UNITED STATES DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

NATIONAL MARINE FISHERIES SERVICE

Northwest Region 

7600 Sand Point Way N.E., Bldg. 1 

Seattle, WA 98115 

Refer to NMFS No. : 

2009/04136 April 21, 2010 

Richard Parkin 

United States Environmental Protection Agency 

Region 10 

1200 Sixth Avenue, Suite 900 

Seattle, Washington 98101-3140 

Re: Endangered Species Act Section 7 Biological Opinion and Magnuson-Stevens Fishery 

Conservation and Management Act Essential Fish Habitat Conservation 

Recommendations for the Siuslaw River Ocean Dredged Material Disposal Site 

Designation. 

Dear Mr. Parkin: 

The enclosed document contains a biological opinion (Opinion) prepared by the National Marine 

Fisheries Service (NMFS) pursuant to section 7(a)(2) of the Endangered Species Act (ESA) on 

the effects of the Environmental Protection Agency’s (EPA) proposal to designate two ocean 

dredged material disposal sites, and to adopt a Site Management and Monitoring Plan pursuant to 

section 102(c) of the Marine Protection, Research and Sanctuaries Act, as amended, 33 U.S.C. 

§§ 1401 to 1445, near the mouth of the Siuslaw River, Lane County, Oregon. Based on 

conversations with EPA, this consultation contains slight refinements to a consultation issued to 

EPA for this action on April 16, 2010. This consultation replaces the April 16, 2010 consultation. 

In this Opinion, NMFS concludes that the proposed action is not likely to jeopardize the 

continued existence of Oregon Coast (OC) coho salmon (Oncorhynchus kisutch) or southern 

green sturgeon (Acipenser medirostris), or to destroy or adversely modify critical habitats 

designated for southern green sturgeon. Moreover, NMFS concludes that the proposed action is 

not likely to adversely affect southern green sturgeon, eulachon (Thaleichthys pacificus), eastern 

Steller sea lions (Eumetopias jubatus), blue whales (Balaenoptera musculus), fin whales 

(Balaenoptera physalus), humpback whales (Megaptera novaeangliae), Southern Resident killer 

whales (Orcinus orca), four marine turtle species, or critical habitat designated for southern 

green sturgeon or proposed for leatherback turtles. 

As required by section 7 of the ESA, an incidental take statement prepared by NMFS is provided 

with this Opinion. However, the proposed site designations and management plan do not 

describe, approve, or compel any specific dredge or dredge disposal action. Thus, all take of OC 

coho salmon that is likely to result from subsequent dredge actions and include spoil disposal at 

these sites will occur at the project-specific level, not the site designation or management plan 

level. Accordingly, NMFS does not exempt incidental take in this Opinion. Take exemption for 

any dredge and dredge disposal action that is interrelated with the EPA’s action to designate 

these sites will occur in a project-specific consultation. 
This document also includes the results of our analysis of the action’s likely effects on essential 

fish habitat (EFH) pursuant to section 305(b) of the Magnuson-Stevens Fishery Conservation and 

Management Act (MSA), and includes two conservation recommendations to avoid, minimize, 

or otherwise offset potential adverse effects on EFH. These conservation recommendations are 

not a subset of the ESA take statement’s terms and conditions. Section 305(b) (4) (B) of the 

MSA requires Federal agencies to provide a detailed written response to NMFS within 30 days 

after receiving these recommendations. 

If the response is inconsistent with the EFH conservation recommendations, the EPA must 

explain why the recommendations will not be followed, including the scientific justification for 

any disagreements over the effects of the action and the recommendations. In response to 

increased oversight of overall EFH program effectiveness by the Office of Management and 

Budget, NMFS established a quarterly reporting requirement to determine how many 

conservation recommendations are provided as part of each EFH consultation and how many are 

adopted by the action agency. Therefore, we request that in your statutory reply to the EFH 

portion of this consultation, you clearly identify the number of conservation recommendations 

accepted. 

If you have questions regarding this consultation, please contact Robert Anderson, Fisheries 

Biologist in the Oregon State Habitat Office, at 503.231.2226. 

 Sincerely, 

 Barry A. Thom 

 Acting Regional Administrator 

cc: Joyce Casey, Corps 
Endangered Species Act 

Biological Opinion 

and 

Magnuson-Stevens Fishery Conservation and 

Management Act 

Essential Fish Habitat 

Conservation Recommendations 

for the 

Siuslaw River Ocean Dredged Material Disposal Site Designation 

Lead Action Agency: Environmental Protection Agency 

Consultation 

Conducted By: National Marine Fisheries Service 

 Northwest Region 

Date Issued: April 21, 2010 

Issued by: ___________________ 

 Barry A. Thom 

 Acting Regional Administrator 

NMFS No.: 2009/04136
-iTABLE OF CONTENTS 

INTRODUCTION .......................................................................................................................... 1

Background and Consultation History ........................................................................................ 1

Description of the Proposed Action ............................................................................................ 3

Interdependent and Interrelated Actions ..................................................................................... 5

Action Area ................................................................................................................................. 6

“Not Likely to Adversely Affect” Finding ................................................................................. 8

ENDANGERED SPECIES ACT BIOLOGICAL OPINION ....................................................... 11

Status of the Species and Critical Habitat ................................................................................. 12

OC Coho Salmon .............................................................................................................. 12

Southern Green Sturgeon Critical Habitat ........................................................................ 15

Environmental Baseline ............................................................................................................ 17

Species Within the Action Area ........................................................................................ 20

Critical Habitat Within the Action Area ........................................................................... 20

Effects of the Proposed Action ................................................................................................. 20

Environment Within the Action Area ............................................................................... 20

Species Within the Action Area ........................................................................................ 22

Critical Habitat Within the Action Area ........................................................................... 22

Cumulative Effects .................................................................................................................... 22

Synthesis and Integration of Effects ......................................................................................... 22

Conclusion ................................................................................................................................ 23

Incidental Take Statement......................................................................................................... 23

Amount or Extent of Take ................................................................................................ 24

Conservation Recommendations .............................................................................................. 24

Reinitiation of Consultation ...................................................................................................... 24

MAGNUSON-STEVENS FISHERY CONSERVATION AND MANAGEMENT ACT .......... 25

EFH Conservation Recommendations ...................................................................................... 25

DATA QUALITY ACT DOCUMENTATION AND PRE-DISSEMINATION REVIEW ........ 26

LITERATURE CITED ................................................................................................................. 28
-1- 

INTRODUCTION 

This document contains a biological opinion (Opinion) that was prepared by National Marine 

Fisheries Service (NMFS) in accordance with section 7(b) of the Endangered Species Act of 

1973, as amended (16 U.S.C. 1531, et seq.), and implementing regulations at 50 CFR 402.1 It 

also contains essential fish habitat (EFH) conservation recommendations prepared by NMFS in 

accordance with section 305(b)(2) of the Magnuson-Stevens Fishery Conservation and 

Management Act (MSA) (16 U.S.C. 1801, et seq.) and implementing regulations at 50 CFR 600. 

The Opinion and EFH conservation recommendations are both in compliance with section 515 of 

the Treasury and General Government Appropriations Act of 2001 (Data Quality Act) (44 U.S.C. 

3504 (d)(1) and 3516), and underwent pre-dissemination review. The administrative record for 

this consultation is on file at the Oregon State Habitat Office in Portland, Oregon. 

Background and Consultation History

On February 23, 2009, NMFS received a request from the U.S. Environmental Protection 

Agency (EPA) requesting a species list for an Ocean Dredged Material Disposal Site (ODMDS) 

proposed offshore of the mouth of the Siuslaw River. 

On March 30, 2009, NMFS provided the following list of threatened or endangered species that 

may occur in the proposed project area, and subsequently amended the list on April 8, 2009 to 

include the following species: 

1. Anadromous Fish 

a. Salmon 

i. Chinook salmon (Oncorhynchus tshawytscha) 

(1) Lower Columbia River (LCR) 

(2) Upper Willamette River (UWR) 

(3) Upper Columbia River spring-run (UCR) 

(4) Snake River spring/summer run (SRSS) 

(5) Snake River fall-run (SRF) 

ii. Coho salmon (O. kisutch) 

(1) LCR 

(2) Southern Oregon / Northern California Coasts (SONCC) 

(3) Oregon Coast (OC) 

b. Southern green sturgeon (Acipenser medirostris) 

2. Marine Mammals 

a. Whales 

i. Southern resident killer whale (Orcinus orca) 

ii. Blue whale (Balaenoptera musculus) 

iii. Fin whale (Balaenoptera physalus) 

iv. Humpback whale (Megaptera novaeangliae) 

b. Pinnipeds 

i. Eastern Steller sea lion (Eumotopias jubatus) 

 

1

 With respect to designated critical habitat, the following analysis relied only on the statutory provisions of the 

ESA, and not on the regulatory definition of “destruction or adverse modification” at 50 CFR 402.02. 
-2- 

In that same letter, NMFS also informed the EPA that 53 species of groundfish, two species of 

Pacific salmon, and five coastal pelagic species have EFH designated within the proposed project 

area. 

