Serious Injury and Mortality 

Determinations for Sea Turtles in 

US Northeast and Mid-Atlantic 

Fishing Gear, 2006-2010

US DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

Northeast Regional Office 

Gloucester, Massachusetts 

April 2013

NOAA Technical Memorandum NMFS-NE-222 
Serious Injury and Mortality 

Determinations for Sea Turtles in 

US Northeast and Mid-Atlantic 

Fishing Gear, 2006-2010 

Carrie M. Upite1, Kimberly T. Murray2, Brian A. Stacy3, 

Sara E. Weeks2

, C. Rogers Williams4

1 NOAA National Marine Fisheries Service, Northeast Regional Office, 55 Great Republic Dr., Gloucester, MA 01930-2276 2

NOAA National Marine Fisheries Service, Northeast Fisheries Science Center, 166 Water St., Woods Hole, MA 02543-1062 3

NOAA National Marine Fisheries Service, Office of Protected Resources, University of Florida, 2187 Mowry Rd, Building 471, Gainesville, FL 32611 4

National Marine Life Center, P.O. Box 269, 120 Main St., Buzzards Bay, MA 02532-02696 

US DEPARTMENT OF COMMERCE 

Rebecca Blank, Acting Secretary 

National Oceanic and Atmospheric Administration 

Pat Montanio, Assistant Administrator 

National Marine Fisheries Service 

Samuel D Rauch III, Acting Assistant Administrator for Fisheries 

Northeast Regional Office 

Gloucester, Massachusetts 

April 2013

NOAA Technical Memorandum NMFS-NE-222 

This series represents a secondary level of scientific publishing. All issues employ thorough internal 

scientific review; some issues employ external scientific review. Reviews are transparent collegial 

reviews, not anonymous peer reviews. All issues may be cited in formal scientific communications. 
Editorial Notes 

Information Quality Act Compliance: In accordance with section 515 of Public Law 106-554, the 

Northeast Fisheries Science Center completed both technical and policy reviews for this report. 

These predissemination reviews are on file at the NEFSC Editorial Office. 

Species Names: The NEFSC Editorial Office’s policy on the use of species names in all 

technical communications is generally to follow the American Fisheries Society’s lists of 

scientific and common names for fishes, mollusks, and decapod crustaceans and to follow the 

Society for Marine Mammalogy's guidance on scientific and common names for marine 

mammals. Exceptions to this policy occur when there are subsequent compelling revisions in the 

classifications of species, resulting in changes in the names of species. 

Statistical Terms: The NEFSC Editorial Office’s policy on the use of statistical terms in all 

technical communications is generally to follow the International Standards Organization’s 

handbook of statistical methods. 

Internet Availability: This issue of the NOAA Technical Memorandum NMFS-NE series is 

being published as a Web document in PDF format and can be accessed at: 

http://www.nefsc.noaa.gov/nefsc/publications/. 
iii 

EXECUTIVE SUMMARY 

The NMFS Northeast Sea Turtle Serious Injury Workgroup reviewed all sea turtle 

interactions recorded by the Northeast Fisheries Observer Program from 2006 to 2010 (n=145). 

The workgroup first determined if each interaction was fresh and then placed the affected turtle 

into one of three injury categories with associated postrelease mortality rates or provided 

justification for a 100% mortality determination according to the “Technical Working Guidelines 

for Assessing Injuries of Sea Turtles Observed in Northeast Region Fishing Gear” (Upite 2011). 

Sea turtle records were subsequently delineated by major gear type, resulting in 97 trawl records, 

29 gillnet records, and 11 dredge records for which injury determinations were made. In 

addition, three cases had insufficient information to make a determination, two records described 

moderately to severely decomposed animals not attributable to the observed fishery, and three 

records were excluded because of confidentiality issues. Considering the 137 records with injury 

determinations, the resulting mortality rate for observable interactions in trawl gear is 47%, for 

gillnet gear is 58%, and for dredge gear is 80%. Additional factors that may influence sea turtle 

serious injury and mortality were considered, such as specific fishery (within an encompassing 

gear type), geographical area, sea turtle species, and life stage. 

 
iv 

TABLE OF CONTENTS 

Executive Summary ....................................................................................................................... iii 

NMFS Northeast Sea Turtle Serious Injury Workgroup ................................................................ 1 

Background ..................................................................................................................................... 1 

Methods........................................................................................................................................... 1 

Additional Considerations ........................................................................................................... 3 

Results and Discussion ................................................................................................................... 4 

Trawl Gear ................................................................................................................................... 5 

Gillnet Gear ................................................................................................................................. 5 

Dredge Gear ................................................................................................................................ 6 

Species Differences ..................................................................................................................... 7 

Conclusion ...................................................................................................................................... 7 

References Cited ............................................................................................................................. 9 

Appendix A. Technical Working Guidelines. ............................................................................... 17 

Appendix B. NMFS Northeast Statistical Areas. .......................................................................... 18 

LIST OF TABLES 

Table 1. Loggerhead (Caretta caretta) size classes used for injury category determinations. ..... 10 

