Further Evaluation of a Topless Bottom Trawl Design with Regard to Not Capturing Sea Turtles

NOAA/NMFS Award Number NA13NMF4720275 (GSAFF #125)

FINAL REPORT

Photo: Meghan Gahm

Lincoln Center, Suite 740 5401 West Kennedy Blvd.

Tampa, Florida 33609-2447

December 2014

This Final Report was prepared by the Gulf & South Atlantic Fisheries Foundation, Inc. under award number NA13NMF4720275 from the National Oceanic and Atmospheric Administration, U.S. Department of Commerce. The statements, findings, conclusions, and recommendations are

those of the author(s) and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration or the Department of Commerce.

Title: Further Evaluation of a Topless Bottom Trawl Design with Regard to Not Capturing Sea Turtles

Authors: Frank C. Helies, Program Director Dr. Joseph DeAlteris, DeAlteris Associates Inc. Judy L. Jamison, Executive Director Gulf & South Atlantic Fisheries Foundation, Inc.

Lincoln Center, Suite 740 5401 W. Kennedy Blvd. Tampa, Florida 33609-2447

Award No: NA13NMF4720275 (Foundation #125) Project Period: October 1, 2013 – September 31, 2014 I. Abstract

This project builds on previous work attempting to mitigate sea turtle interactions with bottom trawls in the Atlantic summer flounder fishery. As an alternative to a TED in the trawl, a topless trawl design was proposed in an effort to mitigate sea turtle interaction with the trawl. Several modifications of the topless trawl have been evaluated for finfish retention and sea turtle exclusion since work started in 2010. The primary goal of this project was to evaluate the ability of the modified topless trawl design with a 160-foot headrope to exclude sea turtles. The traditional trawl and all the topless trawl designs evaluated were developed by a group of academics, trawl designers, fishermen, and NMFS personnel. The F/V Karen Elizabeth was contracted to complete the field testing. Fieldwork was conducted off Brunswick, Georgia during the period 19 and 26 October 2013. When the nets were hauled and the codends emptied, if sea turtles were present, they were measured and tagged following NMFS protocol. For all tows, regardless of sea turtle capture, fish and crustacean species were identified to the genus and counted. A total of 132 paired tows of the control (traditional) and experimental (topless) trawls were completed. Sea turtle catch data, trawl performance data, catch of species other than sea turtle for all tows, and tow by tow catch data were recorded and summarized. The total number of sea turtles captured was 56, and included 52 loggerhead and four Kemp’s ridley sea turtles. The control trawl captured 37 sea turtles while the experimental trawl captured 19 sea turtles, so there was about a 50% reduction overall in sea turtle captures with the experimental trawl. Results from these tests show that the modified 160-foot headrope trawl with restrictor lines was partially successful at excluding or not capturing sea turtles. Results of this project were presented by Research Technician Ms. Meghan Gahm at the 34th Annual Symposium on Sea Turtle Biology and Conservation in New Orleans, LA in April 2014 as a poster and oral presentation.

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II. Executive Summary

Previous work attempting to mitigate sea turtle interactions with a bottom trawl equipped with a turtle excluder device (TED) in the Atlantic summer flounder fishery has resulted in significant loss of target species (Lawson, DeAlteris and Parkins, 2007). As an alternative to a TED in the trawl, a topless trawl design was proposed in an effort to mitigate sea turtle interaction with the trawl net. In the summer of 2010, an evaluation of the catch performance of a topless trawl design was conducted in the Atlantic summer flounder trawl fishery (DeAlteris and Parkins, 2010). The topless trawl design investigated in that study had a 106-foot headrope and an 80-foot footrope. The results of that study prompted a call from the fishing industry to further investigate the ability of the topless trawl to exclude or allow for the escape of sea turtles (DeAlteris, 2011). Field testing to study sea turtle escapability was conducted by a Rhode Island based twin-trawl vessel (DeAlteris and Parkins, 2011). The vessel was uniquely rigged with three tow wires and winches, so as to be able to tow two traditional trawls with legs and ground gear, simultaneously. There was concern that the 106-foot headrope may not allow sufficient time for a sea turtle to escape, but a 160-foot headrope would allow more than a three-fold increase in escapement time (DeAlteris and Parkins, 2011). The 106-foot design trawl was evaluated for its ability to not capture sea turtles off the Georgia coast. Unfortunately, those trials were not going well, so the trawl was further modified in the field to a 160-foot headrope. That design was successful at adequately reducing the catch of sea turtles as compared to the traditional design. In the summer of 2012, the 160-foot headrope trawl was evaluated for its catch efficiency for the target species, summer flounder, and the results were disappointing. The loss of flounder in the 160-foot headrope trawl was substantial. The Northeast Fisheries Science Center (NEFSC) funded a project to evaluate the topless trawl design using a scale model in the flume tank in Newfoundland, Canada. The goal of that effort was to adjust the rigging of the 160-foot trawl to improve catch performance for the target species. As a result of the flume tank evaluation of various topless trawl designs, a third generation topless trawl was developed and tested using headrope restrictor lines. This trawl had a smaller but significant loss (22%) of target species (Gahm, DeAlteris, and Parkins, 2013). The primary goal of this project was to evaluate the ability of this modified topless trawl design with a 160-foot headrope to exclude sea turtles. The traditional trawl and all the topless trawl designs evaluated were developed by a group of academics, trawl designers, fishermen, and NMFS personnel. The F/V Karen Elizabeth was contracted to complete the field testing. The vessel was outfitted with a single control trawl and two experimental topless trawls built with 160-foot headropes. Fieldwork commenced off Brunswick, Georgia on 19 October 2013. The field plan included a standardized tow duration of 30-minutes to reduce the probability of drowning a sea turtle. On each tow, the start and end time and location as determined by GPS were noted. When the nets were hauled and the codends emptied, if sea turtles were present, they were measured and tagged following NMFS protocol. For all tows, regardless of sea turtle capture, fish and crustacean species were identified to the genus and counted. A total of 132 paired tows of the control (traditional) and experimental (topless) trawls were completed during the period 19 and 26 October 2013. Tows were conducted during both day (77) and night (55), and were only stopped temporarily when an injured sea turtle was captured in a

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single trawl. Sea turtle catch data, trawl performance data, catch of species other than sea turtles for all tows, and tow by tow catch data were recorded and summarized. The total number of sea turtles captured was 56, and included 52 loggerhead and four Kemp’s ridley sea turtles. All sea turtles were captured in good condition, and were subsequently released in good condition with the exception of turtle number 34 which had a crushed carapace from unknown cause. This turtle was immediately taken back to port for treatment. The control trawl captured 37 sea turtles while the experimental trawl captured 19 sea turtles, so there was about a 50% reduction overall in the sea turtle captures with the experimental trawl. Interestingly, the experimental topless trawl performed better in terms of not capturing sea turtles during dark conditions (1900 to 0500 hours). Other bycatch data suggests that the topless trawl is capturing only 30% of finfish of the control trawl, 60% of the sharks and rays, yet more than 100% of the crabs. Clearly, the experimental topless trawl is tending bottom properly, but with the large setback in the headrope, the experimental trawl is allowing some finfish to escape, just as it allows some sea turtles to escape. The goals and objectives of this project were successfully completed. The modified 160 foot headrope topless trawl was successfully tested for sea turtle exclusion in the field. Adequate sea turtles were encountered to make this determination and it appears clear that the modified 160-foot headrope trawl with restrictor lines was partially successful at excluding or not capturing sea turtles. Future work will be conducted by researchers in the northeast and will include testing the 160-foot experimental trawl with two restrictor lines in a flume tank to further stabilize the headrope height and wing height. Results of this project were presented by Research Technician Ms. Meghan Gahm at the 34th Annual Symposium on Sea Turtle Biology and Conservation in New Orleans, LA in April 2014 as a poster and oral presentation. Copies of this project’s Final Report will be published and distributed. PDF copies will be made available for download from the Foundation’s website.

III. Purpose

Description of Problem: National Marine Fisheries Service (NMFS) published the intent to implement rule making to mitigate the mortality of sea turtles in the southern New England and mid-Atlantic bottom trawl fisheries several years ago (Feb 15, 2007). Previous work attempting to mitigate sea turtle interactions with a bottom trawl equipped with a turtle excluder device (TED) in the Atlantic summer flounder fishery resulted in a significant loss of target species (Lawson, DeAlteris and Parkins, 2007). As an alternative to a TED in the trawl, a topless trawl design was proposed in an effort to mitigate sea turtle interaction with the trawl net. From a trawl design perspective, the issue is providing sufficient setback of the headrope so that a sea turtle, once alarmed or stimulated by the sweep of the trawl, has sufficient time to swim upward and escape the trawl, before the headrope passes overhead. By increasing the length of the headrope for a given footrope length, the time between passage of the footrope and passage of the headrope is increased, allowing more time for a sea turtle to escape (DeAlteris and Parkins, 2011).