On July 27, 2009, NMFS received a letter and biological assessment (BA) from the EPA the 

requesting formal consultation under section 7(a)(2) of the ESA, and EFH consultation under 

section 305(b) of the MSA regarding the likely effects of designating Siuslaw ODMDS under 

section 102 (c) of the Marine Protection, Research and Sanctuaries Act (MPRSA). 

In that BA, the EPA determined that its proposed action may affect, and is likely to adversely 

affect (LAA) OC coho salmon and southern green sturgeon, and may affect, but is not likely to 

adversely affect (NLAA) the other salmon and marine mammal species on this list. The EPA also 

concluded that eulachon may occur in the proposed action area, although NMFS did not include 

that species on its March 30, 2009 species list, and that the proposed action would be NLAA for 

that that species.2

 Further, the EPA determined the proposed action will have no effect on any 

designated critical habitat, except for southern green sturgeon, for which the EPA concluded the 

proposed action was NLAA. Finally, the EPA’s effects determination regarding EFH for all 

species with EFH within the proposed project area was that the proposed action may adversely 

affect. 

On December 18, 2009, NMFS received a letter from the EPA that withdrew its request for 

formal consultation and requested informal consultation. That letter included a BA Addendum 

that changed the EPA’s previous effect calls for OC coho salmon and southern green sturgeon 

from LAA to NLAA. As a reason for changing its effects calls to NLAA, the EPA cited the lack 

of overlap between peak outmigration and disposal times for OC coho, the small number of 

likely disposal events each year (20 or less), and the fact that disposal would mostly consist of 

sand released gradually from a hopper dredge while the dredge is underway, thus reducing the 

potential for physiological effects to any nearby salmon or sturgeon. NMFS did not respond to 

this request in writing but did discuss the request with the EPA, and explained that NMFS had 

sufficient information to complete the consultation and intended to issue a biological opinion.3

On January 5, 2010, NMFS proposed to revise critical habitat for leatherback turtles by, among 

other things, include offshore marine areas from Cape Flattery, Washington, to the Umpqua 

River, Oregon, in the designation (75 FR 319). In light of this proposal, NMFS provides NLAA 

determinations for marine turtles. 

 

2

 NMFS proposed eulachon for listing on March 13, 2009 (74 FR 10857), and listed this species as threatened on 

March 18, 2010 (75 FR 13012). 

3

 NMFS recently issued two biological opinions to the EPA for designation of ocean dredge disposal sites in 

Oregon: ESA Section 7 Formal Consultation and MSA EFH Consultation for the EPA Site Designation of the 

Rogue River Ocean Disposal Site, Pacific Ocean, Curry County, Oregon (EPA: ETPA-083) (refer to NMFS No.: 

2008/05437) (March 19, 2009) and ESA Section 7 Formal Consultation and MSA EFH Consultation for the EPA 

Site Designation of the North and South Umpqua River Ocean Disposal Sites, Pacific Ocean, Douglas County, 

Oregon (EPA: ETPA-083) (refer to NMFS No.: 2008/05438) (March 20, 2009). 
-3- 

Description of the Proposed Action

The proposed action is the EPA’s proposal to designate the Siuslaw ODMDS pursuant to section 

102(c) of the MPRSA. Included in this designation is the adoption of a Site Management and 

Monitoring Plan (SMMP). These sites are intended primarily for, but will not be limited to, use 

by the U.S. Army Corps of Engineers (Corps) for disposal of material removed from the Siuslaw 

River federal navigation project (Siuslaw River Nav Project). Each specific proposal to dispose 

of dredged material at the proposed Siuslaw sites would require a permit, or in the case of the 

U.S. Army Corps of Engineers (Corps), a demonstration that substantive permit requirements 

have been met, before disposal could occur. 

The proposed Siuslaw ODMDS consists of two areas, North and South, to be designated 

approximately 1 mile offshore of the entrance to the Siuslaw River (Figure 1). For both sites, the 

disposal site, placement area, and drop zone are identical. 

The proposed North Site is 4,800 feet (ft) by 2,000 ft, ranges in depth from approximately 30 ft 

to 120 ft, and has an average depth of 90 ft. North Site coordinates, in longitude and latitude 

relative to North American Datum (NAD) 83, are as follows: 

44o

 01’ 31. 025”N, 124o 10’ 12. 917”W 

44o

 01’ 49. 393”N, 124o 10’ 02. 848”W 

44o 01’ 31. 965”N, 124o 09’ 01. 857”W 

44o

 01’ 13. 454”N, 124o 09’ 11. 408”W 

The proposed South Site is 3,000 ft by 2,000 ft, ranges in depth from approximately 80 ft to 125 

ft, and has an average depth of 78 ft. South Site coordinates, in longitude and latitude relative to 

NAD 83, are: 

44o 00’ 46. 724”N, 124o 10’ 26. 551”W 

44o

 01’ 06. 405”N, 124o 10’ 24. 448”W 

44o

 01’ 04. 13”N, 124o 09’ 43. 516”W 

44o 00’ 44. 446”N, 124o 09’ 45. 626”W 
-4- 

Figure 1. EPA’s proposed Siuslaw ODMDS locations. 
-5- 

The EPA’s proposal to complete this designation and planning are administrative acts that do 

not, by themselves, describe, approve, or compel any specific dredge or dredge disposal action. 

Interdependent and Interrelated Actions 

The EPA and Corps intend for the proposed designation to supersede all other ocean disposal 

sites related to the Siuslaw River Nav Project. Moreover, section 103(b) of the MPRSA requires 

the Corps to use designated ODMDS sites that are designated by the EPA to the maximum extent 

feasible. Because disposal at this site depends on the EPA’s proposed action for its justification, 

NMFS considers further use of the site by the Corps to dispose of dredged material from the 

Siuslaw River Nav Project to be interrelated with the proposed action. Conversely, NMFS does 

not consider the actual dredging of the Siuslaw River Nav Project to be interrelated (or 

independent) with the proposed action because designation of the site does not justify, or 

legitimize, dredging, per se, and because dredging has utility that is independent of the proposed 

action. 

Under section 7(a)(2) of the ESA, the “effects of the action” means 

the direct and indirect effects of an action on the species or critical habitat, 

together with the effects of other activities that are interrelated or interdependent 

with that action, that will be added to the environmental baseline 

50 CFR 402.02 

Accordingly, to complete the analysis of effects in this Opinion, NMFS considered the effects of 

dredge disposal as part of the Siuslaw River Nav Project, an action that NMFS found to be 

interrelated to the proposed action, to be part of the effects of this action. In this case, the effects 

of the interrelated action, dredging, are the only effects that the action will have on the species or 

critical habitat. 

The Siuslaw River Nav Project was authorized by the Rivers and Harbor Acts of September 19, 

1890; June 25, 1910; March 3, 1925; and July 3, 1958; and a 1960 section 107 project and Public 

Law 96-367 dated October 1, 1980. The authorized project includes these nine components: 

 North jetty, 8,390 ft long 

 North spur jetty, 400 ft long 

 South jetty, 4,200 ft long 

 South spur jetty, 400 ft long 

 Entrance channel, ocean to river mile (RM) zero, 300 ft wide, 16 ft deep 

 Navigation channel, 5 mi long, 200 ft wide, 16 ft deep 

 Turning basin at the City of Florence, 600 ft long, 400 ft wide, 16 ft long 

 Navigation channel from Florence to RM 16. 5, 11. 5 miles long, 150 ft wide, 12 ft deep 

 Turning basin at RM 15. 5, 500 ft long, 300 ft wide and 12 ft deep 

Dredging for the Siuslaw River Nav Project occurs between the months of June and October. 

The Corps targets a volume of 100,000 CY (CY) per year, although from 1997 through 2007 was 
-6- 

only 53,136 CY. The dredging occurs over a maximum of 20 days each year, but averages 7.9 

days. Based on the maximum capacity of the dredge Yaquina, the Corps can haul an average of 

800 CY per load, a volume of 100,000 CY would require 125 hauls to remove, or 1 haul every 3. 

84 hours averaged over the 20-day period. 

Action Area 

The action area includes the geographic area contained within each rectangular area in Figure 1 

as described by the boundary points plus an area outside of each rectangle measuring 200 ft in all 

directions from the boundaries of the disposal sites to account for suspended sediment occurring 

outside the ODMDS, based on information provided to NMFS by EPA. 

Based on information provided by the EPA and developed during consultation, NMFS 

determined the proposed action is LAA Oregon coast (OC) coho salmon and, for reasons 

explained below, NLAA for all other species that may occur within the action area (Table 1). 

NMFS also determined that the action is NLAA for critical habitat designated for southern green 

sturgeon, and NLAA critical habitat proposed for leatherback turtle. Critical habitat has not been 

designated or proposed for any other species within the action area. 
-7- 

Table 1. Federal Register notices for final rules that list threatened and endangered species, 

designate critical habitats, or apply protective regulations to listed species 

considered in this consultation. Listing status: ‘T’ means listed as threatened 

under the ESA; ‘E’ means listed as endangered; “P” means proposed. 