Table 2. The number of sea turtle observer records from 2006 to 2010 ....................................... 10 

Table 3. The number and corresponding injury category of sea turtles observed captured in trawl 

gear. ............................................................................................................................................... 10 

Table 4. Number of sea turtle trawl determinations in each category by fishery. ........................ 11 

Table 5. Number of sea turtle trawl determinations in each category by NMFS Northeast 

Statistical Area. ............................................................................................................................. 12 

Table 6. The number and corresponding injury category of sea turtles observed captured in 

gillnet gear. ................................................................................................................................... 12 

Table 7. Number of sea turtle gillnet determinations in each category by fishery. ...................... 13 

Table 8. Number of sea turtle gillnet determinations in each category by NMFS Northeast 

Statistical Areas. ........................................................................................................................... 13 

Table 9. The number and corresponding injury category of sea turtles observed captured in 

dredge gear .................................................................................................................................... 14 

Table 10. Number of sea turtle dredge determinations in each category by NMFS Statistical 

Area. .............................................................................................................................................. 14 

Table 11. Sea turtle determinations in each category by species for all gear types combined. .... 15 

LIST OF FIGURES 

Figure 1. Workgroup size categories and injury determinations for loggerheads (Caretta caretta) 

captured in trawl gear. ................................................................................................................... 16 
1 

NMFS NORTHEAST SEA TURTLE SERIOUS INJURY 

WORKGROUP 

Kimberly T. Murray, NMFS Northeast Fisheries Science Center Protected Species Branch 

Brian A. Stacy, DVM, PhD, DACVP, NMFS Office of Protected Resources, University of Florida 

Carrie M. Upite, NMFS Northeast Regional Office Protected Resources Division 

Sara E. Weeks, NMFS Northeast Fisheries Science Center Fishery Sampling Branch 

C. Rogers Williams, DVM, National Marine Life Center, Vineyard Veterinary Clinic, NMFS 

Northeast Fisheries Science Center 

BACKGROUND 

In 2003 the National Marine Fisheries Service (NMFS) Northeast Regional Office 

(NERO) initiated an assessment of injuries to sea turtles from interactions with Atlantic sea 

scallop dredge gear. Based on a review of various types of observed sea turtle injuries in scallop 

dredge gear, NMFS NERO developed guidance for determining which injury types should be 

considered lethal or nonlethal interactions. That guidance was then applied to observed sea turtle 

captures in scallop dredge gear, with the results used in Endangered Species Act (ESA) section 7 

consultations regarding the impact of the fishery on sea turtles. 

After this guidance was prepared and applied to the scallop dredge fishery, it became 

apparent that consistent injury criteria were needed for all other fishing gear and sea turtle injury 

types. Therefore, in November 2009, the NMFS NERO and Northeast Fisheries Science Center 

(NEFSC) hosted a workshop to discuss sea turtle injuries in the Northeast Region (NER) fishing 

gear and associated postrelease survival (Upite 2011). The workshop convened various experts 

in sea turtle veterinary medicine, health assessment, anatomy, and/or rehabilitation to: (1) discuss 

case studies of sea turtles caught in fishing gear with varying levels of injuries, (2) critique the 

existing NMFS guidance and approach for evaluating postrelease survival, and (3) comment on 

the level of information collected by observers. Workshop participants discussed types of sea 

turtle injuries and associated survival, turtle behavior, and resuscitation, as well as specific 

information that should be collected by observers to better assess sea turtle injuries. The 

information gathered from individual participants at this workshop was then used by NMFS to 

develop “Technical Guidelines” for assessing sea turtle injuries in Northeast fishing gear 

(Appendix A). Those Technical Guidelines were then applied by the NMFS Northeast Sea Turtle 

Serious Injury Workgroup in review of all sea turtle interactions recorded by the Northeast 

Fisheries Observer Program (NEFOP) from 2006 to 2010 (n=145). The results of that review are 

provided here. 

METHODS 

The scope of the review of observed sea turtle interactions was determined to be 5 years, 

2006 to 2010. The scope was also limited to only fisheries found in the NMFS NER (Maine 

through Virginia1), excluding the longline fishery, which has a separate postinteraction mortality 

 

1

 While the NMFS Northeast Region includes Maine through Virginia, the Northeast Fisheries Observer Program 

extends observer coverage into portions of North Carolina, and the NEFSC sea turtle bycatch estimates also include 

portions of North Carolina. 
2 

assessment (Ryder et al. 2006). This resulted in 145 sea turtle observer records. This time period 

was chosen to focus on recent records and to provide a sufficient sample size for review and 

determination. 