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In the summer of 2010, an evaluation of the catch performance of a topless trawl design was conducted in the Atlantic summer flounder trawl fishery (DeAlteris and Parkins, 2010). The topless trawl design investigated in that study had a 106-foot headrope and an 80-foot footrope. The topless trawl design was compared to a trawl net with an identical fishing circle, but of traditional design with a 65-foot headrope and an 80-foot footrope. Both trawls had identical sweeps made of small rubber and lead discs. Based on the results of 80 comparative tows (40 pairs), it was determined that there was no statistical difference between the catch rates of bottom fishes of the traditional trawl and the topless trawl with the 106 foot headrope. The results of that study prompted a call from the fishing industry to further investigate the ability of the topless trawl to exclude or allow for the escape of sea turtles (DeAlteris, 2011). The National Marine Fisheries Service procedure to evaluate the success of a new sea turtle release technology in trawl nets involves the release of small pen-raised sea turtles in the mouth of a trawl net by divers, then the recapture of the same turtles as they pass through a TED opening in the back end of the trawl (NMFS, 1990). This work is conducted annually in the Gulf of Mexico off of Panama City Beach, FL. Unfortunately, this procedure was not possible to implement for the topless trawl design, as the principle of the topless trawl is that sea turtles that encounter the trawl on the seabed will have the opportunity to escape upward before the headrope of the trawl captures them. Releasing turtles under the headrope directly into the mouth of the trawl clearly would not test the effectiveness of this net design (DeAlteris and Parkins, 2011). The field testing procedure that was adopted for that study (DeAlteris, 2011) followed a design that was previously used by NOAA Fisheries, and is referred to as the “wild turtle protocol” (NMFS, 1987). This procedure requires towing both the standard or control trawl and the experimental or topless trawl simultaneously, for the purpose of comparing the sea turtle catch rates between the control and experimental trawls in nearly identical time and space. In the past, this procedure was conducted aboard traditional shrimp trawlers that regularly tow two shrimp trawls simultaneously in the coastal waters of Georgia and Florida, where at certain times of the year there is a high likelihood of sea turtle encounters with trawls. Unlike shrimp trawls where the trawl doors are connected directly to the wing end, the traditional flounder trawls require wire bridles or legs and ground wires between the trawl wing ends and the trawl doors as these are used to increase the herding of flatfish. Therefore, it was not possible to use a shrimp trawler, so a Rhode Island based twin-trawl vessel was chartered to conduct the project (DeAlteris and Parkins, 2011). The vessel was uniquely rigged with three tow wires and winches, so as to be able to tow two traditional flounder trawls with legs and ground gear, simultaneously. Based on the geometry of the net design, the distance between the footrope and the headrope in the center of the trawl can be calculated, and therefore, the time between the passage of the headrope and the footrope estimated. Assuming the net is being towed at a certain number of feet per second, the time delay between passage of the footrope and the headrope can be calculated. This estimated time delay represents the maximum amount of time that a turtle would have to swim upward and escape the net after encountering the footrope. As the headrope is lengthened and the sag in the line extended farther back, sea turtle escapement time increases. For example, at headrope lengths of 133 and 160 feet, the distances between the footrope and the headrope in the center of the trawl are estimated at 26.5 and 48.5 feet, and the escapement times at a towing speed of 3 kts, are estimated to be 5.9 and 10.8 sec, respectively. In the previous study, there was concern that the 106-foot headrope may not allow sufficient time for a sea turtle to escape, but a

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160-foot headrope would allow more than a three-fold increase in escapement time, 3.3 versus 10.8 sec (DeAlteris and Parkins, 2011). The 106-foot headrope design trawl was evaluated for its ability to not capture sea turtles off the Georgia coast. Unfortunately, those trials were not going well, so the trawl was further modified in the field to a 160-foot headrope, and that design was successful at adequately reducing the catch of sea turtles as compared to the traditional design to pass the wild turtle protocol. In the summer of 2012, the 160-foot headrope trawl was evaluated for its catch efficiency for the target species, summer flounder, and the results were disappointing. The loss of flounder in the 160-foot modified trawl was substantial. The Northeast Fisheries Science Center (NEFSC) funded a project to evaluate the topless trawl design using a scale model in the flume tank in Newfoundland, Canada. The goal of that effort was to adjust the rigging of the 160-foot headrope trawl to improve catch performance for the target species. After the flume tank evaluation of various topless trawl designs, a third generation topless trawl was developed and tested using headrope restrictor lines. This trawl had a smaller but significant loss (22%) of target species (Gahm, DeAlteris, and Parkins, 2013). This project evaluated the ‘third generation’ modified topless design for its ability to not catch sea turtles and represents the final step in the long term research effort. Objectives:

1) Test the effectiveness of the 160-foot topless bottom trawl to reduce sea turtle capture using the wild turtle protocol in consultation and collaboration with NOAA NEFSC Fisheries Gear Specialists, members of the fishing industry, and consultants at DeAlteris Associates Inc.

IV. Approach

Statement of Work: Topless Trawl Selection: The primary goal of this project was to evaluate the ability of the ‘third generation’ modified topless trawl design with a 160-foot headrope to exclude sea turtles. The traditional trawl and the topless trawl design evaluated were developed by a group of academics (DeAlteris and Parkins), trawl designers (Mary O’Rourke of Trawlworks and Jon Knight of Superior Trawl), fishermen (Capt. James Ruhle), and NMFS personnel (Henry Milliken and Eric Matzen). The trawls were built by Trawlworks. All trawls had 320 x 6 inch fishing circles with an 80-foot footrope. The experimental topless design had a headrope length of 160 feet. Restrictor lines were 10.4-m. (34.2 ft) and 8.1 m (26.7 ft) in length and installed on the second and third seams of the net (Figures 1 and 2). Additionally, Figures 1 and 2 in Appendix A illustrate the designs of the control trawls and experimental 160-foot topless trawls, respectively. The traditional and topless trawls were rigged with sweeps on travelers made of small rubber discs (cookies) with interspersed lead discs (cookies). The traditional trawl was rigged with 16 8-inch plastic floats and the 160-foot headrope topless trawl was rigged with 24 8-inch plastic floats based on the results of the flume tank testing project in May 2013.

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Figure 1: Experimental trawl schematic. Red lines indicate location of restrictor ropes.

Figure 2: Photo of experimental trawl in flume tank.

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Field Data Collection: The F/V Karen Elizabeth was contracted to complete the field testing. The vessel was outfitted with a single control trawl and two experimental topless trawls built with 160-foot headropes. The vessel and scientific crew included Capt. Chris Roebuck and his deck crew, Chris Parkins and Meghan Gahm from the University of Rhode Island, and Eric Matzen (NMFS). The nets and other gear were loaded and tested in local New Jersey waters on 15 October 2013, and that evening the vessel departed for Georgia where the sea turtles were anticipated to be found. Fieldwork commenced off Brunswick, Georgia on 19 October 2013. The field plan included a standardized tow duration of 30-minutes to reduce the probability of drowning a sea turtle. All the tows with trawl nets were equipped with 90-foot (15 fathom) legs or bridles, 30-foot (5 fathoms) ground wire, and 18-foot (3 fathoms) backstraps on the doors. The target ground gear and bridle angle of attack was 15o, based on the combined bridle, ground wire and door backstrap length of 106 feet (18 fathoms). Observed door spread was controlled by limiting the tow wire length to the extent possible. On each tow, the start and end time and location as determined by GPS were noted. Door spread was monitored constantly during the tow using an acoustic trawl monitoring system. When the nets were hauled and the codends emptied, if sea turtles were present, they were measured and tagged following NMFS protocol. Flipper tags were applied to rear flippers, PIT tags were applied to left front flipper and a biopsy sample was taken from a rear flipper. Curved carapace notch-tip, notch-notch, and width measurements were taken for all turtles as well as tail length. Turtles were then released and GPS locations were recorded. All turtles recaptured were checked for tags and released. Recaptures were identified as such. Due to limited supplies, six turtles were released with one flipper tag (left flipper), without PIT tags, and without biopsy samples. In addition, two sea turtles were released with two rear flipper tags, a biopsy, but no PIT tag. Photographs of carapace, head, and tail were taken for each turtle captured before being released. For all tows, regardless of sea turtle capture, fish and crustacean species were identified to the genus and counted. Depth sensors were attached at the center of the headrope of the experimental topless trawl to evaluate the height of the headrope. Underwater video recording of the trawl was attempted, but no valuable data was collected due to the silt cloud off the soft bottom sediment. The target headrope height was a 1.5-2.0 m (5.0-6.5 ft) opening at the center which would represent what would be expected with a traditional trawl. For all tows with door spread measured, the bridle angle was calculated with a target angle of 15 degrees. A wing spread of 50 feet was assumed for the control trawl, and a wing spread of 46 feet was assumed for the experimental trawl based on measurements from testing at the flume tank in May of 2013. The average headrope height for the experimental trawl was also evaluated for those tows available. The first four minutes and last minute recorded for headrope height was disregarded for these calculations allowing the net time to take shape in the water.