Species Listing Status Critical Habitat Protective Regulations

Marine and Anadromous Fish 

Chinook salmon (Oncorhynchus tshawytscha) 

 Lower Columbia River T 6/28/05; 70 FR 37160 9/02/05; 70 FR 52630 6/28/05; 70 FR 37160 

 Upper Willamette River T 6/28/05; 70 FR 37160 9/02/05; 70 FR 52630 6/28/05; 70 FR 37160 

 Upper Columbia River spring-run E 6/28/05; 70 FR 37160 9/02/05; 70 FR 52630 ESA section 9 applies 

 Snake River spring/summer run T 6/28/05; 70 FR 37160 10/25/99; 64 FR 57399 6/28/05; 70 FR 37160 

 Snake River fall-run T 6/28/05; 70 FR 37160 12/28/93; 58 FR 68543 6/28/05; 70 FR 37160 

Coho salmon (O. kisutch) 

 Lower Columbia River T 6/28/05; 70 FR 37160 Not applicable 6/28/05; 70 FR 37160 

 Oregon Coast T 2/11/08; 73 FR 7816 2/11/08; 73 FR 7816 2/11/08; 73 FR 7816 

Southern Oregon / Northern California 

Coasts 

T 6/28/05; 70 FR 37160 5/5/99; 64 FR 24049 6/28/05; 70 FR 37160 

Green sturgeon (Acipenser medirosris

 Southern T 4/07/06; 71 FR 17757 10/09/09; 74 FR 52300 P 5/21/09; 74 FR 23822 

Eulachon (Thaleichthys pacificus) 

 Eulachon T 3/18/10; 75 FR 13012 Not applicable Not applicable 

Marine Mammals 

Steller sea lion (Eumetopias jubatus) 

 Eastern T 5/5/1997; 63 FR 24345 8/ 27/93; 58 FR 45269 11/26/90; 55 FR 49204 

Blue whale (Balaenoptera musculus) 

 E 12/02/70; 35 FR 18319 Not applicable ESA section 9 applies 

Fin whale (Balaenoptera physalus) 

 E 12/02/70; 35 FR 18319 Not applicable ESA section 9 applies 

Humpback whale (Megaptera novaeangliae) 

 E 12/02/70; 35 FR 18319 Not applicable ESA section 9 applies 

Killer whale (Orcinus orca) 

 Southern Resident E 11/18/05; 70 FR 69903 11/26/06; 71 FR 69054 ESA section 9 applies 

Sei whale (Balaenoptera borealis) 

 E 12/02/70; 35 FR 18319 Not applicable ESA section 9 applies 

Sperm whale (Physeter macrocephalus) 

 E 12/02/70; 35 FR 18319 Not applicable ESA section 9 applies 

Marine Turtles 

Green turtle (Chelonia mydas) 

Excludes Pacific Coast of Mexico and 

Florida 

ET 7/28/78; 43 FR 32800 9/02/98; 63 FR 46693 ESA section 9 applies 

Leatherback turtle (Dermochelys coriacea) 

 E 6/02/70 ; 39 FR 19320 3/23/79; 44 FR 17710 

P 1/5/201075 FR 319 

ESA section 9 applies 

Loggerhead turtle (Caretta caretta) 

 T 7/28/78; 43 FR 32800 Not applicable 7/28/78; 43 FR 32800 

Olive ridley turtle (Lepidochelys olivacea)

 ET 7/28/78; 43 FR 32800 Not applicable ESA section 9 applies 
-8- 

 “Not Likely to Adversely Affect” Finding 

No further consultation is necessary if NMFS concur with an action agency’s determination that 

a proposed action is NLAA for a species or critical habitat. This NMFS concurrence must be 

based on NMFS finding that the effects are all expected to be discountable, insignificant, or 

completely beneficial (USFWS and NMFS 1998). Beneficial effects are contemporaneous 

positive effects without any adverse effects to the species. Insignificant effects relate to the size 

of the impact and should never reach the scale where take occurs. Discountable effects are those 

extremely unlikely to occur. Based on best judgment, a person would not (1) be able to 

meaningfully measure, detect, or evaluate insignificant effects; or (2) expect discountable effects 

to occur. 

Salmon

After most salmon enter coastal waters, their swimming movements are oriented and directed, 

usually to the northwest toward the migration corridor of the Alaska Current although the speed 

of this migration is affected by the size of the salmon and the direction and intensity coastal 

currents (Pearcy 1992). Given this strong natural swimming ability and determined northward 

orientation, it is extremely unlikely that young salmon would find themselves in a nearshore4

area away from their natal stream, where any current or eddy would delay them. Coho salmon 

are an exception to this pattern. They can delay leaving the area near the mouth of their natal 

stream, sometimes for months, before migrating northward (Shapalov and Taft 1954, and 

literature cited therein). OC coho salmon is the only species in Table 1 that spawns in the 

Siuslaw River, and thus is the only species likely to occur within the nearshore action area. Thus, 

NMFS finds that effects of the action are expected to be insignificant or discountable (i.e.,

NLAA) for all ESA-listed salmon in Table 1, except for OC coho salmon. Further, because the 

effects of operations associated with the Corps’ use of the action area are likely to alter migratory 

conditions, water quality and foraging conditions for OC coho salmon, NMFS finds that the 

effects of the proposed action are not all expected to be insignificant or discountable for OC coho 

salmon. 

Green Sturgeon

Southern green sturgeon migrate along the Pacific coast at depths less than 328 feet and are 

typically found at depths ranging between 131 feet and 230 feet over the Continental shelf 

(Erickson and Hightower 2007). At the ODMDS water depths range from minus 30 feet North 

American Datum 1983 (NAD) 83 to minus 120 feet NAD 83, and water depths at the Siuslaw 

River south ODMDS range from minus 80 feet NAD 83 to minus 125 feet NAD 83. Research 

conducted by Moser and Lindley in 2006 on Southern green sturgeon distribution and migration 

patterns reported that Southern green sturgeon are only present in the estuaries of Willipa Bay, 

Washington, Grays Harbor, Washington, and the Columbia River during the months of June 

through October. In addition to the aforementioned estuaries, Southern green sturgeon 

infrequently may occur in Coos Bay, Winchester Bay, and Yaquina Bay, although field surveys 

carried out by the Oregon Department of Fish and Wildlife over a 4-year period (2000-2004) 

 

4

 Nearshore means the zone from coastal high tide line offshore to the 30-fathom (180 feet or 55 meter) depth 

contour (ODFW 2006). 
-9- 

captured no green sturgeon in the Coos, Coquille, Yaquina, or Siuslaw rivers, and 33 green 

sturgeon were captured in the Umpqua River (Farr and Kern 2005). Coos Bay and Winchester 

Bay lie approximately 30 to 50 miles south of the ODMDS, and Yaquina Bay lies approximately 

50 miles to the north of the ODMDS. Based on the water depth preference for oceanic migration 

of Southern green sturgeon, and the field-based evidence on Southern green sturgeon distribution 

and occurrence, or lack thereof, especially in the Siuslaw River, in the aforementioned estuaries, 

NMFS is reasonably certain that Southern green sturgeon are unlikely to occur in the ODMDS as 

the overwhelming majority of Southern green sturgeon are resident in the estuaries of Willipa 

Bay, Washington, Grays Harbor, Washington, the Columbia River, and the Umpqua River 

during the June through October dredge and disposal activities carried out by the Corps. 

Therefore, NMFS finds that effects of the action are expected to be insignificant or discountable 

(i.e., NLAA) for southern green sturgeon. 

Eulachon 

Eulachon have occurred in Siuslaw River, although apparently none have been observed there 

since the 1970s (Drake et al. 2010), such that NMFS considers that an occurrence now would be 

extremely unlikely. Therefore, NMFS finds that all effects of the action are expected to be 

discountable or insignificant (i.e., NLAA) for eulachon. 

Marine Mammals 

Steller sea lions, blue whales, fin whales, humpback whales, and Southern Resident killer whales 

may occur in the action area but, based on previous analyses (NMFS 2009a, 2009b), their 

presence, at most, would be infrequent and transitory. The most proximate Steller sea lion 

haulout (Sea Lion Caves) is sufficiently distant from the proposed action area (at least eight 

miles away from the proposed disposal sites) that NMFS does not anticipate any effects to 

haulout behavior. If marine mammals are present during disposal activities, vessel operations and 

dredge discharge procedures associated with the proposed action may cause temporary 

disturbance. Minimal vessel transits will be associated with the proposed action (hopper dredge, 

estimated 20 days of activity annually). Barge-sized vessels, such as a hopper dredge, associated 

with the proposed action would require short transits to the nearshore or ODMDS, where the 

vessel would remain relatively immobile until work is complete, with minimal sound or potential 

for disturbance. Any temporary disturbance would be short-term and localized, with no lasting 

effects, and therefore insignificant. Vessel strikes are extremely unlikely because the barge-sized 

vessels are slow moving, follow a predictable course, do not target marine mammals, and should 

be easily detected and avoided by marine mammals. Potential effects from vessel strikes are 

therefore discountable. 
-10- 

The proposed action is not likely to adversely affect the quality of marine mammal prey; 

however, it may affect the quantity of prey available, by take of juvenile salmon. Any take of 

juvenile salmon associated with disposal activities would result in an insignificant reduction in 

adult equivalent prey resources for marine mammals that may intercept OC coho salmon and 

other prey species within their range (i.e., Southern Resident killer whales or Steller sea lions). 