Workgroup members reviewed each observer record and made independent injury 

determinations, which were then compared and discussed to come up with consensus 

determinations for each record. To carry out the reviews, a spreadsheet with a unique identifier 

for each observer record was distributed to each workgroup member. The workgroup members 

were granted access to the NEFOP database and individually evaluated all of the information 

available for each sea turtle record. Available information included the turtle capture photos, 

data, and observer comments included on the vessel and trip information logs, incidental take 

logs, sea turtle biological sample logs, and any preexisting veterinarian comments (not available 

for all records). Each member first determined if the turtle capture was “fresh,” by using the 

guidance in Upite (2011) and expert opinion. If fresh, then each member used the Technical 

Guidelines to evaluate any injuries and to place the turtle into one of the three categories with 

identified postrelease mortality rates or to provide justification for a 100% mortality 

determination. Note that all observer records were reviewed by four of the workgroup members; 

one member was unable to complete the review in the necessary time frame because of travel 

and other commitments. However, he had previously reviewed several of the records in his role 

as a contract veterinarian to the NEFOP, so his previous determinations were considered in the 

workgroup discussions. 

After the individual determinations were made and sent to the NERO staff contact, the 

records were reviewed for consistency. For the majority of the cases, the initial injury 

determinations were consistent among members. The records with inconsistent determinations 

between workgroup members were flagged, and the workgroup members reviewed the case 

information again. Workgroup members then provided additional justification for their injury 

category determination, or modified their original determination as appropriate. After workgroup 

discussion and review occurred, consensus was reached for all cases. 

Percent probability of mortality was calculated based on the Technical Guidelines (Upite 

2011). Briefly, those animals in Category I were considered to have a 20% probability of 

postrelease mortality based upon their capture condition and assessment, animals in Category II 

had a 50% probability of postrelease mortality, and animals in Category III had a 80% 

probability of postrelease mortality. Turtles believed to be dead after the workgroup’s review 

(based upon observer logs and comments) or released into the water in an unresponsive state 

were given a 100% mortality rate. For applicability to subsequent management actions, the 

records were organized by major gear type.

Additional factors that may influence sea turtle serious injury and mortality were 

considered; however, substantial biases in the dataset precluded meaningful statistical 

comparisons. Nonetheless, key characteristics, such as specific fishery (within an encompassing 

gear type), geographical area, sea turtle species, and life stage, are included here to provide a 

detailed description of the dataset. It should also be noted that observer effort was not always 

evenly distributed. In some cases, there may have been focused effort in a particular area or 

fishery, which will be noticeable in the results.

Delineation of fishery within a gear type was based on the primary landed fish species by 

weight, as recorded by fishery observers. This approach recognizes that gear and environmental 

factors affect sea turtle incidental captures. The primary landed species was determined to be a 

better proxy for the actual fishery instead of trip or haul target, as the target recorded may not 
3 

reflect the fish species actually caught on the trip. For the purposes of this report, the primary 

landed fish species by weight is used synonymously with “fishery.”

The workgroup referred to the NMFS Northeast statistical areas to help describe 

geographic distribution (Appendix B). Sea turtle records were grouped by statistical area, which 

was calculated by the latitude/longitude position at the beginning of the haul for fixed gear, at the 

end of the haul for mobile gear, or at the sighting position as recorded on the observer logs.

Probability of mortality was considered the same for all sea turtle species based on the 

Technical Guidelines (Upite 2011); however, this recommendation was based on insufficient 

data to support species differences. Data for individual species were considered to detect any 

differences in injury category that would warrant further consideration of this approach. 

The sizes of the observed turtles were evaluated to determine if one life stage was being 

disproportionately affected or if injury rate varied by life stage. For instance, would smaller sea 

turtles be more susceptible to serious injury (e.g., Category III or 100% mortality) when 

compared to larger/adult sea turtles? Categorization by size class was largely limited to 

loggerheads (Caretta caretta), given the predominance of this species in the records reviewed. 

Curved carapace length2

 (CCL) was measured by onboard fishery observers, and the workgroup 

made the assumption that all of the recorded sizes were accurate. Size class categories were 

developed from the 2008 loggerhead recovery plan (NMFS and USFWS 2008) but were 

modified so that individuals could be assigned into mutually exclusive groups (Table 1). These 

size class definitions are for the purposes of this report and are not intended to imply alteration to 

size classes defined in the recovery plan for other purposes. Furthermore, the workgroup 

recognizes that such definitions inevitably result in misclassification of some individuals given 

the variability in sea turtle life history. 

Mortality rates in this report are determined for observable interactions, those that include 

animals brought on board the fishing vessel or that interact with the gear at the surface (Warden 

and Murray 2011). Mortality rates may be different for unobservable interactions, which include 

animals that interact with the gear exclusively subsurface or away from view, due to the design 

of the gear or the behavior of the animal. 

Additional Considerations 

Could not be determined 

Injury category was not assigned if there was insufficient information on which to base 

the assessment. 

Animals not boarded 

 There were several cases in which the turtle was not boarded for a variety of reasons 

(e.g., turtle fell from gear as net was hauled). In these instances, the observer did not engage in a 

hands-on assessment of the turtle. In some cases, however, observer observations and 

photographs were sufficient for the workgroup to assign an injury category. 

