

We have also considered information on shortnose sturgeon interactions with other dredge types. 

Complete data sets from three cutterhead dredging events in the upper Delaware River are available 

(see Table 11 below). As explained in the cutterhead dredging section below, five shortnose 

sturgeon have been observed entrained during two separate dredging events in the upper Delaware 

River with the fish observed at the Money Island disposal site. Complete data is also available for 

two cutterhead dredging events that have occurred for the deepening of the Delaware main channel. 

Dredging occurred in Reach C in 2010 and in Reach B in 2011. The dredge disposal sites were 

inspected daily during the 2010 and 2011 dredge events. No shortnose sturgeon were observed 

entrained during either deepening event. Using these four dredge events, the calculated entrainment 

rate is one shortnose sturgeon for approximately every 1.1 mcy of material removed. 

Table 11. Shortnose Sturgeon Observations during Delaware River Dredging 

Project

Type of 

Dredge Dates CY Removed

Sturgeon 

Observed

Kinkora to Trenton Cutterhead March 1996 509,946 2

Kinkora to Trenton Cutterhead January 1998 512,923 3

Reach C Cutterhead March – September

2010

3,594,963 0

Reach B (rkm 113.3-118) Cutterhead Nov – December 

2011

1,100,000 0

We have also considered information on interactions between hydraulic dredges and other sturgeon 

species. The ACOE reports records of 29 interactions between dredges and sturgeon on the U.S. 

Atlantic coast between 1990 and 2010 (ACOE unpublished information). This number includes the 

10 interactions discussed above (Kennebec River and Delaware River). At least two of the 29 

entrained sturgeon were likely killed prior to entrainment based on the degree of decomposition. 

NMFS is aware of three additional interactions that were not included in this report, including two 

Atlantic sturgeon entrained during dredging in the Chesapeake Bay in May 2011 and 1 shortnose 

sturgeon captured in a dredge bucket operating at Bath Iron Works, Kennebec River, Maine in 2008 

(released alive and unharmed). The ACOE and their contractors remove millions of cubic yards of 

material from rivers and coastal navigation channels, as well as offshore sand borrow areas, every 

year. Interactions with sturgeon remain a rare event, even in areas where sturgeon are relatively 

numerous. 

Limited information is available on the likely entrainment rates and it is difficult to make a 

comparison between the likelihood of entrainment in a hopper dredge vs. a cutterhead dredge. 

However, it is likely that aquatic organisms, including shortnose sturgeon, may be more vulnerable 

to entrainment in a hopper dredge than a cutterhead. This is due to the larger size of the hopper 

draghead, the stronger suction and the faster speed at which the draghead moves which may make 

escape more difficult. A cutterhead dredge has a smaller intake, moves more slowly and is typically 

buried in the sediment. While in theory the risk of entrainment is likely higher in a hopper dredge 

than a cutterhead dredge, there is no quantitative way to calculate the difference in the level of risk. 
135

While neither the Money Island dataset (2 events), the 2010-2011 Reach B and C dredging, or the 

Kennebec River dataset (6 events) are perfect estimates of the risk of entrainment in a hopper

operating in these reaches, the Delaware River data sets, when combined, allow NMFS to calculate 

a risk of entrainment. NMFS believes that using this dataset of four Delaware River cutterhead 

dredging events is reasonable because it is based on dredging events in the same river system and 

incorporates entrainment data from the same dredge types at times of year when shortnose sturgeon 

were likely present in the areas being dredged and the dredge disposal sites were inspected with a 

goal of detecting any entrained sturgeon. Using these data sets, an entrainment rate of 1 shortnose 

sturgeon per approximately every 1.1 million cy of material removed is calculated. 

Based on the above information, we expect one shortnose sturgeon to be entrained for 

approximately every 1,100,000 cy of material removed from Reach A and AA between April and 

November. No entrainment of shortnose sturgeon is anticipated in Reach D or E. The ACOE has 

provided us with a schedule that indicates during what months dredging in Reach A and AA is 

expected to occur; because we expect shortnose sturgeon to be overwintering outside Reach A from 

December – March, we do not expect any entrainment in Reach A during these months. Based on 

the information outlined here, we anticipate the following levels of entrainment:

Reach Scheduled Dates Total Volume April –

November 

Volume

Expected 

shortnose sturgeon

interactions

A Aug 2012 – Feb 13 1,666,600 1,000,000 1

AA August – November 

2014

994,000 994,000 1

E Sept – Dec 2013 1,598,700 1,698,700 0

E April – Aug 2015 2,483,000 2,483,000 0

D Dec 2012 – June 2013 2,051,100 293,014 0

This calculation has been based on a number of assumptions including the following: that shortnose 

sturgeon are evenly distributed throughout all channel reaches used in this estimate, that all dredges 

will have the same entrainment rate, and that shortnose sturgeon are equally likely to be 

encountered throughout the time period when dredging will occur. While this estimate is based on 

several assumptions, it is reasonable because it uses the best available information on entrainment 

of shortnose sturgeon from past dredging operations, including dredging operations in the action 

area, it includes multiple projects over several years, and all of the projects have had observer 

coverage at the disposal site specifically looking for sturgeon. 

There is evidence that some shortnose sturgeon, particularly juveniles or smaller adults, could be 

entrained in the dredge and survive. However, as the extent of internal injuries and the likelihood of 

survival is unknown, and the size of the fish likely to be entrained is impossible to predict, it is 

reasonable to conclude that any shortnose sturgeon entrained in the hopper dredge are likely to be 

killed. 
136

7.1.3 Hopper Dredge Entrainment – Atlantic Sturgeon

Atlantic sturgeon are vulnerable to entrainment in hopper dredges. As explained above, since 1992, 

endangered species observers have been present for at least a portion of all hopper dredging done 

during the June – November time frame below the Delaware Memorial Bridge. No Atlantic

sturgeon have been documented during any hopper dredge activity in the Philadelphia to the Sea 

maintenance dredging. Observers have not been used for hopper dredge activities in other reaches 

of the river. 

Given the large size of adults (greater than 150cm) and the size of the openings on the dragheads, 

adult Atlantic sturgeon are unlikely to be vulnerable to entrainment. ACOE reports that from 1990-

2011, 30 interactions with sturgeon occurred during dredge operations. Of these, 17 were reported 

as Atlantic sturgeon, with 15 of these entrained in hopper dredges. Of the entrained Atlantic 

sturgeon for which size is available, all were subadults (larger than 50cm but less than 150cm). 

Information on these interactions is presented in Table 12. Most of these interactions occurred 

within rivers and harbors. 

Table 12. USACE Atlantic Sturgeon Entrainment Records from Hopper Dredge Operations 

1990-2011

Project Location

Corps 

Division/District*

Month/Year of 

Operation

Cubic 

Yards 

Removed

Observed** 

Entrainment

Winyah Bay, 

Georgetown (SC) SAD/SAC Oct-90 517,032 1

Savannah Harbor 

(GA) SAD/SAS Jan-94 2,202,800 1

Savannah Harbor SAD/SAS Dec-94 2,239,800 2

Wilmington Harbor, 

Cape Fear River 

(NC)

SAD/SAW Sep-98 196,400 1

Charleston Harbor 

(SC) SAD/SAC Mar-00 5,627,386 2

Brunswick Harbor 

(GA) SAD/SAS Feb-02 1,459,630 1

Charleston Harbor SAD/SAC Jan-04 1,449,234 1

Brunswick Harbor SAD/SAS Mar-05 966,000 1

Brunswick Harbor SAD/SAS Dec-06 1,198,571 1

Savannah Entrance 

Channel SAD/SAS Nov-07 973,463 1

Sandy Hook 

Channel (NJ) NAD/NANY Aug-Nov-08 23,500 1
137

York Spit (VA) NAD/NAN Apr-11 1,630,713 2

Total 17,553,816 15

* SAD= South Atlantic Division; NAD= North Atlantic Division; SAC=Charleston District; 

SAS=Savannah District; SAW=Wilmington District; NANY=New York District; 

NAN=Norfolk District.

** Records based on sea turtle observer reports which record listed species entrained as well 

as all other organisms entrained during dredge operations.

In general, entrainment of large mobile animals, such as Atlantic sturgeon, is relatively rare. 

Several factors are thought to contribute to the likelihood of entrainment. In areas where animals 

are present in high density, the risk of an interaction is greater because more animals are exposed to 

the potential for entrainment. The risk of entrainment is likely to be higher in areas where the 

movements of animals are restricted (e.g., in narrow rivers or confined bays) where there is limited 

opportunity for animals to move away from the dredge than in unconfined areas such as wide rivers 

or open bays. The hopper dredge draghead operates on the bottom and is typically at least partially 

buried in the sediment. Sturgeon are benthic feeders and are often found at or near the bottom while 

foraging or while moving within rivers. 

As noted above, no Atlantic sturgeon have been observed entrained in hopper dredges operating in 

the Delaware River. The only instances of Atlantic sturgeon entrainment in hopper dredges in the 

NMFS Northeast Region are two sturgeon entrained at York Spit, VA in 2011 (both were killed) 

and one live Atlantic sturgeon entrained in Sandy Hook, NJ in 2008. As described in the discussion 

of shortnose sturgeon and sea turtles above, many other hopper dredge projects have occurred in the

Northeast Region; nearly all of which overlap with times and areas where Atlantic sturgeon are 

known to be present. Because observers have been present on these dredges and we expect that any 

interactions with Atlantic sturgeon would have been reported to us, the interaction rate between 

hopper dredges and Atlantic sturgeon seems to be very low. Even just considering the projects 

listed in Table 12, where entrainment was recorded, we calculate an entrainment rate of one Atlantic 

sturgeon for approximately every 1.2 million cy of material removed. If we included projects where 

observers were present and no Atlantic sturgeon were observed, the entrainment rate is even lower. 

Even just adding in the seven Delaware Bay projects and the six Kennebec projects presented in 

Tables 10 and 11 above, lowers the entrainment rate to one Atlantic sturgeon for every 1.5 mcy. 

As noted above for sea turtles, there is a relationship between the number of animals entrained and 

the volume of material removed. The volume of material removed is correlated to the amount of 

time spent dredging but is a more accurate measure of effort because reports often provide the total 

days of a project but may not provide information on the actual hours of dredging vs. the number of 

hours steaming to the disposal site or in port for weather or other delays. Using just the information 

available for hopper dredging projects in the action area, we would expect no Atlantic sturgeon 

entrainment because none has been observed. However, because observers have not been used on 

hopper dredges outside of Reach D and E, it is possible that this would be an underestimate of the 

potential for entrainment outside of those reaches. However, it does suggest that entrainment in 

reaches D and E is likely to be very low. As noted above, tracking of sturgeon in Delaware Bay 

indicates that they are more likely to occur outside the channel and along the channel edges than 
138

within the deepwater channel; this likely reduces the risk of entrainment because it minimizes the 

co-occurrence of the dredge and sturgeon. The entrainment estimate generated above using the 

projects in rivers and bays where entrained Atlantic sturgeon have been observed plus the Kennebec 

and Delaware Bay hopper dredge projects, is an overestimate because it does not consider other 

projects where no entrainment occurred. However, at this time, it is the best available estimate of 

in-river entrainment rates for Atlantic sturgeon and hopper dredges. 

Based on the above information, we expect one Atlantic sturgeon to be entrained for approximately 

every 1,500,000 cy of material removed with a hopper dredge. Given the size of adult Atlantic 

sturgeon (greater than 150cm) and the size of observed entrained sturgeon (less than 150cm), we do 

not anticipate the entrainment of any adult Atlantic sturgeon; all entrainment will be YOY, juveniles 

or subadults. Because observers have been used for dredging at Reach D and E in the past and no 

entrainment of Atlantic sturgeon has been observed, we do not anticipate any future entrainment of 

Atlantic sturgeon in these reaches. The reduced risk of entrainment in these reaches is likely due to 

the width of the river and bay in these areas, the known use of areas outside the channel rather than 

in the channel, and the increased availability of habitat outside of the area where dredging is 

occurring which may increase the potential for sturgeon to escape from the dredge. Based on the 

information outlined here, we anticipate the following levels of entrainment:

Reach Scheduled Dates Total Volume Expected Atlantic 

sturgeon

interactions

A Aug 2012 – Feb 13 1,666,600 1

AA August – Nov 2014 994,000 1

E Sept – Dec 2013 1,598,700 0

E April – Aug 2015 2,483,000 0

D Dec 2012 – June 2013 2,051,100 0

There is evidence that some Atlantic sturgeon, particularly juveniles and small subadults, could be 

entrained in the dredge and survive. However, as the extent of internal injuries and the likelihood of 

survival is unknown, and the size of the fish likely to be entrained is impossible to predict, it is 

reasonable to conclude that any Atlantic sturgeon entrained in the hopper dredge are likely to be 

killed. Based on the mixed stock analysis, it is likely that the entrained Atlantic sturgeon will 

originate from the New York Bight DPS but could also originate from the Gulf of Maine, 

Chesapeake Bay or South Atlantic DPS. Given the low numbers of Carolina DPS fish in the action 

area and the low number of mortalities anticipated, it is unlikely that there will be any mortality of 

any Carolina DPS Atlantic sturgeon. 

7.1.4 Interactions with the Sediment Plume- Hopper Dredge 

Dredging operations cause sediment to be suspended in the water column. This results in a 

sediment plume in the water, typically present from the dredge site and decreasing in concentration 

as sediment falls out of the water column as distance increases from the dredge site. The nature, 

degree, and extent of sediment suspension around a dredging operation are controlled by many 

factors including : the particle size distribution, solids concentration, and composition of the 
139

dredged material; the dredge type and size, discharge/cutter configuration, discharge rate, and solids 

concentration of the slurry; operational procedures used; and the characteristics of the hydraulic 

regime in the vicinity of the operation, including water composition, temperature and hydrodynamic 

forces (i.e., waves, currents, etc.) causing vertical and horizontal mixing (ACOE 1983). 

Resuspension of fine-grained dredged material during hopper dredging operations is caused by the 

dragheads as they are pulled through the sediment, turbulence generated by the vessel and its prop 

wash, and overflow of turbid water during hopper filling operations. During the filling operation, 

dredged material slurry is often pumped into the hoppers after they have been filled with slurry in 

order to maximize the amount of solid material in the hopper. The lower density, turbid water at the 

surface of the filled hoppers overflows and is usually discharged through ports located near the 

waterline of the dredge. Use of this “overflow” technique results in a larger sediment plume than if 

no overflow is used. The ACOE has indicated that overflow is not authorized for the deepening 

project. In 2001, a study was done of overflow and nonoverflow hopper dredging. Monitoring of 

the sediment plumes was accomplished using a boat-mounted 1,200-kHz Broad-Band Acoustic 

Doppler Current Profiler (ADCP). The instrument collects velocity vectors in the water column 

together with backscatter levels to determine the position and relative intensity of the sediment 

plume. Along with the ADCP, a MicroLite recording instrument with an Optical Backscatterance 

(OBS) Sensor was towed by the vessel at a depth of 15 ft. The MicroLite recorded data at 0.5-sec 

intervals. Navigation data for monitoring were obtained by a Starlink differential Global 

Positioning System (GPS). The GPS monitors the boat position from the

starting and ending points along each transect.

Transects were monitored in the test area to obtain the background levels of suspended materials 

prior to dredging activities. A period of 8 minutes following the dredge passing during nonoverflow dredging showed the level of suspended material to be returning to background levels. No 

lateral dispersion of the plume out of the channel was observed during the non-overflow dredging 

operation. During overflow dredging, a wider transect was performed to determine the lateral 

extent of the plume. No significant change above background levels could be detected. At 1-hr 

elapsed time following the end of the overflow dredging operation, the levels of suspended material 

returned to background conditions. Again, no lateral dispersion of the plume out of the channel 

area was observed.

No information is available on the effects of total suspended solids (TSS) on juvenile and adult sea 

turtles. Studies of the effects of turbid waters on fish suggest that concentrations of suspended 

solids can reach thousands of milligrams per liter before an acute toxic reaction is expected (Burton 

1993). TSS is most likely to affect sea turtles if a plume causes a barrier to normal behaviors or if 

sediment settles on the bottom affecting sea turtle prey. As sea turtles are highly mobile they are 

likely to be able to avoid any sediment plume and any effect on sea turtle or whale movements is 

likely to be insignificant. While an increase in suspended sediments may cause sea turtles to alter 

their normal movements, any change in behavior is likely to be insignificant as it will only involve 

movement to alter course out of the sediment plume, which is expected to be limited to the 

navigation channel and be present at any location for no more than 8 minutes. Based on this 

information, any increase in suspended sediment is not likely to affect the movement of sea turtles 

between foraging areas or while migrating or otherwise negatively affect listed species in the action 

area. Based on this information, it is likely that the effect of the suspension of sediment resulting 
140

from dredging operations will be insignificant. 

The life stages of sturgeon most vulnerable to increased sediment are eggs and non-mobile larvae 

which are subject to burial and suffocation. As noted above, no shortnose sturgeon eggs and/or 

larvae will be present in the action area. Reach A partially overlaps with one of the areas where 

Atlantic sturgeon are thought to spawn. Dredging is scheduled to begin in this reaches in August. 

At that time of year, Atlantic sturgeon spawned that year (April/May) would be at least two-three 

months old and would be mobile; these fish are no longer considered larvae, but are YOY (see 

Table 4 in Section 4.7 above). All sturgeon in the action area at this time of year would be 

sufficiently mobile to avoid any sediment plume. Therefore, any shortnose and Atlantic sturgeon in 

the action area during dredging would be capable of avoiding any sediment plume by swimming 

around it. Laboratory studies (Niklitschek 2001 and Secor and Niklitschek 2001) have 

demonstrated shortnose and Atlantic sturgeon are able to actively avoid areas with unfavorable 

water quality conditions and that they will seek out more favorable conditions when available. 

While the increase in suspended sediments may cause sturgeon to alter their normal movements, 

any change in behavior is likely to be insignificant as it will only involve movement further up in 

the water column, or movement to an area just outside of the navigation channel. Based on this 

information, any increase in suspended sediment is not likely to affect the movement of shortnose 

or Atlantic sturgeon between foraging areas and/or concentration areas during any phase of 

dredging or otherwise negatively affect shortnose sturgeon in the action area. 

7.2 Hydraulic Cutterhead Dredge

Table 13 describes work to be done with a cutterhead dredge. Dredging in Reach B is planned with 

a cutterhead dredge; dredging in Reaches AA, A and D could occur with a cutterhead or hopper 

dredge. 

Table 13. Scheduled dredging by reach, date and volume to be removed

Channel Reach

Volume 

(CY)

Scheduled 

Dates

AA 994,000 August – November 2014

A 1,666,600

August 2012 – February 

2013

B 3,485,469

August 2016 – January 

2017

D 2,051,100

December 2012 – June 

2013

Sea turtles are extremely unlikely to occur in Reaches AA, A and B and therefore would not be 

exposed to effects of dredging in these reaches. Sea turtles are seasonally present in Reach D. 

However, sea turtles are not known to be vulnerable to entrainment in cutterhead dredges. This is 

thought to be due to the size of sea turtles and their swimming ability that allows them to escape the 

intake velocity near a cutterhead. There are no records of any sea turtles being entrained in 

cutterhead dredges in the Delaware River or anywhere else. Based on the available information, we 

do not anticipate any entrainment of sea turtles in any reaches when a cutterhead dredge is used. 
141

7.2.1 Available Information on the Risk of Entrainment of Sturgeon in Cutterhead Dredge 

Maintenance of the existing 40 foot channel occurs routinely with some dredging accomplished 

with a cutterhead dredge. The cutterhead dredge operates with the dredge head buried in the 

sediment; however, a flow field is produced by the suction of the operating dredge head. The 

amount of suction produced is dependent on linear flow rates inside the pipe and the pipe diameter 

(Clausner and Jones 2004). High flow rates and larger pipes create greater suction velocities and 

wider flow fields. The suction produced decreases exponentially with distance from the dredge 

head (Boysen and Hoover 2009). A cutterhead dredge is also used in the upriver Philadelphia to 

Trenton navigation channel. With a cutterhead dredge, material is pumped directly from the 

dredged area to a disposal site. As such, there is no opportunity to monitor for biological material 

on board the dredge; rather, observers work at the disposal site to inspect material. 

It is generally assumed that sturgeon are mobile enough to avoid the suction of an oncoming 

cutterhead dredge and that any sturgeon in the vicinity of such an operation would be able to avoid 

the intake and escape. However, in mid-March 1996, two shortnose sturgeon were found in a 

dredge discharge pool on Money Island, near Newbold Island. The dead sturgeon were found on 

the side of the spill area into which the hydraulic pipeline dredge was pumping. An assessment of 

the condition of the fish indicated that the fish were likely alive and in good condition prior to 

entrainment and that they were both adult females. The area where dredging was occurring was a 

known overwintering area for shortnose sturgeon and large numbers of shortnose sturgeon were 

known to be concentrated in the general area. A total of 509,946 cy were dredged between Florence 

and the upper end of Newbold Island during this dredge cycle. Since that time, dredging occurring 

in the winter months in the Newbold – Kinkora range require that inspectors conduct daily 

inspections of the dredge spoil area in an attempt to detect the presence of any sturgeon. In January 

1998, three shortnose sturgeon carcasses were discovered in the Money Island Disposal Area. The 

sturgeon were found on three separate dates: January 6, January 12, and January 13. Dredging was 

being conducted in the Kinkora and Florence ranges at this time which also overlaps with the 

shortnose sturgeon overwintering area. A total of 512,923 cy of material was dredged between 

Florence and upper Newbold Island during that dredge cycle. While it is possible that not all 

shortnose sturgeon killed during dredging operations were observed at the dredge disposal pool, 

ACOE has indicated that due to flow patterns in the pool, it is expected that all large material (i.e., 

sturgeon, logs etc.) will move towards the edges of the pool and be readily observable. Deepening 

has occurred in Reach C and Reach B. Dredging in Reach C occurred from March – September

2010 with 3,594,963 cy of material removed with a cutterhead dredge. Dredging in Reach B 

occurred in November and December 2011, with 1,100,000 cy of material removed with a 

cutterhead dredge. In both cases, the dredge disposal area was inspected daily for the presence of 

sturgeon. No sturgeon were detected. 

In an attempt to understand the behavior of sturgeon while dredging is ongoing, the ACOE worked 

with sturgeon researchers to track the movements of tagged Atlantic and shortnose sturgeon while

cutterhead dredge operations were ongoing in Reach B (ERC 2011). The movements of 

acoustically tagged sturgeon were monitored using both passive and active methods. Passive 

monitoring was performed using 14 VEMCO VR2 and VR2W single-channel receivers, deployed 

through the study area. These receivers are part of a network that was established and cooperatively 

maintained by Environmental Research and Consulting, Inc. (ERC), Delaware State University 

(DSU), and the Delaware Department of Natural Resources and Environmental Control (DNREC).
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Nineteen tagged Atlantic sturgeon and three tagged shortnose sturgeon (all juveniles) were in the 

study area during the time dredging was ongoing. Eleven of the 19 juvenile Atlantic sturgeon 

detected during this study remained upriver of the dredging area and showed high fidelity to the 

Marcus Hook anchorage. Three of the juvenile sturgeon detected during this study (Atlantic 

sturgeons 13417, 1769; shortnose sturgeon 58626) appeared to have moved through Reach B when 

the dredge was working. The patterns and rates of movement of these fish indicated nothing to 

suggest that their behavior was affected by dredge operation. The other sturgeon that were detected 

in the lower portion of the study area either moved through the area before or after the dredging 

period (Atlantic sturgeons 2053, 2054), moved through Reach B when the dredge was shut down 

(Atlantic sturgeons 1774, 58628, 58629), or moved through the channel on the east side of Cherry 

Island Flats (shortnose sturgeon 2090, Atlantic sturgeon 2091) opposite the main navigation 

channel. It is unknown whether some of these fish chose behaviors (routes or timing of movement) 

that kept them from the immediate vicinity of the operating dredge. In the report, Brundage 

speculates that this could be to avoid the noisy area near the dredge but also states that on the other 

hand, the movements of the sturgeon reported here relative to dredge operation could simply have 

been coincidence. 

A similar study was carried out in the James River (Virginia) (Cameron 2012). Dredging occurred 

with a cutterhead dredge between January 30 and February 19, 2009 with 166,545 cy of material 

removed over 417.6 hours of active dredge time. Six subadult Atlantic sturgeon (77.5 – 100 cm 

length) were caught, tagged with passive and active acoustic tags, and released at the dredge site. 

The study concluded that: tagged fish showed no signs of impeded up- or downriver movement due 

to the physical presence of the dredge; fish were actively tracked freely moving past the dredge 

during full production mode; fish showed no signs of avoidance response (e.g., due to noise 

generated by the dredge) as indicated by the amount of time spent in close proximity to the dredge 

after release (3.5 – 21.5 hours); and, tagged fish showed no evidence of attraction to the dredge. 

Several scientific studies have been undertaken to understand the ability of sturgeon to avoid 

cutterhead dredges. Hoover et al. (2011) demonstrated the swimming performance of juvenile lake 

sturgeon and pallid sturgeon (12 – 17.3 cm FL) in laboratory evaluations. The authors compared 

swimming behaviors and abilities in water velocities ranging from 10 to 90 cm/second (0.33-3.0 

feet per second). Based on the known intake velocities of several sizes of cutterhead dredges. At 

distances more than 1.5 meters from the dredges, water velocities were negligible (10 cm/s). The 

authors conclude that in order for a sturgeon to be entrained in a dredge, the fish would need to be 

almost on top of the drag head and be unaffected by associated disturbance (e.g., turbidity and 

noise). The authors also conclude that juvenile sturgeon are only at risk of entrainment in a 

cutterhead dredge if they are in close proximity, less than 1 meter, to the drag heads. 

Boysen and Hoover (2009) assessed the probability of entrainment of juvenile white sturgeon by 

evaluating swimming performance of young of the year fish (8-10 cm TL). The authors determined 

that within 1.0 meter of an operating dredge head, all fish would escape when the pipe was 61 cm (2 

feet) or smaller. Fish larger than 9.3 cm (about 4 inches) would be able to avoid the intake when 

the pipe was as large as 66 cm (2.2 feet). The authors concluded that regardless of fish size or pipe 

size, fish are only at risk of entrainment within a radius of 1.5 – 2 meters of the dredge head; 

beyond that distance velocities decrease to less than 1 foot per second. 
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Clarke (2011) reports that a cutterhead dredge with a suction pipe diameter of 36” (larger than the 

one to be used for this project) has an intake velocity of approximately 95 cm/s at a distance of 1 

meter from the dredge head and that the velocity reduces to approximately 40cm/s at a distance of 

1.5 meters, 25cm/s at a distance of 2.0 meters and less than 10cm/s at a distance of 3.0 meters. 

Clarke also reports on swim tunnel performance tests conducted on juvenile and subadult Atlantic, 

white and lake sturgeon. He concludes that there is a risk of sturgeon entrainment only within 1 

meter of a cutterhead dredge head with a 36” pipe diameter and suction of 4.6m/second. This is 

slightly larger than the pipe on the dredge that will be used for deepening (30”). 

The risk of an individual shortnose sturgeon being entrained in a cutterhead dredge is difficult to 

calculate. While a large area overall will be dredged, the dredge operates in an extremely small area 

at any given time (i.e., the river bottom in the immediate vicinity of the intake). As shortnose and 

Atlantic sturgeon are well distributed throughout the action area and an individual would need to be 

in the immediate area where the dredge is operating to be entrained (i.e., within 1 meter of the 

dredge head), the overall risk of entrainment is low. It is likely that the nearly all shortnose and 

Atlantic sturgeon in the action area will never encounter the dredge as they would not occur within 

1 meter of the dredge. Information from the tracking studies in the James and Delaware river 

supports these assessments of risk, as none of the tagged sturgeon were attracted to or entrained in 

the operating dredges. 

The entrainment of five sturgeon in the upper Delaware River indicates that entrainment of sturgeon 

in cutterhead dredges is possible. However, there are several factors that may increase the risk of 

entrainment in that area of the river as compared to the areas where cutterhead dredging will occur 

for the deepening. All five entrainments occurred during the winter months in an area where 

shortnose sturgeon are known to concentrate in dense aggregations; sturgeon in these aggregations 

rest on the bottom and exhibit little movement and may be slow to respond to stimuli such as an 

oncoming dredge. Sturgeon in that areas where dredging with the cutterhead dredge will occur are 

likely to be more active as evidenced by the movements of sturgeon tracked through Reach B in 

November through the end of December (ERC 2012). 

In total, approximately 8.2 million cy of material will be removed with a cutterhead dredge for the 

deepening (inclusive of approximately 5.6 million cy of material that will be removed from Reach 

AA, A and D with either a cutterhead or hopper dredge) during a total of four dredge events. 

Because the only entrainment of Atlantic or shortnose sturgeon in cutterhead dredges in the United 

States has been the five shortnose sturgeon found at the disposal site in the upper Delaware River it 

is difficult to predict the number of shortnose or Atlantic sturgeon that are likely to be entrained 

during the deepening project. Based on the available information presented here, entrainment in a 

cutterhead dredge is likely to be rare, and would only occur if a sturgeon was within 1 meter of the 

dredge head. This determination applies to all life stages of sturgeon that are likely to be in the 

action area during the time of year when dredging will occur, including young of year, juveniles and 

subadult shortnose and Atlantic sturgeon and adult shortnose sturgeon. However, because we know 

that entrainment is possible, we expect that over the duration of the deepening project, some 

entrainment will occur. Based on the predicted rarity of the entrainment event, we expect that no 

more than one shortnose sturgeon and no more than one Atlantic sturgeon will be entrained in the 

2012-2013 dredging of Reaches A and D, no more than one Atlantic sturgeon and no more than one 

shortnose sturgeon will be entrained in the 2014 dredging of Reach AA and no more than one 
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Atlantic sturgeon will be entrained in the 2016-2017 dredging of Reach B. The entrained shortnose 

sturgeon could be a juvenile or adult. The entrained Atlantic sturgeon could be a young of year, 

juvenile or subadult. Based on the mixed stock analysis, it is likely that the entrained Atlantic 

sturgeon will originate from the New York Bight DPS but could also originate from the Gulf of 

Maine, Chesapeake Bay or South Atlantic DPS. Given the low numbers of Carolina DPS fish in the 

action area and the low number of mortalities anticipated, it is unlikely that there will be any 

mortality of any Carolina DPS Atlantic sturgeon. 