Therefore, NMFS finds that all effects of the action are expected to be discountable or 

insignificant (i.e., NLAA) for ESA-listed marine mammals in Table 1.

Marine Turtles

Marine turtles are highly migratory, and the life histories of all species exhibit complex 

movements and migrations through geographically disparate habitats, so defining their 

geographic range is difficult. Green, leatherback, loggerhead and olive ridley turtles all nest on 

beaches within the U.S. and all depend on U.S. coastal waters for foraging and migratory habitat 

during certain stages of their life history. However, marine turtles have no breeding areas in 

Oregon and, except for leatherback turtles, are extremely rare in Oregon’s nearshore habitats, 

although this may change if ocean currents become warmer. Most leatherback sightings occur in 

marine waters within the coastal zone. Although sightings of marine turtles occur in Oregon, 

they are nonetheless exceptionally rare, therefore NMFS finds that all effects of the proposed 

action are expected to be discountable, insignificant or beneficial (i.e., NLAA) for ESA-listed 

marine turtles in Table 1. 

Leatherback Turtle Proposed Critical Habitat 

The PCEs that NMFS identified as essential for the conservation of leatherback turtles when it 

proposed to revise critical habit to include marine waters off the U.S. West Coast, including the 

action area, are: (1) A sufficient quantity and quality of their jellyfish prey; and (2) migratory 

pathway conditions that allow for safe and timely passage to, from, and within high use foraging 

areas, including areas within the action area. Dredge disposal activities may result in the loss of 

polyp life-stage jellyfish and adult medusa jellyfish, on the ocean floor and in the water column, 

respectively, in the immediate area where dredge spoils descend through the water column and 

settle on the ocean floor. However, the small amount of prey losses that may occur intermittently 

and in the small area (ODMDS site) when dredge spoils would be released would result in an 

insignificant reduction in adult-equivalent prey available to leatherbacks in their proposed 

critical habitat. No effects on prey quality are anticipated. Similarly, intermittent vessel traffic 

associated with dredge disposal activities would have a discountable effect on leatherback turtle 

passage through the action area, given the extremely unlikely nature of leatherback turtle 

occurrence in the action area. Therefore, NMFS finds that all effects of the action are expected to 

be discountable or insignificant for proposed critical habitat of leatherback turtles. 

Southern Green Sturgeon Critical Habitat 

The primary constituent elements (PCEs) NMFS identified as essential for the conservation of 

the southern green sturgeon in coastal marine areas, including the action area, are (1) a migratory 

pathway necessary for safe and timely passage within marine and between estuarine and marine 
-11- 

habitats; (2) water quality with adequate dissolved oxygen levels and acceptably low levels of 

contaminants, and (3) abundant prey items for subadults and adults, which may include benthic 

invertebrates and fishes. Because operations associated with the Corps’ use of the action area are 

not likely to significantly alter PCEs for southern green sturgeon critical habitat, NMFS finds 

that the effects of the proposed action are expected to be insignificant or discountable.

ENDANGERED SPECIES ACT BIOLOGICAL OPINION

Section 7(a)(2) of the ESA requires Federal agencies to consult with NMFS to ensure that their 

actions are not likely to jeopardize the continued existence of endangered or threatened species, 

or adversely modify or destroy their designated critical habitat. The Opinion that follows records 

the results of the interagency consultation for this proposed action. The ITS provided after the 

Opinion specifies (1) the impact of any taking of threatened or endangered species that will be 

incidental to the proposed action; (2) reasonable and prudent measures that NMFS considers 

necessary and appropriate to minimize such impact, and (3) nondiscretionary terms and 

conditions (including, but not limited to, reporting requirements) that must be complied with by 

the Federal agency, applicant (if any), or both, to carry out the reasonable and prudent measures. 

To complete the jeopardy analysis presented in this Opinion, NMFS reviewed the status of each 

listed species5

 considered in this consultation, the environmental baseline in the action area, the 

effects of the action, and cumulative effects (50 CFR 402.14(g)). From this analysis, NMFS 

determined whether effects of the action were likely, in view of existing risks, to appreciably 

reduce the likelihood of both the survival and recovery of the affected listed species. 

For the critical habitat adverse modification analysis, NMFS considered the status of the entire 

designated area of the critical habitat considered in this consultation, the environmental baseline 

in the action area, the likely effects of the action on the function and conservation role of the 

affected critical habitat, and cumulative effects. NMFS used this assessment to determine 

whether, with implementation of the proposed action, critical habitat would remain functional, or 

retain the current ability for the PCEs to become functionally established, to serve the intended 

conservation role for the species. 6

If the action under consultation is likely to jeopardize the continued existence of an ESA-listed 

species, or destroy or adversely modify critical habitat, NMFS must identify any reasonable and 

prudent alternatives for the action that avoid jeopardy or destruction or adverse modification of 

critical habitat and meet other regulatory requirements (50 CFR 402.02). 

 

5 An “evolutionarily significant unit” (ESU) of Pacific salmon (Waples 1991) and a “distinct population segment” 

(DPS) (Policy Regarding the Recognition of District Vertebrate Population; 61 FR 4721, Feb 7, 1996) are both 

“species” as defined in section 3 of the ESA. 

6 Memorandum from William T. Hogarth to Regional Administrators, Office of Protected Resources, NMFS 

(November 7, 2005) (Application of the “Destruction or Adverse Modification” Standard Under Section 7(a)(2) of 

the Endangered Species Act). 
-12- 

Status of the Species and Critical Habitat 

The summaries that follow describe the status of the ESA-listed species, and their proposed or 

designated critical habitats, that occur within the geographic area of this proposed action and are 

considered in this Opinion. More detailed information on the status and trends of these listed 

resources, and their biology and ecology, can be found in the listing regulations and critical 

habitat designations published in the Federal Register (Table 1, above). 

It is likely that climate change will play an increasingly important role in determining the 

abundance of ESA-listed species, and the conservation value of designated critical habitats, in 

the Pacific Northwest. During the last century, average regional air temperatures increased by 

1.5°F, and increased up to 4°F in some areas (USGCRP 2009). Warming is likely to continue 

during the next century as average temperatures increase another 3 to 10°F (USGCRP 2009). 

Overall, about one-third of the current cold-water fish habitat in the Pacific Northwest is likely to 

exceed key water temperature thresholds by the end of this century (USGCRP 2009). 

Precipitation trends during the next century are less certain than for temperature but more 

precipitation is likely to occur during October through March and less during summer, and more 

of the winter precipitation is likely to fall as rain rather than snow (ISAB 2007, USGCRP 2009). 

Where snow occurs, a warmer climate will cause earlier runoff so stream flows in late spring, 

summer, and fall will be lower and water temperatures will be warmer (ISAB 2007, USGCRP 

2009). 

Higher winter stream flows increase the risk that winter floods in sensitive watersheds will 

damage spawning redds and wash away incubating eggs (USGCRP 2009). Earlier peak stream 

flows will also flush some young salmon and steelhead from rivers to estuaries before they are 

physically mature, increasing stress and the risk of predation (USGCRP 2009). Lower stream 

flows and warmer water temperatures during summer will degrade summer rearing conditions, in 

part by increasing the prevalence and virulence of fish diseases and parasites (USGCRP 2009). 

Other adverse effects are likely to include altered migration patterns, accelerated embryo 

development, premature emergence of fry, and increased competition and predation risk from 

warm-water, non-native species (ISAB 2007). 

The earth’s oceans are also warming, with considerable interannual and inter-decadal variability 

superimposed on the longer-term trend (Bindoff et al. 2007). Historically, warm periods in the 

coastal Pacific Ocean have coincided with relatively low abundances of salmon and steelhead, 

while cooler ocean periods have coincided with relatively high abundances (Scheuerell and 

Williams 2005, Zabel et al. 2006, USGCRP 2009). Ocean conditions adverse to salmon and 

steelhead may be more likely under a warming climate (Zabel et al. 2006). 

OC Coho Salmon

This species includes all naturally-spawned populations of coho salmon in Oregon coastal 

streams south of the Columbia River and north of Cape Blanco, and progeny of five artificial 

propagation programs. The Oregon Coast Technical Recovery Team (OC-TRT) identified 56 

historical populations, grouped into five major “biogeographic strata,” based on consideration of 
-13- 

historical distribution, geographic isolation, dispersal rates, genetic data, life history information, 

population dynamics, and environmental and ecological diversity (Table 2) (Lawson et al. 2007). 

Of the 56 historical populations identified by the OC-TRT, 13 populations were identified as 

functionally independent, eight as potentially independent, and 35 historical populations were 

identified as dependent populations. Functionally independent populations are identified as highpersistence populations whose population dynamics or extinction risk over a 100-year time frame 

is not substantially altered by exchanges of individuals with other populations. These populations 

are net “donor” populations that may provide migrants for other types of populations. Potentially 

independent populations are identified as high-persistence populations whose population 

dynamics may be substantially influenced by periodic immigration from other populations. In the 

event of the decline or disappearance of migrants from other populations, a potentially 

independent population could become a functionally independent population. Dependent 

populations are considered low-persistence populations that rely upon immigration from other 

populations. Without these inputs, dependent populations would have a lower likelihood of 

persisting over 100 years. Dependant populations are “receiving” populations that are dependent 

on sufficient immigration from surrounding populations to persist. 