 

2

 Curved carapace length of the turtle was measured as the distance between the center of the nuchal scute at the 

anterior of the carapace and the posterior tip of the longest marginal scute, following the curvature of the dorsal 

centerline. 
4 

Mortality not related to the gear interaction 

 No injury determination was made for any cases in which the interaction was not 

attributed to the observed haul/tow/set. For example, a moderately or severely decomposed turtle 

found in active fishing gear (e.g., trawls or dredges) likely died prior to the interaction, so the 

mortality was not assigned to the fishery nor considered in the analysis. 

Pre-existing condition 

The Technical Guidelines state that “[o]ld injuries determined to be unrelated to the 

current gear interaction or animals subject to adverse environmental conditions will be 

considered in the overall health assessment/survivability determination of the animal” (Appendix 

A). By reviewing the observer logs and photographs, the workgroup considered all documented 

injuries and postrelease condition and behavior of the turtle in making the final determination. It 

should be noted that the workgroup did review several records in which the existing condition of 

the animal and environmental conditions (e.g., water temperature upon capture and release) were 

factored into the injury determination. If a turtle was taken to a rehabilitation center (one record), 

the determination was made based on condition at capture, not outcome of rehabilitation. This 

approach was considered a more accurate accounting of real life situations in which a fisherman 

likely releases a turtle overboard in lieu of contacting a rehabilitation facility. 

RESULTS AND DISCUSSION 

All 145 observed sea turtle interactions in the NEFOP database from 2006 to 2010 were 

reviewed, including 97 trawl records, 29 gillnet records, and 11 dredge records for which injury 

determinations were made. Of the total 145 records, three fishery records were reviewed and 

injury determinations were made (two loggerheads in Category I; one Kemp’s ridley in Category 

III), but the results were excluded from this report because of confidentiality issues. There also 

were three trawl records with insufficient information to make a determination, and two records 

that described moderately to severely decomposed animals not attributable to the observed 

interaction. 

Table 2 depicts the injury determinations and final mortality rates by gear type, as 

calculated by the workgroup. Of the total number of records reviewed and for which 

determinations were made and able to be presented in this report (n=137), the workgroup 

determined that 50% of the documented interactions were in Category I, 8% in Category II, 23% 

in Category III, and 19% with a 100% probability of mortality (Table 2). Trawl gear interactions 

were the most common in each of the injury categories, reflecting the fact that turtles were 

caught in trawl gear more often than in any other gear type. Scallop dredge interactions resulted 

in proportionately more Category III determinations (resulting in the highest mortality rate), 

whereas gillnet records were more evenly split between Category I and 100% mortality. This is 

not surprising, as a turtle interacting with a gillnet may be less likely to be injured by the gear 

itself (compared to a scallop dredge for instance), and instead is more likely be found alive or 

dead due to forced submergence. It should be noted, however, that injuries, such as constriction 

wounds, can result from gillnet interactions. 
5 

Trawl Gear 

The observer database indicates whether the gear in question was fish bottom otter trawl, 

scallop bottom otter trawl, or twin trawl. There were 92 observed interactions in fish bottom otter 

trawls, 7 interactions in scallop bottom otter trawls, and 1 interaction in a twin trawl during the 5 

year time period reviewed. All trawl gear records were combined for applicability to section 7 

consultations and are hereby referred to as “trawl gear.” 

After the records with insufficient information were removed, injury category 

determinations were made for 97 interactions involving trawl gear. Numbers of records by 

species, injury category, and estimated probability of mortality are provided in Table 3. The 

resulting mortality rate for observable interactions in trawl gear is 47%. 

Table 4 shows the injury category determinations by fishery for observed sea turtles in 

trawl gear from 2006 to 2010. Observers recorded the highest number of sea turtle interactions in 

the croaker fishery (64%). In that fishery, Category I determinations ranked the highest (56%), 

with a relatively even split between Category III (21%) and 100% mortality (18%) 

determinations. Summer flounder (with most cases in Category I [53%]) ranked second highest, 

followed by scallop (with most cases in Category I [67%]) and squid (with most cases in 

Category III [50%]). 

For trawls, most of the interactions occurred in Statistical Area 635, off North Carolina, 

followed by area 621, off Delaware/Maryland (Table 5). Considering only those two areas (one 

from the most southern extent of the NMFS Northeast Statistical Areas and the other slightly 

more northward), the highest number of interactions was in Category I, followed by Category III. 

In the trawl gear observer records from 2006 to 2010, there were 88 records with sizes 

noted for loggerheads. Most of the trawl gear interactions involved neritic immature turtles 

(n=66; Figure 1B). Of these neritic immature turtles, more than half of the records were in 

Category I. Similarly, Category I determinations ranked the highest in the other two life stages, 

but there was a more even split between the categories (Figure 1A and 1C). It is possible that this 

is a reflection of smaller sample sizes in the transitional immature and adult life stages. Overall, 

it does not appear that one size class is disproportionately affected by trawl gear injuries or 

mortalities. Note that there were no trawl interactions observed with immature oceanic 

loggerheads (8.5-46 cm CCL), and sizes were not recorded for three loggerheads. 

 For non-loggerheads, there were four animals with carapace sizes recorded in trawl gear. 