Due to the suction, travel through up to 3 miles of pipe and any residency period in the disposal 

area, all entrained shortnose and Atlantic sturgeon are expected to be killed. 

7.1.2.2 Interactions with the Sediment Plume

Dredging operations cause sediment to be suspended in the water column. This results in a 

sediment plume in the river, typically present from the dredge site and decreasing in concentration 

as sediment falls out of the water column as distance increases from the dredge site. Dredging with 

a pipeline dredge minimizes the amount of material re-suspended in the water column as the 

material is essentially vacuumed up and transported to the disposal site in a pipe. 

As reported by ACOE, a near-field water quality modeling of dredging operations in the Delaware 

River was conducted in 2001. The purpose of the modeling was to evaluate the potential for 

sediment contaminants released during the dredging process to exceed applicable water quality 

criteria. The model predicted suspended sediment concentrations in the water column at 

downstream distances from a working cutterhead dredge in fine-grained dredged material. 

Suspended sediment concentrations were highest at the bottom of the water column, and returned to 

background concentrations within 100 meters downstream of the dredge. 

In 2005, FERC presented NMFS with an analysis of results from the DREDGE model used to 

estimate the extent of any sediment plume associated with the proposed dredging at the Crown 

Landing LNG berth (FERC 2005). The model results indicated that the concentration of suspended 

sediments resulting from hydraulic dredging would be highest close to the bottom and would 

decrease rapidly downstream and higher in the water column. Based on a conservative (i.e., low) 

TSS background concentration of 5mg/L, the modeling results indicated that elevated TSS 

concentrations (i.e., above background levels) would be present at the bottom 2 meters of the water 

column for a distance of approximately 1,150 feet. Based on these analyses, elevated suspended 

sediment levels are expected to be present only within 1,150 feet of the location of the cutterhead. 

Turbidity levels associated with cutterhead dredge sediment plumes typically range from 11.5 to 

282 mg/L with the highest levels detected adjacent to the cutterhead and concentrations decreasing 

with greater distance from the dredge (see U. Washington 2001). 

Studies of the effects of turbid waters on fish suggest that concentrations of suspended solids can 

reach thousands of milligrams per liter before an acute toxic reaction is expected (Burton 1993). 

The studies reviewed by Burton demonstrated lethal effects to fish at concentrations of 580mg/L to 

700,000mg/L depending on species. Sublethal effects have been observed at substantially lower 

turbidity levels. For example, prey consumption was significantly lower for striped bass larvae 

tested at concentrations of 200 and 500 mg/L compared to larvae exposed to 0 and 75 mg/L 

(Breitburg 1988 in Burton 1993). Studies with striped bass adults showed that pre-spawners did not 
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avoid concentrations of 954 to 1,920 mg/L to reach spawning sites (Summerfelt and Moiser 1976 

and Combs 1979 in Burton 1993). While there have been no directed studies on the effects of TSS 

on shortnose or Atlantic sturgeon, shortnose sturgeon juveniles and adults are often documented in 

turbid water and Dadswell (1984) reports that shortnose sturgeon are more active under lowered 

light conditions, such as those in turbid waters. 

The life stages of sturgeon most vulnerable to increased sediment are eggs and non-mobile larvae 

which are subject to burial and suffocation. As noted above, no shortnose sturgeon eggs and/or 

larvae will be present in the action area. Juvenile and adult shortnose sturgeon are frequently found 

in turbid water and would be capable of avoiding any sediment plume by swimming higher in the 

water column. Reaches A and B overlap with one of the presumed Atlantic sturgeon spawning 

sites. Dredging is scheduled to begin in these reaches in August. At that time of year, Atlantic 

sturgeon spawned that year (April/May) would be at least two-three months old and would be 

mobile; these fish are no longer considered larvae, but are YOY (see Table 4 in Section 4.7 above). 

All sturgeon in the action area at this time of year would be sufficiently mobile to avoid any 

sediment plume. Therefore, any shortnose and Atlantic sturgeon in the action area during dredging 

would be capable of avoiding any sediment plume by swimming around it.

Laboratory studies (Niklitschek 2001 and Secor and Niklitschek 2001) have demonstrated shortnose 

sturgeon are able to actively avoid areas with unfavorable water quality conditions and that they 

will seek out more favorable conditions when available. While the increase in suspended sediments 

may cause shortnose sturgeon to alter their normal movements, any change in behavior is likely to 

be insignificant as it will only involve movement further up in the water column. Based on this 

information, any increase in suspended sediment is not likely to affect the movement of shortnose 

sturgeon between foraging areas and/or concentration areas during any phase of dredging or 

otherwise negatively affect shortnose sturgeon in the action area. 

7.3 Dredged Material Disposal 

As indicated above, all material removed at Reaches AA, A, B, and D will be disposed of at an 

upland location. When a cutterhead dredge is used, the material is piped directly from the intake to 

an upland disposal area. The pipe will extend up to 3 miles, depending on the distance between the 

dredge site and the disposal site. The pipe will be approximately 30” in diameter and be laid on the 

river bottom. While the presence of the pipe will cause a small amount of benthic habitat to be 

unavailable to sturgeon and sea turtles, the extremely small area affected will cause any effects to be 

insignificant and discountable. There are not likely to be any other effects to sturgeon or sea turtles 

from disposal of material at upland disposal sites. 

Material removed from Reach E, approximately 4 million cy of material will be disposed of at the 

Kelly Island and Broadkill Beach disposal areas. For these projects, sand will be placed along the 

shoreline. While this could cause a small increase in suspended sediment in the immediate vicinity 

of sand placement, any effects are likely to be minor and temporary. Impacts associated with this 

action include a short term localized increase in turbidity during disposal operations. During the 

discharge of sediment at a disposal site, suspended sediment levels have been reported as high as 

500mg/L within 250 feet of the disposal vessel and decreasing to background levels (i.e., 15-

100mg/L depending on location) within 1000-6500 feet (ACOE 1983). For this project, the ACOE 

has reported that because the dredged material is clean sand, the material will settle out quickly and 
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any sediment plume will be localized and temporary. Any sea turtles or sturgeon in the vicinity of 

the beach disposal sites during disposal may temporarily avoid the disposal area; however, as any 

effects to movements will be small and temporary, these effects will be insignificant. Effects of 

disposal on prey resources are considered in section 7.5. 

7.4 Blasting and Mechanical Dredging

As part of the proposed deepening project approximately 77,000 cubic yards of bedrock, covering 

18 acres near Marcus Hook, Pennsylvania (River Mile 76.4 to River Mile 84.6) would be removed 

to deepen the navigation channel in this area. Blasting will occur at Reach B (Marcus Hook) from 

December 2013- January 2014 with mechanical rock removal continuing through February 2014. 

During this time of year, the majority of adult shortnose sturgeon are expected to be located at the 

overwintering area between mile 118 and 131 which is over 33 river miles from the blasting site

(RM 76.4-84.6). 

Studies conducted by the ACOE in March 2005, indicate that sturgeon are present in the Marcus 

Hook area during the winter months. While the three sturgeon observed on video at the Marcus 

Hook area could not be identified to species, the size of the fish suggests that they could be adult 

shortnose sturgeon or subadult Atlantic sturgeon. The density estimate calculated in Versar 2006 

(which was based on the video monitoring at Marcus Hook) indicates that there are 0.005 

sturgeon/100 m, or one sturgeon per 20,000m.

Blasting operations would occur up to five days a week during the December – January blasting

period, but the actual blasting would only occur for a brief period each day. Blasting could impact 

sturgeon by causing physical injury or mortality to individual fish and by displacing sturgeon from 

the area where blasting is occurring. Effects to sturgeon also include modifications to the benthic 

community and reduced foraging opportunities. 

The blasting plan has been designed to minimize the potential for fish mortality. As such, as noted 

above, all blasting will occur between December and January when fish density is expected to be 

lowest. Controlled blasting methods will be employed such as delayed blasting and “stemming” to 

reduce the amount of energy that would impact fish. In addition, fish avoidance techniques will be 

utilized to drive fish away from the proposed blasting area to reduce the detrimental impact to the 

fish and benthic community. Monitoring impacts to fish from the blasting will also be conducted to 

verify that impacts are minimal. Additionally, the following measures will be taken: 

 Scare charges will be used for each blast. A scare charge is a small charge of 

explosives detonated immediately prior to a blast for the purpose of scaring aquatic 

organisms away from the location of an impending blast. Two scare charges will be 

used for each blast. The detonation of the first scare charge will be at 45 seconds 

prior to the blast, with the second scare charge detonated 30 seconds prior to the 

blast. Some marine mammals and fish may not locate the origin of the first scare 

charge. The second scare charge allows these creatures to better locate the source of 

the charge and maneuver away from the source.

 Blast pressures will be monitored and upper limits will be imposed on each series of 

5 blasts, with average pressure not exceeding 70 pounds per square inch (psi) at a 
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distance of 140 feet and maximum peak pressure not exceeding 120 psi at a distance 

of 140 feet.

 Surveillance for schools of fish will be conducted by vessels with sonar fish finders 

for a period of 20 minutes before each blast, and if fish schools are detected, blasting 

will be delayed until they leave. The surveillance zone will be approximately circular 

with a radius of about 500 feet extending outward from each blast set. 

7.4.1 Available Information on Effects of Blasting on Fish

There have been numerous studies that have assessed the direct impact of underwater blasting on 

fish. While not all of the studies have focused exclusively on shortnose sturgeon, the results 

demonstrate that blasting does have an adverse impact on fish. Teleki and Chamberlain (1978) 

found that several physical and biological variables were the principal components in determining 

the magnitude of the blasting effect on fish. Physical components include detonation velocity, 

density of material to be blasted, and charge weight, while the biological variables are fish shape, 

location of fish in the water column, and swimbladder development. Composition of the explosive, 

water depth, and bottom composition also interact to determine the characteristics of the explosion 

pressure wave and the extent of any resultant fish kill. Furthermore, the more rapid the detonation 

velocity, the more abrupt the resultant hydraulic pressure gradient, and the more difficulty fish 

appear to have adjusting to the pressure changes. 

A blasting study conducted in Nanticoke, Lake Erie, found that fish were killed in radii ranging 

from 20 to 50 m for 22.7 kg per charge and from 45 to 110 m for 272.4 kg per charge (Teleki and 

Chamberlain 1978). Approximately 201 blasts were detonated in 4 to 8 m of water. Of the thirteen 

fish species studied, mortality differed by species at identical pressure. No shortnose sturgeon were 

tested. Common blast induced injuries included swimbladder rupturing and hemorrhaging in the 

coelomic and pericardial cavities.

The effects of blasting on thirteen species of fish were measured in deep water (46 m) explosion 

tests in the Chesapeake Bay opposite the mouth of the Patuxent River (Wiley et al. 1981). No 

shortnose sturgeon were tested. Fish were held in cages at varying depths during 16 midwater 

detonations with 32 kg explosives. For the 32 kg charges, the pressure wave was propagated 

horizontally most strongly at the depth at which the explosion occurred. While the extent of the 

injury varied with species, the fish with swimbladders are far more vulnerable than those lacking 

swimbladders, and toadfish and catfish were the most resistant to damage of those species with a 

swimbladder. 

Many fish exposed to blasting exhibit injuries to the kidney and swimbladder, thus affecting their 

fitness (Wiley et al. 1981). Efficient osmoregulation is very important in fishes; even slight bruises 

to the kidney could seriously affect this efficiency, causing at least a higher expenditure of energy. 

Burst swimbladders cause the fish to lose their ability to regulate the volume of their swimbladders 

(destroying buoyancy control) and probably increases their vulnerability to predators.

Wiley et al. (1981) found that the oscillatory response of the swimbladder was a likely cause of the 

fishes’ injuries. Their analyses demonstrate that fish mortality is strongly dependent on the depth of 

the fish. For larger fish (like shortnose sturgeon) at shallower depths (~7 to 11 m), the swimbladder 
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does not have time to fully respond to the positive portion of the explosion wave. Thus, at shallow 

depth the larger fish are in effect protected from harm by their swimbladders, while at the resonance 

depth their swimbladders are burst. 

Burton (1994) conducted experiments to estimate the effects of blasting to remove approximately 

1,600 cubic yards of bedrock during construction of a natural gas pipeline in the Delaware River 

near Easton, Pennsylvania (upriver from Marcus Hook area). American shad and smallmouth bass 

juveniles were exposed to charges of 112.5 and 957 kg of explosives in depths ranging between 0.5 

and 2 m. The fish were caged at a range of distances from the blasts. Tests with American shad 

were inconclusive due to an unavoidable delay between stocking the chambers and detonation of 

the explosives; however, successful tests with smallmouth bass suggested that the explosives 

created a maximum kill radius of 12 m (for both charge magnitudes). No fish were killed by the 

shock wave at the 24 m position and beyond.

The preceding studies were conducted on other fish species, but the nature of the injuries and the 

optimal distance from the detonations could be applied to blasting activities and shortnose sturgeon. 

The effects of blasting on shortnose sturgeon have been examined however. Test blasting was 

conducted in the Wilmington Harbor, North Carolina, in December 1998 and January 1999 in order 

to adequately assess the impacts of blasting on shortnose sturgeon, the size of the LD1 area (the 

lethal distance from the blast where 1% of the fish died), and the efficiency of an air curtain for 

mitigating blast effects. An air curtain is a stream of air bubbles created by a manifold system on 

the river bottom surrounding the blast. In theory, when the blast occurs the air bubbles are 

compressed, and the blast pressure is reduced outside the air curtain. 

As explained in Moser 1999(a), the test blasting consisted of 32-33 blasts (3 rows of 10 to 11 blast 

holes per row with each hole and row 10 feet apart), about 24 to 28 kg of explosives per hole, 

stemming each hole with angular rock, and an approximate 25 msec delay after each blast. During 

test blasting, 50 hatchery reared juvenile striped bass and shortnose sturgeon were placed in 0.25” 

plastic mesh cylinder cages (2 feet in diameter by 3 feet long) 3 feet from the bottom (worst case 

scenario for blast pressure as confirmed by test blast pressure results) at 35, 70, 140, 280, and 560 

feet upstream and downstream of the blast location. For each test, 200 caged shortnose sturgeon 

were held at a control location 0.5 mi from the test blast area. The caged fish had a mean weight of 

55 grams. The cages were enclosed in a 0.6” nylon mesh sock to prevent the escape of any sturgeon 

if the cage was damaged during blasting. The caging experiments were conducted during a total of 

seven blasts between December 9, 1998 and January 7, 1999. Three test blasts were conducted with 

the air curtain in place and 4 were conducted without the air curtain. The air curtain (when tested) 

was 50 feet from the blast. The caged fish were visually inspected for survival just after the blast 

and after a 24-hour holding period. Mortality rates for control fish were generally low, with 15 fish 

dead or mortally injured on inspection (out of a total of 1,400 samples). The numbers of injured, 

dead, and mortally injured sturgeon varied greatly between tests. Of the 500 fish tested during each 

blast, mortalities (dead or mortally injured) ranged from 1 to 89 fish. Mortality rates for shortnose 

sturgeon as compared to the other species tested were low, with the author of the report concluding 

that this was likely due to the larger size of shortnose sturgeon tested (approximately 30cm average) 

as compared to the size of the other species (3cm – 20cm). 

In addition to the external examinations of fish immediately following the blast and 24 hours later, a 
149

sample of 10 randomly selected, apparently unaffected, sturgeon from each of seven cages nearest 

the blasts were sacrificed and later necropsied (Moser 1999b). After the necropsy was completed, 

the total extent of injury was scored on a scale of 0-10, with 10 being the most severe level of injury 

observed. It is important to note that all of the fish necropsied were alive 24 hours following the 

blast and appeared to be uninjured based on the initial external observations. Fish scored at 7 or 

higher were thought to be unlikely to survive and function normally with the injuries they sustained. 

Injuries ranged from no sign of external injury to extensive internal hemorrhaging and ruptured 

swim bladders. 

All fish necropsied were in apparently normal condition when sacrificed 24 hours after the blast. 

The fish were swimming normally in their cages and exhibited no outward signs of stress or 

physical discomfort (Moser 1999b). However, internal examinations revealed extensive damage in 

many of the fish necropsied. Of the 70 sturgeon necropsied, ten had an index of injury of 7 or 

higher, meaning that they likely would not have survived the injuries sustained during blasting. 

While sturgeon had relatively little damage to their swim bladders, they more often had distended 

intestines with gas bubbles inside and hemorrhage to the body wall lining. In the fish caged 70 feet 

away, there was no sign of hemorrhage or swim bladder damage but two of the fish exhibited 

distended intestines, which may have been caused by the blast. Moser (1999) speculated that 

sturgeon fared better than striped bass because their air bladder has a free connection to the 

esophagus, allowing gas to be expelled rapidly without damage to the swim bladder. Additionally, 

there was no clear relationship between size and the Index of Injury, size and gut fullness, or Index 

of Injury and gut fullness. The author notes that external observation of the fish following blasting 

was not sufficient to identify all blast-related injuries and that many of the internal injuries observed 

in fish that externally appeared unaffected would have resulted in eventual mortality. 

7.4.2 Effects of Proposed Blasting on Shortnose and Atlantic Sturgeon 

The distribution of adult sturgeon in the lower Delaware River is relatively unknown. While the 

immediate area to be blasted (river mile 76.4 to river mile 84.6) is not a known concentration area 

for adult shortnose sturgeon, the species has been documented below Philadelphia and in the 

vicinity of the blasting area. Due to the lack of studies on overwintering sturgeon outside of the 

known upstream concentration area, the best available information is the survey conducted by 

ACOE in 2005 (Versar 2006). As noted above, in this study, video and net sampling was conducted 

with three sturgeon observed on video in the Marcus Hook area and no shortnose sturgeon captured 

with any nets. Atlantic sturgeon are known to occur in the Marcus Hook area year round, with this 

area recognized as a concentration area for juveniles. 

Sturgeon appear to be able to withstand some degree of blasting at a certain distance from the 

detonation, but it is apparent from the study results outlined above that blasting may injure the 

species both internally and externally. The presence of adults and/or juveniles in the action area 

during blasting could result in injury and/or mortality. The severity of the impact that blasting has 

on fish is dependent on several biological and physical variables. The physical variables are 

detonation velocity, density of material to be blasted and charge weight, while the biological 

variables are fish shape, location of fish in the water column, and swimbladder development( Teleki 

and Chamberlain 1978). The interactions of other factors such as composition of explosive, water 

depth, and bottom composition, determine the extent of the pressure wave and consequential fish 

kills (Teleki and Chamberlain 1978). Results from previous blasting studies conducted on thirteen 
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species of fish other than shortnose sturgeon, revealed that swimbladder rupture and hemorrhaging 

in the pericardial and ceolomic cavities were common injuries that resulted. While studies on 

shortnose sturgeon revealed that they also suffer from swimbladder ruptures, more common blast 

induced injuries that resulted were distended intestines with gas bubbles inside and hemorrhage to 

the body wall lining (Moser 1999a, Moser 1999b). Overall, however, it is difficult to determine the 

extent of internal injury because many fish did not exhibit external stress or physical discomfort 

despite extensive internal damage. Approximately 10% of fish that appeared to have suffered no 

injury, sustained injuries from the blasting that it is speculated would have lead to their eventual 

death. If shortnose sturgeon are present in the action area during blasting, they may suffer injury 

and/or mortality. 

 

Based on the information presented above, shortnose and Atlantic sturgeon within 500 feet of a 

detonation resulting in peak pressures of 120 psi and average pressure of 70 psi, consistent with the 

proposed action would be exposed to noise and pressure levels that could cause adverse effects. 

These effects could range from avoidance behaviors, temporary stunning, external or internal injury 

with full recovery, injury with delayed mortality or injury sufficient to cause immediate mortality. 

Based on the best available information, it is likely that the smaller the fish is and the closer it is to 

the blast the more significant the injuries would be. 

The ACOE will utilize measures to minimize the potential for blasting to occur if shortnose or 

Atlantic sturgeon are within 500 feet of the blast site. The ACOE will use a combination of sonar 

and other imaging (video or DIDSON for example) techniques to monitor an area with a radius of 

500 feet surrounding the blast site. Outside of the 500 foot zone, no effects to fish are likely 

(ACOE 2008 and ACOE 2009). Monitoring will begin 20 minutes prior to the detonation and no 

blasting will occur until any fish observed have left the area. As such, the risk of shortnose or 

Atlantic sturgeon being within close enough proximity to be injured or killed during a detonation is 

low. However, as the survey will need to stop at some point so that detonation can begin, there is a 

small risk that a sturgeon could swim into the area prior to or during blasting and not be detected. 

As this is likely to be a rare occurrence, it is not likely to happen more than once during the entirety 

of the blasting period. Based on the density estimates of sturgeon in the Marcus Hook area 

(0.005/100m) NMFS has estimated that at any given time, no more than 3 sturgeon are likely to 

occur in an area at Marcus Hook with a radius of 500 feet. As such, it is reasonable to expect that if 

the monitoring is not successful, then no more than 3 sturgeon will be close enough to the 

detonation site to experience effects ranging from temporary stunning to death. As explained 

above, sturgeon within 500 feet of the blast are expected to experience effects that could range from 

avoidance of the area to mortality. As such, we expect that over the course of the winter when 

blasting occurs, no more than 3 sturgeon will be stunned, injured or killed due to exposure to a 

detonation. It is difficult to estimate what portion of these sturgeon will be shortnose and what 

portion will be Atlantics; however, given that Atlantic sturgeon are more likely to be present in the 

Marcus Hook area in the winter than shortnose, we expect that no more than 1 of the sturgeon 

exposed to the detonation will be a shortnose sturgeon and the other two will be subadult or juvenile 

Atlantic sturgeon. 

After blasting is completed, mechanical dredging will be used to remove debris. In rare occurrences 

shortnose sturgeon have been captured in dredge buckets and placed in the scow. Very few 

mechanical dredge operations have employed observers to document interactions between sturgeon 
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and the dredge. However, captures of shortnose and Atlantic sturgeon have been documented in the 

Kennebec River, Maine. It is unknown if this is due to a unique situation in this river or if captures 

of sturgeon occur at other projects but that the intense observer coverage at dredging operations in 

this river has allowed detection here. Based on the occurrence of shortnose and Atlantic sturgeon in 

the area where mechanical dredging will take place and the documented vulnerability of this species 

to capture with mechanical dredges, it is likely that a small number of sturgeon will be captured by 

the mechanical dredge removing debris following blasting. Due to the relatively low level of risk 

that an individual sturgeon would be captured in the slow moving dredge bucket, no more than 1 

shortnose sturgeon and no more than 1 Atlantic sturgeon is likely to be captured when mechanical 

dredging is used. Sturgeon captured in a dredge bucket could be injured or killed. Sources of 

mortality include injuries suffered during contact with the dredge bucket or burial in the dredge 

scow. Of the three captures of sturgeon with mechanical dredges in the Kennebec River (two 

shortnose, 1 Atlantic), one of the shortnose sturgeon was killed. This fish suffered from a large 

laceration, likely experienced due to contact with the dredge bucket. As the risk of mortality once 

captured is high, it is reasonable to expect that both the shortnose and Atlantic sturgeon likely to be 

captured in the dredge bucket could suffer injury or mortality due to contact with the dredge bucket 

or through suffocation due to burial in the scow. 

In summary, blasting and subsequent removal of debris with a mechanical dredge is likely to result 

in injury or mortality to no more than 2 Atlantic sturgeon and 1 shortnose sturgeon via exposure to 

the sound and pressure of detonations, and the capture and associated injury or mortality of no more 

than 1 shortnose sturgeon and 1 Atlantic sturgeon in mechanical dredges. The affected shortnose 

sturgeon could be a juvenile or adult. Affected Atlantic sturgeon could be YOY, juveniles or 

subadults. Based on the mixed stock analysis, it is likely that the affected Atlantic sturgeon will 

originate from the New York Bight DPS but could also originate from the Gulf of Maine, 

Chesapeake Bay or South Atlantic DPS. Given the low numbers of Carolina DPS fish in the action 

area and the low number of mortalities anticipated, it is unlikely that there will be any mortality of 

any Carolina DPS Atlantic sturgeon. 

7.5 Maintenance Dredging 

The proposed action includes dredging necessary to maintain the channel at 45 feet once deepening 

has been completed. The proposed action under consideration in this consultation includes 10 years 

of maintenance dredging. The ACOE has indicated that, on average, approximately 472,000 cubic 

yards of material will be removed from Reaches D and E (collectively) each year in order to 

maintain the 45 foot channel. Dredging will not occur within this entire area each year, but would 

only occur in any areas where shoaling created a navigational hazard. As explained above, NMFS 

has estimated an entrainment rate for sea turtles in hopper dredges operating in Reaches D and E of 

the Philadelphia to the Sea project as 1 sea turtle per every 450,000 cubic yards of material removed 

during the time of year when sea turtles are likely to be present (i.e., May – November 15). 

Provided that maintenance occurs during the May – November window when sea turtles are likely 

to be present and that it occurs with a hopper dredge, approximately 1 sea turtle is likely to be 

entrained for each 450,000 cy of material removed. Over the 10 year maintenance cycle, 

approximately 4,720,000 cy of material will be removed from the Bay. No more than 11 sea turtles 

are likely to be killed over the 10 year maintenance cycle, with no more than 1 being a Kemp’s 

ridley and the remainder being loggerheads. Also as explained above, it is extremely unlikely that 
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any shortnose or Atlantic sturgeon will be entrained by a hopper dredge operating in Reaches D or 

E. As such, no sturgeon are likely to be entrained during maintenance dredging operations in these 

reaches. 

Maintenance dredging will also occur in the river. The ACOE has indicated that annually on 

average, approximately 3,845,000 cy of material will be removed from the river (reaches AA, A, B 

and C), typically occurring over a two month period between August and December. The ACOE 

has also indicated that a cutterhead dredge will be used for maintenance dredging activities. As 

explained above, NMFS has calculated an entrainment rate of 1 shortnose sturgeon and 1 Atlantic 

sturgeon for every cutterhead dredge event in the river. As such, no more than 1 shortnose sturgeon 

and no more than 1 Atlantic sturgeon are likely to be killed during each year of maintenance 

dredging. Based on the mixed stock analysis, it is likely that the affected Atlantic sturgeon will 

originate from the New York Bight DPS but could also originate from the Gulf of Maine, 

Chesapeake Bay or South Atlantic DPS. Given the low numbers of Carolina DPS fish in the action 

area and the low number of mortalities anticipated, it is unlikely that there will be any mortality of 

any Carolina DPS Atlantic sturgeon. 

7.6 Effects on Benthic Resources and Foraging

7.6.1 Dredging 

7.6.1.1 Effects to Sea Turtles

Since dredging involves removing the bottom material down to a specified depth, the benthic 

environment will be impacted by dredging operations. No sea grass beds occur in the areas to be 

dredged with a hopper dredge, therefore green sea turtles will not use the areas as foraging areas. 

Thus, NMFS anticipates that the dredging activities are not likely to disrupt normal feeding 

behaviors for green sea turtles. Records from previous dredge events occurring in the lower 

channel indicate that some benthic resources, including whelks, horseshoe crabs, blue crabs and 

rock crabs are entrained during dredging. Other sources of information indicate that potential sea 

turtle forage items are present in the channel, including jellyfish, clams, mussels, sea urchins, 

whelks, horseshoe crabs, blue crabs and rock crabs (ACOE 1997, 2009). 

Of the listed species found in the action area, loggerhead and Kemp’s ridley sea turtles are the most 

likely to utilize the channel areas for feeding with the sea turtles foraging mainly on benthic species, 

namely crabs and mollusks (Morreale and Standora 1992, Bjorndal 1997). As noted above, suitable 

sea turtle items occur in the channel. As preferred sea turtle and sturgeon foraging items occur at 

the channel areas and depths are suitable for use by sea turtles, some foraging by these species 

likely occurs at these sites. 

Dredging can cause indirect effects on sea turtles by reducing prey species through the alteration of 

the existing biotic assemblages. Kemp’s ridley and loggerhead sea turtles typically feed on crabs, 

other crustaceans and mollusks. Some of the prey species targeted by turtles, including crabs, are 

mobile; therefore, some individuals are likely to avoid the dredge; however, there is likely to be 

some entrainment of sea turtle prey items. The Delaware River estuary is approximately 700 square 

miles. The Philadelphia to the Sea navigation channel is approximately 15.3 square miles. The 

ACOE has estimated that approximately 8.5 square miles will be dredged (approximately 55% of 
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the existing channel, or 1.2% of the estuary) with no more than 0.33% of the estuary dredged in a 

particular year. While there is likely to be some reduction in the amount of prey in the channel 

areas, the area affected is small (i.e., less than 1% of the estuary annually) and the action will result 

in the loss of only a portion of the available forage in the dredged area. 

Depending on the species, recolonization of a dredged channel can begin in as short as a month 

(Guerra-Garcia and Garcia-Gomez 2006). The dredged area is expected to be completely 

recolonized by benthic organisms within approximately 12 months (USACE 2001, US DOI 2000). 

These conclusions are supported by the conclusions of a benthic habitat study which examined an 

area of Thimble Shoal following dredging and concluded that recolonization of the dredged area 

was rapid with macrobenthic organisms abundant on the first sampling date following cessation of 

dredging activities (less than a month later). 

The placement of sand at the beneficial use sites may affect benthic resources in those areas. 