The OC-TRT concluded that, if recent past conditions continue into the future, OC coho salmon 

are “moderately likely” to persist over a 100-year period without artificial support, and have a 

“low to moderate likelihood” of being able to sustain their genetic legacy and long-term adaptive 

potential for the foreseeable future (Wainwright et al. 2008). The major factors limiting recovery 

of OC coho salmon include altered stream morphology, reduced habitat complexity, loss of 

overwintering habitat, excessive sediment, high water temperature, and variation in ocean 

conditions. 
-14- 

Table 2. OC coho salmon populations in Oregon. Population type “D” means dependent; 

“FI” means functionally independent; and “PI” means potentially independent. 

Stratum Population Type Stratum Population Type 

North 

Coast 

Necanicum PI 

MidCoast 

(cont.) 

Alsea FI 

Ecola D Big (Alsea) D 

Arch Cape D Vingie D 

Short Sands D Yachats D 

Nehalem FI Cummins D 

Spring D Bob D 

Watseco D Tenmile D 

Tillamook FI Rock D 

Netarts D Big (Siuslaw) D 

Rover D China D 

Sand D Cape D 

Nestucca FI Berry D 

Neskowin D Sutton D 

MidCoast 

Salmon PI 

Lakes 

Siuslaw FI 

Devils D Siltcoos PI 

Siletz FI Tahkenitch PI 

Schoolhouse D Tenmile PI 

Fogarty D 

Umpqua 

Lower Umpqua FI 

Depoe D Middle Umpqua FI 

Rocky D North Umpqua FI 

Spencer D South Umpqua FI 

Wade D 

MidSouth 

Coast 

Threemile D 

Coal D Coos FI 

Moolack D Coquille FI 

Big (Yaquina) D Johnson D 

Yaquina FI Twomile D 

Theil D Floras PI 

Beaver PI Sixes PI 

NMFS does not expect coho salmon from any population other than the Siuslaw to be affected 

by the proposed action, so the remaining analysis will focus only on that population. 

Siuslaw River Population. All coho salmon outmigrating or returning to the Siuslaw 

River move through both the navigation channel and the nearshore ocean portions of the action 

area. Estimates of returning Siuslaw Basin adult coho spawners show considerable variability in 

the annual abundance from year to year (Table 5). Adult OC coho salmon return to the Siuslaw 

River in the fall/winter, migrating upstream to spawn, with a peak in October. Out-migration of 

juveniles to the ocean occurs from February through July, with a peak from April to mid-May. 

The estimated number of wild adults returning to the Yaquina Bay basin since 1990 has averaged 

9,702, with a range of 668 to 57,129 (Table 3). During the period from 2002 to present, these 

data on the number of returning adult OC coho salmon were collected using a different protocol 

then the previous years, and therefore, not entirely comparable. However, during the overlapping 

years of 2002 – 2004, the results were not extremely different, and are the best available for the 

purposes of this evaluation. 
-15- 

Table 3. Estimated wild OC coho salmon spawner abundance in the Siuslaw River basin 

(http://oregonstate. edu/dept/ODFW/spawn/cohoabund. htm) 

 Estimated Wild Coho Population

 Siuslaw Sub-Basin OC ESU 

Year Number of fish Est. % of ESU Number of fish 

1990 2,685 16% 16,510 

1991 3,740 13% 29,078 

1992 3,440 9% 38,604 

1993 4,428 10% 44,266 

1994 3,205 9% 37,477 

1995 6,089 15% 41,303 

1996 7,625 13% 59,453 

1997 668 5% 14,068 

1998 1,089 5% 19,918 

1999 2,724 8% 34,696 

2000 6,767 13% 54,085 

2001 11,024 7% 147,981 

2002 57,129 25% 231,411 

2003 29,257 14% 206,286 

2004 8,443 5% 176,576 

2005 16,907 12% 140,053 

2006 5,869 6% 103,551 

2007 3,552 7% 53,653 

Average 9,702 12% 80,498 

1998-2007 Avg. 14,276 12% 116,821 

The number of OC coho salmon juvenile outmigrants from the Siuslaw River basin has not been 

studied enough to provide a reliable estimate by direct sampling. However, it can be estimated 

by back-calculation dividing the number of returning adults by marine survival. Marine survival 

predictions averaged 4%, with a range of 0. 5% and 11. 7%, between 1970 and 1999 (PMFC 

2000). The average number of outmigrants estimated by this back calculation is 242,550 with a 

range of 16,700 to 5,737,375. 

Southern Green Sturgeon Critical Habitat 

The final designation of critical habitat for southern green sturgeon includes approximately: 

 487 mi of habitat in the Sacramento-San Joaquin Delta, 

 135 mi2

 of habitat within the Yolo and Sutter bypasses of the Sacramento River, 

 320 miles (mi) of riverine habitat, 

 897 mi2

 of estuarine habitat, 

 11,421 mi2

 of coastal marine habitat. 
-16- 

To assist in the designation of critical habitat for southern green sturgeon, NMFS convened a 

Critical Habitat Review Team, or “CHRT,” comprised of 9 federal biologists with demonstrated 

expertise regarding sturgeon habitat and related protective efforts. 

The CHRT assessed biological information pertaining to areas under consideration for 

designation as critical habitat to identify the areas occupied by southern green sturgeon, 

determine whether those areas contained PCEs essential for the conservation of those species, 

and whether unoccupied areas existed within the historical range of the southern green sturgeon 

may also be essential for conservation. The CHRT then scored each habitat area based on the 

quantity and quality of the physical and biological features; rated each habitat area as having a 

‘‘high,’’ ‘‘medium,’’ or ‘‘low’’ conservation value; and identified management actions that 

could affect habitat for southern green sturgeon. 

The ESA gives the Secretary of Commerce discretion to exclude areas from designation if he 

determines that the benefits of exclusion outweigh the benefits of designation. Considering 

economic factors and information from CHRT, NMFS partially or completely excluded the 

following types of areas from the southern green sturgeon critical habitat designation: 

1. Military areas. Some military areas were excluded because of the current national priority 

on military readiness, and in recognition of conservation activities covered by military 

integrated natural resource management plans. 

2. Tribal lands. Some Native American lands were excluded because of the unique trust 

relationship between tribes and the federal government, the federal emphasis on respect 

for tribal sovereignty and self governance, and the importance of tribal participation in 

numerous activities aimed at conserving listed species. 

In designating critical habitat for southern green sturgeon, NMFS organized information at the 

watershed scale then identified and designated critical habitat as “specific areas” within 

freshwater rivers, the bypasses, the Sacramento-San Joaquin Delta, coastal bays and estuaries, 

and coastal marine areas (within 60 fathoms depth). 

NMFS reviews the status of designated critical habitat affected by the proposed action by 

examining the condition and trends of PCEs throughout the designated area. For southern green 

sturgeon, these PCEs consist of site types and site attributes associated with life history events 

(Table 4). 
-17- 

Table 4. PCEs of critical habitat designated for southern green sturgeon and corresponding 

species life history events. 

Primary Constituent Elements 

Life History Event 

Site Type Site Attribute 

Freshwater 

riverine 

system 

Food resources 

Migratory corridor 

Sediment quality 

Substrate type or size 

Water Depth 

Water flow 

Water quality 

Adult spawning 

Embryo incubation, growth and development 

Larval emergence, growth and development 

Juvenile metamorphosis, growth and development 

Estuarine 

areas 

Food resources 

Migratory corridor 

Sediment quality 

Water flow 

Water depth 

Water quality 

Juvenile growth, development, seaward migration 

Subadult growth, development, seasonal holding, and 

 movement between estuarine and marine areas 

Adult growth, development, seasonal holding, movements 

 between estuarine and marine areas, upstream spawning 

 movement, and seaward post-spawning movement 

Coastal 

marine 

Areas (within 

60 fathoms) 

Food resources 

Migratory corridor 

Water quality 

Subadult growth and development, movement between 

 estuarine and marine areas, and migration between marine 

 areas 

Adult sexual maturation, growth and development, 

 movements between estuarine and marine areas, migration 

 between marine areas, and spawning migration 

Environmental Baseline

The Siuslaw River ODMDS are within the nearshore area of the Pacific Ocean off the mouth of 

the Siuslaw River. Sediments at these sites are primarily medium- to fine-grain marine sands and 

shell debris. These sandy sediments are common on the Oregon coast with natural variations in 

percent fines due to variations in currents and riverine inputs. The benthic community is typical 

of nearshore, high-energy environment found along the Oregon coast, largely dominated by very 

mobile organisms. These mobile organisms provide an important link in the marine food web. 

The nearshore ocean environment outside the mouth of the Siuslaw River supports anadromous 

salmonids as well as a variety of other pelagic and demersal fish species. Summer upwelling 

provides the nutrients to fuel primary and secondary production that in turn determines habitat 

quality in the form of available yearling coho salmon forage (Bi et al. 2008, Chase et al. 2007). 

Based on available information regarding general water quality conditions, water depths, and 

primary and secondary production, the baseline conditions of the action area provide, at a 

minimum, sufficient conditions to support coho salmon and southern green sturgeon. The habitat 

quality of these conditions varies from year to year depending on the large scale ocean dynamics 

that determine nutrient upwelling and water quality conditions. 