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Project Management: Principal Investigator: Ms. Judy L. Jamison Executive Director

Foundation Staff: Mr. Frank C. Helies Program Director

Ms. Gwen Hughes Program Specialist Ms. Charlotte Irsch Grants/Contracts Specialist While the Foundation took the lead in project management, this project required the cooperation and active participation of many individuals. The essential personnel we would like to thank for their participation and hard work are: Independent Fishery Consultants:

Dr. Joseph DeAlteris, DeAlteris Associates, Inc. Chris Parkins, Field Technician, DeAlteris Associates, Inc. Megan Gahm, Field Technician, University of Rhode Island

Industry Cooperators:

Capt. Chris Roebuck, F/V Karen Elizabeth Capt. James Ruhle, Commercial Fisherman, Foundation Board Member Mary O’Rourke, Trawlworks Jon Knight, Superior Trawl

NOAA Fisheries Cooperators: Henry Milliken, NMFS NEFSC Eric Matzen, NMFS NEFSC South Atlantic Regional Coordinator:

Capt. Lindsey Parker, UGA Marine Extension

V. Findings

Results: A total of 132 paired tows of the control (traditional) and experimental (topless) trawls were completed during the period 19 and 26 October 2013 (Figure 3 and Table 1; Appendix A). Tows were conducted during both day (77) and night (55), and were only stopped when an injured sea turtle was captured in a single trawl. Sea turtle catch data are summarized in Table 1 and Table 2 in Appendix A. Detailed data on the measurements and tagging of the sea turtles is also presented in Appendix A. Other data summarized in Appendix A include trawl performance data, catch of species other than sea turtle for all tows, and tow by tow catch data. The total number of sea turtles captured was 56, and included 52 loggerhead and four Kemp’s ridley sea turtles. Of the 56 sea turtles captured during the trials, four were recaptures (sea turtles that were tagged after the first capture, and then subsequently recaptured). All sea turtles were

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captured in good condition, and were subsequently released in good condition with the exception of turtle number 34 which had a crushed carapace from unknown cause, and this turtle was immediately taken back to port for treatment. Additional information on this loggerhead sea turtle can be obtained from Eric Matzen, NOAA, NMFS, NEFSC. The control trawl captured 37 sea turtles while the experimental trawl captured 19 sea turtles, so there was about a 50% reduction overall in sea turtle captures with the experimental trawl. Interestingly, the experimental topless trawl performed better in terms of not capturing sea turtles during dark conditions (1900 to 0500 hours) (Figure 3).

Figure 3: Total capture of sea turtles, comparing day and night tows (Gahm et al.,, 2014).

Other bycatch data suggests that the topless trawl is capturing only 30% of finfish of the control trawl, 60% of the sharks and rays, yet more than 100% of the crabs. Clearly, the experimental topless trawl is tending bottom, but with the large setback in the headrope, the experimental trawl is allowing some finfish to escape, just as it allows some sea turtles to escape. Problems Encountered: No significant problems were encountered during project performance. All sea turtles were captured in good condition, and were subsequently released in good condition with the exception of turtle number 34 which had a crushed carapace from unknown cause, and this turtle was immediately taken back to port for treatment. Additional information on this loggerhead turtle can be obtained from Eric Matzen, NOAA, NMFS, NEFSC. Additional Work Needed: Future work will be conducted by researchers in the northeast and will include testing the 48.7 meter experimental trawl with two restrictor lines in a flume tank to help stabilize the headrope height and wing height.

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A conference call was held with cooperators and NMFS NEFSC scientists at the completion of the project. It was the consensus that additional information on sea turtle behavior is needed before additional topless trawl testing is conducted in the field. VI. Evaluation

Achievement of Goals and Objectives: The goals and objectives of this project were successfully completed. The modified topless trawl was successfully tested for sea turtle exclusion in the field with wild turtles. Adequate sea turtles were encountered to make this determination and it appears clear that the modified 160-foot headrope trawl with restrictor lines was partially successful at excluding or not capturing sea turtles. Dissemination of Results: Results of this project were presented by Research Technician Ms. Meghan Gahm at the 34th Annual Symposium on Sea Turtle Biology and Conservation in New Orleans, LA in April 2014 as a poster and oral presentation (Appendix B, poster presentation; Appendix C, power point presentation).

Meghan Gahm and her award winning poster presentation at the Sea Turtle Symposium.

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Summary reports of the project’s findings were published as part of the “Foundation Project Update” section of the “Gulf and South Atlantic News”, a publication of the Gulf & South Atlantic Fisheries Foundation, Inc. This newsletter was distributed to over 700 organizations and individuals throughout the region. An electronic version of this newsletter (PDF) is also included in the regular updates to the Foundation’s website (www.gulfsouthfoundation.org). Copies of this project’s Final Report will be published and distributed to various federal and state fishery agencies, university extension/Sea Grant offices, and Industry associations. In addition, PDF copies of the Final Report will be made available for download from the Foundation’s website. VII. Literature Cited DeAlteris, J. 2011. Report of sea turtle – trawl interaction workshop, Ocean City MD, October

2011. DeAlteris, J and C. Parkins. 2010. Draft report of the evaluation of the catch performance of a

topless trawl design in the summer flounder trawl fishery. Submitted by DeAlteris Associates Inc. to the NOAA NMFS, NERO BAA grant program.

DeAlteris, J. and C. Parkins. 2011. Evaluation of a Topless Bottom Trawl Design with Regard to

Excluding Sea Turtles. Submitted by DeAlteris Associates Inc. to the NOAA NMFS. Contract Number EA133F-10-SE-2491.

Gahm, M., DeAlteris, J., and C. Parkins. 2013. Evaluation of a topless trawl design with a 160-

foot headrope and two restrictor lines for fish capture in the summer flounder fishery. Draft report submitted on 29 October 2013 to NMFS, NEFSC on Contract EA-133F-12-SE2141.

Gahm, M., DeAlteris, J., Parkins, C., Milliken, H., and E. Matzen. 2014. Reducing sea turtle

mortality in the U.S. New England and Mid-Atlantic summer flounder trawl fishery. Presentation given at 34th Annual Symposium on Sea Turtle Biology and Conservation, New Orleans, LA, April 2014.

Lawson D., J.T. DeAlteris and C. Parkins. 2007. Evaluation of the catch efficiency of the NMFS

certified Turtle Excluder Device (TED) in the Mid-Atlantic summer flounder trawl fishery [Summary report; 26 p + appendix] NOAA Contract No. EA133F-05-SE-6561.

National Marine Fisheries Service (NMFS). 1987. Recommended statistical procedure for

evaluating turtle excluder devices in the Cape Canaveral, Florida ship channel. 52 FR 24244, 29 June 1987.

National Marine Fisheries Service (NMFS). 1990. Turtle excluder devices: adoption of an

alternative scientific testing protocol. 55 FR 41092, 9 October 1990.

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Appendices: Appendix A: PRELIMINARY FIELD AND DATA REPORT

Joseph DeAlteris, Meghan Gahm, Christopher Parkins Appendix B: Meghan Gahm Poster Presentation – Sea Turtle Symposium Appendix C: Meghan Gahm Workshop Presentation – Sea Turtle Symposium

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Appendix A

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PRELIMINARY FIELD AND DATA REPORT

EVALUATION OF A MODIFIED TOPLESS BOTTOM TRAWL DESIGN WITH RESTRICTOR LINES WITH REGARD TO EXCLUDING SEA TURTLES

14 November 2013

Joseph DeAlteris Meghan Gahm

Christopher Parkins

Gulf and South Atlantic Fisheries Foundation 5401 West Kennedy Blvd., Suite 740

Tampa, Florida

Report submitted in partial fulfillment of NOAA NMFS Contract Number: NA13NMF4720275

The statements, findings, conclusions, and recommendations are those of the author(s) and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration or the Department of Commerce.

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ABSTRACT

Previous work attempting to mitigate sea turtle interactions with a bottom trawl equipped with a turtle excluder device (TED) in the summer flounder fishery resulted in a significant and substantial loss of target species. A subsequent evaluation of the first generation topless trawl (106-foot headrope and 80-foot footrope) in this fishery resulted in catch rates of target species equivalent to a traditional trawl, but the trawl did capture sea turtles. A second generation design of the topless trawl extended the headrope to 160 feet, and this trawl did not capture sea turtles, but unfortunately had a significant and substantial loss of target species. After flume tank evaluation of various topless trawl designs, a third generation topless trawl was developed and tested using headrope restrictor lines. This trawl had a smaller but significant loss (about 22%) of target species. The purpose of this report is to present the methodology used and the data collected in the evaluation of the ability of this third generation modified topless trawl design, 160-foot headrope with restrictor lines, to exclude or not capture sea turtles, as compared to a traditional trawl design. Intentionally, no attempt has been made to analyze or interpret the data. A total of 132 comparative tows were accomplished off the Georgia coast in October 2013 using the F/V Karen Elizabeth, a Rhode Island based twin-trawl vessel. The sea turtle catch ratio data (topless: traditional) was 19:37, suggesting that overall there was some conservation benefit with the experimental topless trawl. The results of the fieldwork indicate that the 160-foot headrope topless trawl experienced the greatest success in excluding or not capturing sea turtles as compared to the traditional trawl at night when the ratio of sea turtle captures was 3:14, as compared to during the day when the ratio was 16:23. Additionally, the mean catches of other species than sea turtles were compared and the results suggest that the topless trawl did catch less finfish, sharks, and rays.