Mobile organisms, such as crabs are expected to be able to avoid the area where material is being 

deposited. Concern has been raised that the deposition of material on these beaches could affect 

spawning horseshoe crabs which sea turtles eat. Spawning occurs during the full and new moons in 

May and June and peaks during evening high tides. Material will be deposited at Broadkill Beach 

in September – December and is therefore unlikely to affect spawning horseshoe crabs. Material 

will be deposited on Kelly Island between April and August; therefore there is the potential for 

dredged material disposal to overlap with horseshoe crab spawning; however, due to erosion at this 

beach it is not thought to be a constant or consistent spawning site (Weber 2001). Restoration of 

both of these beaches with dredged material will restore beach area and is likely to increase the 

future potential for supporting spawning horseshoe crabs. 

Based on this analysis, while there will be a small reduction in sea turtle prey due to dredging, these 

effects will be insignificant to foraging loggerhead and Kemp’s ridley sea turtles. No effects to the 

prey base of green or leatherback sea turtles are anticipated. 

Shortnose and Atlantic sturgeon feed on a variety of benthic invertebrates. The preferred forage 

item in the Delaware River is the Asiatic river clam (Corbicula manilensis). The proposed dredging 

is likely to entrain and kill at least some of these potential forage items. Given the limited mobility 

of most benthic invertebrates that sturgeon feed on, most are unlikely to be able to actively avoid 

the dredge. Benthic sampling done by O’Herron and Hastings (1985) in association with past 

ACOE maintenance dredging in the Delaware River found that Corbicula recolonized the dredge 

areas during the subsequent growing season. However, the post-dredge individuals collected were 

smaller than pre-dredge individuals and provided less biomass. O’Herron and Hastings (1985) 

found that adult shortnose sturgeon may not be able to efficiently utilize new molluscan colonizers 

due to the limited biomass until the end of the second growing season after dredging. Based on this 

information, sturgeon should only be exposed to a reduction in forage in the areas where dredging 

occurs for one to two seasons immediately following dredging. As explained above for sea turtles, 

the area dredged in any particular year is a very small percentage of the available foraging habitat in 

the river. Because effects to benthic prey will be limited to the area immediately surrounding the 

dredged area, the potential for disruption in foraging is low. Brundage (1985) and Hatin et al. 

(2007) both found that sturgeon were more common outside of the deepwater channel, which 

suggests that loss of forage items within the channel would have an insignificant effect on these 
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species. 

7.6.2 Blasting

Shortnose sturgeon generally feed when the water temperature exceeds 10°C and in general, 

foraging is heavy immediately after spawning in the spring and during the summer and fall, with 

lighter foraging during the winter (ACOE 2000, NMFS 1996). The likelihood that sturgeon are 

actively foraging in the area where blasting will occur is low, but shortnose sturgeon could still be 

feeding in the vicinity of the blasting. The foraging habits of Atlantic sturgeon in the Marcus Hook 

area are unknown, but it is presumed that some foraging occurs in this area. As noted above, 

sturgeon in the Delaware River primarily forage on the Asiatic river clam. Fine clean sand, clay, 

and coarse sand are preferred substrates for this clam, although this species may be present in lower 

numbers on almost any substrate (Gottfried and Osborne 1982, Belanger et al. 1985, Blalock and 

Herod 1999). The substrate in the area proposed for blasting is primarily rock and is not expected 

to be a concentration area for this prey species, but Corbicula has been found on gravel and bedrock 

substrates in the Susquehanna River. Few other benthic invertebrates are present in the rocky area 

where blasting will occur. However, any prey species that is present on the rock that will be 

removed by blasting or in the immediate project area would be destroyed. The impact should not 

extend beyond the immediate blasting area as previous studies indicate that invertebrates are 

relatively insensitive to pressure related damage from underwater detonations (ACOE 2000). This 

could be attributable to the fact that all the invertebrate species tested lack gas-containing organs, 

which have been implicated in internal damage and mortality in vertebrates (Keevin and Hempen 

1997). Nevertheless, the area immediately surrounding the blast zone would be void of preferred 

sturgeon prey and thus, sturgeon would not be likely to forage in this area.

It is important to note however, that while blasting will destroy all of the prey resources in the 

immediate area, the impacts will not be permanent and as discussed above for dredging, the benthic 

community will likely reestablish within two years. However, the area where blasting will occur is 

very small; representing only approximately 1% of the channel area and even smaller percentage of 

the area where foraging is known to occur. 

NMFS anticipates that while the dredging activities may temporarily disrupt normal feeding 

behaviors for sea turtles and sturgeon by causing them to move to alternate areas, the action is not 

likely to remove critical amounts of prey resources from the action area and any disruption to 

normal foraging is likely to be insignificant. Additionally, as (1) the area to be affected by dredging 

and blasting is small; (2) few motile organisms will be affected by the proposed dredging (3), 

recolonization of the benthic community will be rapid and complete within 2 years; and, (4) the 

same area will not be dredged more frequently than once every few years, we have determined that 

any effects to foraging sea turtles and sturgeon will be temporary and insignificant. 

7.7 Dredge and Disposal Vessel Traffic

There have not been any reports of dredge vessels colliding with listed species but contact injuries 

resulting from dredge movements could occur at or near the water surface and could therefore 

involve any of the listed species present in the area. Because the dredge is unlikely to be moving at 

speeds greater than three knots during dredging operations, blunt trauma injuries resulting from 

contact with the hull are unlikely during dredging. It is more likely that contact injuries during 

actual dredging would involve the propeller of the vessel. Contact injuries with the dredge are more 
155

likely to occur when the dredge is moving from the dredging area to port, or between dredge 

locations. While the distance between these areas is relatively short, the dredge in transit would be 

moving at faster speeds than during dredging operations, particularly when empty while returning to 

the borrow area. 

The dredge vessel may collide with sea turtles when they are at the surface. These species have 

been documented with injuries consistent with vessel interactions and it is reasonable to believe that 

the dredge vessels considered in this Opinion could inflict such injuries on sea turtles, should they 

collide. As mentioned, sea turtles are found distributed throughout the action area in the warmer 

months, generally from May through mid-November. 

Interactions between vessels and sea turtles occur and can take many forms, from the most severe 

(death or bisection of an animal or penetration to the viscera), to severed limbs or cracks to the 

carapace which can also lead to mortality directly or indirectly. Sea turtle stranding data for the 

U.S. Gulf of Mexico and Atlantic coasts, Puerto Rico, and the U.S. Virgin Islands show that 

between 1986 and 1993, about 9% of living and dead stranded sea turtles had propeller or other boat 

strike injuries (Lutcavage et al. 1997). According to 2001 STSSN stranding data, at least 33 sea 

turtles (loggerhead, green, Kemp’s ridley and leatherbacks) that stranded on beaches within the 

northeast (Maine through North Carolina) were struck by a boat. This number underestimates the 

actual number of boat strikes that occur since not every boat struck turtle will strand, every stranded 

turtle will not be found, and many stranded turtles are too decomposed to determine whether the 

turtle was struck by a boat. It should be noted, however, that it is not known whether all boat strikes 

were the cause of death or whether they occurred post-mortem (NMFS SEFSC 2001).

Information is lacking on the type or speed of vessels involved in turtle vessel strikes. However, 

there does appear to be a correlation between the number of vessel struck turtles and the level of 

recreational boat traffic (NRC 1990). Although little is known about a sea turtle’s reaction to vessel 

traffic, it is generally assumed that turtles are more likely to avoid injury from slower-moving 

vessels since the turtle has more time to maneuver and avoid the vessel. The speed of the dredge is 

not expected to exceed 3 knots while dredging or while transiting to the pump out site with a full 

load and it is expected to operate at a maximum speed of 10 knots while empty. In addition, the 

risk of ship strike will be influenced by the amount of time the animal remains near the surface of 

the water. For the proposed action, the greatest risk of vessel collision will occur during transit 

between shore and the areas to be dredged. The presence of an experienced endangered species 

observer who can advise the vessel operator to slow the vessel or maneuver safely when sea turtles 

are spotted will further reduce the potential risk for interaction with vessels. The addition of one to 

two slow moving vessels in the action area have an insignificant effect on the risk of interactions 

between sea turtles and vessels in the action area. 

Available information on the risk of vessel operations to shortnose sturgeon is discussed in the 

Environmental Baseline section above. Aside from the incidents discussed there, no information on 

the characteristics of vessels that are most likely to interact with shortnose sturgeon is available and 

there is no information on the rate of interactions. However, assuming that the likelihood of 

interactions increases with the number of vessels present in an area, we have considered the 

likelihood that an increase in ship traffic associated with dredging, blasting and disposal would 

increase the risk of interactions between shortnose sturgeon and vessels in the action area. 
156

Approximately 3,000 cargo vessels transit the Delaware River annually as well as numerous smaller 

commercial and recreational vessels. Dredging, blasting and disposal for deepening and 

maintenance of the deepened channel is likely to result in an increase of one to two slow moving 

vessels during the times when project operations are ongoing (typically a 2-3 month period each 

year). Based on the high ship traffic currently experienced in the action area, it is unlikely that an 

increase of only one to two slow moving vessels per day would increase the risk of interactions 

between shortnose sturgeon and vessels operating in the Delaware River generally. As such, the 

increase in risk is likely to be insignificant and interactions between project vessels and shortnose 

sturgeon are extremely unlikely to occur. 

Information regarding the risk of vessel strikes to Atlantic sturgeon is discussed in the Status of the 

Species and Environmental Baseline sections above. As explained there, we have limited 

information on vessel strikes and many variables likely affect the potential for vessel strikes in a 

given area. Assuming that the risk of vessel strike increases with an increase in vessel traffic, we 

have considered whether an increase in vessel traffic in the action area during dredging, blasting 

and disposal (one to two slow moving vessels per day) would increase the risk of vessel strike for 

Atlantic sturgeon in this area. Given the large volume of traffic on the river and the wide variability 

in traffic in any given day, the increase in traffic of one to two vessels per day is negligible and the 

increased risk to Atlantic sturgeon is insignificant.

7.8 Effects of Deepening on Substrate/Habitat Type 

During the consultation process, NMFS requested information on the potential of the proposed 

deepening to alter the substrate type in areas to be dredged. If substrate type was altered, the 

benthic community that recolonizes the dredged area could be fundamentally different than the 

original community and this could affect the availability of forage items for listed species. 

However, the ACOE has indicated that the remaining sub-surface strata below the dredging payprism is consistent with the maintenance material removed during a typical dredging operation. The 

maintenance material removed from this project historically consists of a mixture of sand and mud. 

Typical material densities vary in range from silt/mud between 1137 (g/l) to 1337 (g/l) and sands 

1526 (g/l) to 1874 (g/l). The ACOE has indicated that the same ratio is anticipated as a result of the 

deepening project and that no alterations in the type of sediment occurring in the dredged areas will 

result from the proposed action. ACOE has also indicated that while blasting within the Marcus 

Hook area will remove bedrock, it is only removing enough rock to deepen the area to 45 feet. 

Because only the top layers of the rock will be removed, and the bedrock extends deep into the river 

bottom, rock will remain in all areas where blasting will occur. 

At our request the ACOE conducted sediment sampling both before and after deepening occurred in 

Reach B (ACOE 2012). These reports confirmed that sediment type was unchanged after 

deepening. 

Based on the information provided by ACOE and confirmation sampling that has occurred to date, 

no changes in substrate type are anticipated to result from dredging. Effects to forage items are 

considered in section 7.5 and effects to Atlantic sturgeon spawning are considered in section 7.9. 
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7.9 Effects of Deepening on Salinity 

Salinity is the concentration of inorganic salts (total dissolved solids, or "TDS") by weight in water, 

and is commonly expressed in units of "psu" (practical salinity units) or "ppt" (parts per thousand). 

By example, ocean water with a salinity of 30 ppt contains ~30 grams of salt per 1,000 grams of 

water. As explained above, the action area experiences a wide variety of salinity influenced by 

multiple factors. Also as explained above, the salinity gradient effects the distribution of listed 

species in the action area with sea turtles less likely to occur as salinity decreases and shortnose 

sturgeon more prevalent in the low salinity reaches. Concerns have been raised that the proposed 

deepening could alter the salinity regime in the estuary. 

7.9.1 Existing Salinity Conditions in the Delaware River 

The distribution of salinity in the Delaware estuary exhibits significant variability on both spatial 

and temporal scales, and at any given time reflects the opposing influences of freshwater inflow 

from tributaries (and groundwater) versus saltwater inflow from the Atlantic Ocean. Saltwater 

inflow from the ocean is in turn dependent on the tidal discharge and the ocean salinity. Salinity at 

the bay mouth typically ranges from about 28 to 32 ppt. Tributary inflows by definition have "zero" 

salinity in the sense of ocean-derived salt; however, these inflows contain small but finite 

concentrations of dissolved salts, typically in the range of 100 to 250 parts per million (ppm) or 

from 0.1 to 0.25 ppt TDS. 

A longitudinal salinity gradient is a permanent feature of salt distribution in the Delaware estuary. 

That is, salinity is always higher at the mouth and downstream end of the system and decreases in 

the upstream direction. The upstream limit of ocean-derived salinity is customarily treated as the 

location of the 0.5 ppt (or 500 ppm) isohaline. For purposes of monitoring water quality in the 

Philadelphia-Camden area, the DRBC has adopted the 7-day average location of the 250 ppm 

isochlor as the “salt line”. Because chloride ions represent approximately 55% by weight of the 

total dissolved ions in seawater, a “salt line” defined by a chlorinity of 250 ppm approximates a 

salinity of 450 ppm, or 0.45 ppt. 

There is also a lateral salinity gradient present in the bay portion of the estuary, between the mouth 

and about RM 50, with higher salinities near the axis of the bay, and lower salinities on the east and 

west sides. Upstream of Artificial Island at RM 50, salinity tends to be more uniformly distributed 

across the channel. Under most conditions in the estuary, there is only a small vertical salinity 

gradient, due to the dominance of tidal circulation and mixing relative to the normal freshwater 

inflow. However, under prolonged high-flow conditions, such as during the spring freshet, vertical 

salinity gradients of as much as 5 ppt can occur in the lower bay, with corresponding smaller 

vertical gradients at locations further upstream to the limit of the salt line. At any given point in the 

estuary between the bay mouth and the location of the salt line, the salinity of the water column will 

vary directly with the phase of the tidal currents. Maximum salinity at a point occurs around the 

time of slack water after high tide, and minimum salinity occurs at the time of slack after low. This 

condition reflects the significant role played by tidal currents in advecting higher salinity water in 

the upstream direction during flood flow, with lower salinity water being advected in the 

downstream direction during ebb. For periods longer than a single tidal cycle, the salinity at a given 

location varies in response to other important forcing functions, including the short-term and 

seasonal changes in freshwater inflow, wind forcing over the estuary and adjacent portions of the 

continental shelf, and salinity and water level changes at the bay mouth. Over longer periods (years 
158

to decades and longer), sea level changes and modifications to the geometry of the estuary also 

affect the long-term patterns of salinity distribution.

 

To illustrate the variability of salt distribution in the estuary over time, Figure 4 presents a plot of 

the “salt line” location within Delaware estuary, along with average daily inflow at Trenton, for the 

period 1 January 1998 through 30 November 2008 (10.9 years). The term “salt line” refers to the 7-

day average location of the 250 mg/l (ppm) isochlor (equivalent to 0.45 ppt salinity), and is used as 

an approximate indicator of the upstream penetration of ocean-derived salinity. In the ~11-year 

period shown, the salt line has been as far north as RM 90 in late summer 2005, and at or below RM 

40 during multiple high-flow periods in 2006, a range that exceeds 50 miles along the axis of the 

estuary for a period just over a decade. Figure 5 is a histogram of the daily salt line location for the 

same January 1998 to November 2008 period, and shows that the average location over this period 

is about RM 71, upstream of the Delaware Memorial Bridge and near the mouth of the Christina 

River in Wilmington, Delaware. Based on monthly averages, the salt line maximum penetration 

occurs in October (RM 81) with the minimum in April (RM 61), reflecting the typical seasonal 

pattern of freshwater discharge to the estuary. A general observation is that the salt line location 

varies directly with the volume of freshwater inflow, and is located in the twenty-mile long zone 

between RM 61 and RM 81 during an “average” year. 

The four longitudinal salinity zones within the Delaware Estuary, starting at the downstream end, 

are referred to as: polyhaline (18 - 30 ppt) from the mouth of the bay to the vicinity of the Leipsic 

River (RM 34); mesohaline (5 - 18 ppt) from the Leipsic River to the vicinity of the Smyrna River 

(RM 44); oligohaline (0.5 - 5 ppt) from the Smyrna River to the vicinity of Marcus Hook (RM 79), 

and fresh (0.0 - 0.5 ppt) from Marcus Hook to Trenton. Although these zones are useful to describe 

the long-term average distribution of salinity in the estuary, the longitudinal salinity gradient is 

dynamic and subject to short and long-term changes caused by variations in freshwater inflows, 

tides, storm surge, weather (wind) conditions, etc. These variations can cause a specific salinity 

value (isohaline) to move upstream or downstream by as much as 10 miles in a day due to semidiurnal tides, and by more than 20 miles over periods ranging from a day to weeks or months due to 

storm and seasonal effects on freshwater inflows. 
159

Figure 4 AND 5
160

7.9.2 Projected Changes in Salinity 

The ACOE has conducted several models to estimate any modifications to the salinity regime that 

could result from deepening. 

In order to estimate the potential for the proposed channel deepening to affect salinity distribution, 

the ACOE applied the 3-D numerical hydrodynamic model “CH3D-WES” (Curvilinear 

Hydrodynamics in Three Dimensions) to develop data on the movement of the salt line and the 5, 

10, and 15 ppt isohalines that cover various locations in the estuary and correspond to salinities 

significant to various components of the estuarine ecosystem.

 

CH3D-WES includes as input data (“boundary conditions”) the most important physical factors 

affecting circulation and salinity within the modeled domain. As its name implies, CH3D-WES 

makes computations on a curvilinear, or boundary fitted, planform grid. Physical processes 

affecting baywide hydrodynamics that are modeled include tides, wind, density effects (salinity and 

temperature), freshwater inflows, turbulence, and the effect of the earth's rotation. The 

representation of vertical turbulence is crucial to a successful simulation of stratification in the bay. 

The boundary fitted coordinates feature of the model provides enhancement to fit the scale of the 

navigation channel and irregular shoreline of the bay and permits adoption of an accurate and 

economical grid schematization. The vertical dimension is Cartesian which allows for modeling 

stratification on relatively coarse horizontal grids. 

The principal goal of the modeling effort was to identify and quantify any impacts of the proposed 

5-foot channel deepening on spatial and temporal salinity distribution. A number of modeling 

scenarios were developed to represent a range of boundary and forcing conditions of potential 

importance to both human and non-human resources of the Delaware Estuary. Several scenarios 

were identified and selected for application in the 3-D model to address the impact of channel 

deepening on salinity distribution and subtidal circulation in the Delaware Estuary. The selection of 

these sets of conditions was based on coordination accomplished through interagency workshops. 

The selected scenarios include: 

1. The June-November 1965 drought of record, with Delaware River discharges adjusted to 

reflect the existing reservoir regulation plan and corresponding flows ("Regulated 1965"); 

2. Long-term monthly-averaged inflows with June-November 1965 wind and tide forcings; 

and 

3. A high-flow transition period, represented by the April-May 1993 prototype data set. 

Each of these periods was simulated first with the existing 40 foot navigation channel, and then with 

the proposed 45 foot channel in place. Based on these model results, the ACOE concluded that 

while deepening would result in salinity increases in the Philadelphia area during a recurrence of the 

drought of record, these increases would be small. The model estimates that the 10 ppt isohaline, 

which can fluctuate naturally over a 30 mile zone of the estuary, moved upstream an average of 

from 0.0 to 1.0 miles with the deepened channel. The maximum monthly average increase in 

salinity within the mesohaline zone was 0.1 to 0.3 ppt. 

Updated modeling was conducted in 2003 to consider effects of deepening in conjunction with 

other factors that were likely to increase salinity. Section 4.1.2.3 of the 2009 EA reports salinity 
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modeling results from simulation of the 1965 drought of record with a channel deepened to 45 feet, 

DRBC projected 2040 consumptive use and a 2040 sea level rise projection based on NOS tide 

gauge data collected during the 20th century along the coasts of New Jersey and Delaware. Results 

are reported at the Delaware Memorial Bridge (RM 69 (Rkm 111)), Chester, PA (RM 83 (rkm 

134)) and the Ben Franklin Bridge (RM 100 (rkm 161)) (Table 4-1 of the April 2009 EA). 

Modeling results are provided for each scenario (deepened channel, 2040 consumptive use, 2040 

sea level rise) and for the three scenarios combined. Results are the peak 7-day-average change in 

salinity resulting from each scenario compared with the background range of salinity during the 

1965 simulation period. 

At the Delaware Memorial Bridge, background salinity for the 1965 drought of record ranged from 

0 to 6 ppt. The projected peak 7-day average increase for the three combined scenarios is 0.9 ppt; 

resulting in a projected salinity level during worst case drought conditions of 0.9- 6.9 ppt. At 

Chester, PA, background salinity for the 1965 drought of record ranged from 0 to 1.8 ppt. The

projected peak 7-day-average increase for the three combined scenarios is 0.3 ppt; resulting in a 

projected salinity level during worst case drought conditions of 0.3-2.1 ppt. At the Ben Franklin 

Bridge, background salinity for the 1965 drought of record ranged from 0 to 0.3 ppt. The projected 

peak 7-day-average increase for the three combined scenarios is 0.036 ppt; resulting in a projected 

salinity level during worst case drought conditions of 0.036 – 0.336 ppt. Projected salinity 

increases resulting from a deepened channel, 2040 consumptive use and 2040 sea level rise would 

continue to decrease moving upstream. 

7.9.3 Effects of Salinity Changes on sturgeon 

Changes in salinity could affect the distribution of shortnose and Atlantic sturgeon in the river. In 

the Delaware River, subadult Atlantic sturgeon are known to congregate and overwinter within 

brackish river waters (Brundage and Meadows, 1982). Previous studies have noted that subadult 

Atlantic sturgeon typically occupy both the oligohaline and moderately mesohaline (<10ppt) 

environments (Dovel and Berggren, 1983; Kiefer and Kynard, 1993; Moser and Ross, 1995; 

Simpson, 2008). For both of these species, early life stages (i.e., eggs and larvae) have little to no 

tolerance to salinity and therefore, spawning occurs in fresh water. Tolerance to salinity increases 

with age and size (Jenkins et al. 1993, McEnroe and Cech 1985). During at least the first year, 

shortnose and Atlantic sturgeon are limited in distribution to fresh water; as a result their 

distribution is typically upstream of the “salt wedge.” If the salt wedge moved further upstream, 

there could be a reduction in available spawning or rearing habitat. 

Based on seasonal movements of tagged adults in conjunction with habitat data, Atlantic sturgeon 

spawning in the Delaware River is thought to occur between rkm 120-150 and 170-190 in areas 

where salinity is around 0.5 ppt (Breece 2011). In April, the average salt line location (measured as 

0.25 ppt) is rkm 98; in August the average salt line location is rkm 130. Near rkm 161, salinity 

could peak at 0.336 ppt. It is important to note that the deepening of the channel is only one factor 

contributing to this increase in salinity and that it causes only about 25% of this increase. The

primary factor is expected sea level rise. 

Salinity near rkm 161 peaks around 0.3 ppt even during drought conditions; this is within the range 

where spawning and rearing can occur. The expected increase in 2040, even under the worst 
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conditions, is only 0.036 ppt, which would not increase salinity enough to cause it to be no longer 

suitable for spawning. Based on the model results, it is unlikely that the increase of salinity at rkm 

161 and further upstream would affect the selection of spawning sites or the success of 

development of any eggs or larvae in this area. Thus, the potential for spawning at the rkm 170-190 

site is likely to be unaffected due to effects of the deepening project on salinity. 

Modeling discussed above indicates that in 2040, with deepening and predicted increases in 

consumptive water use and sea level rise, salinity near Chester (rkm 134) could be approximately 

0.3ppt higher than it is now during worst case drought conditions and would peak at 2.1ppt rather 

than the historical high of 1.8ppt; deepening accounts for 0.07 ppt of the 0.3 ppt increase in salinity. 

In meteorologically average years, the spawning location of rkm 120-150 is within the 32 km 

average range of the spring/summer location of the 0.45 ppt salt line (rkm 98-130) and located just 

upstream of the longterm average salt line location (rkm 115). A predicted increase in salinity due 

to the deepening of 0.07 ppt in this area (i.e., near the modeled point of Chester, rkm 134) would 

still be within the range (approximately 0.5 ppt) where spawning is expected to occur. This 

increase in salinity is not likely to affect the selection of spawning sites or the success of 

development of eggs or larvae in this area. 

During extremely dry years, such as the record drought year of 1965, salinity in at least portions of 

the rkm 120-150 spawning area can be too high to support the development of eggs and larvae (1.8 

ppt). When sea level rise and increases in consumptive water use are considered, the increase in 

salinity in this area could be as much as 0.3 ppt during worst case drought conditions. Given the 

small increase in salinity caused by the deepening, the deepening would not exacerbate these 

conditions or cause these areas to be unsuitable more often than they have historically been. 

Shortnose sturgeon spawning occurs near Scudder Falls, well upstream of the any areas where 

deepening will occur and outside the area where increased salinity is expected. Therefore, selection 

of spawning sites or the development of eggs and larvae is unlikely to be affected by the deepening. 

Between now and 2040, due to sea level rise and increases in consumptive water use, there may be 

a reduction of available habitat for juvenile shortnose sturgeon in some years. However, given the 

small effect of the deepening on the predicted change in the location of the salt line, effects of the 

deepening on the distribution of shortnose sturgeon are likely to be insignificant. 

7.9.4 Effects of salinity Change on Sea Turtles

Sea turtles occur in saline sea water. Sea turtles do not occur in the reaches of the river where 

increases in salinity may be experienced. No impacts to sea turtles from increase in salinity will 

occur. 

7.10 Effects of Deepening on Dissolved Oxygen

Shortnose and Atlantic sturgeon are known to be more sensitive to low dissolved oxygen levels than 

many other fish species and juvenile sturgeon are particularly sensitive to low dissolved oxygen 

levels. In comparison to other fishes, sturgeon have a limited behavioral and physiological capacity 

to respond to hypoxia (multiple references reviewed and cited in Secor and Niklitschek 2001, 

2003). Sturgeon basal metabolism, growth, consumption and survival are all very sensitive to 

changes in oxygen levels, which may indicate their relatively poor ability to oxyregulate. Sturgeon 
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may be negatively affected, primarily through changes in behavior and distribution, when dissolved 

oxygen levels are below 5mg/l, particularly at times when water temperatures are higher than 28oC

(see Flourney et al.1992; Campbell and Goodman 2004). 

In certain areas and during certain times of year, dissolved oxygen levels in the Delaware River may 

be stressful to sturgeon. As sea turtles are air breathers, they are not directly affected by dissolved 

oxygen levels; however, if dissolved oxygen levels affect sea turtle prey, sea turtles could be 

affected as well. We have considered whether the deepening project and subsequent maintenance

are likely to affect dissolved oxygen levels in the action area. Dissolved oxygen levels could be 

affected due to increases in suspended sediment and if submerged aquatic vegetation was affected. 

The ACOE has indicated that there is no SAV in the areas where dredging will occur or where 

dredged material will be disposed of (i.e., the areas at Kelly Island and Broadkill Beach). There 

may be SAV, particularly wild celery, near areas where pipes transporting dredged material will be 

placed. However, pre-construction surveys will take place to ensure that pipe is laid out in a way 

that avoids SAV. No SAV will be destroyed or buried due to dredging or dredged material 

disposal. Further, because there is no SAV where dredging will occur, no SAV will be exposed to 

turbidity or suspended sediment.

As discussed in Sections 7.1, 7.2, 7.3 and 7.4, there will be small, short term increases in suspended 

sediment and turbidity near where dredging is occurring and when dredged material is disposed of 

at Kelly Island and Broadkill Beach. However, given the short duration and limited geographic 

extent of these increases in suspended sediment and turbidity any effects to dissolved oxygen are 

similarly likely to be limited to small areas and for short periods of time. As such, any effects to sea 

turtles, shortnose sturgeon or Atlantic sturgeon will be insignificant and discountable. 

7.11 Effects to Atlantic sturgeon spawning 

Atlantic sturgeon spawning is believed to occur in flowing water between the salt front and fall line 

of large rivers, where optimal flows are 46-76 cm/s and depths of 11-27 meters (Borodin 1925, 

Leland 1968, Scott and Crossman 1973, Crance 1987, Bain et al. 2000). Sturgeon eggs are highly 

adhesive and are deposited on the bottom substrate, usually on hard surfaces (e.g., cobble) (Gilbert 

1989, Smith and Clugston 1997). Here, we consider effects of the deepening project on factors that 

are important to Atlantic sturgeon spawning habitat selection. 

Spawning is thought to occur at two locations, rkm 170-190 and rkm 120-150 (Breece 2011). The 

upriver site is outside of the area where deepening will occur. The lower site overlaps with portions 

of Reach A and Reach B. The timing of dredging in those reaches has been designed to minimize 

the potential for disruption of spawning adults or effects to early life stages. All work in these 

reaches will occur between August and February; spawning occurs in April and May. Spawning 

adults are not likely to be present when dredging or blasting occurs; thus, there will be no direct 

disruption of spawning activity. No eggs will be present during this time of year and all larvae are 

likely to have developed to a mobile stage which reduces their vulnerability to the proposed action. 

During the spring of 2013 and 2015, dredging will be ongoing in Reach D and E, respectively, 

while adults are making upstream movements to the spawning grounds. Due to the localized effects 

of dredging (sediment disturbance, noise), we do not anticipate that their movements will be 

disrupted or delayed by the dredging activity. The documented movement of tagged sturgeon 
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through areas where active dredging is occurring (see Section 7.2), supports this determination. 