The Corps has used this general area to dispose of material removed from the Siuslaw River Nav 

Project since 1929, and part of the proposed site (Area A) on an interim basis since 1977 (Table 
-18- 

5; Figure 2). Because of mounding of dredged material at the interim site A, the Corps began 

disposing of dredged material from the Siuslaw River Nav Project at sites B and C in 1997. Sites 

B and C also show mounding. Until lifted in 2008, disposal restrictions were placed on the 

southeast corner of Site B which overlapped the interim Site A. The bulk of the material dredged 

has been placed in the larger Site B. In 2004, the Corps extended the use of sites B and C for 

another 5-year period in 2004. However, section 102 of the MPRSA now requires the EPA to 

designate this site as an ODMDS for dredged material to continue to be disposed here. 

Table 5. Siuslaw River Nav Project dredging volumes. 

Fiscal 

Year 

Dredging 

Volumes (x 1,000 

CY) 

Fiscal 

Year 

Dredging 

Volumes (x 1,000 CY) 

Fiscal 

Year 

Dredging 

Volumes (x 1,000 

CY) 

1929/1977 2,800. 0 1987 215. 8 * 1998 69. 6 (C) 

1977 139. 3* 1988 114. 5 * 1999 43. 5 (B) 

1978 191. 4* 1989 116. 8 * 2000 55. 1 (C) 

1979 246. 6* 1990 99. 0 * 2001 101. 2 (C) 

1980 94. 2* 1991 65. 9 * 2002 117. 3 (B) 

1981 388. 4* 1992 194. 2 * 2003 55. 0 (B) 

1982 193. 4* 1993 239. 6 * 2004 23. 1 (B+C) 

1983 213. 3* 1994 223. 3 * 2005 33. 4 (B) 

1984 221. 1* 1995 121. 6 * 2006 22. 3 (B) 

1985 271. 2* 1996 84. 8 * 2007 76. 0 (B) 

1986 218. 8 * 1997 40. 0 (C) 2008 69. 9 (B) 

* Dredged material from 1977 to 1996 was placed in the EPA-designated Interim ODMDS (Area A).

 
-19- 

Figure 2. Historical Siuslaw River Nav Project ocean disposal sites. 
-20- 

Species Within the Action Area 

OC Coho Salmon. Juvenile OC coho salmon begin to enter the action area at the ocean 

in April and out-migration is nearly complete by May 15. Once there, these fish either transit the 

action area toward their open ocean migration, or they may delay, sometimes for months, rearing 

near the mouth of their natal stream (Shapalov and Taft 1954, and literature cited therein). Fish 

that stay nearshore generally continue to school in groups of 10 to 50 or more similar sized 

individuals as they become acclimated to salt water and grow rapidly. It is unlikely that juvenile 

OC coho salmon occur within the action area between late September and early April. 

Critical Habitat Within the Action Area 

Southern Green Sturgeon Critical Habitat. Although southern green sturgeon are not 

confirmed to occur in the Siuslaw River or its estuary, the action area is within a coastal marine 

area that was designated as “high conservation value” critical habitat for this species because it is 

part of the primary migratory/connectivity corridor used by for subadult and adult southern green 

sturgeon as they migrate to and from summer habitats in coastal bays and estuaries, and winter 

habitats within coastal waters between Vancouver Island, BC, and southeast Alaska (Moser and 

Lindley 2007). 

Activities that NMFS identified as threats during the designation process that may require special 

management consideration to protect the conservation value of this critical habitat include 

bottom trawl fishing, dredging and deposition of dredged material, alternative energy 

hydrokinetic projects, liquid natural gas projects, and point and nonpoint pollution generating 

actions. 

Effects of the Proposed Action 

All effects of the proposed action identified in this Opinion are the direct effects of the 

interrelated action of dredge disposal at the ODMDS that will be carried out by the Corps as part 

of the Siuslaw Nav Project. These effects will occur as the result of vessel traffic to and from the 

ODMDS, and the release dredge material into the water column within the ODMDS such that it 

falls through the open water and settles on the ocean floor. 

Environment Within the Action Area 

Vessel Traffic. Approximately 65 vessel trips per year by a dredge or barge will occur 

each year, between June and October, to transport the Corps’ average annual volume of 53,000 

CY of dredged material between the Siuslaw River Nav Project and the ODMDS, and 

approximately 125 trips will be required to transport the full target volume of 100,000 CY. Each 

trip will average 3 nautical miles (NM) or less. Thus, the average annual vessel traffic in terms of 

NM travelled is likely to be 195 NM, and the maximum is likely to be 375 NM. 

Dredge Material Disposal. Between 65 and 125 loads of dredged material, consisting of 

approximately 800 CY per load, for a total of 53,000 to 100,000 CY will be disposed of at the 

OMDMS each year. 
-21- 

Based on EPA’s review of modeling, monitoring data, analysis of sediment quality, and history 

of use (75 FR 5708; 2/4/2010), no detectable contaminant concentrations or water quality effects, 

e.g., suspended solids, would be expected to reach any beach or shoreline from disposal activities 

at the sites. The primary impact of disposal activities on water quality is expected to be 

temporary turbidity caused by the physical movement of sediment through the water column. All 

dredged material proposed for disposal will be evaluated according to the ocean dumping 

regulations and guidance developed by EPA and the Corps. 

Under the proposed action, disposal of suitable material meeting the regulatory criteria and 

deemed environmentally acceptable for ocean dumping will be allowed at the proposed sites. 

Most of the dredged material (approximately 97%) to be disposed of at the sites is expected to be 

sandy material, while a small amount of material (up to 3% of the material) would be classified 

as fine-grained. Occasionally, naturally occurring debris may be present in the dredged material. 

Hopper dredges, which are used for the Corps' annual navigational dredging, are not capable of 

removing debris from the dredge site. However, specific projects may utilize a clamshell dredge, 

in which case there is the potential for the occasional placement of naturally occurring debris at 

the disposal sites. 

Initially, coarser dredged material will descend at a rate of 11 ft/second (sec), slowing to 7 ft/sec 

near the end of the load. As water is added to the dredged material to help wash it out of the 

hopper, the slurry mixture becomes more neutrally buoyant and descends at a slower rate. 

Although large pelagic organisms will likely be able to avoid the column of dredged material as 

it makes its 3 to 20 sec descent though the water column, smaller organisms, including plankton 

and small nekton are more likely to be entrained with the material, and to suffer injury or death 

due to impact and abrasion, unless they are pushed aside by a boundary layer of water created by 

the material’s descent. 

Sediment movement in the littoral zone consists of two mechanisms depending upon the size of 

the sediment. Material that is finer than sand size is carried in suspension in the water and moves 

offshore relatively quickly. Sediments sand size or coarser may be occasionally suspended by 

wave action near the bottom, and are moved by bottom currents or directly as bedload. Tidal, 

wind and wave forces contribute to generating bottom currents, which act in relation to the 

sediment grain size and water depth to transport sediment. 

Based on EPA’s review of dispersal, horizontal transport and vertical mixing characteristics of 

the area at and in the vicinity of the sites, the marine sands and fluvial gravels from the Siuslaw 

River distribute away from the river mouth rapidly. The beaches do not show significant 

accretion or loss. The bottom current records suggest a bias in transport to the north. Fine grained 

material tends to remain in suspension and to experience rapid offshore transport compared to 

other sediment sizes. Sediment transport of sand-sized or coarser material tends to move directly 

as bedload, but is occasionally suspended by wave action near the seafloor. The proposed sites 

are not expected to change these characteristics. Sediment mounding will be closely monitored 

under terms of the proposed SMMP and the EPA and Corps will use adaptive management 

measures to address any mounding issues that may arise. 
-22- 

Species Within the Action Area 

OC Coho Salmon. In recent biological opinions on the effects of similar disposal site 

designations for the Rogue and Umpqua rivers on OC coho salmon, NMFS developed a method 

to estimate the number of OC coho salmon that are likely to be adversely affected through 

dredging operations for each year that dredging at Oregon Coastal (NMFS 2009a, 2009b, and in 

preparation). That analysis was based on consideration of ship avoidance behavior, avoidance of 

disposed material, discharge field size, spatial overlap, swimming speed, avoidance possibilities 

due to material descent rate and swimming speed, disposal quantity and weight, the physical 

interaction between fish and disposed material, and the number of fish likely to be exposed. 

Application of that method to the Siuslaw River results in an estimate of 19 juvenile OC coho 

salmon per year that are likely to be injured or killed due to the effects of the Corps use of the 

action area to dispose of dredged material from the Siulsaw Nav Project (NMFS in preparation).

Critical Habitat Within the Action Area 

Southern Green Sturgeon. Since NMFS does not expect southern green sturgeon to occur in 

the ODMDS during the June through October dredge and disposal period, we do not expect 

disposal of dredged materials to have an effect on the primary constituent element migration 

corridor, especially when compared to the overall scale of the migration corridor. Therefore, 

NMFS finds that all potential adverse effects to are discountable or insignificant and concurs 

with EPA’s determination of NLAA for designated critical habitat for southern green sturgeon. 