INTRODUCTION Previous work attempting to mitigate sea turtle interactions with a bottom trawl equipped with a turtle excluder device (TED) in the summer flounder fishery resulted in a significant loss of target species (Lawson, DeAlteris and Parkins, 2007). As an alternative to a TED in the trawl, a topless trawl design was proposed in an effort to mitigate sea turtle interaction with the trawl net. In essence, the theory is that if the topless trawl is successful, sea turtles will not be captured in the trawl. From a trawl design perspective, the issue is providing sufficient setback of the headrope so that a sea turtle, once alarmed or stimulated by the sweep of the trawl, has sufficient time to swim upward and escape the trawl before the headrope passes overhead. By increasing the length of the headrope for a given footrope length, the time between passage of the footrope and passage of the headrope is increased, allowing more time for a sea turtle to escape. In the summer of 2010, an evaluation of the catch performance of a topless trawl design was conducted in the summer flounder trawl fishery (DeAlteris and Parkins, 2010; 2012a). The

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topless trawl design investigated in that study had a 106-foot headrope and an 80-foot footrope. That topless trawl design was compared to a trawl net with an identical fishing circle, but of traditional design with a 65-foot headrope and an 80-foot footrope. Both trawls had identical sweeps made of small rubber and lead discs (cookies). Based on the results of 80 comparative tows (40 pairs), it was determined that there was no statistical difference between the catch rates of bottom fishes of the traditional trawl and the topless trawl with a 106-foot headrope. The results of that study prompted a call from the fishing industry to further investigate the ability of the topless trawl to exclude or allow for the escape of sea turtles (DeAlteris, 2011). Subsequent testing of that trawl for not capturing sea turtles indicated that the 106-foot headrope was unsuccessful at not capturing sea turtles, but that a 160-foot headrope topless trawl would be effective (DeAlteris and Parkins, 2012b). That second generation design of the topless trawl did not capture sea turtles, and unfortunately also had a significant and substantial loss of target species (DeAlteris et al., 2013). After flume tank evaluation of various topless trawl designs, a third generation topless trawl was developed and tested using headrope restrictor lines. This trawl had a smaller but significant loss (20%) of target species (Gahm, DeAlteris, and Parkins, 2013). The purpose of this report is to present the methodology used and the data collected in the evaluation of the ability of this third generation modified topless trawl design, 160-foot headrope with restrictor lines, to exclude or not capture sea turtles, as compared to a traditional trawl design. The field testing procedure that was adopted for this 2013 study followed a design that was previously used by NMFS, and is referred to as a “wild turtle test” (NMFS, 1987; 1990), and is the same procedure that was used in the 2012 testing of the various early topless trawl designs (DeAlteris and Parkins, 2012b). This procedure required towing both the standard or control trawl and the experimental or topless trawl simultaneously, for the purpose of comparing the sea turtle catch rates between the control and experimental trawls in nearly identical time and space. In the past, this procedure was conducted aboard traditional shrimp trawlers that regularly tow two shrimp trawl nets simultaneously in the coastal waters of Georgia and Florida, where at certain times of the year there is a high likelihood of sea turtle encounters with trawl nets. Unlike shrimp trawls, where the trawl doors are connected directly to the wing end, the traditional flounder trawls require wire bridles or legs and ground wires between the trawl wing ends and the trawl doors as these are used to increase the herding of flatfish. Therefore, it was not possible to use a shrimp trawler, so a Rhode Island based twin-trawl vessel, the F/V Karen Elizabeth, was chartered to conduct this project. She is uniquely rigged with three tow wires and winches, so as to be able to tow two traditional trawls with legs and ground gear, simultaneously. In fact, this vessel has been used by the NMFS NEFSC to compare the catch performance of the new NEFSC bottom survey trawl with two different sweep designs, towing both sweeps simultaneously (Henry Milliken, NMFS, pers. comm.).

16

METHODS Trawl designs The primary goal of this project was to evaluate the ability of the topless trawl design with a 160-foot headrope and restrictor lines to exclude sea turtles. The traditional trawl and the topless trawl designs evaluated were developed by a group of academics (DeAlteris, Parkins, and Gahm), trawl designers (Mary O’Rourke of Trawlworks and Jon Knight of Superior Trawl), fishermen (Captain Jim Ruhle), and NMFS personnel (Henry Milliken and Eric Matzen). The trawls were built by Trawlworks and serviced by Jon Knight of Superior Trawl. Both trawls had 320 x 6 inch fishing circles, and had an 80-foot footrope. The experimental topless design had headrope length of 160 feet, and two restrictor lines were placed in the headrope to ensure that the wings of the trawl remained upright. Figures 1 and 2 illustrate the designs of the control and 160-foot topless trawl design trawls, respectively. The traditional and topless trawls were rigged with sweeps on travelers made of small rubber discs (cookies) with interspersed lead discs (cookies). Both the traditional trawl was rigged with 16 8-inch plastic floats, while the topless trawl was rigged with 24 8-inch plastic floats. The chartered fishing vessel traveled to Georgia with a single control trawl and two experimental topless trawls built with 108-foot headropes. Fieldwork The vessel and scientific crew included Capt. Chris Roebuck and his deck crew, Chris Parkins and Meghan Gahm from the University of Rhode Island, and Eric Matzen (NMFS). The nets and other gear were loaded and tested in local New Jersey waters on 15 October 2013, and that evening the vessel departed for Georgia where the sea turtles were anticipated to be found. Fieldwork commenced off Brunswick, Georgia on 19 October 2013. The field plan included a standardized tow duration of 30-minutes to reduce the probability of drowning a sea turtle. All the tows with trawl nets were equipped with 90-foot (15 fathom) legs or bridles, 30-foot (5 fathoms) ground wire, and 18-foot (3 fathoms) backstraps on the doors. The target ground gear and bridle angle of attack was 15o, based a combined bridle, ground wire and door backstrap length of 108 feet (18 fathoms). Observed door spread was controlled by limiting the tow wire length to the extent possible. On each tow, the start and end time and location as determined by GPS were noted. Door spread was monitored constantly during the tow using an acoustic trawl monitoring system. When the nets were hauled and the codends emptied, if sea turtles were present, they were measured and tagged following NMFS protocol. Flipper tags were applied to rear flippers, PIT tags were applied to left front flipper and a biopsy sample was taken from a rear flipper. Curved carapace notch-tip, notch-notch, and width measurements were taken for all turtles as well as tail length. Turtles were then released and GPS locations were recorded. All turtles recaptured were checked

17

for tags and released. Recaptures were identified as such. Due to limited supplies, six turtles were released with one flipper tag (left flipper), without PIT tags, and without biopsy samples. In addition, two sea turtles were released with two rear flipper tags, a biopsy, but no PIT tag. Photographs of carapace, head, and tail were taken for each turtle captured before being released. For all tows, regardless of sea turtle capture, fish and crustacean species were identified to the genus and counted. Depth sensors were attached at the center of the headrope of the experimental topless trawl to evaluate the height of the headrope. At this time in the analysis, headrope height data is available for a series of tows from 10/19/2013-10/22/2013 and 10/26/2013. Underwater video recording of the trawl was attempted, but no valuable data was collected due to the silt cloud off the soft bottom sediment. For all tows with door spread measured, the bridle angle was calculated with a target angle of 15 degrees. A wing spread of 50 feet was assumed for the control trawl, and a wing spread of 46 feet was assumed for the experimental trawl based on measurements from testing at the flume tank in May of 2013. The average headrope height for the experimental trawl was also evaluated for those tows available. The first four minutes and last minute recorded for headrope height was disregarded for these calculations allowing the net time to take shape in the water.

RESULTS A total of 132 paired tows of the control (traditional) and experimental (topless) trawls were completed in the ocean off Brunswick, Georgia during the period 19 and 26 October 2013 (Figure 3 and Appendix 1, Table 1). Tows were conducted during both day (77) and night (55), and were only stopped when an injured sea turtle was captured in a single trawl. Sea turtle catch data are summarized in Table 1 and by individual capture are provided in Appendix 1, Table 2. Detailed data on the measurements and tagging of the sea turtles is presented in Appendix 1, Table 3. Figure 4 shows the locations of all tows when turtles were encountered. Table 2 summarizes the trawl performance data, in terms of door spread, estimated bridle angle, and experimental trawl headrope height. Table 3 summarizes the catch of species other than sea turtle for all tows, and the detailed tow by tow catch data are presented in Appendix 1, Table 4. An electronic EXCEL file accompanies this report in Appendix 2, that provides all the EXCEL files with raw data and the summary tables included in the report body and Appendix 1. The total number of sea turtles captured was 56, and included 52 loggerhead and 4 Kemp’s ridley sea turtles. Of the 56 sea turtles captured during the trials, four were recaptures, that is sea turtles that were tagged after the first capture, and then subsequently recaptured (see Appendix 2, final sea turtle data file). All sea turtles were captured in good condition, and were subsequently released in good condition with the exception of turtle number 34 which had a crushed carapace

18

from unknown cause, and this turtle was immediately taken back to port for treatment. Additional information on this loggerhead turtle can be obtained from Eric Matzen, NOAA, NMFS, NEFSC. The control trawl captured 37 sea turtles while the experimental trawl captured 19 sea turtles, so there was about a 50% reduction overall in the sea turtle captures with the experimental trawl. More interestingly, when the sea turtle captures are divided according to the time of day, day versus night, with night or darkness considered to extend with trawl start times from 1900 (7 PM) to 0500 (5 AM), the captures of sea turtles in the control trawl was 14, while the captures of sea turtles in the experimental trawl was 3. In contrast, during daylight conditions, defined here to extend with trawl start times of after 0500 (5 AM) to before 1900 (7 PM), the control trawl captured 23 sea turtles compared to 16 in the experimental trawl. Clearly the experimental (topless trawl) performed better in terms of not capturing sea turtles, during darkness. In terms of the physical performance of the trawls, both trawls performed as designed. The average door spread for the control and experimental trawls was 19.3 and 19.1 fathoms, respectively. This resulted in estimated wing bridle angles of 14.6 and 13.6 degrees. The average headrope opening of the experimental trawl was 3.9 feet. Other bycatch suggests that the topless trawl is capturing only 30% of finfish of the control trawl, 60% of the sharks and rays, and more than 100% of the crabs. Clearly, the experimental topless trawl is tending bottom properly, but with the large setback in the headrope, the experimental trawl is allowing some finfish to escape, just as it allows some sea turtles to escape.