Two Kemp’s ridleys were observed with sizes of 27.2 and 33.5 cm CCL, both in Category I. One 

green with a size of 27.5 cm CCL was determined to be in Category III, and one leatherback with 

a size of 155 cm CCL was in Category II. All of these cheloniid sea turtles are considered 

immature, while the leatherback is likely an adult (using the adult size class of >145 cm CCL 

reported in TEWG 2007). 

Gillnet Gear 

 All records were classified as “sink gillnet, fixed or anchored, other species” in the 

observer database and will hereby be referred to as “gillnet gear.” For gillnet gear, there were 29 

records reviewed from 2006 to 2010. Numbers of records by species, injury category, and 

estimated probability of mortality are provided in Table 6. The resulting mortality rate for 

observable interactions in gillnet gear is 58%. 

Table 7 shows the injury category determinations by fishery for observed sea turtles in 

gillnet gear from 2006 to 2010. Observers recorded the highest number of sea turtle interactions 
6 

in the southern flounder fishery, with Category I determinations composing more than half of 

those total interactions (62%). 

 For gillnet gear, most of the interactions occurred in NMFS Statistical Area 701, which 

was a result of the high observed bycatch in the southern flounder fishery off North Carolina in 

2009 (Table 8). In Area 701, 59% of the records were in Category I compared to 32% of the 

animals with 100% mortality results. 

 Green turtles had the highest number of observed gillnet interactions, followed by 

loggerheads, Kemp’s ridleys, leatherbacks, and unknown species (Table 6). This species 

breakdown is largely driven by the high observed captures in the southern flounder fishery off 

North Carolina in one year and is not likely reflective of the entire Northeast Region observed 

species composition. In the gillnet gear observer records from 2006 to 2010, there were 12 turtles 

with carapace sizes recorded. All of the green turtles measured (7 of 12) were immature animals 

with a size range of 27.6-34.3 cm CCL. Of these seven turtles, four were determined to have a 

100% mortality probability, while two had a 20% mortality probability (Category I), and one had 

a 50% mortality probability (Category II). For loggerheads, carapace measurements were 

recorded for only two of the seven animals, and both of these turtles were immature animals 

(60.6 and 75 cm CCL). One of these turtles was found to have a 100% mortality probability and 

the other was determined to have a 80% mortality probability (Category III). Measurements were 

taken for three of the six Kemp’s ridleys. The sizes were 27.5, 28, and 29.6 cm CCL, 

representing immature animals. Two of the Kemp’s ridleys were determined to have a 20% 

mortality probability (Category I), while the other had an 80% mortality probability (Category 

III). 

Dredge Gear 

 For dredge fishing gear, which only involved scallop dredges, 11 records were reviewed 

from 2006 to 2010. Numbers of records by species, injury category, and estimated probability of 

mortality are provided in Table 9. The resulting mortality rate for observable interactions in 

dredge gear is 80%. 

 For dredges, the highest number of interactions occurred in NMFS Northeast Statistical 

Area 615, which is offshore of New Jersey, followed by Area 621 (offshore of 

Delaware/Maryland) and then Area 626 (offshore of Virginia; Table 10). For most of the areas, 

the majority of injuries were determined to be Category III.

 Loggerheads were the most common species with observed dredge interactions (10 of 11; 

Table 9). Carapace size measurements were recorded for eight of the loggerheads. The majority 

of these measured loggerheads were neritic immature turtles (n=6), with one injury 

determination in Category I, four in Category III and one with 100% mortality. One loggerhead 

was in the oceanic or neritic transitional phase with a Category III injury determination, and one 

adult was determined to be in Category III. 

 Beginning on September 25, 2006, chain mats were required in the scallop dredge 

fishery, south of 41° 9’ N. latitude from May 1 through November 30 (71 FR 50361). Besides 

one interaction which was before the September 2006 requirement and another interaction that 

was north of the regulated area, chain mats were used on all of the dredges with observed sea 

turtle interactions. However, in at least three of the instances, the chain mats were improperly 

configured. 

It should be noted that NMFS, in conjunction with the New England Fishery 

Management Council (NEFMC), has required a Turtle Deflector Dredge (TDD) in certain 
7 

Atlantic sea scallop (Placopecten magellanicus) fishery vessels west of 71° W longitude from 

May through October (77 FR 20728, April 6, 2012). Observations of interactions between turtle 

carcasses and the TDD suggest that the injury rate of the TDD is lower than a traditional dredge 

(Smolowitz et al. 2010). The NEFMC has estimated that the TDD dredge with chain mats has a 

maximum estimated serious injury rate of 28% (New England Fishery Management Council 

2011). As such, after the TDD is required to be used (May 1, 2013), the workgroup will need to 

consider the injury rate calculated for that gear modification in the assessments of future scallop 

dredge interactions. 

Species Differences 

 The majority of the observed fishery interactions from 2006 to 2010 involved 

loggerheads. For non-loggerheads, the sample size was too small to develop valid mortality rates 

for each species by gear type, and there were insufficient data to support species differences. 