Cumulative Effects 

‘Cumulative effects’ are those effects of future state or private activities, not involving Federal 

activities, that are reasonably certain to occur within the action area of the Federal action subject 

to consultation (50 CFR 402.02). Current non-Federal activities in the action areas are limited to 

transit of recreational and commercial fishing vessels entering or leaving the Port of Siuslaw. 

Those activities are likely to continue at the current levels. The NMFS is not aware of any 

specific future non-Federal activities within the action area that would cause greater adverse 

effects to listed species than presently occur in the area. 

Synthesis and Integration of Effects 

Species. The direct and indirect effects of the EPA’s proposed designation of the Siuslaw 

OMDMS, including the effects of the Corps’ interrelated action of disposing of dredge material 

from the Siuslaw Nav Project, are likely to injure or kill approximately 19 juvenile OC coho 

salmon per year. Those individuals are part of the Siuslaw River Population that consists of 

approximately 9,700 adults, or 12% of the number of OC coho salmon overall (Table 2). 

Assuming a 0.25 smolt-to-adult survival ratio, 19 smolts are equivalent to approximately five 

adults, or less than 0.5 x 10-3% of the average population size. Environmental baseline conditions 

within the action area appear stable, at least since completion of the Siuslaw Nav Project, are 

sufficient to meet the needs of the species, and are unlikely to be unchanged by the proposed 

action. Any environmental changes which do occur (including frequent but brief reduction in 

nearshore rearing and migration) have not been identified by NMFS as factors limiting the 
-23- 

recovery of this species. Similarly, cumulative effects do not appear likely to add any significant 

additional risk to this species. 

Critical habitats. The direct and indirect effects of the EPA’s proposed designation of the 

Siuslaw OMDMS, including the effects of the Corps’ interrelated action of disposing of dredge 

material from the Siuslaw Nav Project, are not likely to adversely affect critical habitat for 

southern green sturgeon. 

For southern green sturgeon designated critical habitat, those adverse effects include degraded 

PCEs for marine coastal food resources, migratory corridor and water quality. Environmental 

baseline conditions within the action area appear stable, at least since completion of the Siuslaw 

Nav Project, and are unlikely to be unchanged by the proposed action. Any environmental 

changes which do occur (including frequent but brief reduction in nearshore food resources, 

passage, and water quality) have not been identified by NMFS as factors limiting the recovery of 

this species. However, dredging and deposition of dredge material is among the activities 

identified by NMFS when it designated this critical habitat. These effects are insignificant 

within the action area, and the area is still functional as a feeding area and migratory corridor. Of 

the total of 11,423 mi2

 of marine coastal habitat has been designated for southern green sturgeon, 

less than 2 mi2 will be insignificantly affected by the proposed action, or less than 0.2 x 10-3% of 

the total coastal marine area designated. Cumulative effects do not appear likely to add any 

significant additional risk to these PCEs. 

Conclusion 

After reviewing the current status of OC coho salmon, the environmental baseline for the action 

area, the effects of the proposed designation of the Siuslaw ODMDS, and the cumulative effects, 

it is NMFS’ biological opinion that activities associated with the proposed action are likely to 

adversely affect, but are not likely to jeopardize, the continued existence of OC coho salmon. 

It is also NMFS’ biological opinion that activities associated with this proposed action are not 

likely to adversely affect critical habitat that has been designated for southern green sturgeon in 

the action area, and therefore are not likely to result in the destruction or adverse modification of 

that critical habitat. 

Incidental Take Statement 

Section 9 of the ESA and Federal regulation pursuant to section 4(d) of the ESA prohibit the take 

of endangered and threatened species, respectively, without a special exemption. 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 as significant habitat 

modification or degradation that results in death or injury to listed species by significantly 

impairing essential behavioral patterns, including breeding, 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. 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 action is not prohibited under the ESA, provided that such 

taking is in compliance with the terms and conditions of an incidental take statement. 
-24- 

Amount or Extent of Take 

The EPA’s designation and development of an SMMP for the Siuslaw OMDMS, together with 

the Corps’ interrelated actions that use the site to dispose of dredged material from the Siuslaw 

River Nav Project, are likely to result in some level of incidental take of OC coho salmon. 

However, because the proposed designation and SMMP do not describe, approve, or compel any 

project-specific use by the Corps, all incidental take will occur at the project-specific level, 

NMFS does not authorize any take in this Opinion. All take authorization will occur in 

subsequent site-specific consultations. 

Conservation Recommendations 

Section 7(a)(1) of the ESA directs Federal agencies to use their authorities to further the 

purposes of the ESA by carrying out conservation programs for the benefit of the threatened and 

endangered species. The following recommendations are discretionary measures that are 

consistent with this obligation and therefore should be carried out by the EPA. 

1. Collaborate with NMFS and the Corps to finalize the interagency methodology to 

evaluate the effects of dredging and disposal on ESA-listed species. 

2. Undertake a study to determine the seasonal distribution, abundance, and habitat use of 

salmon, sturgeon, and marine turtles that occur nearshore within and near the contour of 

ODMDS designations. 

Please notify NMFS if the EPA carries out this recommendation so that we will be kept informed 

of actions that are intended to improve the conservation of listed species or their designated 

critical habitats. 

Reinitiation of Consultation 

Reinitiation of formal consultation is required and shall be requested by the Federal agency or by 

NMFS where discretionary Federal involvement or control over the action has been retained or is 

authorized by law and: (a) If the amount or extent of taking specified in the incidental take 

statement is exceeded; (b) if new information reveals effects of the action that may affect listed 

species or designated critical habitat in a manner or to an extent not previously considered; (c) if 

the identified action is subsequently modified in a manner that has an effect to the listed species 

or designated critical habitat that was not considered in the biological opinion; or (d) if a new 

species is listed or critical habitat is designated that may be affected by the identified action (50 

CFR 402.16). 

To reinitiate consultation, contact the Oregon State Habitat Office of NMFS, and refer to NMFS 

Number 2009/04136). 
-25- 

MAGNUSON-STEVENS FISHERY CONSERVATION AND MANAGEMENT ACT 

The consultation requirement of section 305(b) of the MSA directs Federal agencies to consult 

with NMFS on all actions, or proposed actions that may adversely affect EFH. Adverse effects 

include the direct or indirect physical, chemical, or biological alterations of the waters or 

substrate and loss of, or injury to, benthic organisms, prey species and their habitats, and other 

ecosystem components, if such modifications reduce the quality or quantity of EFH. Adverse 

effects on EFH may result from actions occurring within EFH or outside EFH, and may include 

site-specific or EFH-wide impacts, including individual, cumulative, or synergistic consequences 

of actions (50 CFR 600.810). Section 305(b) also requires NMFS to recommend measures that 

may be taken by the action agency to conserve EFH. 

The Pacific Fishery Management Council (PFMC) described and identified EFH for groundfish 

(PFMC 2005), coastal pelagic species (PFMC 1998), and Chinook salmon, coho salmon, and 

Puget Sound pink salmon (PFMC 1999). The proposed action and action area for this 

consultation are described in the Introduction to this document. The action area includes areas 

designated as EFH for various life-history stages of groundfish, coastal pelagic species, and 

Pacific salmon. 

Based on information provided by the action agency and the analysis of effects presented in the 

ESA portion of this document, NMFS concludes that proposed action will have the following 

adverse effects on EFH designated for those species: 

1. Increased turbidity and sedimentation within the action area over the annual dredge 

disposal period. 

2. Loss of pelagic and macroinvertebrate prey resources and nursery grounds within the 

action area due to the passage of dredge materials through the water column and their 

settling on the ocean floor. 

EFH Conservation Recommendations 

The following two conservation recommendations are necessary to avoid, mitigate, or offset the 

impact of the proposed action on EFH. These conservation recommendations are not a subset of 

the ESA terms and conditions. 

1. Collaborate with NMFS and the Corps to finalize the interagency methodology to 

evaluate the effects of dredging and disposal on ESA-listed species. 

2. Undertake a study to determine the seasonal distribution, abundance, and habitat use of 

salmon, sturgeon, and marine turtles that occur nearshore within and near the contour of 

ODMDS designations. 

The EPA is required to complete a supplemental EFH consultation with NMFS if it substantially 

revises its plans for this action in a manner that may adversely affect EFH or if new information 
-26- 

becomes available that affects the basis for NMFS’ EFH conservation recommendations (50 

CFR 600. 920(k)). 

DATA QUALITY ACT DOCUMENTATION AND PRE-DISSEMINATION REVIEW 

Section 515 of the Treasury and General Government Appropriations Act of 2001 (Public Law 

106-554) (Data Quality Act) specifies three components contributing to the quality of a 

document. They are utility, integrity, and objectivity. This section of the Opinion addresses these 

Data Quality Act (DQA) components, documents compliance with the DQA, and certifies that 

this Opinion has undergone pre-dissemination review. 

Utility: Utility principally refers to ensuring that the information contained in this consultation is 

helpful, serviceable, and beneficial to the intended users. 