DISCUSSION The purpose of this report is to present the methodology used and the data collected in the evaluation of the ability of modified topless trawl design with headrope restrictor lines to exclude or not capture sea turtles, as compared to a traditional trawl design. No attempt has been made to analyze or interpret the data. However, it appears clear that the modified 160-foot headrope trawl with restrictor lines was partially successful at excluding or not capturing sea turtles.

ACKNOWLEDGMENTS

As noted previously, this project would not have been possible without the cooperation and participation of many individuals: Henry Milliken, Heather Haas and Eric Matzen of the NMFS Northeast Fisheries Science Center, Captains Jim Ruhle and Chris Roebuck, Jon Knight of Superior Trawl and Mary O’Rourke of Trawlworks, Lindsey Parker of the University of Georgia.

19

LITERATURE CITED

DeAlteris, J.2011. Report of sea turtle – trawl interaction workshop, Ocean City MD, October 2011.

DeAlteris, J. and C. Parkins. 2010. Draft report on the evaluation of the catch performance of a topless trawl design in the summer flounder trawl fishery. Submitted by DeAlteris Associates Inc. to NMFS NERO, BAA grant program.

DeAlteris, J and C. Parkins. 2012a. An evaluation of the catch efficiency of a topless trawl design with a 106 foot headrope and 80 foot sweep for target species and sea turtles in the southern New England and mid-Atlantic summer flounder trawl fishery. Submitted by DeAlteris Associates Inc. to the NOAA NMFS, NERO Cooperative Research Program, Contract EA 133F-10-CN-0057

DeAlteris, J. and C. Parkins. 2012b. Field and data report; Evaluation of a topless bottom trawl designs with regard to excluding sea turtles.[NOAA Contract No. EA 133F-10-SE-2491, Mod. 002].

DeAlteris J., Parkins, C., Hasbrouck, E., Scotti, J., Froehlich, T., and J. Costanzo, 2013. Evaluation of a topless bottom trawl design with a 160 foot headrope for fish capture. [NOAA NMFS Contract Number: EA 133F-10-SE-2491, Mod. 002]

Gahm, M., DeAlteris, J., and C. Parkins. 2013. Evaluation of a topless trawl design with a 160 foot headrope and two restrictor lines for fish capture in the summer flounder fishery. Draft report submitted on 29 October 2013 to NMFS, NEFSC on Contract EA-133F-12-SE2141.

Lawson D., J. T. DeAlteris and C. Parkins. 2007. Evaluation of the catch efficiency of the NMFS certified Turtle Excluder Device (TED) in the Mid-Atlantic summer flounder trawl fishery [Summary report; 26 p + appendix] NOAA Contract No. EA133F-05-SE-6561.

NMFS. 1987. Recommended statistical procedure for evaluating turtle excluder devices in the Cape Canaveral, Florida ship channel. 52 FR 24244, 29 June 1987.

NMFS. 1990. Turtle excluder devices: adoption of an alternative scientific testing protocol. 55 FR 41092, 9 October 1990.

20

Figure 1. Schematic of 360x6” control or traditional trawl with a 65-foot headrope used in this study.

21

Figure 2. Schematic of 320 x 6 inch topless trawl with 160-foot headrope used in this study.

22

Figure 3. Chart showing all 132 tows paths conducted in this study between 10/19/2013 and 10/26/2013

23

Figure 4. Chart showing all tow paths that captured sea turtles in this study.

24

Figure 5. Comparison of the number of individuals captured in the control and experimental topless trawls by species group.

0

500

1000

1500

2000

2500

3000

Sharks, Rays Finfish Crabs

Num

bers

of i

ndiv

idua

ls c

aptu

red

Control

Experimantal

25

Table 1. Summary of sea turtle catch data in the experimental (topless) and control trawl nets.

All Day Night Number of tows 132 77 55 Total turtles cap. 56 39 17

Control turtle cap. 37 23 14 Exp. turtle cap. 19 16 3

Table 2. Summary of trawl performance in terms of mean observed door spread and bridle angle for the experimental (topless) and control trawl nets, and headrope height for the experimental (topless) trawl.

Control Door

Spread (fthm)

Control Bridle Angle

(Degrees)

Experimental Door Spread

(fthm)

Experimental Bridle Angle

(Degrees)

Experimental Headrope Height (ft)

19.3 14.6 19.1 13.6 3.9

Table 3. Summary of catch data other than sea turtles (mean # of animals by species group) in the experimental (topless) and control trawl nets.

Species Group Control Experimental

Sharks, Rays 968 593

Finfish 2661 863

Crabs 68 84

26

Appendix Table 1. Start and end date, time and location data for each tow conducted in this study.

Date Tow # Start Time

Start Latitude degrees-min.

Start Longitude degrees-min.

End Time

End Latitude degrees-min.

End Longitude degrees-min.

10/19/2013 1 1026 31 2.669 -81 15.969 1056 31 1.073 -81 15.570 10/19/2013 2 1110 31 0.237 -81 15.638 1140 31 1.277 -81 17.427 10/19/2013 3 1303 31 0.904 -81 17.503 1333 31 0.611 -81 15.680 10/19/2013 4 1345 31 0.740 -81 15.763 1415 31 1.349 -81 17.421 10/19/2013 5 1427 31 1.075 -81 17.062 1457 31 0.420 -81 15.373 10/19/2013 6 1509 31 0.627 -81 15.261 1539 31 2.253 -81 15.759 10/19/2013 7 1553 31 2.244 -81 16.033 1624 31 0.653 -81 16.031 10/19/2013 8 1635 30 59.980 -81 15.866 1705 30 58.437 -81 15.561 10/19/2013 9 1716 30 58.601 -81 15.496 1746 31 0.318 -81 15.596 10/19/2013 10 1757 31 0.950 -81 15.747 1827 31 2.682 -81 16.100 10/19/2013 11 1839 31 2.699 -81 16.076 1910 31 1.218 -81 15.545 10/19/2013 12 1922 31 1.224 -81 15.310 1953 31 2.542 -81 14.063 10/19/2013 13 2004 31 2.298 -81 13.963 2034 31 0.666 -81 13.913 10/19/2013 14 2049 31 0.750 -81 14.087 2119 31 2.083 -81 13.065 10/19/2013 15 2131 31 2.115 -81 13.382 2201 31 1.257 -81 14.553 10/19/2013 16 2215 31 1.063 -81 15.074 2245 30 59.800 -81 13.840 10/19/2013 17 2258 31 0.026 -81 13.690 2328 31 1.605 -81 13.714 10/19/2013 18 2339 31 1.649 -81 14.140 0900 31 0.821 -81 15.730 10/20/2013 19 0719 30 57.821 -81 14.637 0749 30 59.437 -81 14.885 10/20/2013 20 0801 31 0.013 -81 15.227 0831 31 1.513 -81 16.008 10/20/2013 21 0919 31 1.191 -81 15.437 0949 31 2.415 -81 14.214 10/20/2013 22 1000 31 2.077 -81 14.016 1030 31 0.365 -81 14.015 10/20/2013 23 1049 31 0.661 -81 14.452 1119 31 1.174 -81 16.187 10/20/2013 24 1134 31 1.260 -81 16.055 1204 31 1.253 -81 14.092 10/20/2013 25 1215 31 1.313 -81 13.964 1245 31 2.655 -81 14.846 10/20/2013 26 1256 31 2.311 -81 14.818 1326 31 0.556 -81 14.823 10/20/2013 27 1337 31 0.615 -81 14.961 1407 31 2.087 -81 15.733 10/20/2013 28 1418 31 1.787 -81 15.908 1448 31 0.090 -81 15.922 10/20/2013 29 1458 31 0.073 -81 15.512 1528 31 1.456 -81 14.434 10/20/2013 30 1541 31 1.553 -81 14.439 1611 31 1.410 -81 16.310 10/20/2013 31 1624 31 1.176 -81 16.214 1655 31 0.583 -81 14.498 10/20/2013 32 1709 31 0.579 -81 14.527 1739 31 1.381 -81 16.277 10/20/2013 33 1757 31 1.365 -81 16.173 1827 31 0.515 -81 14.464 10/20/2013 34 1839 31 0.584 -81 14.552 1909 31 0.971 -81 16.505

27

Appendix Table 1 (continued).

Date Tow # Start Time

Start Latitude degrees-min.

Start Longitude degrees-min.

End Time

End Latitude degrees-min.

End Longitude degrees-min.