The deepening is expected to result in a minor increase in salinity in some areas of the river. 

Models indicate that the expected change in salinity is very small. As such, it is not expected that 

the deepening will affect salinity enough to change the suitability of spawning sites, the selection of 

spawning locations by adults, or the success of development of any eggs or larvae. 

The deepening is expected to have an insignificant effect on water velocity in the river. Models 

indicate that the expected change in flow near the bottom of the river is less than 1 cm/sec (ACOE 

1997). As such, it is not expected that the deepening will affect the substrate in a way that will have 

any effect on the suitability of spawning sites, the selection of spawning locations by adults, or the 

success of development of any eggs or larvae. 

The deepening will increase depths in the dredged areas from 40 to 45 feet. However, because both 

of these depths are within the range of depths used for sturgeon spawning, it is not expected that the 

increase in depth will have any effect on the suitability of spawning sites, the selection of spawning 

locations by adults, or the success of development of any eggs or larvae. 

The deepening will remove substrate from the river bottom. However, no changes in substrate type 

are anticipated and there will be no reduction in hard bottom habitat in the river. Because of that, it 

is not expected that the deepening will affect the substrate in a way that will have any effect on the 

suitability of spawning sites, the selection of spawning locations by adults, or the success of 

development of any eggs or larvae. 

Maintenance dredging activity will occur between August and December; thus, the analysis for 

effects of deepening also applies to maintenance activities. Based on our analysis, we have 

determined that any effects of the deepening on Atlantic sturgeon spawning will be insignificant 

and discountable. 

7.12 Increased Use of Channel by Vessels 

During the consultation process, we requested information from ACOE as to whether there would 

be any expected port expansion resulting from the proposed deepening. The ACOE indicated that 

the 45-foot project was formulated, evaluated, and authorized by Congress based on the parameter 

that no tonnage will be induced or attracted to the port's facilities as a direct result of the proposed 

deepening of the channel depth for the five-foot increment from 40 to 45 feet. Any future increase 

in the amount of tonnage through the port over the project life will be an equivalent amount for 

either the 40 or 45 foot channel depth conditions, and would be predicated on the performance of 

the U.S. economy. A deeper channel will allow vessels to more efficiently apportion vessel 

operating costs over the same magnitude of tonnage, resulting in transportation savings. The largest 

vessels in the fleet, crude oil tankers, will continue to carry the same amount of imported crude to 

the Big Stone Beach anchorage (located in the naturally deeper water in the lower Delaware Bay). 

The Coast Guard allowance for sailing drafts of the tankers into the anchorage is 55 feet. 

Lightering requirements will be reduced for these tankers with the channel deepening, which will 

lessen the number of barge trips required to carry crude to the refineries upriver. So, overall, the 

total vessel/barge traffic through the Delaware River port system will be less with the 45 foot 

deepening as compared to the traffic for the existing 40 foot channel depth. Overall, future cargo 
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growth is expected to be modest (with flat tonnage factored for crude oil and petroleum products, 

and only small to moderate growth for dry bulk and container traffic). In summary, the 45 foot 

channel depth improvement would not necessitate any expansion of the port facilities utilized for 

tonnage with the current 40 foot channel scenario; therefore, there is not expected to be any increase 

in risk of vessel strike for any listed species due to the increased depth of the channel. 

Two new marine terminals have been proposed since the deepening was initiated (Paulsboro and 

Southport); however, as explained in the 2011 EA, these terminals are not dependent on the 

deepening as they do not require depths of 45 feet in order to be used. Therefore, their effects are 

not effects of this proposed action, the deepening of the Federal Navigation Channel. To date, only 

the Paulsboro project has been permitted; a separate consultation was completed between ACOE 

and NMFS in 2010 to consider effects of the project on shortnose and Atlantic sturgeon and sea 

turtles. The wharf will accommodate four berths and is expected to handle a variety of general 

cargo. Berths 1, 2 and 3 are designed to accommodate Handymax class cargo vessels, which are 

typically 650 feet long and 95 feet wide. The fourth berth will be designated as a barge berth and is 

designed to accommodate a typical 400-foot long by 100-foot wide barge. A ship traffic modeling 

study dated September 2010 was provided to NMFS by the ACOE during the consultation. The 

results of the model show the expected increase in the daily number of vessels at seven locations 

within the Delaware River once the Paulsboro terminal is operational. The increase in daily counts 

at any location is consistently less than 1 and the 95% confidence interval is between 0.7 and 1. 

Using this model, the ACOE predicted that the construction and operation of the Paulsboro Marine 

Terminal will, on average, result in an increase of one additional ship in the Delaware River per 

day. In our 2010 consultation we determined, given the large volume of traffic on the river and the 

wide variability in traffic in any given day, the increase in traffic of one cargo vessel per day is 

negligible and that it is unlikely there would be any detectable increase in the risk of vessel strike to 

shortnose or Atlantic sturgeon or sea turtles. 

8.0 CUMULATIVE EFFECTS

Cumulative effects, as defined in 50 CFR 402.02, are those effects of future State or private 

activities, not involving Federal activities, which are reasonably certain to occur within the action 

area. Future Federal actions are not considered in the definition of “cumulative effects.” 

Actions carried out or regulated by the States of New Jersey, Delaware and Pennsylvania within the 

action area that may affect shortnose and Atlantic sturgeon include the authorization of state 

fisheries and the regulation of point and non-point source pollution through the National Pollutant 

Discharge Elimination System. We are not aware of any local or private actions that are reasonably 

certain to occur in the action area that may affect listed species. It is important to note that the 

definition of “cumulative effects” in the section 7 regulations is not the same as the NEPA 

definition of cumulative effects19. The activities discussed in the Cumulative Effects section of the 

2011 EA developed for the deepening project – the Paulsboro Marine Terminal and the Southport 

 

19 Cumulative effects are defined for NEPA as “the impact on the environment, which results from the incremental 

impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what 

agency (Federal or non-Federal) or person undertakes such other actions. Cumulative impacts can result from 

individually minor but collectively significant actions taking place over a period of time.”
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Marine Terminal require authorization by the US Army Corps of Engineers, therefore they are 

considered Federal actions and do not meet the definition of “cumulative effects” under the ESA. 

The ACOE has stated that both of these actions involve dredging up to 40 feet, and are not 

dependent on the deepening project, thus they cannot be considered interrelated or interdependent 

actions either. 

The Paulsboro Marine Terminal has received a Department of the Army permit for construction. 

We completed section 7 consultation with the ACOE to consider the effects of this project on 

shortnose and Atlantic sturgeon. In a letter dated July 25, 2011, we determined that all effects to 

these species would be insignificant and discountable. The New Jersey Department of 

Environmental Protection issued their permit including water quality certification and coastal zone 

management approval on October 15, 2010. The project is to re-develop the former 130-acre 

British Petroleum (BP) Oil Terminal and the adjacent 45-acre former Essex Industrial Chemicals, 

Inc. (Essex) properties located adjacent to the Delaware River and Mantua Creek in the Borough of 

Paulsboro, Gloucester County into a new, deep-water marine terminal with associated processing, 

distribution, assembly and intermodal operations. 

The Southport Marine Terminal is still in the planning stages, and is currently undergoing the 

Department of the Army permit process. The project location is at the eastern end of the 

Philadelphia Naval Business Center, formerly known as the Philadelphia Naval Shipyard, in the city 

and county of Philadelphia, Pennsylvania. The proposed project would construct a new marine 

terminal on approximately 116 acres of currently vacant land. We provided comments to the ACOE 

in response to an August 24, 2010, Public Notice. No section 7 consultation has occurred to date, 

but we expect that any necessary consultation will occur prior to any ACOE approval of the project. 

While there may be other in-water construction or coastal development within the action area, all of 

these activities are likely to need a permit or authorization from the US Army Corps of Engineers 

and would therefore, be subject to section 7 consultation. 

State Water Fisheries - Future recreational and commercial fishing activities in state waters may 

take shortnose and Atlantic sturgeon. In the past, it was estimated that over 100 shortnose sturgeon 

were captured annually in shad fisheries in the Delaware River, with an unknown mortality rate

(O’Herron and Able 1985); no recent estimates of captures or mortality are available. Atlantic 

sturgeon were also likely incidentally captured in shad fisheries in the river; however, estimates of 

the number of captures or the mortality rate are not available. Recreational shad fishing is currently 

allowed within the Delaware River with hook and line only; commercial fishing for shad occurs 

with gill nets, but only in Delaware Bay. In 2012, only one commercial fishing license was granted 

for shad in New Jersey. Shortnose and Atlantic sturgeon continue to be exposed to the risk of 

interactions with this fishery; however, because increased controls have been placed on the shad 

fishery, impacts to shortnose and Atlantic sturgeon are likely less than they were in the past. 

Information on interactions with shortnose and Atlantic sturgeon for other fisheries operating in the 

action area is not available, and it is not clear to what extent these future activities would affect 

listed species differently than the current state fishery activities described in the Status of the 

Species/Environmental Baseline section. However, this Opinion assumes effects in the future 

would be similar to those in the past and are, therefore, reflected in the anticipated trends described 

in the status of the species/environmental baseline section. 
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State PDES Permits – The states of New Jersey, Delaware and Pennsylvania have been delegated 

authority to issue NPDES permits by the EPA. These permits authorize the discharge of pollutants 

in the action area. Permitees include municipalities for sewage treatment plants and other industrial 

users. The states will continue to authorize the discharge of pollutants through the SPDES permits. 

However, this Opinion assumes effects in the future would be similar to those in the past and are 

therefore reflected in the anticipated trends described in the status of the species/environmental 

baseline section.

9.0 INTEGRATION AND SYNTHESIS OF EFFECTS

In the effects analysis outlined above, NMFS considered potential effects from the following 

sources: (1) deepening of the channel with cutterhead and hopper dredges; (2) blasting at Marcus 

Hook and associated debris removal with a mechanical dredge; (3) physical alteration of the action 

area including disruption of benthic communities, changes in substrate type and changes in salinity 

in the action area. In addition to these categories of effects, NMFS considered the potential for 

collisions between listed species and project vessels, the potential for the deepened channel to result 

in an increase in vessel traffic in the action area and the potential for effects to Atlantic sturgeon 

spawning. We anticipate the mortality of a small number of loggerhead and Kemp’s ridley sea

turtles, shortnose sturgeon, and Atlantic sturgeon from the five DPSs. Mortality of sea turtles will 

result from entrainment in hopper dredges operating in the Bay. Mortality of Atlantic and shortnose 

sturgeon will occur from entrainment in hopper and/or cutterhead dredges, exposure to blasting at 

Marcus Hook, and capture during mechanical dredging. As explained in the “Effects of the Action” 

section, effects of the deepening on habitat and benthic resources will be insignificant and 

discountable. We do not anticipate any take of shortnose or Atlantic sturgeon due to any of the 

other effects including vessel traffic and dredge disposal. 

In the discussion below, we consider whether the effects of the proposed action reasonably would 

be expected, directly or indirectly, to reduce appreciably the likelihood of both the survival and 

recovery of the listed species in the wild by reducing the reproduction, numbers, or distribution of 

the listed species that will be adversely affected by the action. The purpose of this analysis is to 

determine whether the proposed action, in the context established by the status of the species, 

environmental baseline, and cumulative effects, would jeopardize the continued existence of 

shortnose sturgeon. In the NMFS/USFWS Section 7 Handbook, for the purposes of determining 

jeopardy, survival is defined as, “the species’ persistence as listed or as a recovery unit, beyond the 

conditions leading to its endangerment, with sufficient resilience to allow for the potential recovery 

from endangerment. Said in another way, survival is the condition in which a species continues to 

exist into the future while retaining the potential for recovery. This condition is characterized by a 

species with a sufficient population, represented by all necessary age classes, genetic heterogeneity, 

and number of sexually mature individuals producing viable offspring, which exists in an 

environment providing all requirements for completion of the species’ entire life cycle, including 

reproduction, sustenance, and shelter.” Recovery is defined as, “Improvement in the status of listed 

species to the point at which listing is no longer appropriate under the criteria set out in Section 

4(a)(1) of the Act.” Below, for the listed species that may be affected by the proposed action, we 

summarize the status of the species and consider whether the proposed action will result in 

reductions in reproduction, numbers or distribution of these species and then considers whether any 

reductions in reproduction, numbers or distribution resulting from the proposed action would reduce 
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appreciably the likelihood of both the survival and recovery of these species, as those terms are 

defined for purposes of the federal Endangered Species Act. 

9.1 Shortnose sturgeon

Historically, shortnose sturgeon are believed to have inhabited nearly all major rivers and estuaries 

along nearly the entire east coast of North America. Today, only 19 populations remain. The 

present range of shortnose sturgeon is disjunct, with northern populations separated from southern 

populations by a distance of about 400 km. Population sizes range from under 100 adults in the 

Cape Fear and Merrimack Rivers to tens of thousands in the St. John and Hudson Rivers. As 

indicated in Kynard 1996, adult abundance is less than the minimum estimated viable population 

abundance of 1,000 adults for 5 of 11 surveyed northern populations and all natural southern 

populations. The only river systems likely supporting populations close to expected abundance are 

the St John, Hudson and possibly the Delaware and the Kennebec (Kynard 1996). The species as a 

whole is considered to be stable. 

The Delaware River population of shortnose sturgeon is the second largest in the United States. 

Historical estimates of the size of the population are not available as historic records of sturgeon in 

the river did not discriminate between Atlantic and shortnose sturgeon. The most recent population 

estimate for the Delaware River is 12, 047 (95% CI= 10,757-13,580) and is based on mark 

recapture data collected from January 1999 through March 2003 (ERC Inc. 2006). Comparisons 

between the population estimate by ERC Inc. and the earlier estimate by Hastings et al. (1987) of 

12,796 (95% CI=10,228-16,367) suggests that the population is stable, but not increasing. 

While no reliable estimate of the size of either the shortnose sturgeon population in the Northeastern 

US or of the species throughout its range exists, it is clearly below the size that could be supported 

if the threats to shortnose sturgeon were removed. Based on the number of adults in population for 

which estimates are available, there are at least 104,662 adult shortnose sturgeon, including 18,000 

in the Saint John River in Canada. The lack of information on the status of some populations, such 

as that in the Chesapeake Bay, add uncertainty to any determination on the status of this species as a 

whole. Based on the best available information, we consider the status of shortnose sturgeon 

throughout their range to be stable. 

As described in the Status of the Species, Environmental Baseline, and Cumulative Effects sections 

above, shortnose sturgeon in the Delaware River are affected by impingement at water intakes, 

habitat alteration, dredging, bycatch in commercial and recreational fisheries, water quality and inwater construction activities. It is difficult to quantify the number of shortnose sturgeon that may be 

killed in the Delaware River each year due to anthropogenic sources. Through reporting 

requirements implemented under Section 7 and Section 10 of the ESA, for specific actions we

obtain some information on the number of incidental and directed takes of shortnose sturgeon each 

year. Typically, scientific research results in the capture and collection of less than 100 shortnose 

sturgeon in the Delaware River each year, with little if any mortality. With the exception of the five 

shortnose sturgeon observed during dredging activities in the 1990s, we have no reports of 

interactions or mortalities of shortnose sturgeon in the Delaware River resulting from dredging or 

other in-water construction activities. NMFS also has no quantifiable information on the effects of 

habitat alteration or water quality; in general, water quality has improved in the Delaware River

since the 1970s when the CWA was implemented, with significant improvements below 
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Philadelphia which was previously considered unsuitable for shortnose sturgeon and is now well 

used. Shortnose sturgeon in the Delaware River have full, unimpeded access to their historic range 

in the river and appear to be fully utilizing all suitable habitat; this suggests that the movement and 

distribution of shortnose sturgeon in the river is not limited by habitat or water quality impairments. 

Impingement at the Salem nuclear power plant occurs occasionally, with typically less than one 

mortality per year. In high water years, there is some impingement and entrainment of larvae at 

facilities with intakes in the upper river; however, these instances are rare and involve only small 

numbers of larvae. Bycatch in the shad fishery, primarily hook and line recreational fishing, 

historically may have impacted shortnose sturgeon, particularly because it commonly occurred on 

the spawning grounds. However, little to no mortality was thought to occur and due to decreases in 

shad fishing, impacts are thought to be less now than they were in the past. Despite these ongoing 

threats, the Delaware River population of shortnose sturgeon is stable at high numbers. Over the 

life of the action, shortnose sturgeon in the Delaware River will continue to experience 

anthropogenic and natural sources of mortality. However, we are not aware of any future actions 

that are reasonably certain to occur that are likely to change this trend or reduce the stability of the 

Delaware River population. If the salt line shifts further upstream as is predicted in climate change 

modeling, the range of juvenile shortnose sturgeon is likely to be restricted. However, because 

there is no barrier to upstream movement it is not clear if this will impact the stability of the 

Delaware River population of shortnose sturgeon; we do not anticipate changes in distribution or 

abundance of shortnose sturgeon in the river due to climate change in the time period considered in 

this Opinion. As such, NMFS expects that numbers of shortnose sturgeon in the action area will 

continue to be stable at high levels over the life of the proposed action. 

We have estimated that the ongoing deepening will result in the mortality of five shortnose sturgeon 

during the initial construction period, inclusive of two shortnose sturgeon during blasting and 

subsequent debris removal with a mechanical dredge, and ten mortalities during the 10-year 

maintenance phase. We expect that there will be no more than one mortality per year, except during 

the winter when blasting occurs when we expect two mortalities, one due to exposure to blasting 

and one due to capture in the mechanical dredge bucket. We expect that the shortnose sturgeon 

killed could be juveniles or adults. All other effects to shortnose sturgeon, including effects to 

habitat and prey due to dredging and dredge disposal, will be insignificant and discountable. 

The number of shortnose sturgeon that are likely to die as a result of the ongoing deepening project 

and 10 years of maintenance (15), represents an extremely small percentage of the shortnose 

sturgeon population in the Delaware River, which is believed to be stable at high numbers, and an 

even smaller percentage of the total population of shortnose sturgeon rangewide, which is also 

stable. The best available population estimates indicate that there are approximately 12,047

shortnose sturgeon in the Delaware River (ERC 2006). While the death of up to 15 shortnose 

sturgeon between now and 2027 will reduce the number of shortnose sturgeon in the population 

compared to the number that would have been present absent the proposed action, it is not likely 

that this reduction in numbers will change the status of this population or its stable trend as this loss 

represents a very small percentage of the population (approximately 0.13%). The effect of this loss 

is also lessened as it will be experienced slowly over time, with the death of an average of one 

shortnose sturgeon per year. 
170

Reproductive potential of the Delaware population is not expected to be affected in any other way 

other than through a reduction in numbers of individuals. A reduction in the number of shortnose 

sturgeon in the Delaware River would have the effect of reducing the amount of potential 

reproduction in this system as the fish killed would have no potential for future reproduction. 

However, it is estimated that on average, approximately 1/3 of adult females spawn in a particular 

year and approximately 1⁄2 of males spawn in a particular year. Given that the best available 

estimates indicate that there are more than 12,000 shortnose sturgeon in the Delaware River, it is 

reasonable to expect that there are at least 5,000 adults spawning in a particular year. It is unlikely 

that the loss of 15 shortnose sturgeon over a 15-year period at a rate of approximately one per year 

would affect the success of spawning in any year. Additionally, this small reduction in potential 

spawners is expected to result in a small reduction in the number of eggs laid or larvae produced in 

future years and similarly, a very small effect on the strength of subsequent year classes. Even 

considering the potential future spawners that would be produced by the individuals that would be 

killed as a result of the proposed action, any effect to future year classes is anticipated to be very 

small and would not change the stable trend of this population. Additionally, the proposed action 

will not affect spawning habitat in any way and will not create any barrier to pre-spawning sturgeon 

accessing the overwintering sites or the spawning grounds. 

The proposed action is not likely to reduce distribution because the action will not impede shortnose 

sturgeon from accessing any seasonal concentration areas, including foraging, spawning or 

overwintering grounds in the Delaware River. Further, the action is not expected to reduce the river 

by river distribution of shortnose sturgeon. Additionally, as the number of shortnose sturgeon likely 

to be killed as a result of the proposed action is approximately 0.13% of the Delaware River 

population, there is not likely to be a loss of any unique genetic haplotypes and therefore, it is 

unlikely to result in the loss of genetic diversity. 

While generally speaking, the loss of a small number of individuals from a subpopulation or species 

can have an appreciable effect on the numbers, reproduction and distribution of the species, this is 

likely to occur only when there are very few individuals in a population, the individuals occur in a 

very limited geographic range or the species has extremely low levels of genetic diversity. This 

situation is not likely in the case of shortnose sturgeon because: the species is widely 

geographically distributed, it is not known to have low levels of genetic diversity (see status of the 

species/environmental baseline section above), and there are thousands of shortnose sturgeon 

spawning each year. 

Based on the information provided above, the death of up to 15 shortnose sturgeon over a 15-year 

period resulting from the ongoing deepening of the Delaware River and 10-years of maintenance, 

will not appreciably reduce the likelihood of survival of this species (i.e., it will not decrease the 

likelihood that the species will continue to persist into the future with sufficient resilience to allow 

for the potential recovery from endangerment). The action will not affect shortnose sturgeon in a 

way that prevents the species from having a sufficient population, represented by all necessary age 

classes, genetic heterogeneity, and number of sexually mature individuals producing viable 

offspring, and it will not result in effects to the environment which would prevent shortnose

sturgeon from completing their entire life cycle, including reproduction, sustenance, and shelter

(i.e., it will not increase the risk of extinction faced by this species). This is the case because: given 

that: (1) the population trend of shortnose sturgeon in the Delaware River is stable; (2) the death of
171

up to 15 shortnose sturgeon represents an extremely small percentage of the number of shortnose 

sturgeon in the Delaware River and an even smaller percentage of the species as a whole; (3) the 

loss of these shortnose sturgeon is likely to have such a small effect on reproductive output of the 

Delaware River population of shortnose sturgeon or the species as a whole that the loss of these 

shortnose sturgeon will not change the status or trends of the Delaware River population or the 

species as a whole; (4) the action will have only a minor and temporary effect on the distribution of 

shortnose sturgeon in the action area (related to movements around the working dredge) and no 

effect on the distribution of the species throughout its range; and, (5) the action will have no effect 

on the ability of shortnose sturgeon to shelter and only an insignificant effect on individual foraging 

shortnose sturgeon.

In certain instances, an action that does not appreciably reduce the likelihood of a species’ survival 

might affect its likelihood of recovery or the rate at which recovery is expected to occur. As 

explained above, NMFS has determined that the proposed action will not appreciably reduce the 

likelihood that shortnose sturgeon will survive in the wild. Here, NMFS considers the potential for 

the action to reduce the likelihood of recovery. As noted above, recovery is defined as the 

improvement in status such that listing is no longer appropriate. Section 4(a)(1) of the ESA requires 

listing of a species if it is in danger of extinction throughout all or a significant portion of its range 

(i.e., “endangered”), or likely to become in danger of extinction throughout all or a significant 

portion of its range in the foreseeable future (i.e., “threatened”) because of any of the following five 

listing factors: (1) the present or threatened destruction, modification, or curtailment of its habitat 

or range, (2) overutilization for commercial, recreational, scientific, or educational purposes, (3) 

disease or predation, (4) the inadequacy of existing regulatory mechanisms, (5) other natural or 

manmade factors affecting its continued existence. 

The proposed action is not expected to modify, curtail or destroy the range of the species since it 

will result in a small reduction in the number of shortnose sturgeon in the Delaware River and since 

it will not affect the overall distribution of shortnose sturgeon other than to cause minor temporary 

adjustments in movements in the action area. The proposed action will not utilize shortnose 

sturgeon for recreational, scientific or commercial purposes or affect the adequacy of existing 

regulatory mechanisms to protect this species. The proposed action is likely to result in the 

mortality of up to 15 shortnose sturgeon; however, over the 15-year period considered here, the loss 

of these individuals and what would have been their progeny is not expected to affect the 

persistence of the Delaware River population of shortnose sturgeon or the species as a whole. The 

loss of these individuals will not change the status or trend of the Delaware River population, which 

is stable at high numbers. As it will not affect the status or trend of this population, it will not affect 

the status or trend of the species as a whole. As the reduction in numbers and future reproduction is 

very small, this loss would not result in an appreciable reduction in the likelihood of improvement 

in the status of shortnose sturgeon throughout their range. The effects of the proposed action will 

not hasten the extinction timeline or otherwise increase the danger of extinction since the action will 

cause the mortality of only a small percentage of the shortnose sturgeon in the Delaware River and 

an even smaller percentage of the species as a whole and these mortalities are not expected to result 

in the reduction of overall reproductive fitness for the species as a whole. The effects of the 

proposed action will also not reduce the likelihood that the status of the species can improve to the 

point where it is recovered and could be delisted. Therefore, the proposed action will not 

appreciably reduce the likelihood that shortnose sturgeon can be brought to the point at which they 
172

are no longer listed as endangered or threatened. 

Despite the threats faced by individual shortnose sturgeon inside and outside of the action area, the 

proposed action will not increase the vulnerability of individual sturgeon to these additional threats 

and exposure to ongoing threats will not increase susceptibility to effects related to the proposed 

action. While we are not able to predict with precision how climate change will continue to impact 

shortnose sturgeon in the action area or how the species will adapt to climate-change related 

environmental impacts, we have considered the effects of the proposed action in light of other 

threats, including climate change, and have concluded that even in light of the ongoing impacts of 

these activities and conditions, the conclusions reached above do not change. 

Based on the analysis presented herein, the proposed action, resulting in the mortality of no more 

than 15 shortnose sturgeon over the 15-year period considered here is not likely to appreciably 

reduce the survival and recovery of this species. 

9.2 Atlantic sturgeon 

As explained above, the proposed action is likely to result in the mortality of a total of six Atlantic 

sturgeon from the Gulf of Maine, New York Bight, Chesapeake Bay and South Atlantic DPSs 

during the initial construction period, inclusive of the mortality of three Atlantic sturgeon during 

blasting and subsequent debris removal with a mechanical dredge, and an additional ten total during 

ten years of maintenance dredging. We expect that there will be no more than one mortality per 

year, except during the winter when blasting occurs when we expect three mortalities, two due to 

exposure to blasting and one due to capture in the mechanical dredge bucket. We expect that the 

Atlantic sturgeon killed will be YOY, juveniles or subadults. No mortality of any adults is 

anticipated. All other effects to Atlantic sturgeon, including effects to habitat and prey due to 

dredging and dredge disposal, will be insignificant and discountable. 

9.2.1 Determination of DPS Composition 

We have considered the best available information to determine from which DPSs individuals that 

will be killed are likely to have originated. Using mixed stock analysis explained above, we have 

determined that Atlantic sturgeon in the action area likely originate from the five DPSs at the 

following frequencies: NYB 58%; Chesapeake Bay 18%; South Atlantic 17%; Gulf of Maine 7%; 

and Carolina 0.5%. Given these percentages, we expect that nine of the Atlantic sturgeon will 

originate from the New York Bight DPS, three from the Chesapeake Bay DPS, three from the South 

Atlantic DPS and one from the Gulf of Maine DPS. Given the low numbers of Carolina DPS fish in 

the action area and the low number of mortalities anticipated, it is unlikely that there will be any 

mortality of any Carolina DPS Atlantic sturgeon. 

9.2.2 Gulf of Maine DPS 

Individuals originating from the GOM DPS are likely to occur in the action area. The GOM DPS 

has been listed as threatened. While Atlantic sturgeon occur in several rivers in the GOM DPS, 

recent spawning has only been documented in the Kennebec and Androscoggin rivers. No total 

population estimates are available. We have estimated, based on fishery-dependent data, that there 

are approximately 215 mature adults in the GOM DPS, at least 645 subadults and additional 

numbers of juveniles (which remain in their natal river and would not be present in the action area). 

We expect that 7% of the Atlantic sturgeon in the action area will originate from the GOM DPS. 
173

Most of these fish are expected to be subadults, with few adults from the GOM DPS expected to be 

present in the Delaware River. GOM origin Atlantic sturgeon are affected by numerous sources of 

human induced mortality and habitat disturbance throughout the riverine and marine portions of 

their range. While there are some indications that the status of the GOM DPS may be improving, 

there is currently not enough information to establish a trend for any life stage or for the DPS as a 

whole. 

We anticipate the mortality of 16 Atlantic sturgeon over the 15 year period considered here, with 

one likely to originate from the GOM DPS. Because we do not anticipate the mortality of any 

adults, we consider here the effects to the GOM DPS from the loss of one subadult (>500mm TL 

<1,500 mm TL) over the 15 year time period. 

The death of one subadult Atlantic sturgeon from the GOM DPS over a 15-year period represents a 

very small percentage of the subadult population (i.e., approximately 0.16% of the population, just 

considering the minimum estimated number of subadults). While the death of one subadult Atlantic 

sturgeon will reduce the number of GOM DPS Atlantic sturgeon compared to the number that 

would have been present absent the proposed action, it is not likely that this reduction in numbers 

will change the status of this species as this loss represents a very small percentage of the subadult 

population and an even smaller percentage of the overall population of the DPS (juveniles, 

subadults and adults combined). Even when converting this fish to an adult equivalent20 (using a 

conversion rate of 0.48), and assuming no growth in the adult population, this mortality represent a 

very small percentage of the adult population (approximately 0.23%). 

The reproductive potential of the GOM DPS will not be affected in any way other than through a 

reduction in numbers of individuals. The loss of one subadult would have the effect of reducing the 

amount of potential reproduction as any dead GOM DPS Atlantic sturgeon would have no potential 

for future reproduction. This small reduction in potential future spawners is expected to result in an 

extremely small reduction in the number of eggs laid or larvae produced in future years and 

similarly, an extremely small effect on the strength of subsequent year classes. Even considering 

the potential future spawners that would be produced by the individual that would be killed as a 

result of the proposed action, any effect to future year classes is anticipated to be extremely small 

and would not change the status of this species. Reproductive potential of other captured or injured 

individuals is not expected to be affected in any way. Additionally, we have determined that any 

impacts to behavior will be minor and temporary and that there will not be any delay or disruption 

of any normal behavior including spawning; there will also be no reduction in individual fitness or 

any future reduction in numbers of individuals. 