This document records the results of one interagency consultation, completed under two separate 

legal authorities. The information presented in this document is useful to three agencies of the 

Federal government (NMFS, the EPA and the Corps), and the residents of Lane County, Oregon, 

and the general public. These consultations help fulfill multiple legal obligations of the named 

agencies. The information is also useful and of interest to the other identified people and 

organizations because it describes the manner in which public trust resources are being managed 

and conserved. The information presented in this document and used in the underlying 

consultation represents the best available scientific and commercial information and has been 

improved through interaction with the consulting agency. 

Individual copies were provided to the above-listed entities. This consultation will be posted on 

the NMFS Northwest Region website (http://www. nwr. noaa. gov). The format and naming 

adheres to conventional standards for style. 

Integrity: This consultation was completed on a computer system managed by NMFS in 

accordance with relevant information technology security policies and standards set out in 

Appendix III, ‘Security of Automated Information Resources,’ Office of Management and 

Budget Circular A-130; the Computer Security Act; and the Government Information Security 

Reform Act. 

Objectivity: 

Information Product Category: Natural Resource Plan. 

Standards: This consultation and supporting documents are clear, concise, complete, and 

unbiased; and were developed using commonly accepted scientific research methods. They 

adhere to published standards including the NMFS ESA Consultation Handbook, ESA 

Regulations, 50 CFR 402.01, et seq. , and the MSA implementing regulations regarding EFH, 50 

CFR 600. 920(j). 
-27- 

Best Available Information: This consultation and supporting documents use the best 

available information, as referenced in the Literature Cited section. The analyses in this 

Opinion/EFH consultation contain more background on information sources and quality. 

Referencing: All supporting materials, information, data and analyses are properly 

referenced, consistent with standard scientific referencing style. 

Review Process: This consultation was drafted by NMFS staff with training in ESA and 

MSA implementation, and reviewed in accordance with Northwest Region ESA quality control 

and assurance processes. 
-28- 

LITERATURE CITED 

Berg, L. and T. G. Northcote. 1985. Changes In Territorial, Gill-Flaring, and Feeding Behavior 

in Juvenile Coho Salmon (Oncorhynchus kisutch) Following Short-Term Pulses of 

Suspended Sediment. Canadian Journal of Fisheries and Aquatic Sciences 42: 1410-1417. 

Bi, H. , R. E. Ruppel, W. T. Peterson and E. Casillas. 2008. Spatial distribution of ocean habitat 

of yearling Chinook (Oncorhynchus tshawytscha) and coho (Oncorhynchus kisutch) 

salmon off Washington and Oregon, USA. Fisheries Oceanography 17(6):463-476. 

Brodeur, Rick, C. , Emmett, Robert, L. , Fisher, Joseph, P. , Casillas, Edmundo, Teel, David, J. , 

and Miller, Todd, W. 2003. Juvenile salmonid distribution, growth, condition, origin, and 

environmental and species associations in the Northern California Current. 

Chase, Z. , P. G. Strutton and B. Hales. 2007. Iron links river runoff and shelf width to 

phytoplankton biomass along the U.S. West Coast. Geophysical Research Letters 

34:L04607, 4 pp. 

CIG (Climate Impacts Group). 2004. Overview of climate change impacts in the U.S. Pacific 

Northwest (July 29, 2994, updated August 17, 2004). Climate Impacts Group, University 

of Washington, Seattle, Washington. 

Conant, T.A., P.H. Dutton, T. Eguchi, S.P. Epperly, C.C. Fahy, M.H. Godfrey, S.L. MacPherson, 

E.E. Possardt, B.A. Schroeder, J.A. Seminoff, M.L. Snover, C.M. Upite, and B.E. 

Witherington. 2009. Leatherback sea turtle (Caretta caretta) 2009 status review under the 

U.S. Endangered Species Act. Report of the Leatherback Biological Review Team to the 

National Marine Fisheries Service, August 2009. 222 pages. 

Corps (U.S. Army Corps of Engineers). 2009. Sediment evaluation framework for the Pacific 

Northwest. 

Drake, J. et al., 2010. Status Review Update for Eulachon in Washington, Oregon, and 

California Prepared by the Eulachon Biological Review Team1 (20 January 2010). 

Erickson, D. L. and J. E. Hightower. 2007. Ocean distribution and behavior of green sturgeon. 

American Fisheries Society Symposium 56:197-211. 

Farr, R. A. and J. C. Kern. 2005. Green sturgeon population characteristics in Oregon. Final 

progress report to U.S. Fish and Wildlife. Project number: F-178-R. 

ISAB (Independent Scientific Advisory Board). 2007. Climate change impacts on Columbia 

River Basin fish and wildlife. ISAB Climate Change Report, ISAB 2007-2, Northwest 

Power and Conservation Council, Portland, Oregon. 
-29- 

Lawson, P. W. , E. Bjorkstedt, M. Chilcote, C. Huntington, J. Mills, K. Moore, T. Nickelson, G. 

H. Reeves, H. A. Stout and T. C. Wainwright. 2007. Identification of historical 

populations of coho salmon (Oncorhynchus kisutch) in the Oregon Coast Evolutionarily 

Significant Unit. Co-manager's Draft ONCC-TRT. U.S. Department of Commerce, Draft 

Technical Report of the Oregon Coast Workgroup, Oregon and Northern California 

Coasts. Technical Recovery Team, NOAA-NMFS-NWFSC. 

Moser, M. and S. Lindley. 2006. Use of Washington estuaries by subadult and adult green 

sturgeon. Environmental Biology of Fishes DOI 10 1007/sl0641-006-9028-1. 

NMFS (National Marine Fisheries Service). 2009a. Endangered Species Act Section 7 Formal 

Consultation and Magnuson-Stevens Fishery Conservation and Management Act 

Essential Fish Habitat Consultation for the Port of Siuslaw Maintenance Dredging, 

Siuslaw River (6th field HUC 171002060804), Lane County, Oregon (Corps No.: NWP1997-1360) (refer to NMFS No: 2008/02367) (March 4, 2009). 

NMFS (National Marine Fisheries Service). 2009a. Endangered Species Act Section 7 Formal 

Consultation and Magnuson-Stevens Fishery Management and Conservation Act 

Essential Fish Habitat Consultation for the U.S. Environmental Protection Agency Site 

Designation of the North and South Umpqua River Ocean Disposal Sites, Pacific Ocean, 

Douglas County, Oregon (EPA: ETPA-083) (refer to NMFS No.: 2008/05438) (March 

20, 2009). 

NMFS (National Marine Fisheries Service). 2009b. Designation of Critical Habitat for the 

threatened Southern Distinct Population Segment of North American Green Sturgeon. 

Final Biological Report. Southwest Region Protected Resources Division, Long Beach, 

California (October 2009). 

NMFS (National Marine Fisheries Service). In preparation. Endangered Species Act Section 7 

Formal Consultation and Magnuson-Stevens Fishery Management and Conservation Act 

Essential Fish Habitat Consultation for the Corps Maintenance Dredging Program for the 

Oregon Coastal Projects (refer to NMFS No.: 2009/01756) (In preparation). 

Noggle, C. C. 1978. Behavioral, physiological and lethal effects of suspended sediment on 

juvenile salmonids. [Thesis] Seattle: University of Washington. 

ODFW (Oregon Department of Fish and Wildlife). 2006. The Oregon Nearshore Strategy. 

Oregon Department of Fish and Wildlife, Marine Resources Program, Newport, Oregon. 

Pearcy, W.G. 1992. Ocean Ecology of North Pacific Salmonids. University of Washington Press, 

Seattle. 

PFMC (Pacific Fishery Management Council). 2000. 2000 Review of Amendment 13 to the 

Pacific Coast Salmon Plan. Pacific Fishery Management Council, Portland, Oregon 

(October). 

 
-30- 

PFMC. 1999. Amendment 14 to the Pacific Coast Salmon Plan. Appendix A: Description and 

Identification of Essential Fish Habitat, Adverse Impacts and Recommended 

Conservation Measures for Salmon. PFMC (Pacific Fishery Management Council), 

editor. Pacific Fishery Management Council, Portland, Oregon. 

Shapolvalov, L. and A.C. Taft. 1954. The life histories of the steelhead rainbow trout (Salmo 

gairdneri gairdneri) and silver salmon (Oncorhychus kisutch). State of California, 

Department of Fish and Game, Fish Bulletin No. 98. 

Scheuerell, M. D., and J. G. Williams. 2005. Forecasting climate-induced changes in the survival 

of Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha). 

USFWS and NMFS (U.S. Fish and Wildlife Service and National Marine Fisheries Service) 

1998. Endangered Species Consultation Handbook: Procedures for Conducting 

Consultation and Conference Activities Under Section 7 of the Endangered Species Act. 

(March 1998, Final). 

Wainwright, T.C., M.W. Chilcote, P.W. Lawson, T.E., Nickelson, C.W. Huntington, J.S. Mills, 

K.M.S. Moore, G.H. Reeves, H.A. Stout, and L.A. Weitkamp. 2008. Biological, recovery 

criteria for the Oregon Coast coho salmon evolutionarily significant unit. U.S. 

Department of Commerce, NOAA Technical Memorandum NMFS-NWFSC-91, 199 p. 

Zabel, R. W., M. D. Scheuerell, M. M. McClure, and J. G. Williams. 2006. The interplay 

between climate variability and density dependence in the population viability of 

Chinook salmon. Conservation Biology 20:190-200.