10/20/2013 35 1921 31 1.154 -81 16.343 1951 10/20/2013 36 2003 31 1.488 -81 14.845 2033 31 1.089 -81 16.700 10/20/2013 37 2044 31 1.052 -81 16.558 2114 31 0.603 -81 14.793 10/20/2013 38 2126 31 0.899 -81 14.078 2156 31 2.447 -81 13.979 10/20/2013 39 2211 31 2.245 -81 14.367 2241 31 1.085 -81 15.757 10/20/2013 40 2252 31 1.183 -81 15.704 2322 31 1.228 -81 13.874 10/20/2013 41 2348 31 1.570 -81 14.394 1800 31 1.162 -81 16.229 10/21/2013 42 0739 31 1.166 -81 16.387 0809 31 0.785 -81 14.659 10/21/2013 43 0827 31 0.638 -81 14.668 0857 31 0.974 -81 16.635 10/21/2013 44 0911 31 1.077 -81 16.388 0941 31 1.254 -81 14.551 10/21/2013 45 0956 31 1.370 -81 14.685 1026 31 1.390 -81 16.640 10/21/2013 46 1054 31 1.058 -81 15.786 1124 31 0.376 -81 14.034 10/21/2013 47 1157 31 0.714 -81 14.261 1227 31 0.705 -81 16.099 10/21/2013 48 1252 31 0.649 -81 15.783 1322 31 0.150 -81 13.878 10/21/2013 49 1340 31 0.402 -81 13.731 1410 31 1.923 -81 13.568 10/21/2013 50 1427 31 2.042 -81 13.861 1457 31 0.676 -81 15.264 10/21/2013 51 1515 31 0.958 -81 15.284 1545 31 2.214 -81 14.097 10/21/2013 52 1558 31 1.971 -81 14.363 1628 31 0.986 -81 15.962 10/21/2013 53 1639 31 0.834 -81 15.824 1709 31 0.308 -81 13.992 10/21/2013 54 1726 31 0.610 -81 14.378 1756 31 1.608 -81 15.918 10/21/2013 55 1809 31 1.891 -81 15.825 1839 31 2.787 -81 14.312 10/21/2013 56 1851 31 2.563 -81 14.352 1821 31 1.218 -81 15.633 10/21/2013 57 1935 31 1.215 -81 15.592 2005 31 2.213 -81 14.158 10/21/2013 58 2018 31 1.966 -81 14.221 2046 31 1.367 -81 15.986 10/21/2013 59 2058 31 1.211 -81 16.074 2128 31 0.517 -81 14.410 10/22/2013 60 0736 31 1.099 -81 16.550 0806 31 0.603 -81 14.716 10/22/2013 61 0821 31 0.746 -81 14.528 0851 31 1.427 -81 16.357 10/22/2013 62 0904 31 1.428 -81 16.283 0935 31 1.338 -81 14.397 10/22/2013 63 0948 31 1.723 -81 14.434 1018 31 3.258 -81 15.401 10/22/2013 64 1054 31 2.162 -81 14.235 1124 31 0.813 -81 13.037 10/22/2013 65 1139 31 0.546 -81 12.626 1209 30 59.633 -81 11.010 10/22/2013 66 1222 30 59.527 -81 11.318 1252 30 59.989 -81 13.081 10/22/2013 67 1305 31 0.269 -81 13.762 1335 31 0.945 -81 15.471 10/22/2013 68 1347 31 1.322 -81 15.284 1417 31 1.092 -81 13.498 10/22/2013 69 1428 31 0.950 -81 13.511 1458 31 2.173 -81 14.526

28

Appendix Table 1 (continued).

Date Tow # Start Time

Start Latitude degrees-min.

Start Longitude degrees-min.

End Time

End Latitude degrees-min.

End Longitude degrees-min.

10/22/2013 70 1510 31 2.080 -81 14.542 1540 31 0.815 -81 15.834 10/22/2013 71 1555 31 0.545 -81 15.970 1625 31 2.093 -81 15.698 10/22/2013 72 1645 31 1.925 -81 14.795 1717 31 0.663 -81 13.599 10/22/2013 73 1728 31 0.639 -81 14.070 1758 31 1.131 -81 15.665 10/22/2013 74 1813 31 1.033 -81 15.879 1843 31 0.352 -81 14.119 10/22/2013 75 1859 31 0.624 -81 14.301 1929 31 1.315 -81 16.099 10/23/2013 76 1323 31 1.504 -81 16.145 1353 31 0.719 -81 14.357 10/23/2013 77 1407 31 0.526 -81 14.456 1437 31 1.190 -81 16.105 10/23/2013 78 1449 31 1.348 -81 15.808 1519 31 1.139 -81 13.795 10/23/2013 79 1904 30 59.658 -81 11.557 1934 31 0.505 -81 13.207 10/23/2013 80 1946 31 0.611 -81 13.856 2016 31 1.299 -81 15.659 10/23/2013 81 2031 31 1.490 -81 15.780 2101 31 1.409 -81 13.912 10/23/2013 82 2113 31 1.136 -81 13.322 2143 30 59.810 -81 12.254 10/23/2013 83 2157 30 59.936 -81 12.907 2227 31 0.830 -81 14.667 10/23/2013 84 2242 31 0.581 -81 14.606 2312 30 59.490 -81 13.190 10/23/2013 85 2326 30 59.730 -81 13.042 2356 31 1.339 -81 13.485 10/24/2013 86 2100 31 2.010 -81 14.266 0051 31 1.434 -81 16.073 10/24/2013 87 0103 31 1.254 -81 16.054 0134 31 0.468 -81 14.294 10/24/2013 88 0148 31 0.612 -81 14.271 0218 31 1.504 -81 15.823 10/24/2013 89 0232 31 1.124 -81 15.808 0302 31 0.101 -81 13.965 10/24/2013 90 0317 31 0.317 -81 13.997 0347 31 1.372 -81 15.440 10/24/2013 91 0400 31 1.382 -81 15.041 0430 31 0.536 -81 13.400 10/24/2013 92 0442 31 0.381 -81 13.692 0512 31 1.151 -81 15.333 10/24/2013 93 0528 31 0.879 -81 15.505 0558 31 2.419 -81 15.899 10/24/2013 94 0634 31 0.986 -81 15.739 0704 30 59.418 -81 14.846 10/24/2013 95 1631 31 0.687 -81 15.019 1701 31 2.193 -81 15.685 10/24/2013 96 1717 31 1.910 -81 15.793 1747 31 0.156 -81 15.877 10/24/2013 97 1804 31 0.158 -81 15.593 1834 31 1.525 -81 14.431 10/24/2013 98 1856 31 1.770 -81 14.221 1926 31 1.479 -81 16.203 10/24/2013 99 2014 31 1.211 -81 16.145 2045 31 0.358 -81 14.467 10/24/2013 100 2056 31 0.662 -81 14.509 2126 31 1.761 -81 16.079 10/24/2013 101 2136 31 1.629 -81 16.052 2206 30 59.991 -81 15.779 10/24/2013 102 2217 31 0.138 -81 15.538 2247 31 1.550 -81 14.539 10/24/2013 103 2300 31 1.600 -81 14.641 2330 31 1.396 -81 16.584 10/24/2013 104 2341 31 1.195 -81 16.496 2411 31 0.361 -81 14.781

29

Appendix Table 1 (continued).

Date Tow # Start Time

Start Latitude degrees-min.

Start Longitude degrees-min.

End Time

End Latitude degrees-min.

End Longitude degrees-min.

10/25/2013 105 0023 31 0.041 -81 14.225 0053 30 59.080 -81 12.558 10/25/2013 106 0107 30 59.247 -81 12.327 0137 31 0.404 -81 13.717 10/25/2013 107 0149 31 0.625 -81 14.289 0219 31 1.439 -81 15.870 10/25/2013 108 0231 31 1.418 -81 15.861 0301 31 1.146 -81 13.888 10/25/2013 109 0314 31 1.198 -81 13.815 0344 31 2.478 -81 14.706 10/25/2013 110 0830 31 2.142 -81 16.043 0900 31 0.469 -81 16.394 10/25/2013 111 0911 31 0.444 -81 16.202 0943 31 1.494 -81 14.802 10/25/2013 112 0952 31 1.609 -81 14.903 1022 31 1.460 -81 16.960 10/25/2013 113 1034 31 1.282 -81 17.013 1104 31 0.519 -81 15.358 10/25/2013 114 1122 31 0.835 -81 15.306 1153 31 2.450 -81 15.921 10/25/2013 115 1203 31 2.431 -81 16.087 1233 31 0.841 -81 16.753 10/25/2013 116 1244 31 0.823 -81 16.536 1316 31 1.234 -81 14.611 10/25/2013 117 1326 31 1.414 -81 14.786 1358 31 1.478 -81 16.727 10/25/2013 118 1407 31 1.207 -81 16.706 1439 30 59.781 -81 15.547 10/25/2013 119 1914 31 0.529 -81 15.221 1944 31 2.115 -81 15.654 10/25/2013 120 1956 31 2.043 -81 15.849 2025 31 0.397 -81 16.392 10/25/2013 121 2035 31 0.423 -81 16.165 2107 31 1.356 -81 14.668 10/25/2013 122 2116 31 1.539 -81 14.841 2146 31 1.414 -81 16.827 10/25/2013 123 2200 31 1.169 -81 16.866 2231 30 59.831 -81 15.624 10/25/2013 124 2240 31 0.027 -81 15.535 2310 31 1.672 -81 15.757 10/25/2013 125 2325 31 1.562 -81 15.742 2355 31 0.018 -81 16.155 10/26/2013 126 2200 31 0.703 -81 16.062 0052 31 1.442 -81 14.423 10/26/2013 127 0113 31 1.586 -81 14.718 0144 31 1.416 -81 16.682 10/26/2013 128 0152 31 1.213 -81 16.674 0222 31 0.486 -81 14.990 10/26/2013 129 0235 31 0.761 -81 14.974 0305 31 2.213 -81 15.829 10/26/2013 130 0319 31 1.980 -81 15.977 0349 31 0.234 -81 16.003 10/26/2013 131 0826 31 0.508 -81 14.486 0859 31 1.243 -81 16.242 10/26/2013 132 0909 31 1.378 -81 16.181 0941 31 1.274 -81 14.234

30

Table 2. Trawl performance data including door spread (fathoms), estimated bridle angle, measured headrope height for topless trawl, and environmental data including water depth (fathoms) and surface and bottom water temperature (o F).