The proposed action will also not affect the spawning grounds within the rivers where GOM DPS 

fish spawn. The action will also not create any barrier to pre-spawning sturgeon accessing the 

overwintering sites or the spawning grounds used by GOM DPS fish. 

 

20 The “adult equivalent” rate converts a number of subadults to adult equivalents (the number of subadults that would, 

through natural mortality, live to be adults; for Atlantic sturgeon, this is calculated as 0.48).
174

The proposed action is not likely to reduce distribution because the action will not impede Atlantic 

sturgeon from accessing any seasonal concentration areas, including foraging areas within the 

Delaware River that may be used by GOM DPS subadults or adults. Further, the action is not 

expected to reduce the river by river distribution of Atlantic sturgeon. Any effects to distribution 

will be minor and temporary and limited to the temporary avoidance of the ensonified area. 

Based on the information provided above, the death of no more than one GOM DPS Atlantic 

sturgeon over the 15 year period when deepening and maintenance will occur, will not appreciably 

reduce the likelihood of survival of the GOM DPS (i.e., it will not decrease the likelihood that the 

species will continue to persist into the future with sufficient resilience to allow for the potential 

recovery from endangerment). The action will not affect GOM DPS Atlantic sturgeon in a way that 

prevents the species from having a sufficient population, represented by all necessary age classes, 

genetic heterogeneity, and number of sexually mature individuals producing viable offspring, and it 

will not result in effects to the environment which would prevent Atlantic sturgeon from completing 

their entire life cycle, including reproduction, sustenance, and shelter. This is the case because: (1) 

the death of one subadult GOM DPS Atlantic sturgeon over a 5-year period represents an extremely 

small percentage of the species as a whole; (2) the death of one subadult GOM DPS Atlantic 

sturgeon will not change the status or trends of the species as a whole; (3) the loss of this subadult 

GOM DPS Atlantic sturgeon is not likely to have an effect on the levels of genetic heterogeneity in 

the population; (4) the loss of this subadult GOM DPS Atlantic sturgeon is likely to have such a 

small effect on reproductive output that the loss of this individual will not change the status or 

trends of the species; (5) the action will have only a minor and temporary effect on the distribution 

of GOM DPS Atlantic sturgeon in the action area and no effect on the distribution of the species 

throughout its range; and, (6) the action will have no effect on the ability of GOM DPS Atlantic 

sturgeon to shelter and only an insignificant effect on individual foraging GOM DPS Atlantic 

sturgeon.

In certain instances an action that does not appreciably reduce the likelihood of a species survival 

(persistence) may affect its likelihood of recovery or the rate at which recovery is expected to occur. 

As explained above, we have determined that the proposed action will not appreciably reduce the 

likelihood that GOM DPS Atlantic sturgeon will survive in the wild. Here, we consider the 

potential for the action to reduce the likelihood of recovery. As noted above, recovery is defined as 

the improvement in status such that listing is no longer appropriate. Section 4(a)(1) of the ESA 

requires listing of a species if it is in danger of extinction throughout all or a significant portion of 

its range (i.e., “endangered”), or likely to become in danger of extinction throughout all or a 

significant portion of its range in the foreseeable future (i.e., “threatened”) because of any of the 

following five listing factors: (1) The present or threatened destruction, modification, or curtailment 

of its habitat or range, (2) overutilization for commercial, recreational, scientific, or educational 

purposes, (3) disease or predation, (4) the inadequacy of existing regulatory mechanisms, (5) other 

natural or manmade factors affecting its continued existence.

The proposed action is not expected to modify, curtail or destroy the range of the species since it 

will result in an extremely small reduction in the number of GOM DPS Atlantic sturgeon in any 

geographic area and thus, it will not affect the overall distribution of GOM DPS Atlantic sturgeon. 

The proposed action will not utilize GOM DPS Atlantic sturgeon for recreational, scientific or 

commercial purposes, affect the adequacy of existing regulatory mechanisms to protect this species 
175

or affect its continued existence. The proposed action is likely to result in the capture and injury of 

Atlantic sturgeon and the mortality of no more than one subadult GOM DPS Atlantic sturgeon; 

however, as explained above, the loss of this individual and what would have been their progeny is 

not expected to affect the persistence of the GOM DPS. As the reduction in numbers and future 

reproduction is very small, the loss of these individuals will not change the status of GOM DPS 

Atlantic sturgeon. The effects of the proposed action will not delay the recovery timeline or 

otherwise decrease the likelihood of recovery since the action will cause the mortality of only a very 

small percentage of the species as a whole and this mortality is not expected to result in the 

reduction of overall reproductive fitness for the species as a whole. The effects of the proposed 

action will also not reduce the likelihood that the status of the species can improve to the point 

where it is recovered and could be delisted. Therefore, the proposed action will not appreciably 

reduce the likelihood that the GOM DPS can be brought to the point at which they are no longer 

listed as threatened. 

Despite the threats faced by individual GOM DPS Atlantic sturgeon inside and outside of the action 

area, the proposed action will not increase the vulnerability of individual sturgeon to these 

additional threats and exposure to ongoing threats will not increase susceptibility to effects related 

to the proposed action. While we are not able to predict with precision how climate change will 

continue to impact Atlantic sturgeon in the action area or how the species will adapt to climatechange related environmental impacts, we have considered the effects of the proposed action in 

light of other threats, including climate change, and have concluded that even in light of the 

ongoing impacts of these activities and conditions, the conclusions reached above do not change. 

Based on the analysis presented herein, the proposed action, resulting in the mortality of one 

subadult GOM DPS Atlantic sturgeon, is not likely to appreciably reduce the survival and recovery 

of this species.

9.2.3 New York Bight DPS 

Individuals originating from the NYB DPS are likely to occur in the action area. The NYB DPS has 

been listed as endangered. While Atlantic sturgeon occur in several rivers in the NYB DPS, recent 

spawning has only been documented in the Delaware and Hudson rivers. Kahnle et al. (2007) 

estimated that there is a mean annual total mature adult population of 863 Hudson River Atlantic 

sturgeon. Using fishery-dependent data we have estimated that there are 88 Delaware River origin 

adults; combined, we estimate a total adult population of 951 in the New York Bight DPS. We 

have also estimated that there are at least a mean annual of 2,853 subadults and additional numbers 

of juveniles resulting from continuing annual spawning in the Delaware and Hudson rivers. We 

expect that 58% of the Atlantic sturgeon in the action area will originate from the NYB DPS. NYB 

DPS origin Atlantic sturgeon are affected by numerous sources of human induced mortality and 

habitat disturbance throughout the riverine and marine portions of their range. There is currently 

not enough information to establish a trend for any life stage, for the Hudson or Delaware River 

spawning populations or for the DPS as a whole. 

We have estimated that the proposed deepening and 10 years of maintenance will result in the 

mortality of 16 Atlantic sturgeon, with nine originating from the NYB DPS. No mortality of adults 

is anticipated; thus, there will be no loss of Delaware or Hudson River origin adults. We do not 

anticipate the mortality of any eggs or larvae. Here, we consider the effects of the mortality of nine 
176

YOY, juvenile, or subadult NYB DPS Atlantic sturgeon over the 15 year time period. Because 

YOY and juveniles remain in their natal river, any YOY or juveniles killed would be Delaware 

River origin. Any New York Bight DPS subadults could originate from the Delaware or Hudson 

river. We have limited information from which to determine the percentage of NYB DPS fish in 

the Delaware River that are likely to originate from the Delaware vs. the Hudson river. Given the 

sizes of the two populations, the worst case scenario is that all nine NYB fish that are killed are 

Delaware River fish; however, that appears to be unlikely. Of the 11 fish captured in the Delaware 

for which genetic assignments are available, six were from the New York Bight DPS, with four 

originating from the Delaware River and two from the Hudson River. This suggest that within the 

Delaware River, the compostion of New York Bight fish is approximately 2/3 Delaware and 1/3 

Hudson. Thus, of the nine NYB Atlantic sturgeon likely to be killed, six are likely to originate from 

the Delaware River and three from the Hudson River. 

There are an estimated 88 adult Atlantic sturgeon in the Delaware River population and at least 264

subadults and an unknown additional number of juveniles. Some Delaware River fish have a 

unique genetic haplotype (the A5 haplotype); however, whether there is any evolutionary 

significance or fitness benefit provided by this genetic makeup is unknown. Genetic evidence 

indicates that while spawning continued to occur in the Delaware River and in some cases Delaware 

River origin fish can be distinguished genetically from Hudson River origin fish, there is free 

interchange between the two rivers. This relationship is recognized by the listing of the New York 

Bight DPS as a whole and not separate listings of a theoretical Hudson River DPS and Delaware 

River DPS. Thus, while we can consider the loss of Delaware River fish on the Delaware River 

population and the loss of Hudson River fish on the Hudson River population, it is more 

appropriate, because of the interchange of individuals between these two populations, to consider 

the effects of these mortalities on the New York Bight DPS as a whole. 

The mortality of nine juvenile or subadult Atlantic sturgeon from the NYB DPS over a 15-year 

period represents a very small percentage of the YOY, juvenile and subadult population (i.e., 

approximately 0.3% of the population, just considering the minimum estimated number of 

subadults; the percentage would be much less if the number of YOY and juveniles was considered). 

While the death of nine juvenile or subadult Atlantic sturgeon will reduce the number of NYB DPS 

Atlantic sturgeon compared to the number that would have been present absent the proposed action, 

it is not likely that this reduction in numbers will change the status of this species as this loss 

represents a very small percentage of the juvenile and subadult population and an even smaller 

percentage of the overall population of the DPS (juveniles, subadults and adults combined). Even 

when converting these nine fish to adult equivalents21 (assuming the worst case that they were all

subadults; using a conversion rate of 0.48 considering the adult equivalent), and assuming no 

growth in the adult population, these nine mortalities represent an extremely small percentage of the 

adult population (approximately 0.45%). The effect of this loss is even smaller when considering 

that these mortalities will occur over a 15 year period, with no more than three occurring in any one 

year. When considered on an annual basis this loss of 1-3 Atlantic sturgeon per year, even 

assuming the worst case that all mortalities are subadults, the annual loss is equivalent to 0.04-0.1% 

 

21 The “adult equivalent” rate converts a number of subadults to adult equivalents (the number of subadults that would, 

through natural mortality, live to be adults; for Atlantic sturgeon, this is calculated as 0.48).
177

of the annual subadult population and, using the adult equivalent conversion, 0.05-0.15% of the 

mean annual adult population. 

Because there will be no loss of adults, the reproductive potential of the NYB DPS will not be 

affected in any way other than through a reduction in numbers of individual future spawners. The 

loss of nine YOY, juveniles or subadults would have the effect of reducing the amount of potential

reproduction as any dead NYB DPS Atlantic sturgeon would have no potential for future 

reproduction. This small reduction in potential future spawners is expected to result in an extremely 

small reduction in the number of eggs laid or larvae produced in future years and similarly, an 

extremely small effect on the strength of subsequent year classes. Even considering the potential 

future spawners that would be produced by the individual that would be killed as a result of the 

proposed action, any effect to future year classes is anticipated to be extremely small and would not 

change the status of this species. The proposed action will also not affect the spawning grounds 

within the Hudson River where most NYB DPS fish spawn. Additionally, we have considered 

effects of the proposed action on habitat used for spawning in the Delaware River and have 

determined that all effects will be insignificant and discountable. We have also determined that 

dredging will not result in any delay or disruption in any normal behavior including movements of 

adults from the ocean to the in-river spawning grounds. There will be no effects to spawning adults 

and therefore no reduction in individual fitness or any future reduction in spawning by these 

individuals. 

The proposed action is not likely to reduce distribution because the action will not impede Atlantic 

sturgeon from accessing any seasonal concentration areas, including foraging, spawning or 

overwintering grounds in the Delaware River. Further, the action is not expected to reduce the river 

by river distribution of Atlantic sturgeon. 

The proposed action is not likely to reduce distribution because the action will not impede NYB 

DPS Atlantic sturgeon from accessing any seasonal concentration areas, including foraging, 

spawning or overwintering grounds in the Delaware or Hudson River or elsewhere. Any effects to 

distribution will be minor and temporary and limited to the temporary avoidance of the area 

immediately surrounding an active dredge. 

Based on the information provided above, the death of up to nine NYB DPS Atlantic sturgeon over 

the 15 year period considered here, will not appreciably reduce the likelihood of survival of the 

New York Bight DPS (i.e., it will not decrease the likelihood that the species will continue to persist 

into the future with sufficient resilience to allow for the potential recovery from endangerment). 

The action will not affect NYB DPS Atlantic sturgeon in a way that prevents the species from 

having a sufficient population, represented by all necessary age classes, genetic heterogeneity, and 

number of sexually mature individuals producing viable offspring, and it will not result in effects to 

the environment which would prevent Atlantic sturgeon from completing their entire life cycle, 

including reproduction, sustenance, and shelter. This is the case because: (1) the death of nine 

YOY, juvenile or subadult NYB DPS Atlantic sturgeon over a 15-year period represents an 

extremely small percentage of the species as a whole; (2) the death of two juvenile or subadult 

NYB DPS Atlantic sturgeon will not change the status or trends of the species as a whole; (3) the 

loss of these juvenile or subadult NYB DPS Atlantic sturgeon is not likely to have an effect on the 

levels of genetic heterogeneity in the population; (4) the loss of these juvenile or subadult NYB 
178

DPS Atlantic sturgeon is likely to have such a small effect on reproductive output that the loss of 

these individuals will not change the status or trends of the species; (5) the action will have only a 

minor and temporary effect on the distribution of NYB DPS Atlantic sturgeon in the action area and 

no effect on the distribution of the species throughout its range; and, (6) the action will have no 

effect on the ability of NYB DPS Atlantic sturgeon to shelter and only an insignificant effect on 

individual foraging NYB DPS Atlantic sturgeon.

In certain instances an action that does not appreciably reduce the likelihood of a species survival 

(persistence) may affect its likelihood of recovery or the rate at which recovery is expected to occur. 

As explained above, NMFS has determined that the proposed action will not appreciably reduce the 

likelihood that NYB DPS Atlantic sturgeon will survive in the wild. Here, we consider the potential 

for the action to reduce the likelihood of recovery. As noted above, recovery is defined as the 

improvement in status such that listing is no longer appropriate. Section 4(a)(1) of the ESA requires 

listing of a species if it is in danger of extinction throughout all or a significant portion of its range 

(i.e., “endangered”), or likely to become in danger of extinction throughout all or a significant 

portion of its range in the foreseeable future (i.e., “threatened”) because of any of the following five 

listing factors: (1) The present or threatened destruction, modification, or curtailment of its habitat 

or range, (2) overutilization for commercial, recreational, scientific, or educational purposes, (3) 

disease or predation, (4) the inadequacy of existing regulatory mechanisms, (5) other natural or 

manmade factors affecting its continued existence.

The proposed action is not expected to modify, curtail or destroy the range of the species since it 

will result in an extremely small reduction in the number of NYB DPS Atlantic sturgeon in any 

geographic area and thus, it will not affect the overall distribution of NYB DPS Atlantic sturgeon. 

The proposed action will not utilize NYB DPS Atlantic sturgeon for recreational, scientific or 

commercial purposes, affect the adequacy of existing regulatory mechanisms to protect this species 

or affect its continued existence. The proposed action is likely to result in the mortality of nine 

YOY, juvenile or subadult NYB DPS Atlantic sturgeon; however, as explained above, the loss of 

these individuals and what would have been their progeny is not expected to affect the persistence 

of the NYB DPS. As the reduction in numbers and future reproduction is very small, the loss of 

these individuals will not change the status of NYB DPS Atlantic sturgeon. The effects of the 

proposed action will not delay the recovery timeline or otherwise decrease the likelihood of 

recovery since the action will cause the mortality of only a very small percentage of the species as a 

whole and these mortalities are not expected to result in the reduction of overall reproductive fitness 

for the species as a whole. The effects of the proposed action will also not reduce the likelihood 

that the status of the species can improve to the point where it is recovered and could be delisted. 

Therefore, the proposed action will not appreciably reduce the likelihood that NYB DPS can be 

brought to the point at which they are no longer listed as endangered or threatened. 

Despite the threats faced by individual NYB DPS Atlantic sturgeon inside and outside of the action 

area, the proposed action will not increase the vulnerability of individual sturgeon to these 

additional threats and exposure to ongoing threats will not increase susceptibility to effects related 

to the proposed action. While we are not able to predict with precision how climate change will 

continue to impact Atlantic sturgeon in the action area or how the species will adapt to climatechange related environmental impacts, we have considered the effects of the proposed action in 
179

light of other threats, including climate change, and have concluded that even in light of the 

ongoing impacts of these activities and conditions, the conclusions reached above do not change. 

Based on the analysis presented herein, the proposed action, resulting in the mortality of up to nine 

YOY, juvenile or subadult NYB DPS Atlantic sturgeon over a 15 year period, is not likely to 

appreciably reduce the survival and recovery of this species.

9.2.4 Chesapeake Bay DPS 

Individuals originating from the CB DPS are likely to occur in the action area. The CB DPS has 

been listed as endangered. While Atlantic sturgeon occur in several rivers in the CB DPS, recent 

spawning has only been documented in the James River. Using fishery-dependent data, we have 

estimated that there are 273 adults in the James River population, 819 subadults and additional 

juveniles (which remain in the James River). Because the James River is the only river in this DPS 

known to support spawning, this is also an estimate of the total number of adults and subadults in 

the Chesapeake Bay DPS. We expect that 17% of the Atlantic sturgeon in the action area will 

originate from the CB DPS. Most of these fish are expected to be subadults, with few adults from 

the CB DPS expected to be present in the Delaware River. Chesapeake Bay DPS origin Atlantic 

sturgeon are affected by numerous sources of human induced mortality and habitat disturbance 

throughout the riverine and marine portions of their range. There is currently not enough 

information to establish a trend for any life stage, for the James River spawning population or for 

the DPS as a whole. 

 

We anticipate the mortality of 16 Atlantic sturgeon over the 15 year period considered here, with 

three likely to originate from the CB DPS. Because we do not anticipate the mortality of any adults, 

we consider here the effects to the CB DPS from the loss of three subadults (>500mm TL <1,500 

mm TL) over the 15 year time period. 

The death of three subadult Atlantic sturgeon from the CB DPS over a 15-year period represents a 

very small percentage of the subadult population (i.e., approximately 0.4% of the population, just 

considering the minimum estimated number of subadults). While the death of three subadult

Atlantic sturgeon will reduce the number of CB DPS Atlantic sturgeon compared to the number that 

would have been present absent the proposed action, it is not likely that this reduction in numbers 

will change the status of this species as this loss represents a very small percentage of the subadult 

population and an even smaller percentage of the overall population of the DPS (juveniles, 

subadults and adults combined). Even when converting this fish to an adult equivalent22 (using a 

conversion rate of 0.48), and assuming no growth in the adult population, this mortality represent a 

very small percentage of the adult population (approximately 0.5%). On an annual basis, there will 

be one mortality of a Chesapeake Bay DPS fish in each of three years. When this loss is considered 

this way, the annual loss is equivalent to 0.1% of the annual subadult population and, using the 

adult equivalent conversion, 0.18% of the mean annual adult population. 

The reproductive potential of the CB DPS will not be affected in any way other than through a 

 

22 The “adult equivalent” rate converts a number of subadults to adult equivalents (the number of subadults that would, 

through natural mortality, live to be adults; for Atlantic sturgeon, this is calculated as 0.48).
180

reduction in numbers of individuals. The loss of three subadults would have the effect of reducing 

the amount of potential reproduction as any dead CB DPS Atlantic sturgeon would have no 

potential for future reproduction. This small reduction in potential future spawners is expected to 

result in an extremely small reduction in the number of eggs laid or larvae produced in future years 

and similarly, an extremely small effect on the strength of subsequent year classes. Even 

considering the potential future spawners that would be produced by the individual that would be 

killed as a result of the proposed action, any effect to future year classes is anticipated to be 

extremely small and would not change the status of this species. Reproductive potential of other 

captured or injured individuals is not expected to be affected in any way. Additionally, we have 

determined that any impacts to behavior will be minor and temporary and that there will not be any 

delay or disruption of any normal behavior including spawning; there will also be no reduction in 

individual fitness or any future reduction in numbers of individuals. 

The proposed action will also not affect the spawning grounds within the rivers where CB DPS fish 

spawn. The action will also not create any barrier to pre-spawning sturgeon accessing the 

overwintering sites or the spawning grounds used by CB DPS fish. 

The proposed action is not likely to reduce distribution because the action will not impede Atlantic 

sturgeon from accessing any seasonal concentration areas, including foraging areas within the 

Delaware River that may be used by CB DPS subadults or adults. Further, the action is not 

expected to reduce the river by river distribution of Atlantic sturgeon. Any effects to distribution 

will be minor and temporary and limited to the temporary avoidance of the immediate area where 

dredging is occuring. 

Based on the information provided above, the death of no more than three CB DPS Atlantic 

sturgeon over a 15-year period resulting from the proposed deepening and ten years maintenance 

will not appreciably reduce the likelihood of survival of the CB DPS (i.e., it will not decrease the 

likelihood that the species will continue to persist into the future with sufficient resilience to allow 

for the potential recovery from endangerment). The action will not affect CB DPS Atlantic 

sturgeon in a way that prevents the species from having a sufficient population, represented by all 

necessary age classes, genetic heterogeneity, and number of sexually mature individuals producing 

viable offspring, and it will not result in effects to the environment which would prevent Atlantic 

sturgeon from completing their entire life cycle, including reproduction, sustenance, and shelter. 

This is the case because: (1) the death of three subadult CB DPS Atlantic sturgeon over a 15-year 

period represents an extremely small percentage of the species as a whole; (2) the death of three

subadult CB DPS Atlantic sturgeon will not change the status or trends of the species as a whole; 

(3) the loss of these subadult CB DPS Atlantic sturgeon is not likely to have an effect on the levels 

of genetic heterogeneity in the population; (4) the loss of these subadult CB DPS Atlantic sturgeon 

is likely to have such a small effect on reproductive output that the loss of this individual will not 

change the status or trends of the species; (5) the action will have only a minor and temporary effect 

on the distribution of CB DPS Atlantic sturgeon in the action area and no effect on the distribution 

of the species throughout its range; and, (6) the action will have no effect on the ability of CB DPS 

Atlantic sturgeon to shelter and only an insignificant effect on individual foraging CB DPS Atlantic 

sturgeon.

In certain instances an action that does not appreciably reduce the likelihood of a species survival 
181

(persistence) may affect its likelihood of recovery or the rate at which recovery is expected to occur. 

As explained above, we have determined that the proposed action will not appreciably reduce the 

likelihood that CB DPS Atlantic sturgeon will survive in the wild. Here, we consider the potential 

for the action to reduce the likelihood of recovery. As noted above, recovery is defined as the 

improvement in status such that listing is no longer appropriate. Section 4(a)(1) of the ESA requires 

listing of a species if it is in danger of extinction throughout all or a significant portion of its range 

(i.e., “endangered”), or likely to become in danger of extinction throughout all or a significant 

portion of its range in the foreseeable future (i.e., “threatened”) because of any of the following five 

listing factors: (1) The present or threatened destruction, modification, or curtailment of its habitat 

or range, (2) overutilization for commercial, recreational, scientific, or educational purposes, (3) 

disease or predation, (4) the inadequacy of existing regulatory mechanisms, (5) other natural or 

manmade factors affecting its continued existence.

The proposed action is not expected to modify, curtail or destroy the range of the species since it 

will result in an extremely small reduction in the number of CB DPS Atlantic sturgeon in any 

geographic area and thus, it will not affect the overall distribution of CB DPS Atlantic sturgeon. 

The proposed action will not utilize CB DPS Atlantic sturgeon for recreational, scientific or 

commercial purposes, affect the adequacy of existing regulatory mechanisms to protect this species 

or affect its continued existence. The proposed action is likely to result in the capture and injury of 

Atlantic sturgeon and the mortality of no more than three subadult CB DPS Atlantic sturgeon; 

however, as explained above, the loss of these individuals and what would have been their progeny 

is not expected to affect the persistence of the CB DPS. As the reduction in numbers and future 

reproduction is very small, the loss of these individuals will not change the status of CB DPS 

Atlantic sturgeon. The effects of the proposed action will not delay the recovery timeline or 

otherwise decrease the likelihood of recovery since the action will cause the mortality of only a very 

small percentage of the species as a whole and this mortality is not expected to result in the 

reduction of overall reproductive fitness for the species as a whole. The effects of the proposed 

action will also not reduce the likelihood that the status of the species can improve to the point 

where it is recovered and could be delisted. Therefore, the proposed action will not appreciably 

reduce the likelihood that the CB DPS can be brought to the point at which they are no longer listed 

as threatened. 

Despite the threats faced by individual CB DPS Atlantic sturgeon inside and outside of the action 

area, the proposed action will not increase the vulnerability of individual sturgeon to these 

additional threats and exposure to ongoing threats will not increase susceptibility to effects related 

to the proposed action. While we are not able to predict with precision how climate change will 

continue to impact Atlantic sturgeon in the action area or how the species will adapt to climatechange related environmental impacts, we have considered the effects of the proposed action in 

light of other threats, including climate change, and have concluded that even in light of the 

ongoing impacts of these activities and conditions, the conclusions reached above do not change. 

Based on the analysis presented herein, the proposed action, resulting in the mortality of three

subadult CB DPS Atlantic sturgeon, is not likely to appreciably reduce the survival and recovery of 

this species.
182

9.2.5 South Atlantic DPS 

Individuals originating from the SA DPS are likely to occur in the action area. The SA DPS has 

been listed as endangered. The SA DPS consists of Atlantic sturgeon origingating from at least six 

rivers where spawning is still thought to occur. Currently, there are an estimated 343 spawning 

adults in the Altamaha and there are estimated to be less than 300 spawning adults (total of both 

sexes) in each of the other five river systems where spawning occurs. Adding these estimates 

together results in a total mean annual adult population estimated of less than 1,843 mature adults. 

Our fishery dependent estimate is 324. This is likely an underestimate of the total number of adults 

in the SA DPS because genetic analysis of individuals observed through the NEFOP program 

indicate that only individuals from the Savannah and Ogeechee are being captured in Northeast 

fisheries considered in the NEFSC bycatch report from which these estimates were derived. 

Because of this, it is difficult to compare these two estimates. It may be reasonable to consider the 

estimate of 324 adults to be an estimate of the number of adults in the Savannah and Ogeechee 

rivers only; this results in a population estimate for adults in the three major rivers of 667. Using 

these estimates of adults, there are an estimated 2,001-5,529 subadults. 

We expect that 17% of the Atlantic sturgeon in the action area will originate from the SA DPS. 

Most of these fish are expected to be subadults, with few adults from the SA DPS expected to be 

present in the Delaware River. South Atlantic DPS origin Atlantic sturgeon are affected by 

numerous sources of human induced mortality and habitat disturbance throughout the riverine and 

marine portions of their range. There is currently not enough information to establish a trend for 

any life stage, for any of the spawning populations or for the DPS as a whole. 

 

We anticipate the mortality of 16 Atlantic sturgeon over the 15 year period considered here, with 

three likely to originate from the SA DPS. Because we do not anticipate the mortality of any adults, 

we consider here the effects to the SA DPS from the loss of three subadults (>500mm TL <1,500 

mm TL) over the 15 year time period. 

The death of three subadult Atlantic sturgeon from the SA DPS over a 15-year period represents a 

very small percentage of the subadult population (i.e., approximately 0.26% of the population, just 

considering the minimum estimated number of subadults). While the death of three subadult

Atlantic sturgeon will reduce the number of SA DPS Atlantic sturgeon compared to the number that 

would have been present absent the proposed action, it is not likely that this reduction in numbers 

will change the status of this species as this loss represents a very small percentage of the subadult 

population (0.05-0.26%) and an even smaller percentage of the overall population of the DPS 

(juveniles, subadults and adults combined). Even when converting this fish to an adult equivalent23

(using a conversion rate of 0.48), and assuming no growth in the adult population, this mortality 

represent a very small percentage of the adult population (approximately 0.08-0.2%). On an annual 

basis, there will be one mortality of a South Atlantic DPS fish in each of three years. When this 

loss is considered this way, the annual loss is equivalent to 0.02-0.05% of the annual subadult 

population and, using the adult equivalent conversion, 0.03-0.08% of the mean annual adult 

 

23 The “adult equivalent” rate converts a number of subadults to adult equivalents (the number of subadults that would, 

through natural mortality, live to be adults; for Atlantic sturgeon, this is calculated as 0.48).
183

population. 

The reproductive potential of the SA DPS will not be affected in any way other than through a 

reduction in numbers of individuals. The loss of three subadults would have the effect of reducing 

the amount of potential reproduction as any dead SA DPS Atlantic sturgeon would have no 

potential for future reproduction. This small reduction in potential future spawners is expected to 

result in an extremely small reduction in the number of eggs laid or larvae produced in future years 

and similarly, an extremely small effect on the strength of subsequent year classes. Even 

considering the potential future spawners that would be produced by the individual that would be 

killed as a result of the proposed action, any effect to future year classes is anticipated to be 

extremely small and would not change the status of this species. Additionally, we have determined 

that any impacts to behavior will be minor and temporary and that there will not be any delay or 

disruption of any normal behavior; there will also be no reduction in individual fitness or any future 

reduction in numbers of individuals. 

The proposed action will also not affect the spawning grounds within the rivers where SA DPS fish 

spawn. The action will also not create any barrier to pre-spawning sturgeon accessing the 

overwintering sites or the spawning grounds used by SA DPS fish. 