Therefore, data for all species were combined to develop one average mortality rate by gear type 

(see Table 11 for species comparison). The differences in species survival from the various 

injuries encountered in NER fishing gear are likely so small that the combined mortality rate is 

applicable for all species. 

CONCLUSION 

The NMFS Northeast Sea Turtle Serious Injury Workgroup was convened to evaluate 

observed fishery sea turtle interactions and to determine which would result in serious injury or 

mortality. The workgroup considered the 2009 workshop discussion and applied the resulting 

Technical Guidelines (Upite 2011) while reviewing NEFOP sea turtle interactions from 2006 to 

2010. The members first determined if the interaction was fresh, then reviewed any injuries and 

placed the turtle into one of the three Technical Guidelines categories with the identified 

postrelease mortality rates, or provided justification for a 100% mortality determination. 

As noted, 145 sea turtle interaction records were reviewed. There were three cases with 

insufficient information to make a determination, and two records that were not attributable to 

the observed interaction. Injury determinations were made for three additional records, but 

excluded from this report because of confidentiality issues. The remaining 137 records were 

subsequently delineated by major gear type, resulting in 97 trawl records, 29 gillnet records, and 

11 dredge records for which injury determinations were made. The resulting mortality rate for 

observable interactions in trawl gear is 47%, in gillnet gear is 58%, and in dredge gear is 80%. 

When considering the impact of different fisheries on sea turtle populations, it is 

important to consider the total magnitude of interactions by gear type. Mortality rates reported in 

this document can be applied to estimates of observed interactions calculated for each gear type 

to determine the number of mortalities (i.e., removals from the population). Depending on 

bycatch rates and total fishing effort, the population level impact from a gear type with a high 

mortality rate may have the same or smaller impact compared to a gear type with a lower 

mortality rate. 

One of the primary reasons for developing the Technical Guidelines, establishing the sea 

turtle serious injury workgroup, and reviewing these observer records is the potential use of these 

data in section 7 consultations, specifically in the development of the lethal and nonlethal 

incidental take estimates. It is the workgroup’s recommendation that the calculated mortality 

percentages be applied to the observable portion of the total estimated incidental take for the 
8 

respective gear types in each Fishery Management Plan managed by the NERO, in order to 

develop a lethal incidental take estimate by gear type. For those gear types equipped with a 

bycatch reduction device, which prevent animals from being captured and observed, a separate 

mortality rate may need to be applied to the portion of interactions that are unobservable, yet 

quantifiable (Warden and Murray 2011). The workgroup recommends that the best available 

information be used to identify mortality rates (and lethal incidental take) for observable and 

unobservable interactions. 

The information in this report represents the best assessment of injury and mortality for 

NEFOP sea turtle observer records from 2006 to 2010. The workgroup intends to review the 

latest year of sea turtle observer records annually and maintain a rolling 5 year average for 

gillnet, trawl, and dredge mortality rate calculations. It is possible that future regulations or other 

changes in interactions may require changes in the workgroup assessment process. 

 
9 

REFERENCES CITED 

NMFS (National Marine Fisheries Service) and USFWS (U.S. Fish and Wildlife Service). 2008. 

Recovery plan for the Northwest Atlantic population of the loggerhead turtle (Caretta 

caretta), Second revision. Washington, D.C.: National Marine Fisheries Service. 325 pp. 

New England Fishery Management Council. 2011. Final environmental assessment for 

Framework 23 to the scallop fishery management plan. 234 pp. 

Ryder CE, Conant TA, Schroeder BA. 2006. Report of the workshop on marine turtle longline 

post-interaction mortality. U.S. Dep. Commerce, NOAA Tech. Memo. NMFS-F/OPR-29, 

36 pp. 

Smolowitz R, Haas H, Milliken HO, Weeks M, Matzen E. 2010. Using sea turtle carcasses to 

assess the conservation potential of a turtle excluder dredge. North American Journal of 

Fisheries Management 30:993–1000. 

TEWG (Turtle Expert Working Group). 2007. An assessment of the leatherback turtle population 

in the Atlantic Ocean. NOAA Technical Memorandum NMFS-SEFSC-555, 116 pp. 

Upite CM. 2011. Evaluating sea turtle injuries in northeast fishing gear. U.S. Dep. Commerce, 

NEFSC Reference Document 11-10, 26 p. 

Warden ML, Murray KT. 2011. Reframing protected species interactions with commercial 

fishing gear: Moving toward estimating the unobservable. Fish. Res. 110:387-390. 

 
10 

Table 1. Loggerhead (Caretta caretta) size classes used for injury category determinations. 

Size class for categorization by injury workgroup Curved carapace length (cm) 

Oceanic phase, immature 8.5-46.0 

Transitional phase (oceanic or neritic), immature 46.01-64.0 

Neritic phase, immature 64.01-87.0 

Adult3 >87.0 

Table 2. The number of sea turtle observer records from 2006 to 2010 in each injury category by 

gear type, as well as the overall mortality percentage by gear type. 

Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL Overall 

mortality 

percentage 

Trawl 53 10 22 12 97 47% 

Gillnet 14 1 3 11 29 58% 

Dredge 1 0 7 3 11 80% 

TOTAL 68 11 32 26 137 

Table 3. The number and corresponding injury category of sea turtles observed captured in trawl 

gear from 2006 to 2010. 

Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL Mortality 

Percentage

Loggerhead 

(Caretta caretta) 

50 9 17 12 88 

Leatherback 

(Dermochelys 

coriacea) 

0 1 1 0 2 

Kemp’s ridley 

(Lepidochelys 

kempii) 

2 0 0 0 2 

Green 

(Chelonia mydas) 

0 0 1 0 1 

Unknown 1 0 3 0 4 

TOTAL 53 10 22 12 97 

Percentage of turtles 

in each category 

55% 10% 23% 12% 

Dead turtles 

(total * mortality %) 

10.6 5 17.6 12 45.2 47% 

 

3

 The recovery plan has an additional category for adult males (>83 cm CCL), which overlaps with the size range for 

neritic immature loggerheads (46-87 cm CCL). The workgroup reviewed the available tail photographs of those 

loggerheads between 83-87 cm CCL to confirm that they should be considered in the immature neritic phase. 
11 

Table 4. Number of sea turtle trawl determinations in each category by fishery, 2006-2010. 

 Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL 

Fishery 

Atlantic croaker 

(Micropogonias 

undulatus) 35 3 13 11 62 

Horseshoe crab 

(Merostomata 

limulidae) 3 0 0 0 3 

Little skate 

(Leucoraja 

erinacea) 0 1 0 0 1 

Atlantic sea scallop 

(Placopecten 

magellanicus) 4 2 0 0 6 

Smooth dogfish 

(Mustelus canis) 1 0 0 0 1 

Squid4 1 2 3 0 6 

Summer flounder 

(Paralichthys 

dentatus) 8 2 4 1 15 

Unassigned 1 0 0 0 1 

Whiting (Merluccius 

bilinearis or 

Merluccius albidus) 0 0 1 0 1 

Winter flounder 

(Pseudopleuronectes 

americanus) 0 1 0 1 

2 

TOTAL 53 10 22 12 97 

 

4

 For the purposes of this report, the squid fishery includes both longfin inshore squid (Loligo pealeii) and northern 

shortfin squid (Illex illecebrosus). 
12 

Table 5. Number of sea turtle trawl determinations in each category by NMFS Northeast Statistical 

Area, 2006-2010. 

 Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL

Statistical Area 

537 0 0 2 0 2 

539 0 1 1 0 2 

561 0 0 1 0 1 

611 1 1 1 0 3 

615 3 1 0 0 4 

616 1 0 0 0 1 

621 10 2 5 1 18 

622 0 1 0 0 1 

625 2 0 2 1 5 

626 0 0 1 0 1 

631 1 0 0 2 3 

635 31 4 9 6 50 

636 4 0 0 2 6 

TOTAL 53 10 22 12 97 

Table 6. The number and corresponding injury category of sea turtles observed captured in gillnet 

gear from 2006 to 2010. 

Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL Mortality 

Percentage

Loggerhead 

(Caretta 

caretta) 

3 0 2 2 7 

Leatherback 

(Dermochelys 

coriacea) 

1 0 0 1 2 

Kemp’s ridley 

(Lepidochelys 

kempii) 

4 0 1 1 6 

Green 

(Chelonia 

mydas) 

6 1 0 5 12 

Unknown 0 0 0 2 2 

TOTAL 14 1 3 11 29 

Percentage of 

turtles in each 

category5

48% 3% 10% 38% 

Dead turtles 

(total * 

mortality %)

2.8 0.5 2.4 11 16.7 58% 

 

5

 The combined percentages do not equal 100%, due to rounding. 
13 

Table 7. Number of sea turtle gillnet determinations in each category by fishery, 2006-2010. 

 Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL 

Fishery 

Atlantic croaker 

(Micropogonias 

undulatus) 0 0 1 0 1 

Monkfish (Lophius 

americanus) 0 0 1 2 3 

Sandbar shark 

(Carcharhinus 

plumbeus) 0 0 0 1 1 

Southern flounder 

(Paralichthys 

lethostigma) 13 1 0 7 21 

Spanish mackerel 

(Scomberomorus 

maculatus) 1 0 1 0 2 

Winter skate 

(Leucoraja 

ocellata) 0 0 0 1 1 

TOTAL 14 1 3 11 29 

Table 8. Number of sea turtle gillnet determinations in each category by NMFS Northeast 

Statistical Areas, 2006-2010. 

 Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL 

Statistical 

Area 

537 0 0 0 1 1 

612 0 0 0 1 1 

615 0 0 1 1 2 

625 1 0 0 1 2 

635 0 0 1 0 1 

701 13 1 1 7 22 

TOTAL 14 1 3 11 29 
14 

Table 9. The number and corresponding injury category of sea turtles observed captured in 

dredge gear from 2006 to 2010. 

Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL Mortality 

Percentage 

Loggerhead 

(Caretta 

caretta) 

1 0 7 2 10 

Leatherback 

(Dermochelys 

coriacea) 

0 0 0 0 0 

Kemp’s ridley 

(Lepidochelys 

kempii) 

0 0 0 1 1 

Green 

(Chelonia 

mydas) 

0 0 0 0 0 

Unknown 0 0 0 0 0 

TOTAL 1 0 7 3 11 

Percentage of 

turtles in each 

category 

9% 0% 64% 27% 

Dead turtles 

(total * 

mortality %)

0.2 0 5.6 3 8.8 80% 

Table 10. Number of sea turtle dredge determinations in each category by NMFS Statistical Area, 

2006-2010. 

 Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL 

Statistical 

Area 

522 0 0 0 1 1 

615 0 0 3 1 4 

621 0 0 2 1 3 

622 0 0 1 0 1 

626 1 0 1 0 2 

TOTAL 1 0 7 3 11 
15 

Table 11. Sea turtle determinations in each category by species for all gear types combined, 2006-

2010. 

Category I 

(20% 

mortality) 

Category II 

(50% 

mortality) 

Category III 

(80% 

mortality) 

100% 

mortality 

TOTAL 

Loggerhead 

(Caretta 

caretta)

54 9 26 16 105

Leatherback 

(Dermochelys 

coriacea) 

1 1 1 1 4

Kemp’s 

ridley 

(Lepidochelys 

kempii)

6 0 1 2 9

Green 

(Chelonia 

mydas)

6 1 1 5 13

Unknown 1 0 3 2 6

TOTAL 68 11 32 26 137

 
16 

 

 

 

Figure 1. Workgroup size categories and injury determinations for loggerheads (Caretta caretta) 

captured in trawl gear, 2006-2010. (A) Transitional phase (oceanic or neritic), immature 

loggerheads (46.01-64.0 cm CCL); (B) Neritic phase, immature loggerheads (64.01 - 87.0 cm CCL); 

(C) Adult loggerheads (>87.0 cm CCL). 

3 1

1

A. Transitional phase, immature

Category I (20%)

Category II (50%)

Category III (80%)

100% mortality

39

7

13

7

B. Neritic phase, immature

Category I (20%)

Category II (50%)

Category III (80%)

100% mortality

6

1

4

3

C. Adults

Category I (20%)

Category II (50%)

Category III (80%)

100% mortality
17 

APPENDIX A. TECHNICAL WORKING GUIDELINES (FROM UPITE 

(2011)).

TECHNICAL WORKING GUIDELINES

FOR ASSESSING INJURIES OF SEA TURTLES 

OBSERVED IN NORTHEAST REGION FISHING GEAR6

 

Category I – Low probability of mortality (20% mortality rate) 

 Any shell fractures of the area of the marginal scutes, involving less than 50% of width of 

the underlying peripheral bone 

 Superficial abrasions, chips, or scuffs to carapace or plastron 

 Minor or superficial injuries to skin 

 Animals with no apparent injuries and active normal behavior 

Category II – Intermediate probability of mortality (50% mortality rate) 

 Any shell fractures of the area of the marginal scutes, involving 50% or more of width of 

the underlying peripheral bone 

 Injuries to flippers (including ligature wounds), which may impair movement or function 

 Injuries to one eye 

 Lethargic, but becomes active before release 

Category III – High probability of mortality (80% mortality rate) 

 Any shell fracture, excluding marginals 

 Fractures or wounds penetrating the body cavity 

 Evidence of bleeding from cloaca, nares, eyes, or oral cavity, unrelated to superficial 

wounds 

 Skull or mandibular fracture 

 Injuries to both eyes 

 Injuries to neck (including ligature wounds) which affects the spinal cord, major blood 

vessels, or airway 

 Amputation of half or more of one or more flippers 

 Any open fracture of major long bones 

 Behavioral abnormality, including circling, not using all four flippers appropriately, head 

tilting, not raising head, not breathing, eyes closed, listing/rolling, lethargic at release, 

inability to right itself in the water 

 Unresponsive7

, revived, and released 

 Any remaining gear left on the animal at release 

If an animal is found with multiple injuries in different categories, the animal should be placed in the category 

encompassing the most severe of the injuries. 

A 100% mortality rate will be assigned to any animal released into the water in a dead or unresponsive state 

regardless of its condition at first encounter. 

Old injuries determined to be unrelated to the current gear interaction or animals subject to adverse environmental 

conditions will be considered in the overall health assessment/survivability determination of the animal. 

 

6 For the purposes of this guidance, Northeast Region fishing gear excludes longline gear. 7

 Unresponsive refers to an episode of lack of response to external stimuli at any time. Lack of response criteria may 

include bilateral eye reflex, bilateral front and rear flipper pinch, corneal reflex, or cloacal clasp. 
18 

APPENDIX B. NMFS NORTHEAST STATISTICAL AREAS. 
Publishing in NOAA Technical Memorandum NMFS-NE

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