Tow #

EXP (P/S)

Door Spread (fthm)

Bridle Angle

(Degrees) CNTRL (P/S)

Door Spread (fthm)

Bridle Angle

(Degrees)

Topless Headrope Height (ft)

Depth (fthm)

Surface Temp

(Farenheit)

Bottom Temp

(Farenheit) 1 P 18 13.0 S 18 12.1 N/A 6.7 76.5 75.9 2 P 18 13.0 S 17 10.9 N/A 7.7 76.9 76.3 3 P 12 5.4 S 13 5.8 3.3 6.0 77.1 77.2 4 P 17 11.7 S 16 9.6 3.0 5.9 77.3 76.3 5 P 16 10.4 S 16 9.6 3.2 5.7 77.4 76.6 6 P 16 10.4 S 17 10.9 3.4 7.0 77.4 76.3 7 P 18 13.0 S 21 16.0 3.0 6.1 77.9 76.6 8 P 22 18.2 S 19 13.4 3.8 6.5 77.7 76.6 9 P 17 11.7 S 17 10.9 3.7 6.9 78.1 46.6

10 P 18 13.0 S 15 8.3 3.2 6.8 78.2 76.6 11 P 18 13.0 S 23 18.6 2.7 7.0 77.2 76.3 12 P 21 16.8 S 19 13.4 4.2 8.2 77.9 76.5 13 P 18 13.0 S 22 17.3 4.0 8.0 78.2 76.5 14 P 17 11.7 S 17 10.9 N/A 8.2 77.7 76.8 15 P 19 14.3 S 17 10.9 N/A 7.7 77.9 76.6 16 P 16 10.4 S 17 10.9 3.8 8.2 77.4 76.5 17 P 15 9.2 S 20 14.7 3.9 8.0 77.7 75.9 18 P 21 16.8 S 18 12.1 3.9 6.9 77.7 76.6 19 P 17 11.7 S 17 10.9 4.0 8.1 76.7 75.9 20 P 21 16.8 S 20 14.7 4.0 7.2 76.6 76.6 21 S 21 16.8 P 19 13.4 4.1 8.3 76.5 76.3 22 S 20 15.6 P 18 12.1 4.2 8.3 76.4 76.1 23 S 20 15.6 P 20 14.7 4.2 8.1 76.6 76.3 24 S 18 13.0 P 17 10.9 4.3 7.8 76.4 76.3 25 S 20 15.6 P 17 10.9 4.4 7.6 76.5 76.3 26 S 18 13.0 P 20 14.7 4.4 7.2 76.3 76.1 27 S 21 16.8 P 18 12.1 N/A 7.6 76.4 76.3 28 S 18 13.0 P 18 12.1 N/A 6.5 76.3 75.9 29 S 19 14.3 P 17 10.9 4.5 6.2 76.4 76.3 30 S 18 13.0 P 16 9.6 4.6 6.7 76.3 75.9 31 S 18 13.0 P 18 12.1 4.6 6.8 76.2 75.9 32 S 19 14.3 P 16 9.6 4.7 7.4 76.3 75.9 33 S 20 15.6 P 20 14.7 4.7 7.0 76.2 75.9 34 S 19 14.3 P 17 10.9 4.8 7.0 76.3 76.2

31

Table 2 (continued)

Tow #

EXP (P/S)

Door Spread (fthm)

Bridle Angle

(Degrees) CNTRL (P/S)

Door Spread (fthm)

Bridle Angle

(Degrees)

Topless Headrope Height (ft)

Depth (fthm)

Surface Temp

(Farenheit)

Bottom Temp

(Farenheit) 35 S 20 15.6 P 20 14.7 4.6 7.1 76.1 76.2 36 S 15 9.2 P 16 9.6 3.9 7.3 76.3 75.9 37 S 21 16.8 P 20 14.7 4.9 7.5 76.2 75.9 38 S 17 11.7 P 16 9.6 3.8 8.1 76.4 76.5 39 S 18 13.0 P 18 12.1 4.5 7.9 76.3 75.9 40 S 18 13.0 P 17 10.9 4.4 7.8 76.2 76.3 41 P 21 16.8 S 20 14.7 4.4 7.2 76.4 76.1 42 P 20 15.6 S 21 16.0 N/A 6.7 75.9 75.9 43 P 16 10.4 S 18 12.1 N/A 7.6 76.1 75.9 44 P 19 14.3 S 20 14.7 N/A 7.1 76.1 76.5 45 P 17 11.7 S 19 13.4 N/A 8.0 76.1 75.9 46 P 19 14.3 S 22 17.3 3.1 7.8 76.0 75.9 47 P 19 14.3 S 19 13.4 3.9 8.1 76.1 75.9 48 P 18 13.0 S 18 12.1 3.3 7.5 76.0 75.7 49 P 20 15.6 S 21 16.0 4.4 7.3 76.1 76.3 50 P 15 9.2 S 19 13.4 3.9 7.6 76.0 75.9 51 P 18 13.0 S 21 16.0 4.0 7.9 75.9 75.7 52 P 17 11.7 S 18 12.1 3.7 6.8 75.8 75.6 53 P 16 10.4 S 20 14.7 2.9 7.3 75.8 75.4 54 P 17 11.7 S 16 9.6 3.6 7.4 75.8 75.9 55 P 18 13.0 S 18 12.1 3.7 6.3 75.8 75.7 56 P 16 10.4 S 19 13.4 N/A 7.6 75.9 75.7 57 P 20 15.6 S 20 14.7 N/A 7.8 75.8 75.9 58 P 16 10.4 S 18 12.1 N/A 7.5 75.9 75.6 59 P 20 15.6 S 22 17.3 3.0 7.5 75.8 75.6 60 S 22 18.2 P 20 14.7 3.3 6.9 75.7 75.2 61 S 21 16.8 P 20 14.7 N/A 8.1 75.8 75.7 62 S 21 16.8 P 20 14.7 N/A 7.8 75.7 75.6 63 S 21 16.8 P 19 13.4 N/A 7.4 75.8 75.6 64 S 22 18.2 P 20 14.7 N/A 7.8 75.9 75.7 65 S 21 16.8 P 18 12.1 N/A 8.0 76.1 76.1 66 S 22 18.2 P 22 17.3 N/A 8.3 76.3 76.3 67 S 21 16.8 P 20 14.7 N/A 8.0 76.1 75.7 68 S 20 15.6 P 18 12.1 N/A 8.0 75.9 75.6 69 S 21 16.8 P 20 14.7 N/A 7.9 75.9 75.9

32

Table 2. continued

Tow #

EXP (P/S)

Door Spread (fthm)

Bridle Angle

(Degrees) CNTRL (P/S)

Door Spread (fthm)

Bridle Angle

(Degrees)

Topless Headrope Height (ft)

Depth (fthm)

Surface Temp

(Farenheit)

Bottom Temp

(Farenheit) 70 S 18 13.0 P 21 16.0 N/A 6.9 75.8 75.9 71 S 22 18.2 P 20 14.7 N/A 6.6 75.8 75.7 72 S 18 13.0 P 17 10.9 N/A 6.4 75.7 75.6 73 S 20 15.6 P 18 12.1 N/A 7.2 75.8 75.2 74 S 20 15.6 P 19 13.4 N/A 7.2 75.6 75.6 75 S 20 15.6 P 18 12.1 N/A 7.5 76.7 75.6 76 S 20 15.6 P 18 12.1 N/A 7.8 75.1 74.7 77 S 20 15.6 P 17 10.9 N/A 8.1 75.0 75.2 78 S 22 18.2 P 19 13.4 N/A 7.4 75.3 75.2 79 P 16 10.4 S P N/A 7.5 75.7 74.7 80 P 19 14.3 S 22 17.3 N/A 7.5 75.4 75.2 81 P 22 18.2 S 21 16.0 N/A 7.6 75.1 74.8 82 P 21 16.8 S 22 17.3 N/A 7.5 75.2 75 83 P 16 10.4 S 19 13.4 N/A 7.8 75.3 75 84 P 21 16.8 S 22 17.3 N/A 8.0 75.2 75 85 P 16 10.4 S 16 9.6 N/A 7.6 75.2 75 86 P 19 14.3 S 19 13.4 N/A 7.4 75.1 74.8 87 P 20 15.6 S 22 17.3 N/A 7.4 74.9 74.7 88 P 21 16.8 S 23 18.6 N/A 7.7 75.0 73.9 89 P 17 11.7 S 18 12.1 N/A 7.8 74.7 74.3 90 P 21 16.8 S 22 17.3 N/A 7.5 74.9 74.7 91 P 19 14.3 S 19 13.4 N/A 7.5 74.6 74.5 92 P 21 16.8 S 22 17.3 N/A 7.5 74.6 74.5 93 P 18 13.0 S 18 12.1 N/A 7.1 74.3 73.9 94 P 19 14.3 S 19 13.4 N/A 7.1 73.9 73.6 95 P 19 14.3 S 19 13.4 N/A 7.7 74.3 73.9 96 P 20 15.6 S 20 14.7 N/A 6.7 73.9 73.4 97 P 18 13.0 S 20 14.7 N/A 6.6 73.9 72.1 98 P 19 14.3 S 20 14.7 N/A 6.5 73.8 76.1 99 S 21 16.8 P 20 14.7 N/A 7.3