The proposed action is not likely to reduce distribution because the action will not impede Atlantic 

sturgeon from accessing any seasonal concentration areas, including foraging areas within the 

Delaware River that may be used by SA DPS subadults or adults. Further, the action is not 

expected to reduce the river by river distribution of Atlantic sturgeon. Any effects to distribution 

will be minor and temporary and limited to the temporary avoidance of the immediate area where 

dredging is occuring. 

Based on the information provided above, the death of no more than three SA DPS Atlantic 

sturgeon over a 15-year period resulting from the proposed deepening and ten years maintenance 

will not appreciably reduce the likelihood of survival of the SA DPS (i.e., it will not decrease the 

likelihood that the species will continue to persist into the future with sufficient resilience to allow 

for the potential recovery from endangerment). The action will not affect SA DPS Atlantic 

sturgeon in a way that prevents the species from having a sufficient population, represented by all 

necessary age classes, genetic heterogeneity, and number of sexually mature individuals producing 

viable offspring, and it will not result in effects to the environment which would prevent Atlantic 

sturgeon from completing their entire life cycle, including reproduction, sustenance, and shelter. 

This is the case because: (1) the death of three subadult SA DPS Atlantic sturgeon over a 15-year 

period represents an extremely small percentage of the species as a whole; (2) the death of three

subadult SA DPS Atlantic sturgeon will not change the status or trends of the species as a whole; 

(3) the loss of these subadult SA DPS Atlantic sturgeon is not likely to have an effect on the levels 

of genetic heterogeneity in the population; (4) the loss of these subadult SA DPS Atlantic sturgeon 

is likely to have such a small effect on reproductive output that the loss of this individual will not 

change the status or trends of the species; (5) the action will have only a minor and temporary effect 

on the distribution of SA DPS Atlantic sturgeon in the action area and no effect on the distribution 

of the species throughout its range; and, (6) the action will have no effect on the ability of SA DPS 

Atlantic sturgeon to shelter and only an insignificant effect on individual foraging SA DPS Atlantic 

sturgeon.
184

In certain instances an action that does not appreciably reduce the likelihood of a species survival 

(persistence) may affect its likelihood of recovery or the rate at which recovery is expected to occur. 

As explained above, we have determined that the proposed action will not appreciably reduce the 

likelihood that SA DPS Atlantic sturgeon will survive in the wild. Here, we consider the potential 

for the action to reduce the likelihood of recovery. As noted above, recovery is defined as the 

improvement in status such that listing is no longer appropriate. Section 4(a)(1) of the ESA requires 

listing of a species if it is in danger of extinction throughout all or a significant portion of its range 

(i.e., “endangered”), or likely to become in danger of extinction throughout all or a significant 

portion of its range in the foreseeable future (i.e., “threatened”) because of any of the following five 

listing factors: (1) The present or threatened destruction, modification, or curtailment of its habitat 

or range, (2) overutilization for commercial, recreational, scientific, or educational purposes, (3) 

disease or predation, (4) the inadequacy of existing regulatory mechanisms, (5) other natural or 

manmade factors affecting its continued existence.

The proposed action is not expected to modify, curtail or destroy the range of the species since it 

will result in an extremely small reduction in the number of SA DPS Atlantic sturgeon in any 

geographic area and thus, it will not affect the overall distribution of SA DPS Atlantic sturgeon. The 

proposed action will not utilize SA DPS Atlantic sturgeon for recreational, scientific or commercial 

purposes, affect the adequacy of existing regulatory mechanisms to protect this species or affect its 

continued existence. The proposed action is likely to result in the mortality of no more than three

subadult SA DPS Atlantic sturgeon; however, as explained above, the loss of these individuals and 

what would have been their progeny is not expected to affect the persistence of the SA DPS. As the 

reduction in numbers and future reproduction is very small, the loss of these individuals will not 

change the status of SA DPS Atlantic sturgeon. The effects of the proposed action will not delay the 

recovery timeline or otherwise decrease the likelihood of recovery since the action will cause the 

mortality of only a very small percentage of the species as a whole and this mortality is not 

expected to result in the reduction of overall reproductive fitness for the species as a whole. The 

effects of the proposed action will also not reduce the likelihood that the status of the species can 

improve to the point where it is recovered and could be delisted. Therefore, the proposed action will 

not appreciably reduce the likelihood that the SA DPS can be brought to the point at which they are 

no longer listed as threatened. 

Despite the threats faced by individual SA DPS Atlantic sturgeon inside and outside of the action 

area, the proposed action will not increase the vulnerability of individual sturgeon to these 

additional threats and exposure to ongoing threats will not increase susceptibility to effects related 

to the proposed action. While we are not able to predict with precision how climate change will 

continue to impact Atlantic sturgeon in the action area or how the species will adapt to climatechange related environmental impacts, we have considered the effects of the proposed action in 

light of other threats, including climate change, and have concluded that even in light of the 

ongoing impacts of these activities and conditions, the conclusions reached above do not change. 

Based on the analysis presented herein, the proposed action, resulting in the mortality of three

subadult SA DPS Atlantic sturgeon over a 15 year period, is not likely to appreciably reduce the 

survival and recovery of this species.
185

9.2.6 Carolina DPS 

As explained in section 4.7, no Carolina DPS fish have been documented in the action area. This is 

based on genetic sampling of fish in the Delaware River (n=11 individuals) and sampling in 

Delaware coastal waters (n=105). However, Carolina DPS fish have been documented in Long 

Island Sound (0.5% of samples). Because Carolina fish would swim past Delaware Bay on their 

way to Long Island Sound, we considered the possibility that up to 0.5% of the Atlantic sturgeon in 

the action area would originate from the Carolina DPS. However, given the low level of take 

anticipated (16 over a 15 year period) and the expected rarity of Carolina fish in the action area, it is 

extremely unlikely that any of the 16 fish that will be killed during the deepening of 10 years of 

subsequent maintenance will originate from the Carolina DPS. All other effects to Atlantic 

sturgeon, including habitat and prey, will be insignificant and discountable. Therefore, the action 

considered in this Opinion is not likely to adversely affect the Carolina DPS of Atlantic sturgeon. 

9.3 Green sea turtles 

As noted in sections above, the physical disturbance of sediments and entrainment of associated 

benthic resources could reduce the availability of sea turtle prey in the affected areas, but these 

reductions will be localized and temporary, and foraging turtles are not likely to be limited by the 

reductions and any effects will be insignificant. Also, as explained above, no green sea turtles are 

likely to be entrained in any dredge operating to deepen or maintain the channel and this species is

not likely to be involved in any collision with a project vessel. As all effects to green sea turtles 

from the proposed project are likely to be insignificant or discountable, this action is not likely to 

adversely affect this species. 

9.4 Leatherback sea turtles

As noted in sections above, the physical disturbance of sediments and entrainment of associated 

benthic resources could reduce the availability of sea turtle prey in the affected areas, but these 

reductions will be localized and temporary, and foraging turtles are not likely to be limited by the 

reductions and any effects will be insignificant. Also, as explained above, no leatherback sea turtles 

are likely to be entrained in any dredge operating to deepen or maintain the channel and this species 

is not likely to be involved in any collision with a project vessel. As all effects to leatherback sea 

turtles from the proposed project are likely to be insignificant or discountable, this action is not 

likely to adversely affect this species. 

9.5 Kemp’s ridley sea turtles

In the “Effects of the Action” section above, we determined that Kemp’s ridleys could be entrained 

in a hopper dredge working to deepen Reach D or E or by a hopper dredge conducting maintenance 

dredging activities in either of these reaches. Based on a calculated entrainment rate of sea turtles 

for projects using hopper dredges in the action area, we estimate that 1 sea turtle is likely to be 

entrained for every 450,000 cy of material removed with a hopper dredge. Also, based on the ratio 

of loggerhead and Kemp’s ridleys entrained in other hopper dredge operations in the ACOE North 

Atlantic Division, we estimate that no more than 10% of the sea turtles entrained during project 

operations were likely to be Kemp’s ridleys with the remainder loggerheads. Based on this, we 

determined that of the 11 sea turtles likely to be entrained during the initial deepening, no more than 

1 is likely to be a Kemp’s ridley, with the remainder loggerheads. Similarly, of the 11 sea turtles 

likely to be entrained during 10 years of maintenance dredging in the Bay, no more than 1 is likely 

to be a Kemp’s ridley, with the remainder loggerheads. As such, the proposed action is likely to 
186

result in the entrainment and mortality of no more than 2 Kemp’s ridleys and the remainder 

loggerheads. No entrainment of Kemp’s ridley sea turtles is anticipated if a cutterhead dredge is 

used for deepening in Reach D. 

Kemp’s Ridley sea turtles are listed as a single species classified as “endangered” under the ESA. 

Kemp’s ridleys occur in the Atlantic Ocean and Gulf of Mexico. The only major nesting site for 

Kemp’s ridleys is a single stretch of beach near Rancho Nuevo, Tamaulipas, Mexico (Carr 1963; 

USFWS and NMFS 1992; NMFS and USFWS 2007c). 

Nest count data provides the best available information on the number of adult females nesting each 

year. As is the case with the other sea turtle species discussed above, nest count data must be 

interpreted with caution given that these estimates provide a minimum count of the number of 

nesting Kemp’s ridley sea turtles. In addition, the estimates do not account for adult males or 

juveniles of either sex. Without information on the proportion of adult males to females, and the 

age structure of the Kemp’s ridley population, nest counts cannot be used to estimate the total 

population size (Meylan 1982; Ross 1996; Zurita et al. 2003; Hawkes et al. 2005; letter to J. Lecky, 

NMFS Office of Protected Resources, from N. Thompson, NMFS Northeast Fisheries Science 

Center, December 4, 2007). Nevertheless, the nesting data does provide valuable information on 

the extent of Kemp’s ridley nesting and the trend in the number of nests laid. Estimates of the adult 

female nesting population reached a low of approximately 250-300 in 1985 (USFWS and NMFS 

1992; TEWG 2000). From 1985 to 1999, the number of nests observed at Rancho Nuevo and 

nearby beaches increased at a mean rate of 11.3% per year (TEWG 2000). Current estimates 

suggest an adult female population of 7,000-8,000 Kemp’s ridleys (NMFS and USFWS 2007c). 

The most recent review of the Kemp’s ridleys suggests that this species is in the early stages of 

recovery (NMFS and USFWS 2007b). Nest count data indicate increased nesting and increased 

numbers of nesting females in the population. NMFS also takes into account a number of recent 

conservation actions including the protection of females, nests, and hatchlings on nesting beaches 

since the 1960s and the enhancement of survival in marine habitats through the implementation of 

TEDs in the early 1990s and a decrease in the amount of shrimping off the coast of Tamaulipas and 

in the Gulf of Mexico in general (NMFS and USFWS 2007b). We expect this increasing trend to 

continue over the time period considered in this Opinion. 

The mortality of 2 Kemp’s ridleys over a 15 year time period represents a very small percentage of 

the Kemp’s ridleys worldwide. Even taking into account just nesting females, the death of 2

Kemp’s ridley represents less than 0.03% of the population. While the death of 2 Kemp’s ridley 

will reduce the number of Kemp’s ridleys compared to the number that would have been present 

absent the proposed action, it is not likely that this reduction in numbers will change the status of 

this species or its stable to increasing trend as this loss represents a very small percentage of the 

population (less than 0.03%). Reproductive potential of Kemp’s ridleys is not expected to be 

affected in any other way other than through a reduction in numbers of individuals. A reduction in 

the number of Kemp’s ridleys would have the effect of reducing the amount of potential 

reproduction as any dead Kemp’s ridleys would have no potential for future reproduction. In 2006, 

the most recent year for which data is available, there were an estimated 7-8,000 nesting females. 

While the species is thought to be female biased, there are likely to be several thousand adult males 
187

as well. Given the number of nesting adults, it is unlikely that the loss of 2 Kemp’s ridleys would 

affect the success of nesting in any year. Additionally, this small reduction in potential nesters is 

expected to result in a small reduction in the number of eggs laid or hatchlings produced in future 

years and similarly, a very small effect on the strength of subsequent year classes. Even 

considering the potential future nesters that would be produced by the individuals that would be 

killed as a result of the proposed action, any effect to future year classes is anticipated to be very 

small and would not change the stable to increasing trend of this species. Additionally, the 

proposed action will not affect nesting beaches in any way or disrupt migratory movements in a 

way that hinders access to nesting beaches or otherwise delays nesting. 

The proposed action is not likely to reduce distribution because the action will not impede Kemp’s 

ridleys from accessing foraging grounds or cause more than a temporary disruption to other 

migratory behaviors. Additionally, given the small percentage of the species that will be killed as a 

result of the deepening and maintenance, there is not likely to be any loss of unique genetic 

haplotypes and no loss of genetic diversity. 

While generally speaking, the loss of a small number of individuals from a subpopulation or species 

may have an appreciable reduction on the numbers, reproduction and distribution of the species this 

is likely to occur only when there are very few individuals in a population, the individuals occur in a 

very limited geographic range or the species has extremely low levels of genetic diversity. This 

situation is not likely in the case of Kemp’s ridleys because: the species is widely geographically 

distributed, it is not known to have low levels of genetic diversity, there are several thousand 

individuals in the population and the number of Kemp’s ridleys is likely to be increasing and at 

worst is stable. 

Based on the information provided above, the death of two Kemp’s ridley sea turtles between now 

and 2027 will not appreciably reduce the likelihood of survival (i.e., it will not decrease the 

likelihood that the species will continue to persist into the future with sufficient resilience to allow 

for the potential recovery from endangerment). The action will not affect Kemp’s ridleys in a way 

that prevents the species from having a sufficient population, represented by all necessary age 

classes, genetic heterogeneity, and number of sexually mature individuals producing viable 

offspring and it will not result in effects to the environment which would prevent Kemp’s ridleys 

from completing their entire life cycle, including reproduction, sustenance, and shelter. This is the 

case because: (1) the species’ nesting trend is increasing; (2) the death of 2 Kemp’s ridleys

represents an extremely small percentage of the species as a whole; (3) the death of 2 Kemp’s 

ridleys will not change the status or trends of the species as a whole; (4) the loss of these Kemp’s 

ridleys is not likely to have an effect on the levels of genetic heterogeneity in the population; (5) the 

loss of these Kemp’s ridleys is likely to have such a small effect on reproductive output that the loss 

of these individuals will not change the status or trends of the species; (5) the action will have only 

a minor and temporary effect on the distribution of Kemp’s ridleys in the action area and no effect 

on the distribution of the species throughout its range; and, (6) the action will have no effect on the 

ability of Kemp’s ridleys to shelter and only an insignificant effect on individual foraging Kemp’s 

ridleys. 

In certain instances an action that does not appreciably reduce the likelihood of a species survival 

(persistence) may affect its likelihood of recovery or the rate at which recovery is expected to occur. 
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As explained above, NMFS has determined that the proposed action will not appreciably reduce the 

likelihood that Kemp’s ridleys will survive in the wild. Here, we consider the potential for the 

action to reduce the likelihood of recovery. As noted above, recovery is defined as the 

improvement in status such that listing is no longer appropriate. Section 4(a)(1) of the ESA requires 

listing of a species if it is in danger of extinction throughout all or a significant portion of its range 

(i.e., “endangered”), or likely to become in danger of extinction throughout all or a significant 

portion of its range in the foreseeable future (i.e., “threatened”) because of any of the following five 

listing factors: (1) The present or threatened destruction, modification, or curtailment of its habitat 

or range, (2) overutilization for commercial, recreational, scientific, or educational purposes, (3) 

disease or predation, (4) the inadequacy of existing regulatory mechanisms, (5) other natural or 

manmade factors affecting its continued existence. 

The proposed action is not expected to modify, curtail or destroy the range of the species since it 

will result in an extremely small reduction in the number of Kemp’s ridley sea turtles in any

geographic area and since it will not affect the overall distribution of Kemp’s ridley sea turtles other 

than to cause temporary delays in migratory movements. The proposed action will not utilize 

Kemp’s ridley sea turtles for recreational, scientific or commercial purposes, affect the adequacy of 

existing regulatory mechanisms to protect this species or affect its continued existence. The 

proposed action is likely to result in the mortality of up to two Kemp’s ridleys; however, as 

explained above, the loss of these individuals and what would have been their progeny is not 

expected to affect the persistence of Kemp’s ridleys. As the reduction in numbers and future 

reproduction is very small, the loss of these individuals will not change the status or trend of 

Kemp’s ridleys, which is stable to increasing. The effects of the proposed action will not hasten the 

extinction timeline or otherwise increase the danger of extinction since the action will cause the 

mortality of only a very small percentage of the species as a whole and these mortalities are not 

expected to result in the reduction of overall reproductive fitness for the species as a whole. The 

effects of the proposed action will also not reduce the likelihood that the status of the species can 

improve to the point where it is recovered and could be delisted. Therefore, the proposed action 

will not appreciably reduce the likelihood that Kemp’s ridleys can be brought to the point at which 

they are no longer listed as endangered or threatened. 

Despite the threats faced by individual Kemp’s ridley sea turtles inside and outside of the action 

area, the proposed action will not increase the vulnerability of individual sea turtles to these 

additional threats and exposure to ongoing threats will not increase susceptibility to effects related 

to the proposed action. While NMFS is not able to predict with precision how climate change will 

continue to impact Kemp’s ridley sea turtles in the action area or how the species will adapt to 

climate-change related environmental impacts, we have considered the effects of the proposed 

action in light of other threats, including climate change, and have concluded that even in light of 

the ongoing impacts of these activities and conditions, the conclusions reached above do not 

change. 

Based on the analysis presented herein, the proposed action, resulting in the mortality of no more 

than 2 Kemp’s ridleys is not likely to appreciably reduce the survival and recovery of this species. 

9.6 Northwest Atlantic DPS of Loggerhead sea turtles 

In the “Effects of the Action” section above, we determined that loggerheads could be entrained in a 
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hopper dredge working to deepen Reach D or E or in a hopper dredge conducting maintenance 

dredging activities in either of these reaches. Based on a calculated entrainment rate of sea turtles 

for projects using hopper dredges in the action area, we estimate that 1 sea turtle is likely to be 

entrained for every 450,000 cy of material removed with a hopper dredge. Also, based on the ratio

of loggerhead and Kemp’s ridleys entrained in other hopper dredge operations in the ACOE North 

Atlantic Division, we estimate that 90% of the sea turtles entrained during project operations were 

likely to be loggerheads. Based on this, we determined that of the 11 sea turtles likely to be 

entrained during the initial deepening, 10 are likely to be loggerheads. Similarly, of the 11 sea 

turtles likely to be entrained during 10 years of maintenance dredging in the Bay, 10 are likely to be 

loggerheads. All entrained loggerheads are expected to be juveniles. We determined that all other 

effects of the action on this species will be insignificant and discountable. 

The Northwest Atlantic DPS of loggerhead sea turtles is listed as “threatened” under the ESA. 

It takes decades for loggerhead sea turtles to reach maturity. Once they have reached maturity, 

females typically lay multiple clutches of eggs within a season, but do not typically lay eggs every 

season (NMFS and USFWS 2008). There are many natural and anthropogenic factors affecting the 

survival of loggerheads prior to their reaching maturity as well as for those adults who have reached 

maturity. As described in the Status of the Species, Environmental Baseline and Cumulative 

Effects sections above, loggerhead sea turtles in the action area continue to be affected by multiple 

anthropogenic impacts including bycatch in commercial and recreational fisheries, habitat 

alteration, dredging, power plant intakes and other factors that result in mortality of individuals at 

all life stages. Negative impacts causing death of various age classes occur both on land and in the 

water. Many actions have been taken to address known negative impacts to loggerhead sea turtles. 

However, many remain unaddressed, have not been sufficiently addressed, or have been addressed 

in some manner but whose success cannot be quantified. 

The SEFSC (2009) estimated the number of adult females in the NWA DPS at 30,000, and if a 1:1 

adult sex ratio is assumed, the result is 60,000 adults in this DPS. Based on the reviews of nesting 

data, as well as information on population abundance and trends, NMFS and USFWS determined in 

the September 2011 listing rule that the NWA DPS should be listed as threatened. They found that 

an endangered status for the NWA DPS was not warranted given the large size of the nesting 

population, the overall nesting population remains widespread, the trend for the nesting population 

appears to be stabilizing, and substantial conservation efforts are underway to address threats. This 

stable trend is expected to continue over the time period considered in this Opinion. 

As stated above, we expect the lethal entrainment of 20 loggerheads over the 15 year time period 

considered here; with an average mortality rate of 1-2 loggerheads per year. The lethal removal of 

up to 20 loggerhead sea turtles from the action area over this time period would be expected to 

reduce the number of loggerhead sea turtles from the recovery unit of which they originated as 

compared to the number of loggerheads that would have been present in the absence of the 

proposed actions (assuming all other variables remained the same). However, this does not 

necessarily mean that these recovery units will experience reductions in reproduction, numbers or 

distribution in response to these effects to the extent that survival and recovery would be 

appreciably reduced. The final revised recovery plan for loggerheads compiled the most recent 

information on mean number of loggerhead nests and the approximated counts of nesting females 

per year for four of the five identified recovery units (i.e., nesting groups). They are: (1) for the 
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NRU, a mean of 5,215 loggerhead nests per year with approximately 1,272 females nesting per 

year; (2) for the PFRU, a mean of 64,513 nests per year with approximately 15,735 females nesting 

per year; (3) for the DTRU, a mean of 246 nests per year with approximately 60 females nesting per 

year; and (4) for the NGMRU, a mean of 906 nests per year with approximately 221 females 

nesting per year. For the GCRU, the only estimate available for the number of loggerhead nests per 

year is from Quintana Roo, Yucatán, Mexico, where a range of 903-2,331 nests per year was 

estimated from 1987-2001 (NMFS and USFWS 2007a). There are no annual nest estimates 

available for the Yucatán since 2001 or for any other regions in the GCRU, nor are there any 

estimates of the number of nesting females per year for any nesting assemblage in this recovery 

unit. 

It is likely that the loggerhead sea turtles in Delaware Bay originate from several of the recovery 

units. Limited information is available on the genetic makeup of sea turtles in the mid-Atlantic, 

where the majority of sea turtle interactions are expected to occur. Cohorts from each of the five 

western Atlantic subpopulations are expected to occur in the action area. Genetic analysis of 

samples collected from immature loggerhead sea turtles captured in pound nets in the PamlicoAlbemarle Estuarine Complex in North Carolina from September-December of 1995-1997 

indicated that cohorts from all five western Atlantic subpopulations were present (Bass et al. 2004). 

In a separate study, genetic analysis of samples collected from loggerhead sea turtles from 

Massachusetts to Florida found that all five western Atlantic loggerhead subpopulations were 

represented (Bowen et al. 2004). Bass et al. (2004) found that 80 percent of the juveniles and subadults utilizing the foraging habitat originated from the south Florida nesting population, 12 percent 

from the northern subpopulation, 6 percent from the Yucatan subpopulation, and 2 percent from 

other rookeries. The previously defined loggerhead subpopulations do not share the exact 

delineations of the recovery units identified in the 2008 recovery plan. However, the PFRU 

encompasses both the south Florida and Florida panhandle subpopulations, the NRU is roughly 

equivalent to the northern nesting group, the Dry Tortugas subpopulation is equivalent to the 

DTRU, and the Yucatan subpopulation is included in the GCRU. 

Based on the genetic analysis presented in Bass et al. (2004) and the small number of loggerheads 

from the DTRU or the NGMRU likely to occur in the action area it is extremely unlikely that the 

loggerheads likely to be killed during the deepening project will originate from either of these 

recovery units. The majority, at least 80% of the loggerheads killed, are likely to have originated 

from the PFRU, with the remainder from the NRU and GCRU. As such, of the 20 loggerheads 

likely to be killed, 16 are expected to be from the PFRU, with 3 from the NRU and 1 from the 

GCRU. Below, we consider the effects of these mortalities on these three recovery units and the 

species as a whole. 

As noted above, the most recent population estimates indicate that there are approximately 15,735 

females nesting annually in the PFRU and approximately 1,272 females nesting per year in the 

NRU. For the GCRU, the only estimate available for the number of loggerhead nests per year is 

from Quintana Roo, Yucatán, Mexico, where a range of 903-2,331 nests per year was estimated 

from 1987-2001 (NMFS and USFWS 2007a). There are no annual nest estimates available for the 

Yucatán since 2001 or for any other regions in the GCRU, nor are there any estimates of the number 

of nesting females per year for any nesting assemblage in this recovery unit; however, the 2008 

recovery plan indicates that the Yucatan nesting aggregation has at least 1,000 nesting females 
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annually. As the numbers outlined here are only for nesting females, the total number of 

loggerhead sea turtles in each recovery unit is likely significantly higher. 

The loss of 16 loggerheads over a 15-year period represents an extremely small percentage of the 

number of sea turtles in the PFRU. Even if the total population was limited to 15,735 loggerheads, 

the loss of 1 individual would represent approximately 0.1% of the population. Similarly, the loss 

of 3 loggerheads from the NRU represents an extremely small percentage of the recovery unit. 

Even if the total population was limited to 1,272 sea turtles, the loss of 1 individual would represent 

approximately 0.3% of the population. The loss of 1 loggerhead from the GCRU, which is expected 

to support at least 1,000 nesting females, represents less than 0.1% of the population. The loss of 

such a small percentage of the individuals from any of these recovery units represents an even 

smaller percentage of the species as a whole. The impact of these losses is even less when 

considering that these losses will occur over a span of 15 years. Considering the extremely small 

percentage of the populations that will be killed, it is unlikely that these deaths will have a 

detectable effect on the numbers and population trends of loggerheads in these recovery units or the 

number of loggerheads in the population as a whole. 

All of the loggerheads that are expected to be killed will be juveniles. Thus, any effects on 

reproduction are limited to the loss of these individuals on their year class and the loss of future 

reproductive potential. Given the number of nesting adults in each of these populations, it is 

unlikely that the expected loss of loggerheads would affect the success of nesting in any year. 

Additionally, this small reduction in potential nesters is expected to result in a small reduction in the 

number of eggs laid or hatchlings produced in future years and similarly, a very small effect on the 

strength of subsequent year classes. Even considering the potential future nesters that would be 

produced by the individuals that would be killed as a result of the proposed action, any effect to 

future year classes is anticipated to be very small and would not change the stable trend of this 

species. Additionally, the proposed action will not affect nesting beaches in any way or disrupt 

migratory movements in a way that hinders access to nesting beaches or otherwise delays nesting. 

The proposed action is not likely to reduce distribution because the action will not impede 

loggerheads from accessing foraging grounds or cause more than a temporary disruption to other 

migratory behaviors. Additionally, given the small percentage of the species that will be killed as a 

result of the deepening and maintenance, there is not likely to be any loss of unique genetic

haplotypes and no loss of genetic diversity. 

While generally speaking, the loss of a small number of individuals from a subpopulation or species 

may have an appreciable reduction on the numbers, reproduction and distribution of the species this 

is likely to occur only when there are very few individuals in a population, the individuals occur in a 

very limited geographic range or the species has extremely low levels of genetic diversity. This 

situation is not likely in the case of loggerheads because: the species is widely geographically 

distributed, it is not known to have low levels of genetic diversity, there are several thousand 

individuals in the population and the number of loggerheads is likely to be stable or increasing over 

the time period considered here. 

Based on the information provided above, the death of up to 20 loggerheads between now and 2027

will not appreciably reduce the likelihood of survival (i.e., it will not decrease the likelihood that the 
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species will continue to persist into the future with sufficient resilience to allow for the potential 

recovery from endangerment). The action will not affect loggerheads in a way that prevents the 

species from having a sufficient population, represented by all necessary age classes, genetic

heterogeneity, and number of sexually mature individuals producing viable offspring and it will not 

result in effects to the environment which would prevent loggerheads from completing their entire 

life cycle, including reproduction, sustenance, and shelter. This is the case because: (1) the 

species’ nesting trend is stabilizing; (2) the death of 20 loggerheads represents an extremely small 

percentage of the species as a whole; (3) the death of 20 loggerheads will not change the status or 

trends of the species as a whole; (4) the loss of these loggerheads is not likely to have an effect on 

the levels of genetic heterogeneity in the population; (5) the loss of these loggerheads is likely to 

have such a small effect on reproductive output that the loss of these individuals will not change the 

status or trends of the species; (5) the action will have only a minor and temporary effect on the 

distribution of loggerheads in the action area and no effect on the distribution of the species 

throughout its range; and, (6) the action will have no effect on the ability of loggerheads to shelter 

and only an insignificant effect on individual foraging loggerheads. 

In certain instances an action may not appreciably reduce the likelihood of a species survival 

(persistence) but may affect its likelihood of recovery or the rate at which recovery is expected to 

occur. As explained above, NMFS has determined that the proposed action will not appreciably 

reduce the likelihood that loggerheads will survive in the wild. Here, we consider the potential for 

the action to reduce the likelihood of recovery. As noted above, recovery is defined as the 

improvement in status such that listing is no longer appropriate. 

Section 4(a)(1) of the ESA requires listing of a species if it is in danger of extinction throughout all 

or a significant portion of its range (i.e., “endangered”), or likely to become in danger of extinction 

throughout all or a significant portion of its range in the foreseeable future (i.e., “threatened”) 

because of any of the following five listing factors: (1) The present or threatened destruction, 

modification, or curtailment of its habitat or range, (2) overutilization for commercial, recreational, 

scientific, or educational purposes, (3) disease or predation, (4) the inadequacy of existing 

regulatory mechanisms, (5) other natural or manmade factors affecting its continued existence. 

The proposed action will not appreciably reduce the likelihood of survival of the loggerhead sea 

turtle species. Also, it is not expected to modify, curtail or destroy the range of the species since it 

will result in an extremely small reduction in the number of loggerheads in any geographic area and 

since it will not affect the overall distribution of loggerheads other than to cause minor temporary 

adjustments in movements in the action area. The proposed action will not utilize loggerheads for 

recreational, scientific or commercial purposes, affect the adequacy of existing regulatory 

mechanisms to protect loggerhead sea turtles, or affect their continued existence. As explained 

above, the proposed action is likely to result in the mortality of up to 20 loggerheads between now 

and 2027; however, as explained above, the loss of these individuals over this time period is not 

expected to affect the persistence of loggerhead sea turtles. In summary, the effects of the proposed 

action will not hasten the extinction timeline or otherwise increase the danger of extinction; further, 

the action will not prevent the species from growing in a way that leads to recovery and the action 

will not change the rate at which recovery can occur. This is the case because while the action may 

result in a small reduction in the number of loggerheads and a small reduction in the amount of 

potential reproduction due to the loss of these individuals, these effects will be undetectable over 
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the long-term and the action is not expected to have long term impacts on the future growth of the 

population or its potential for recovery. Therefore, based on the analysis presented above, the 

proposed action will not appreciably reduce the likelihood that loggerhead sea turtles can be 

brought to the point at which they are no longer listed as endangered or threatened. 

Despite the threats faced by individual loggerhead sea turtles inside and outside of the action area, 

the proposed action will not increase the vulnerability of individual sea turtles to these additional 

threats and exposure to ongoing threats will not increase susceptibility to effects related to the 

proposed action. While NMFS is not able to predict with precision how climate change will 

continue to impact loggerhead sea turtles in the action area or how the species will adapt to climatechange related environmental impacts, we have considered the effects of the proposed action in 

light of other threats, including climate change, and have concluded that even in light of the 

ongoing impacts of these activities and conditions, the conclusions reached above do not change. 

Based on the analysis presented herein, the proposed action is not likely to appreciably reduce the 

survival and recovery of the NWA DPS of loggerhead sea turtles. 

10.0 CONCLUSION

After reviewing the best available information on the status of endangered and threatened species 

under NMFS jurisdiction, the environmental baseline for the action area, the effects of the action, 

and the cumulative effects, it is NMFS’ biological opinion that the proposed action may adversely 

affect but is not likely to jeopardize the continued existence of the shortnose sturgeon, any DPS of 

Atlantic sturgeon, Kemp’s ridley and loggerhead sea turtles and is not likely to adversely affect 

green or leatherback sea turtles. Because no critical habitat is designated in the action area, none 

will be affected by the proposed action.

11.0 INCIDENTAL TAKE STATEMENT

Section 9 of the ESA prohibits the take of endangered species of fish and wildlife. “Fish and 

wildlife” is defined in the ESA “as any member of the animal kingdom, including without limitation 

any mammal, fish, bird (including any migratory, non-migratory, or endangered bird for which 

protection is also afforded by treaty or other international agreement), amphibian, reptile, mollusk, 

crustacean, arthropod or other invertebrate, and includes any part, product, egg, or offspring thereof, 

or the dead body or parts thereof.” 16 U.S.C. 1532(8). “Take” is defined as to harass, harm, pursue, 

hunt, shoot, wound, kill, trap, capture or collect, or to attempt to engage in any such conduct. Harm 

is further defined by NMFS to include any act which actually kills or injures fish or wildlife. Such 

an act may include significant habitat modification or degradation that actually kills or injures fish 

or wildlife by significantly impairing essential behavioral patterns including breeding, spawning, 

rearing, migrating, feeding, or sheltering. Incidental take is defined as take that is incidental to, and 

not the purpose of, the carrying out of an otherwise lawful activity. “Otherwise lawful activities” 

are those actions that meet all State and Federal legal requirements except for the prohibition 

against taking in ESA Section 9 (51 FR 19936, June 3, 1986), which would include any state 

endangered species laws or regulations. Section 9(g) makes it unlawful for any person “to attempt 

to commit, solicit another to commit, or cause to be committed, any offense defined [in the ESA.]” 

16 U.S.C. 1538(g). See also 16 U.S.C. 1532(13)(definition of “person”). Under the terms of 

section 7(b)(4) and section 7(o)(2), taking that is incidental to and not intended as part of the agency 
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action is not considered to be prohibited under the ESA provided that such taking is in compliance 

with the terms and conditions of this Incidental Take Statement. 

The measures described below are non-discretionary, and must be undertaken by ACOE so that they 

become binding conditions for the exemption in section 7(o)(2) to apply. ACOE has a continuing 

duty to regulate the activity covered by this Incidental Take Statement. If ACOE (1) fails to assume 

and implement the terms and conditions or (2) fails to require any contractors to adhere to the terms 

and conditions of the Incidental Take Statement through enforceable terms that are added contracts 

or other documents as appropriate, the protective coverage of section 7(o)(2) may lapse. In order to 

monitor the impact of incidental take, ACOE must report the progress of the action and its impact 

on the species to us as specified in the Incidental Take Statement [50 CFR §402.14(i)(3)] (See U.S. 

Fish and Wildlife Service and National Marine Fisheries Service’s Joint Endangered Species Act 

Section 7 Consultation Handbook (1998) at 4-49). 

11.1 Amount or Extent of Incidental Take 

The proposed dredging project has the potential to directly affect loggerhead and Kemp’s ridlely sea 

turtles, shortnose sturgeon, and individuals from the New York Bight, Gulf of Maine, Chesapeake 

Bay and South Atlantic DPSs of Atlantic sturgeon to become entrained in the dredge. These 

interactions are likely to cause mortality. Shortnose sturgeon and individuals from the New York 

Bight, Gulf of Maine, Chesapeake Bay and South Atlantic DPSs of Atlantic sturgeon may be 

exposed to noise and pressure during blasting and may be captured in the dredge bucket during 

debris removal after blasting. Entrainment of sea turtles is only likely to occur in hopper dredges 

working in Reach D and Reach E. Entrainment of shortnose and Atlantic sturgeon is likely to occur 

in hopper and cutterhead dredges operating in Reaches AA, A, B and C. Take may occur during the 

initial construction period as well as during the 10 years of planned maintenance dredging. This 

level of take is expected to occur over the entire 15 year period and is not likely to jeopardize the 

continued existence of listed species. 

This ITS exempts the following lethal take: 

 20 Northwest Atlantic DPS loggerhead sea turtles;

 2 Kemp’s ridley sea turtles;

 15 shortnose sturgeon;

 9 New York Bight DPS Atlantic sturgeon; 

 3 Chesapeake Bay DPS Atlantic sturgeon;

 3 South Atlantic DPS Atlantic sturgeon; and, 

 1 Gulf of Maine DPS Atlantic sturgeon. 

The level of take of loggerhead sea turtles would be less if a cutterhead dredge was used to deepen 

Reach D. In that case, the total level of lethal take would be 18 instead of 20. During the 

maintenance dredging period, we anticipate a total entrainment level of 11 loggerheads and one

Kemp’s ridley; the other turtles are expected to be entrained during the initial construction period. 

We expect that five of the shortnose sturgeon will be killed during the initial construction period, 

inclusive of two killed during blasting and associated mechanical dredging, and that the remaining 

ten shortnose sturgeon will be killed during the 10-year maintenance period at an average rate of 

one shortnose sturgeon per year. Shortnose sturgeon that will be killed will be subadults or adults. 

We expect that six of the Atlantic sturgeon will be killed during the initial construction period, 
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inclusive of three killed during blasting and associated mechanical dredging, and that the remaining 

ten Atlantic sturgeon will be killed during the 10-year maintenance period at an average rate of one 

Atlantic sturgeon per year. The nine New York Bight DPS Atlantic sturgeon killed will consist of 

YOY, juveniles and subadults. The three Chesapeake Bay, three South Atlantic, and one Gulf of 

Maine DPS Atlantic sturgeon will be subadults. No take of any adult Atlantic sturgeon is 

anticipated. 

11.2 Reasonable and prudent measures 

NMFS believes the following reasonable and prudent measures are necessary and appropriate to 

minimize and monitor impacts of incidental take resulting from the proposed action: 

RPMs related to Cutterhead and Hopper Dredging Activities 

1. NMFS must be contacted prior to the commencement of dredging and again upon 

completion of the dredging activity. This applies to all contracts executed in the initial 

construction of the 45-foot channel and all subsequent maintenance dredging activities. 

2. For cutterhead dredging, an inspector, with sufficient training to identify sturgeon, must be 

present at the disposal site to conduct daily inspections for biological materials, including 

shortnose sturgeon or sturgeon parts. The inspection schedule and procedures must be 

sufficient to ensure a high likelihood of documenting entrained sturgeon and must involve 

inspections of ponded areas and inspections at the area where water is discharged from the 

disposal site. This requirement applies to the initial construction of the 45-foot channel and 

all subsequent maintenance dredging activities using a cutterhead dredge, regardless of time 

of year or reach being dredged. 

3. The ACOE shall ensure that for dredging occurring in Reaches D and E) from May 1 –

November 15, hopper dredges are outfitted with state-of-the-art sea turtle deflectors on the 

draghead and operated in a manner that will reduce the risk of interactions with sea turtles.

4. For hopper dredge operations in the reaches AA, A, B, or C, a NMFS-approved observer 

must be present on board the hopper dredge any time it is operating.

5. For hopper dredge operations in Reaches D and E, a NMFS-approved observer must be 

present on board the hopper dredge from May 1 – November 15.

6. The ACOE shall ensure that dredges are equipped and operated in a manner that provides 

endangered/threatened species observers with a reasonable opportunity for detecting 

interactions with listed species and that provides for handling, collection, and resuscitation 

of turtles injured during project activity. Full cooperation with the endangered/threatened 

species observer program is essential for compliance with the ITS.

7. The ACOE shall ensure that all measures are taken to protect any turtles or sturgeon that 

survive entrainment in a hopper dredge.

RPMs related to Blasting and Associated Mechanical Dredging 

8. NMFS must be contacted prior to the commencement of blasting and again upon completion 
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of the blasting and subsequent mechanical dredging activity. 

9. The ACOE must utilize a procedure designed in association with NMFS to minimize the 

potential for detonations to occur when shortnose or Atlantic sturgeon are within 500 feet of 

the blast location. 

10. The ACOE must monitor the blasting site for the presence of acoustically tagged sturgeon 

and monitor their movements during the blasting period. 

11. Blasting must be conducted in a manner designed to minimize the potential for fish kills. 

12. Acoustic measurement of the first three detonations must be conducted to confirm the 

underwater pressure levels estimated by ACOE. 

13. The ACOE must design and implement a monitoring plan to ensure that any sturgeon killed 

during blasting are recorded. 

14. An endangered species observer must be present to observe all mechanical dredging 

activities where debris will be deposited to monitor for any capture of sturgeon. 

15. The ACOE must ensure that all measures are taken to protect any sturgeon that survive 

capture in the mechanical dredge.

RPMs for all aspects of the project: 

16. The ACOE must conduct sediment sampling following the completion of dredging to 

confirm that substrate type is unchanged following the deepening in Reach AA, A, B, D and 

E. In the unlikely event that it is found that substrate type has changed as a result of the 

deepening, ACOE must work with us to develop an appropriate restoration method to 

restore substrate types in these reaches. 

17. The ACOE must develop a program to monitor the movement of acoustically tagged 

Atlantic and shortnose sturgeon during the dredging operations. 

18. All Atlantic sturgeon captured must have a fin clip taken for genetic analysis. This sample 

must be transferred to NMFS. 

19. All shortnose and Atlantic sturgeon that are captured during the project must be scanned for 

the presence of Passive Integrated Transponder (PIT) tags. Tag numbers must be recorded 

and reported to NMFS. 

20. Any dead sturgeon must be transferred to NMFS or an appropriately permitted research 

facility NMFS will identify so that a necropsy can be undertaken to attempt to determine the 

cause of death. Sturgeon must be held in cold storage. 

21. Any dead sea turtles must be held until proper disposal procedures can be discussed with 

NMFS. Turtles must be held in cold storage. 
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22. All sturgeon and turtle captures, injuries or mortalities associated with the deepening and 

maintenance activities and any sturgeon and sea turtle sightings in the action area must be 

reported to NMFS within 24 hours.

11.3 Terms and conditions 

In order to be exempt from prohibitions of section 9 of the ESA, the ACOE must comply with 

the following terms and conditions, which implement the reasonable and prudent measures 

described above and outline required reporting/monitoring requirements. These terms and 

conditions are non-discretionary.

1. To implement RPM #1, the ACOE must contact NMFS (Julie Crocker: by email 

(julie.crocker@noaa.gov) or phone (978) 282-8480 or (978)-281-9328)) within 3 days of the 

commencement of each dredging cycle (initial construction and maintenance) and again 

within 3 days of the completion of dredging activity. This correspondence will serve both to 

alert NMFS of the commencement and cessation of dredging activities and to give NMFS an 

opportunity to provide ACOE with any updated contact information or reporting forms. 

2. To implement RPM #2, for cutterhead dredging, the ACOE must require inspections at the 

disposal area at least four times a day in order to document any sturgeon entrained in the 

dredge, including shortnose and Atlantic sturgeon or their parts. The ACOE must provide 

training in sturgeon identification to inspectors working at the dredge disposal site. Species 

identification must be verified by an expert. 

3. To implement RPM #2, the ACOE shall ensure that the disposal site is equipped and 

operated in a manner that provides the inspector with a reasonable opportunity for detecting 

interactions with listed species and that provides for handling and collection of listed species 

during project activity. 

4. To implement RPM #3, hopper dredges operating in Reaches D or E from May 1 –

November 15, must be equipped with the rigid deflector draghead as designed by the ACOE 

Engineering Research and Development Center, formerly the Waterways Experimental 

Station (WES), or if that is unavailable, a rigid sea turtle deflector attached to the draghead. 

Deflectors must be checked and/or adjusted by a designated expert prior to a dredge 

operation to insure proper installment and operation during dredging. The deflector must be 

checked after every load throughout the dredge operation to ensure that proper installation is 

maintained. Since operator skill is important to the effectiveness of the WES-developed 

draghead, operators must be properly instructed in its use. Dredge inspectors must ensure 

that all measures to protect sea turtles are being followed during dredge operations.

5. To implement RPM #4, observer coverage on hopper dredges operating in the river (reaches 

AA – C) must be sufficient for 100% monitoring of hopper dredging operations. This 

monitoring coverage must involve the placement of a NMFS-approved observer on board 

the dredge for every day that dredging is occurring. The observer must work a shift 

schedule appropriate to allow for the observation of at least 50% of the dredge loads (e.g., 

12 hours on, 12 hours off). The ACOE must ensure that ACOE dredge operators and/or any 

dredge contractor adhere to the attached “Monitoring Specifications for Hopper Dredges” 
198

with trained NMFS-approved observers, in accordance with the attached “Observer 

Protocol” and “Observer Criteria” (Appendix A). No observers can be deployed to the 

dredge site until ACOE has written confirmation from NMFS that they have met the 

qualifications to be a “NMFS-approved observer” as outlined in Appendix A. If substitute 

observers are required during dredging operations, ACOE must ensure that NMFS approval 

is obtain before those observers are deployed on dredges. 

6. To implement RPM #5, observer coverage is required on all hopper dredges operating in the 

Bay (reaches D and E) during the period of May 1 - November 15. This monitoring 

coverage must involve the placement of a NMFS-approved observer on board the dredge for 

every day that dredging is occurring. The observer must work a shift schedule appropriate 

to allow for the observation of at least 50% of the dredge loads (e.g., 12 hours on, 12 hours 

off). ACOE must ensure that ACOE dredge operators and/or any dredge contractor adhere 

to the attached “Monitoring Specifications for Hopper Dredges” with trained NMFSapproved observers, in accordance with the attached “Observer Protocol” and “Observer 

Criteria” (Appendix A). No observers can be deployed to the dredge site until ACOE has 

written confirmation from NMFS that they have met the qualifications to be a “NMFSapproved observer” as outlined in Appendix A. If substitute observers are required during 

dredging operations, ACOE must ensure that NMFS approval is obtain before those 

observers are deployed on dredges. 

7. To implement RPM #5, the ACOE shall require of the dredge operator that, when the 

observer is off watch, the cage shall not be opened unless it is clogged. The ACOE shall 

also require that if it is necessary to clean the cage when the observer is off watch, any 

aquatic biological material is left in the cage for the observer to document and clear out 

when they return on duty. In addition, the observer shall be the only one allowed to clean 

off the overflow screen. 

8. To implement RPM #6, if sea turtles are present during dredging or material transport, 

vessels transiting the area must post a bridge watch, avoid intentional approaches closer than 

100 yards when in transit, and reduce speeds to below 4 knots if bridge watch identifies a 

listed species in the immediate vicinity of the dredge.

9. To implement RPM #6, the ACOE must ensure that all contracted personnel involved in 

operating hopper dredges receive thorough training on measures of dredge operation that 

will minimize takes of sea turtles. Training shall include measures discussed in Appendix 

A. 

10. To implement RPM #7, the procedures for handling live sea turtles must be followed in the 

unlikely event that a sea turtle survives entrainment in the dredge (Appendix B). 

11. To implement RPM #8, each winter that blasting is undertaken, the ACOE must inform 

NMFS of the commencement of blasting operations 3 days prior to the actual start date and 

of the completion date within 3 days after the actual end of operations.
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12. To implement RPM #9, at least 45 days prior to the commencement of blasting, the ACOE 

must submit to NMFS a plan outlining the measures the ACOE will take to ensure that no 

shortnose or Atlantic sturgeon are present within 500 feet of the detonation site. This plan 

may involve the use of an underwater imaging system (sonar fish finder, DIDSON, video 

etc.) to document the presence of fish in the area surrounding the blast site or could involve 

relocation trawling. This plan must be developed with input from shortnose and Atlantic 

sturgeon experts. The plan must also contain measures to ensure that the 500-foot radius 

surrounding the detonation site is clear within 30 minutes of the commencement of the 

detonation. 

13. To implement RPM#9, the ACOE must not commence blasting operations prior to 

receiving confirmation from NMFS that the blasting plan is acceptable. 

14. To implement RPM#10, the ACOE must work with Atlantic and shortnose sturgeon 

researchers to monitor the movement of acoustically tagged sturgeon during the blasting 

operations. The monitoring plan must be submitted to NMFS 45 days prior to the 

commencement of blasting. 

15. To implement RPM#11, the ACOE must ensure that no blasting occur when shortnose or 

Atlantic sturgeon are detected within 500 feet of the blast site and that the contractor follows 

all procedures outlined in the plan described in T&C #20. 

16. To implement RPM #12, acoustic monitoring must be conducted on the first day of blasting 

to verify that sound levels at 140 feet and 500 feet from the blasting is less than or equal to 

the values estimated by ACOE (i.e., peak 120psi, average 70psi at 140 feet, with noise levels 

below 180dB at 500 feet). Results of this monitoring must be reported to NMFS prior to 

any subsequent blasting. 

17. To implement RPM#13, at least 45 days prior to the commencement of blasting, the ACOE 

will submit to NMFS a plan outlining the measures the ACOE must take to monitor for 

injured or dead sturgeon following blasting. This plan must include the use of observers to 

monitor an area with a radius of at least 1,000 feet surrounding the blast site for dead fish. 

18. To implement RPM#14, for mechanical dredging following blasting operations, the ACOE 

must require that observer coverage is sufficient for 100% monitoring of dredging 

operations. This monitoring coverage must involve the placement of a NMFS-approved 

observer on board the dredge for every day that dredging is occurring. The observer must 

work a shift schedule appropriate to allow for the observation of at least 50% of the dredge 

loads (e.g., 12 hours on, 12 hours off). The NMFS approved observer must observe all 

discharges of dredged material from the dredge bucket to the scow or hopper. All biological 

material disposed of at the disposal site must be documented by a NMFS-approved observer 

as outlined in Appendix B). No observers can be deployed to the dredge site until ACOE 

has written confirmation from NMFS that they have met the qualifications to be a “NMFSapproved observer” as outlined in Appendix A. If substitute observers are required during 

dredging operations, ACOE must ensure that NMFS approval is obtained before those 

observers are deployed on dredges. 
200

19. To implement RPM #15, any sturgeon observed in the dredge scow during mechanical 

dredging operations must be removed with a net and, if alive, returned to the river away 

from the blasting site. 

20. To implement RPM #16, the ACOE must conduct sediment sampling following the 

completion of dredging to confirm that substrate type is unchanged following the deepening 

in Reach AA, A, B, D and E. In the unlikely event that it is found that substrate type has 

changed as a result of the deepening, ACOE must work with us to develop an appropriate 

restoration method to restore substrate types in these reaches. Sediment samples must be 

taken pre- and post-deepening that are sufficient to document any changes in sediment type. 

This sampling must include a pre- and post- blasting survey of hard bottom habitat in 

Marcus Hook to document any unanticipated loss of hard bottom habitat in the area. Should 

it be found that substrate type has changed as a result of the deepening, ACOE must work 

with us to develop an appropriate restoration method to restore substrate types in this reach.

21. To implement RPM#17, the ACOE must work with Atlantic and shortnose sturgeon 

researchers to monitor the movement of acoustically tagged sturgeon during dredging 

operations. The monitoring program must be designed to provide coverage of one full 

dredge cycle in each affected reach during the initial construction period and one full dredge 

cycle in each affected reach during the maintenance period. The monitoring program must 

also cover one dredge cycle with a hopper dredge in Reach AA, A, B or C and one dredge 

cycle with a hopper dredge in Reach D or E. The monitoring plan must be submitted to 

NMFS 45 days prior to the commencement of dredging where monitoring will occur. 

Preliminary reports containing information on the number of tagged sturgeon detected and 

their movements must be provided to NMFS within 90 days of the completion of dredging. 

This term and condition does not require ACOE to tag any sturgeon with telemetry tags. 

22. To implement RPM #18, the ACOE must ensure that fin clips are taken (according to the 

procedure outlined in Appendix E) of any sturgeon captured during the project and that the 

fin clips are sent to NMFS for genetic analysis. Fin clips must be taken prior to preservation 

of other fish parts or whole bodies. 

23. To implement RPM #19, all collected sturgeon must be inspected for a PIT tag with an 

appropriate PIT tag reader. Any tag numbers must be recorded and reported to NMFS. 

24. To implement RPM #20, in the event of any lethal takes of shortnose or Atlantic sturgeon, 

any dead specimens or body parts must be photographed, measured, and preserved 

(refrigerate or freeze) until disposal procedures are discussed with NMFS. The form 

included as Appendix F (sturgeon salvage form) must be completed and submitted to 

NMFS. 

25. To implement RPM #21, in the event of any lethal takes of sea turtles, any dead specimens 

or body parts must be photographed, measured, and preserved (refrigerate or freeze) until 

disposal procedures are discussed with NMFS. 

26. To implement RPM #21, if a decomposed turtle or turtle part is entrained during dredging 

operations, an incident report must be completed and the specimen must be photographed. 

Any turtle parts that are considered ‘not fresh’ (i.e., they were obviously dead prior to the 
201

dredge take and ACOE anticipates that they will not be counted towards the ITS) must be 

frozen and transported to a nearby stranding or rehabilitation facility for review. ACOE 

must ensure that the observer submits the incident report for the decomposed turtle part, as 

well as photographs, to NMFS within 24 hours of the take (see Appendix D) and request 

concurrence that this take should not be attributed to the Incidental Take Statement. NMFS 

shall have the final say in determining if the take should count towards the Incidental Take 

Statement.

27. To implement RPM #22, the ACOE must contact NMFS within 24 hours of any 

interactions with sturgeon or sea turtles, including non-lethal and lethal takes. NMFS will 

provide contact information annually when alerted of the start of dredging activity. Until 

alerted otherwise, the ACOE should contact Julie Crocker: by email 

(julie.crocker@noaa.gov) or phone (978) 282-8480 or the Section 7 Coordinator by phone 

(978)281-9328 or fax 978-281-9394). Take information should also be reported by e-mail 

to: incidental.take@noaa.gov. 

28. To implement RPM #22, the ACOE must photograph and measure any sturgeon or sea 

turtles observed during project operations (including whole sturgeon or sea turtles or body 

parts observed at the disposal location or on board the dredge, hopper or scow) and the 

corresponding form (Appendix D) must be completed and submitted to NMFS within 24 

hours by fax (978-281-9394) or e-mail (incidental.take@noaa.gov).

29. To implement RPM #22, any time a take occurs ACOE must immediately contact NMFS to 

review the situation. At that time, ACOE must provide NMFS with information on the 

amount of material dredged thus far and the amount remaining to be dredged during that

cycle. Also at that time, ACOE should discuss with NMFS whether any new management 

measures could be implemented to prevent the total incidental take level from being 

exceeded and will work with NMFS to determine whether this take represents new 

information revealing effects of the action that may not have been previously considered. 

30. To implement RPM #8, the ACOE must submit a final report summarizing the results of 

dredging and any takes of listed species to NMFS within 30 working days of the completion 

of each dredging contract (by mail to the attention of the Section 7 Coordinator, NMFS 

Protected Resources Division, 55 Great Republic Drive, Gloucester, MA 01930). This 

report must be submitted at the close of each dredging contract during construction of the 45 

foot channel as well as each time maintenance dredging is required. 

The reasonable and prudent measures, with their implementing terms and conditions, are designed 

to minimize and monitor the impact of incidental take that might otherwise result from the proposed 

action. Specifically, these RPMs and Terms and Conditions will keep us informed of when and 

where dredging and blasting activities are taking place and will require ACOE to report any take in 

a reasonable amount of time, as well as implement measures to monitor for entrainment during 

dredging and avoid conducting blasting activities when sturgeon are in the immediate area 

surrounding the blast site. The ACOE has reviewed the RPMs and Terms and Conditions outlined 

above and has agreed to implement all of these measures as described herein and in the referenced 

Appendices. The discussion below explains why each of these RPMs and Terms and Conditions 
202

are necessary and appropriate to minimize or monitor the level of incidental take associated with the 

proposed action and how they represent only a minor change to the action as proposed by the 

ACOE. 

RPM #1 and #8 and Term and Condition #1 and #11 are necessary and appropriate because they 

will serve to ensure that we are aware of the dates and locations of all dredging and blasting 

activities. This will allow us to monitor the duration and seasonality of dredging activities as well 

as give us an opportunity to provide ACOE with any updated contact information for NMFS staff. 

This is only a minor change because it is not expected to result in any delay to the project and will 

merely involve an occasional telephone call or e-mail between ACOE and NMFS staff.

Several of the RPMs (#2,4, 5 and 14) as well as the implementing Term and Conditions (#2, 3, 

5,6,7, and 18) are necessary and appropriate because they require that the ACOE have sufficient 

observer coverage to ensure the detection of any interactions with listed species. This is necessary 

for the monitoring of the level of take associated with the proposed action. The inclusion of these 

RPMs and Terms and Conditions is only a minor change as the ACOE included some level of 

observer coverage in the original project description and the increase in coverage (i.e., the addition 

of the month of May for hopper dredges operating in the Bay, the addition of observers for hopper 

dredges operating in the river) will represent only a small increase in the cost of the project and will 

not result in any delays. These also represent only a minor change as in many instances they serve 

to clarify the duties of the inspectors or observers.

RPM #3 and Term and Condition #4, is necessary and appropriate as the use of draghead deflectors 

is accepted standard practice for hopper dredges operating in places and at times of year when sea 

turtles are known to be present and has been documented to reduce the risk of entrainment for sea 

turtles, thereby minimizing the potential for take of these species. This represents only a minor 

change as all of the hopper dredges likely to be used for this project, including the ACOE owned 

McFarland which may be used for maintenance dredging, already have draghead deflectors, dredge 

operators are already familiar with their use, and the use will not affect the efficiency of the 

dredging operation. Additionally, maintenance of the existing channel is conducted with draghead 

deflectors in place. 

RPM #6 and Term and Conditions #8 and 9 are necessary and appropriate as they will require that 

dredge operators use best management practices, including slowing down to 4 knots should listed 

species be observed, that will minimize the likelihood of take. This represents only a minor change 

as following these procedures should not increase the cost of the dredging operation or result in any 

delays of reduction of efficiency of the dredging project. 

RPM #7 and #15 and Term and Condition #10 and 19 are necessary and appropriate to ensure that 

any sea turtles or sturgeon that survive entrainment in a hopper dredge or capture in a mechanical 

dredge are given the maximum probability of remaining alive and not suffering additional injury or 

subsequent mortality through inappropriate handling. This represents only a minor change as 

following these procedures will not result in an increase in cost or any delays to the proposed 

project. 

RPM #8-13 and their implementing Terms and Conditions (#11-17) are necessary and appropriate 
203

to minimize the potential for blasting activities to take place when sturgeon are within 500 meters of 

the detonation site. These conditions are also designed to verify that the sound and pressure levels 

presented by ACOE and relied on by NMFS in estimating take are valid and that a 500 meter 

exclusion zone is sufficient. This does not cause more than minor changes because it merely 

provides additional clarification to the requirement already imposed by the ACOE to conduct 

underwater monitoring of pressure levels associated with blasting. The clarification of the already 

required pressure monitoring and the inclusion of sound monitoring will not cause delays to the 

project or add a significant cost. The monitoring plan represents only a minor change as the plan to 

be implemented will be designed by ACOE in cooperation with us and is not anticipated to result in 

any increased cost, delays of the project or decreased efficiency of blasting operations. Further, the 

plan will not alter the time of year or location of detonation sites. 

RPM #16 and Term and Condition #20 are necessary and appropriate as they will serve to verify the 

ACOE’s determination that deepening will not alter the substrate type in any reach of the river. The 

monitoring plan represents only a minor change as some post-construction monitoring is already 

planned. Also, any necessary restoration will be designed by ACOE in cooperation with us and is 

not anticipated to result in any delays of the project or changes to dredging operations. 

RPM #17 and Term and Condition #21 are necessary and appropriate as they will serve to monitor 

the movements of tagged sturgeon during dredging. A successful study was carried out in 2011; the 

continuation of a similar study in different river reaches and at different times of year will serve to 

verify assumptions made by us and ACOE regarding the movements of sturgeon near operating 

dredges, which were based on the 2011 study and other similar studies. The monitoring plan 

represents only a minor change as it will not result in any delays to dredging or modifications of the 

dredge plan and any increased cost will be very small in comparison to the total costs of the project. 

RPM #18-22 and Terms and Conditions #22-30 are necessary and appropriate to ensure the proper 

handling and documentation of any interactions with listed species as well as requiring that these 

interactions are reported to us in a timely manner with all of the necessary information. This is 

essential for monitoring the level of incidental take associated with the proposed action. Theses 

RPMs and Terms and Conditions represent only a minor change as compliance will not result in any 

increased cost, delay of the project or decrease in the efficiency of the dredging operations. 

12.0 CONSERVATION RECOMMENDATIONS

In addition to Section 7(a)(2), which requires agencies to ensure that all projects will not jeopardize 

the continued existence of listed species, Section 7(a)(1) of the ESA places a responsibility on all 

federal agencies to “utilize their authorities in furtherance of the purposes of this Act by carrying 

out programs for the conservation of endangered species.” Conservation Recommendations are 

discretionary agency activities to minimize or avoid adverse effects of a proposed action on listed 

species or critical habitat, to help implement recovery plans, or to develop information. As such, 

NMFS recommends that the ACOE consider the following Conservation Recommendations: 

(1) To the extent practicable, the ACOE should avoid dredging during times of year when listed 

species are likely to be present.
204

(2) Population information on certain life stages of shortnose sturgeon is still sparse for this 

river system. The ACOE should continue to support studies to evaluate habitat and the use 

of the river, in general, by juveniles as well as use of the area below Philadelphia by all life 

stages.

(3) If any lethal take occurs, the ACOE should arrange for contaminant analysis of the 

specimen. If this recommendation is to be implemented, the fish should be immediately 

frozen and NMFS should be contacted within 24 hours to provide instructions on shipping 

and preparation.

(4) The ACOE should conduct studies at the upland dredged material disposal areas to assess 

the potential for improved screening to : (1) establish the type and size of biological material 

that may be entrained in the cutterhead dredge, and (2) verify that monitoring the disposal 

site without screening is providing an accurate assessment of entrained material. 

(5) If a hopper dredge is used outside of Reaches D and A, the ACOE should consider using a 

dredge equipped with the rigid deflector draghead as designed by the ACOE Engineering 

Research and Development Center, formerly the Waterways Experimental Station or, if that 

is unavailable, a rigid sea turtle deflector attached to the draghead. While sea turtles are 

unlikely to occur in these reaches, the sea turtle deflector may also work to reduce the 

number of interactions between the dredge and sturgeon. 

(6) The ACOE should support studies to determine the effectiveness of using a sea turtle 

deflector to minimize the potential entrainment of sturgeon during hopper dredging. 

13.0 REINITIATION OF CONSULTATION

This concludes formal consultation on the proposal by the ACOE to deepen the Delaware River 

Philadelphia to the Sea federal navigation project. As provided in 50 CFR §402.16, reinitiation of 

formal consultation is required where discretionary federal agency involvement or control over the 

action has been retained (or is authorized by law) and if: (1) the amount or extent of taking specified 

in the incidental take statement is exceeded; (2) new information reveals effects of the action that 

may not have been previously considered; (3) the identified action is subsequently modified in a 

manner that causes an effect to listed species; or (4) a new species is listed or critical habitat 

designated that may be affected by the identified action. In instances where the amount or extent of 

incidental take is exceeded, Section 7 consultation must be reinitiated immediately. 
205

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247

APPENDIX A.

MONITORING SPECIFICATIONS FOR HOPPER DREDGES

I. EQUIPMENT SPECIFICATIONS 

A. Baskets or screening 

Baskets or screening must be installed over the hopper inflows with openings no smaller than 4 

inches by 4 inches to provide 100% coverage of all dredged material and shall remain in place 

during all dredging operations. Baskets/screening will allow for better monitoring by observers of 

the dredged material intake for sea turtles, sturgeon and their remains. The baskets or screening 

must be safely accessible to the observer and designed for efficient cleaning.

B. Draghead

The draghead of the dredge shall remain on the bottom at all times during a pumping operation, 

except when:

1) the dredge is not in a pumping operation, and the suction pumps are turned completely off;

2) the dredge is being re-oriented to the next dredge line during borrow activities; and

3) the vessel’s safety is at risk (i.e., the dragarm is trailing too far under the ship’s hull).

At initiation of dredging, the draghead shall be placed on the bottom during priming of the suction 

pump. If the draghead and/or dragarm become clogged during dredging activity, the pump shall be 

shut down, the dragarms raised, whereby the draghead and/or dragarm can be flushed out by trailing 

the dragarm along side the ship. If plugging conditions persist, the draghead shall be placed on 

deck, whereby sufficient numbers of water ports can be opened on the draghead to prevent future 

plugging. 

Upon completion of a dredge track line, the drag tender shall:

1) throttle back on the RPMs of the suction pump engine to an idling speed (e.g., generally less 

than 100 RPMs) prior to raising the draghead off the bottom, so that no flow of material is 

coming through the pipe into the dredge hopper. Before the draghead is raised, the vacuum 

gauge on the pipe should read zero, so that no suction exists both in the dragarm and draghead, 

and no suction force exists that can impinge a turtle on the draghead grate;

2) hold the draghead firmly on the bottom with no flow conditions for approximately 10 to 15 

seconds before raising the draghead; then, raise the draghead quickly off the bottom and up to 

a mid-water column level, to further reduce the potential for any adverse interaction with 

nearby turtles;

3) re-orient the dredge quickly to the next dredge line; and

4) re-position the draghead firmly on the bottom prior to bringing the dredge pump to normal 

pumping speed, and re-starting dredging activity. 
248

C. Floodlights

Floodlights must be installed to allow the NMFS-approved observer to safely observe and 

monitor the baskets or screens.

D. Intervals between dredging

Sufficient time must be allotted between each dredging cycle for the NMFS-approved observer 

to inspect and thoroughly clean the baskets and screens for sea turtles and/or turtle parts and 

document the findings. Between each dredging cycle, the NMFS-approved observer should also 

examine and clean the dragheads and document the findings.

II. OBSERVER PROTOCOL 

A. Basic Requirement

A NMFS-approved observer with demonstrated ability to identify sea turtle and sturgeon species 

must be placed aboard the dredge(s) being used, starting immediately upon project 

commencement to monitor for the presence of listed species and/or parts being entrained or 

present in the vicinity of dredge operations. 

B. Duty Cycle

Observers are required at times and locations outlined in the ITS. While onboard, the observer 

must work a shift schedule appropriate to allow for the observation of at least 50% of the dredge 

loads (e.g., 12 hours on, 12 hours off). The ACOE shall require of the dredge operator that, 

when the observer is off watch, the cage shall not be opened unless it is clogged. The ACOE 

shall also require that if it is necessary to clean the cage when the observer is off watch, any 

aquatic biological material is left in the cage for the observer to document and clear out when 

they return on duty. In addition, the observer shall be the only one allowed to clean off the 

overflow screen. 

C. Inspection of Dredge Spoils

During the required inspection coverage, the trained NMFS-approved observer shall inspect the 

galvanized screens and baskets at the completion of each loading cycle for evidence of sea turtles 

or shortnose sturgeon. The Endangered Species Observation Form shall be completed for each 

loading cycle, whether listed species are present or not. If any whole (alive or dead) or turtle 

parts are taken incidental to the project(s), NMFS Protected Resources Division must be 

contacted by phone (978-281-9328) or e-mail (incidental.take@noaa.gov) within 24 hours of the 

take. An incident report for sea turtle/shortnose sturgeon take (Appendix D) shall also be 

completed by the observer and sent via FAX (978) 281-9394 or e-mail 

(incidental.take@noaa.gov) within 24 hours of the take. Incident reports shall be completed for 

every take regardless of the state of decomposition. NMFS will determine if the take should be 

attributed to the incidental take level, after the incident report is received. Every incidental take 

(alive or dead, decomposed or fresh) should be photographed, and photographs shall be sent to 

NMFS either electronically (incidental.take@noaa.gov) or through the mail. Weekly reports, 
249

including all completed load sheets, photographs, and relevant incident reports, as well as a final 

report, shall be submitted to NMFS NER, Protected Resources Division, 55 Great Republic 

Drive, Gloucester, MA 01930-2298.

D. Information to be Collected

For each sighting of any endangered or threatened marine species (including whales as well as 

sea turtles), record the following information on the Endangered Species Observation Form 

(Appendix D):

1) Date, time, coordinates of vessel

2) Visibility, weather, sea state

3) Vector of sighting (distance, bearing)

4) Duration of sighting

5) Species and number of animals

6) Observed behaviors (feeding, diving, breaching, etc.)

7) Description of interaction with the operation

E. Disposition of Parts

If any whole turtles or sturgeon (alive or dead, decomposed or fresh) or turtle or shortnose 

sturgeon parts are taken incidental to the project(s), NMFS Protected Resources must be 

contacted within 24 hours of the take (phone: 978-281-9328 or e-mail 

(incidental.take@noaa.gov). All whole dead sea turtles or sturgeon, or turtle or shortnose 

sturgeon parts, must be photographed and described in detail on the Incident Report of Sea Turtle 

Mortality (Appendix D). The photographs and reports should be submitted by email 

(incidental.take@noaa.gov) or mail (Attn: Section 7 Coodinator, NMFS, Protected Resources 

Division, 55 Great Republic Drive, Gloucester, MA 01930-2298). After NMFS is notified of 

the take, it may instruct the observer to save the animal for future analysis if there is freezer 

space. Disposition of dead sea turtles/ sturgeon will be determined by NMFS at the time of the 

take notification. If the species is unidentifiable or if there are entrails that may have come from 

a turtle, the subject should be photographed, placed in plastic bags, labeled with location, load 

number, date and time taken, and placed in cold storage.

Live turtles (both injured and uninjured) should be held onboard the dredge until transported as 

soon as possible to the appropriate stranding network personnel for rehabilitation (Appendix C). 

No live turtles should be released back into the water without first being checked by a qualified 

veterinarian or a rehabilitation facility. The NMFS Stranding Network Coordinator ((978) 282-

8470) should also be contacted immediately for any marine mammal injuries or mortalities.

III. OBSERVER REQUIREMENTS 

Submission of resumes of endangered species observer candidates to NMFS for final approval 

ensures that the observers placed onboard the dredges are qualified to document takes of 

endangered and threatened species, to confirm that incidental take levels are not exceeded, and to 
250

provide expert advice on ways to avoid impacting endangered and threatened species. NMFS 

does not offer certificates of approval for observers, but approves observers on a case-by-case 

basis.

A. Qualifications

Observers must be able to:

1) differentiate between leatherback (Dermochelys coriacea), loggerhead Caretta caretta), 

Kemp's ridley (Lepidochelys kempii), green (Chelonia mydas), and hawksbill 

(Eretmochelys imbricata) turtles and their parts, and shortnose (Acipenser brevirostrum) 

and Atlantic (Acipenser oxyrinchus oxyrinchus) sturgeon and their parts; 

2) handle live sea turtles and sturgeon and resuscitate and release them according accepted 

procedures;

3) correctly measure the total length and width of live and whole dead sea turtle and 

sturgeon species; 

4) observe and advise on the appropriate screening of the dredge’s overflow, skimmer 

funnels, and dragheads; and

5) identify marine mammal species and behaviors.

B. Training

Ideally, the applicant will have educational background in marine biology, general experience

aboard dredges, and hands-on field experience with the species of concern. For observer 

candidates who do not have sufficient experience or educational background to gain immediate 

approval as endangered species observers, the below observer training is necessary to be 

considered admissible by NMFS. We can assist the ACOE by identifying groups or individuals 

capable of providing acceptable observer training. Therefore, at a minimum, observer training 

must include:

1) instruction on how to identify sea turtles and sturgeon and their parts;

2) instruction on appropriate screening on hopper dredges for the monitoring of sea turtles 

and sturgeon (whole or parts);

3) demonstration of the proper handling of live sea turtles and sturgeon incidentally 

captured during project operations. Observers may be required to resuscitate sea turtles 

according to accepted procedures prior to release; 

4) instruction on standardized measurement methods for sea turtle and sturgeon lengths and 

widths; and

5) instruction on how to identify marine mammals; and

6) instruction on dredging operations and procedures, including safety precautions onboard 

a vessel. 
251
252
253

APPENDIX B. 

MONITORING SPECIFICATIONS FOR MECHANICAL DREDGES

I. EQUIPMENT SPECIFICATIONS

A. Floodlights

Should dredging occur at night or in poor lighting conditions, floodlights must be installed to 

allow the NMFS-approved observer to safely observe and monitor dredge bucket and scow.

B. Intervals between dredging

Sufficient time must be allotted between each dredging cycle for the NMFS-approved observer 

to inspect the dredge bucket and scow for shortnose sturgeon and/or sturgeon parts and document 

the findings. 

II. OBSERVER PROTOCOL

A. Basic Requirement

A NMFS-approved observer with demonstrated ability to identify shortnose sturgeon must be 

placed aboard the dredge(s) being used; starting immediately upon project commencement to 

monitor for the presence of listed species and/or parts being taken or present in the vicinity of 

dredge operations. 

B. Duty Cycle

A NMFS-approved observer must be onboard during dredging until the project is completed. 

While onboard, observers shall provide the required inspection coverage to provide 100% 

coverage of all dredge-cycles. 

C. Inspection of Dredge Spoils

During the required inspection coverage, the NMFS-approved observer shall observe the bucket 

as it comes out of the water and as the load is deposited into the scow during each dredge cycle 

for evidence of shortnose sturgeon. If any whole sturgeon (alive or dead) or sturgeon parts are 

taken incidental to the project(s), NMFS must be contacted within 24 hours of the take (phone: 

978-281-9328 or email (incidental.take@noaa.gov). An incident report for sturgeon take shall 

also be completed by the observer and sent to NMFS via FAX (978) 281-9394 or e-mail 

(incidental.take@noaa.gov) within 24 hours of the take. Incident reports shall be completed for 

every take regardless of the state of decomposition. Every incidental take (alive or dead, 

decomposed or fresh) must be photographed. A final report including all completed load sheets, 

photographs, and relevant incident reports are to be submitted to the attention of the Section 7 

Coordinator, NMFS Protected Resources Division, 55 Great Republic Drive, Gloucester, MA 

01930.
254

D. Inspection of Disposal

The NMFS-approved observer shall observe all disposal operations to inspect for any whole 

sturgeon or sturgeon parts that may have been missed when the load was deposited into the 

scow. If any whole sturgeon (alive or dead) or sturgeon parts are observed during disposal 

operation, the procedure for notification and documentation outlined above should be completed. 

E. Disposition of Parts

As required above, NMFS must be contacted as soon as possible following a take. Any dead 

sturgeon should be refrigerated or frozen until disposition can be discussed with NMFS. Under 

no circumstances should dead sturgeon be disposed of without confirmation of disposition details 

with NMFS. 

III. OBSERVER REQUIREMENTS

Submission of resumes of endangered species observer candidates to NMFS for final approval 

ensures that the observers placed onboard the dredges are qualified to document takes of 

endangered and threatened species, to confirm that incidental take levels are not exceeded, and to 

provide expert advice on ways to avoid impacting endangered and threatened species. NMFS 

does not offer certificates of approval for observers, but approves observers on a case-by-case 

basis.

A. Qualifications

Observers must be able to:

1) differentiate between shortnose (Acipenser brevirostrum) and Atlantic (Acipenser 

oxyrinchus oxyrinchus) sturgeon and their parts; 

2) handle live sturgeon;

3) correctly measure the total length and width of live and whole dead sturgeon species; 

B. Training

Ideally, the applicant will have educational background in biology, general experience 

aboard dredges, and hands-on field experience with the species of concern. For observer 

candidates who do not have sufficient experience or educational background to gain 

immediate approval as endangered species observers, we note below the observer training 

necessary to be considered admissible by NMFS. We can assist the ACOE by identifying 

groups or individuals capable of providing acceptable observer training. Therefore, at a 

minimum, observer training must include:

1) instruction on how to identify sturgeon and their parts;

2) instruction on appropriate screening on hopper dredges for the monitoring of 
255

sturgeon(whole or parts);

3) demonstration of the proper handling of live sturgeon incidentally captured during 

project operations; 

 4) instruction on standardized measurement methods for sturgeon lengths and widths; and

5) instruction on dredging operations and procedures, including safety precautions 

onboard.
APPENDIXC 

. Sea Turtle Handling and Resuscitation 

It is unlikely that sea turtles will survive entrainment in a hopper dredge, as the turtles found in 

the dragheads are usually dead, dying, or dismantled. However, the procedures for handling live 

sea turtles follow in case the unlikely event should occur. These guidelines are adapted from 50 

CFR § 223.206(d)(1). 

Please photograph all turtles (alive or dead) and turtle parts found during dredging activ,ities 

and complete the Incident Report ofSea Turtle Take (Appendix D). 

Dead sea turtles
 

The procedures for handling dead sea turtles and parts are described in Appendix C-II-E.
 

Live sea turtles
 

When a sea turtle is found in the dredge gear, observe it for. activity and potential injuries.
 

<	 Ifthe turtle is actively moving, it should be retained onboard until evaluated for injuries 

by a pennitted rehabilitation facility. Due to the potential for internal injuries associated 

. with hopper entrainment, it is necessary to transport the live turtle to the nearest 

rehabilitation facility as soon as possible, following these steps: 

1) Contact the nearest rehabilitation facility to infonn them ofthe incident. If the 

.	 rehabilitation personnel cannot be reached immediately, please contact NMFS 

stranding hotline at 978-281-9351 or NMFS Sea Turtle Stranding Coordinator at 978­

281-9328. 

2)	 Keep.the turtle shaded and moist (e.g., with a water-soaked towel over the eyes, 

carapace, and flippers), and in a confined location free from potential injury. 

3)	 Contact the crew boat to pick up the turtle as soon as possible from the dredge (within 

12to 24 hours maximum). The crew boat should be aware of the potential for such 

an incident to occur and should develop an appropriate protocol for transporting live 

sea turtles. 

4) Transport the live turtle to the closest pennitted rehabilitation facility able to handle 

.such a case. 

Do not assume that all inactive turtle is dead. The onset ofrigor mortis and/or rotting 

flesh are often the only definite indications that a turtle is dead. Releasing a comatose 

turtle into any amount ofwater will drown it, and a turtle may recover once its lungs have 

had a chance to drain. . 

<	 If a turtle appears to be comatose (unconscious), contact the designated 

strandinglrehabilitationpersonnel immediately. Once the rehabilitation personnel has 

been infonned ofthe incident, attempts should be made to revive the turtle at once. Sea· 

turtles have been known to revive up to 24 hours after resuscitation procedures have been 

followed. 

•	 Place the animal on its bottom shell (plastron) so that the turtle is right side up and 

elevate the hindquarters at least 6 inches for a period of4 up to 24 hours..The 
degree of elevation depends on the size of the turtle; greater elevations are 

required for larger turtles. 

Periodically, rock the turtle gently left to right and right to left by holding the 

outer edge ofthe shell (carapace) and lifting one side about 3 inches then alternate 

to the other side. 

Periodically, gently touch the eye and pinch thetail (reflex test) to see ifthere is a 

response. 

Keep the turtle in a safe, contained place, shaded, and moist (e.g., with a watersoaked towel over the eyes, carapace, and flippers) and observe it for up to 24 

hours. . . 

If the turtle begins actively moving, retain the turtle until the appropriate 

rehabilitation personnel can evaluate the animal. The rehabilitation facility 

should eventually release the animal in a manner thatminimizes the chances of 

re-impingement and potential harm to the animal (i.e., from cold stunning). 

Turtles that fail to move within several hours (up to 24) must be handled in the 

manner described in Appendix C-II-E, or transported to a suitable facility for 

necropsy (if the condition ofthe sea turt,le allows and the rehabilitation facility 

wants to 

necropsy the 

animal). 

Strandinglrehabiliton contacts 

Sea Turtles in Delaware Bay 

<.	 NMFS Stranding Hotline: (978) 281-9351 or NERStranding.staff@noaa.gov 

Delaware: 

<	 MERR Institute, Inc.
 

Nassau, DE
 

302-228-5029
 

New Jersey 

•	 Marine Mammal Stranding Center
 

Brigantine, NJ
 

609-266-0538
 
258

APPENDIX D

ENDANGERED SPECIES OBSERVER FORM

Delaware River Deepening

Daily Report

Date: _________________________________

Geographic Site:_______________________________________________________________ 

Location: Lat/Long _____________________ Vessel Name ____________________________

Weather conditions:_____________________________________________________________

______________________________________________________________________________

Water temperature: Surface _____________ Below midwater (if known) _____________

Condition of screening apparatus: __________________________________________________ 

______________________________________________________________________________

______________________________________________________________________________ 

Incidents involving endangered or threatened species? (Circle) Yes No

(If yes, fill out Incident Report of Sea Turtle/ Sturgeon Mortality)

Comments (type of material, biological specimens, unusual circumstances, etc:) 

___________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Observer’s Name: _______________________________________________

Observer’s Signature: ____________________________________________

Species # of Sightings # of Animals Comments

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ ________________________

______________ ______________ ____________ _______________________
259

Incident Report of Sea Turtle Take

Species _____________ Date _______________ Time (specimen found) ________________

Geographic Site _______________________________________________________________ 

Location: Lat/Long ____________________________________________________________

Vessel Name _________________________ Load # ______________________________

Begin load time _______________________ End load time_________________________

Begin dump time ______________________ End dump time _______________________

Sampling method _____________________________________________________________ 

Condition of screening _________________________________________________________ 

Location where specimen recovered_______________________________________________ 

____________________________________________________________________________

Draghead deflector used? YES NO Rigid deflector draghead? YES NO 

Condition of deflector ___________________________________________________________

______________________________________________________________________________

Weather conditions______________________________________________________________

______________________________________________________________________________

Water temp: Surface ________________ Below midwater (if known) _____________________

Species Information: (please designate cm/m or inches.)

Head width __________________________ Plastron length ___________________________

Straight carapace length ________________ Straight carapace width_____________________

Curved carapace length _________________ Curved carapace width _____________________ 

Condition of specimen/description of animal (please complete attached diagram) 

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Turtle Decomposed: NO SLIGHTLY MODERATELY SEVERELY

Turtle tagged: YES NO Please record all tag numbers. Tag # ______________________

Genetic sample taken: YES NO

Photograph attached: YES NO 

(please label species, date, geographic site and vessel name on back of photograph)

Comments/other (include justification on how species was identified) _____________________ 

______________________________________________________________________________

______________________________________________________________________________ 

Observer's Name _______________________________________

Observer’s Signature __________________________________
260

Incident Report of Sea Turtle Take

Draw wounds, abnormalities, tag locations on diagram and briefly describe below. 

Description of animal:
261

Incident Report of Sturgeon Take

Photographs should be taken and the following information should be collected from all 

sturgeon (alive and dead) 

Date _______________ Time (specimen found) ________________

Geographic Site_______________________________________________________

Location: Lat/Long________________________________________________________

Vessel Name _________________________ Load # ___________________________

Begin load time _______________________ End load time_______________________

Begin dump time ______________________ End dump time _____________________

Sampling method _______________________________________________________

Condition of screening _____________________________________________________ 

Location where specimen 

recovered______________________________________________________________________

_____________________________________________________

Draghead deflector used? YES NO Rigid deflector draghead? YES NO 

Condition of deflector _____________________________________________________

____________________________________________________________________

Weather conditions______________________________________________________________

________________________________________________________________________

Water temp: Surface ________________ Below midwater (if known) _______________

Species Information: (please designate cm/m or inches.)

Fork length (or total length) _____________________ Weight _____________________

Condition of specimen/description of animal

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

Fish Decomposed: NO SLIGHTLY MODERATELY SEVERELY

Fish tagged: YES / NO Please record all tag numbers. Tag # ________________

Genetic sample taken: YES NO

Photograph attached: YES / NO

(please label species, date, geographic site and vessel name on back of photograph)

Comments/other (include justification on how species was identified) 

______________________________________________________________________________

__________________________________________________________________

Observer's Name ___________________Observer’s Signature_____________________ 
262

Draw wounds, abnormalities, tag locations on diagram and briefly describe below

Description of fish condition:
263

APPENDIX E

Procedure for obtaining fin clips from sturgeon for genetic analysis

Obtaining Sample

1. Wash hands and use disposable gloves. Ensure that any knife, scalpel or scissors

 used for sampling has been thoroughly cleaned and wiped with alcohol to minimize

 the risk of contamination.

2. For any sturgeon, after the specimen has been measured and photographed, take a

 one-cm square clip from the pelvic fin.

3. Each fin clip should be placed into a vial of 95% non-denatured ethanol and the vial

 should be labeled with the species name, date, name of project and the fork length

 and total length of the fish along with a note identifying the fish to the appropriate

 observer report. All vials should be sealed with a lid and further secured with tape

 Please use permanent marker and cover any markings with tape to minimize the

 chance of smearing or erasure.

Storage of Sample

1. If possible, place the vial on ice for the first 24 hours. If ice is not available, please

 refrigerate the vial. Send as soon as possible as instructed below.

Sending of Sample

1. Vials should be placed into Ziploc or similar resealable plastic bags. Vials should be

then wrapped in bubble wrap or newspaper (to prevent breakage) and sent to:

Julie Carter

NOAA/NOS – Marine Forensics

219 Fort Johnson Road

Charleston, SC 29412-9110

Phone: 843-762-8547

a. Prior to sending the sample, contact Russ Bohl at NMFS Northeast Regional

 Office (978-282-8493) to report that a sample is being sent and to discuss

 proper shipping procedures.
STURGEON SALVAGE FORM
 

For use in documenting dead sturgeon in the wild under ESA permit no. 1614 (version 05-16-2012) 

INVESTIGATORS'S CONTACT INFORMATION
 

Name: First 

Agency Affiliation 

Address 

Area code/Phone number 

SPECIES: (check one) o shortnose sturgeon

o Atlantic sturgeon

o Unidentified Acipenser species 

Check ·Unidentified" if uncertain. 

See reverse side of this,form for 

aid in identification. 

Last
 

. Email
 , 

IUNIQUE IDENTIFIER (Assigiled by NMFS) 

\ 

DATE REPORTED:
 

Month DO Day[]O Year 2000
 

DATE EXAMINED:
 

Month CID DayDD Year20DD
 

LOCATION FOUND: OOffshore (Atlantic or Gulf beach) Olnshore (bay, river, sound, inlet, etc)
 

River/Body of Water City· State -
 Descriptivelocation (be specific)
 

Latitude N(Dec. Degrees) Longitude W(Dec. Degrees)
 

CARCASS CONDITION at 

time examined: (check one) . 

o 1;: Fresh dead 

o 2;: Moderately decomposed

o 3;: Severely decomposed o 4;: Dried carcass 

o 5;: Skeletal, scutes & cartilage 

SEX:
 

o Undetermined
 

o Female 0 Male
 

How was sex determined?
 . 0 Necropsy . 

o Eggs/milt present when pressed

o Borescope 

MEASUREMENTS: 

Fork length 

Total length 

L~ngth 0 actual 0 estimate 

.. Mouth width (inside lips, see reverse side) 

Interorbital width (see reverse side) 

Weight 0 actual 0 estimate 

Circle unit 

__~cm/in

__-,--cm / in 

__ cm I in 

_~_ em I in 

kg /Ib 

I,TAGS PRESENT? Examined for external tags including fin clips? 0 Yes 0 No Scanned for PIT tags? DYesDNo 

Tag # . Tag Type Location of tag on carcass 

, 

CARCASS DISt:tOSITION: (check one or more)

01 ;: Left where found 

02 =Buried 

03 =Collected for necropsy/salvage

04 =Frozen for later examination 

05 =Other (describe) 

Carcass Necropsied?
 

DYes DNo
 

Date Necropsied:
 

Necropsy Lead:
 

.. 

PHOTODOCUMENTATION: 

Photoslvide taken? 0 Yes 0 No 

Disposition of PhotosNideo:_.__ 

.', .,.,..... 

.."­ .. 

. ; 

. ~: ,

SAMPLES COLLECTED? 0 Yes 0 No
 

Sample How preserved Dispo$ition (person, affiliation, use) .
 .. 

.. <) 

'. 

Comm~nts:

"~'." ., 
Distinguishing Characteristics of Atlantic and Shortnose Sturgeon (version 07-20-2009) 

Characteristic Atlantic Sturgeon, Acipenser oxyrinchus Shortnose Sturgeon, Acipenser brevirostrum 

Maximum length > 9feet' 274 cm \ 

Football shaped and small. Width inside lips <55% of 

bony interorbital width 

Paired plates posterior to the rectum & anterior to the 

anal fin. 

Rhombic, bony plates found along the lateral base of 

the anal fin (see diagram below) 

Anadromous; spawn in freshwater but primarily lead a 

marine existence 

4feet' 122 cm / 

Wide and oval in shape. Width inside lips> 62% of 

bony interorbital width 

1-3 pre-anal plates almost always occurring as median 

structures (occurring singly) 

No plates along the base of anal fin 

Freshwater amphidromous; found primarily in fresh 

water but does make some coastal migrations 

Mouth 

*Pre-anal plates 

Plates along the 

anal fin 

Habitat'Range 

* From Vecsei and Peterson, 2004 

ATLANTIC 

Describe any wounds / abnormalities (note tar or oil, gear or debris entanglement, propeller damage, etc.). Please note if no 

wounds I abnormaliti~s are found. 

Data Access Policy: Upon written request, information submitted to Natiomil Manne Fisheries Service (NOAA Fisheries) on this form 

will be released to the requestor provided that the requestor credit the collector of the information and NOAA Fisheries. NOAA 

Fisheries will notify the collector that these data have been requested and the intent of their use. 

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