100 S 21 16.8 P 20 14.7 N/A 7.5 73.8 73.6 101 S 22 18.2 P 19 13.4 N/A 7.4 73.6 73.4 102 S 21 16.8 P 21 16.0 N/A 7.0 73.9 73.8 103 S 17 11.7 P 17 10.9 N/A 7.1 73.8 73.8 104 S 22 18.2 P 21 16.0 N/A 6.5 73.6 73.8

33

Table 2. continued

Tow #

EXP (P/S)

Door Spread (fthm)

Bridle Angle

(Degrees) CNTRL (P/S)

Door Spread (fthm)

Bridle Angle

(Degrees)

Topless Headrope Height (ft)

Depth (fthm)

Surface Temp

(Farenheit)

Bottom Temp

(Farenheit) 105 S 21 16.8 P 19 13.4 N/A 8.3 73.8 73.8 106 S 22 18.2 P 21 16.0 N/A 7.5 74.0 107 S 20 15.6 P 18 12.1 N/A 8.0 73.8 73.6 108 S 19 14.3 P 18 12.1 N/A 8.0 73.6 73.4 109 S 22 18.2 P 16 9.6 N/A 6.7 73.7 73.4 110 S 21 16.8 P 20 14.7 N/A 6.0 72.6 72 111 S 19 14.3 P 20 14.7 N/A 6.6 72.1 72.3 112 S 19 14.3 P 19 13.4 N/A 7.1 73.0 72.9 113 S 21 16.8 P 20 14.7 N/A 6.3 72.4 72.7 114 S 19 14.3 P 21 16.0 N/A 8.2 73.1 73 115 S 20 15.6 P 18 12.1 N/A 6.6 73.1 72.9 116 S 22 18.2 P 20 14.7 N/A 7.1 73.2 73 117 S 20 15.6 P 21 16.0 N/A 7.8 73.5 73.4 118 S 22 18.2 P 20 14.7 N/A 6.6 73.2 73 119 S 21 16.8 P 21 16.0 N/A 7.3 73.1 72.3 120 S 22 18.2 P 21 16.0 N/A 6.3 73.0 72.7 121 S 22 18.2 P 22 17.3 N/A 6.4 72.8 72.3 122 S 18 13.0 P 18 12.1 N/A 7.0 73.1 73 123 S 22 18.2 P 18 12.1 N/A 6.0 72.7 72.5 124 S 20 15.6 P 21 16.0 N/A 6.7 72.7 72.3 125 S 21 16.8 P 19 13.4 N/A 7.4 72.8 72.5 126 P 21 16.8 S 22 17.3 N/A 7.2 72.8 72.9 127 P S 3.4 6.8 73.0 72.7 128 P 18 13.0 S 22 17.3 3.3 6.2 72.7 72.3 129 P 21 16.8 S 22 17.3 3.3 8.1 73.0 72.9 130 P 17 11.7 S 18 12.1 3.4 6.6 72.6 72.5 131 P 22 18.2 S 21 16.0 3.4 7.6 72.4 71.2 132 P 19 14.3 S 22 17.3 3.4 7.3 72.1 71.6

34

Appendix 1, Table 3. Summary of sea turtles captured with measurements and tag data. Sea turtle species codes are: CC is Loggerhead and LK is Kemps Ridley; and all measurements are in centimeters. Empty cells indicate no data collected. More complete data with notes is available in Appendix 2 as an electronic file.

Turtle # Haul # Net Species Notch to Notch

Notch to Tip Width Total

Tail Vent to Tip (tail)

Flipper tag L

Flipper tag R Pit tag #

1 2 C Cc 71.0 73.5 68.0 8.0 5.0 501 502 434B477158 2 6 C Cc 72.5 76.0 69.5 10.0 7.5 504 505 436A20113C 3 10 E Cc 84.5 87.0 76.0 14.0 5.0 506 507 4349065159 4 10 E Cc 81.0 82.5 74.0 14.0 4.0 509 508 436A323B46 5 12 E Cc 91.0 93.0 78.5 17.0 5.0 524 525 434A6A7C1B 6 13 C Cc 70.0 72.0 66.5 12.0 4.0 510 511 436761072B 7 13 C Cc 76.0 77.0 74.0 13.0 3.0 512 513 436A284661 8 18 E Cc 79.0 80.5 73.0 12.5 7.0 514 515 43695E0E3C 9 20 C Cc 78.5 80.0 73.5 19.5 14.5 522 523 4349237913

10 20 C Cc 79.0 81.0 76.5 8.0 5.0 520 521 4349256F28 11 23 E Cc 81.0 82.5 74.0 14.0 4.0 509 508 436A323B46 12 23 C Cc 79.5 82.0 76.0 16.0 8.0 516 517 436A371922 13 23 C Cc 76.0 78.5 70.0 15.0 4.0 518 519 434A357A10 14 24 C Cc 75.5 78.0 72.0 13.0 8.0 526 527 43697E6B68 15 29 E Cc 74.0 76.0 71.0 10.0 3.5 528 529 4369692B02 16 30 E Cc 75.0 77.5 74.0 12.0 5.0 530 531 4348382D22 17 31 C Cc 82.0 83.0 75.5 10.0 3.5 532 533 434934430F 18 31 E Cc 62.0 62.5 58.0 9.5 4.5 534 535 4367643459 19 32 C Cc 84.0 86.0 79.0 6.0 3.5 536 537 43693B5D42 20 32 E Lk 45.0 46.0 49.0 6.0 3.5 538 539 4367471F6F 21 38 C Cc 74.0 76.0 71.5 8.0 5.0 540 541 436A027A67 22 42 C Lk 42.0 43.0 44.0 5.0 3.0 542 543 436A094929 23 42 C Cc 67.0 69.0 65.0 8.5 3.0 544 545 436A177A13 24 46 C Cc 86.0 89.0 83.0 16.0 10.0 546 547 434A2E375E 25 50 E Cc 71.0 73.5 68.0 8.0 5.0 501 502 434B477158 26 59 C Cc 80.0 82.5 76.0 8.0 6.0 548 549 436A360820 27 63 E Cc 66.0 69.0 66.0 12.0 5.0 550 551 43482B1D40 28 66 C Cc 81.0 83.5 76.0 8.0 4.0 552 553 43636302D

35

Appendix Table 2 (continued)

Turtle # Haul # Net Species Notch to Notch

Notch to Tip Width Total

Tail Vent to Tip (tail)

Flipper tag L

Flipper tag R Pit tag #

29 68 C Cc 75.0 76.0 70.0 7.0 5.5 554 555 4367552345 30 71 E Cc 53.0 54.5 54.0 8.0 4.5 556 557 436A03762F 31 73 C Cc 67.0 69.5 63.5 10.0 3.0 558 559 4349275540 32 73 C Cc 63.0 65.0 62.0 9.0 3.0 560 561 434B6A1443 33 74 C Cc 77.0 77.5 72.0 14.0 5.0 562 563 436A2E1B72 34 E Cc 77.0 35 78 E Cc 85.5 87.0 76.0 12.0 6.0 564 565 43676E1B21 36 80 C Cc 77.0 79.0 72.0 10.0 5.0 566 567 436A10797B 37 84 C Cc 88.5 91.0 80.0 15.0 12.0 568 569 436975547A 38 85 C Cc 101.0 102.0 89.5 39.0 29.0 570 571 4348665B39 39 87 C Cc 80.5 83.0 76.5 16.0 9.0 572 573 43493E4511 40 88 C Cc 80.5 83.5 72.0 33.0 8.5 574 575 430352151F 41 91 C Cc 66.5 68.5 65.5 11.0 3.0 576 577 4349074856 42 93 C Lk 58.0 58.0 66.0 6.0 2.0 580 581 4369323709 43 93 C Cc 83.0 85.0 78.0 13.0 5.0 578 579 4349291D43 44 96 E Cc 80.5 82.5 74.0 19.0 4.0 582 583 45 96 E Cc 77.5 79.5 72.0 17.0 4.0 584 585 46 112 E Cc 86.0 89.0 78.5 24.0 7.0 586 47 112 C Cc 77.5 78.0 73.0 8.0 3.0 587 48 112 C Cc 91.0 92.0 80.0 9.0 3.0 588 49 113 C Cc 72.5 75.0 68.0 8.0 4.0 589 50 115 C Cc 78.0 80.0 73.5 9.0 3.0 590 51 116 E Cc 83.0 85.5 75.0 13.0 5.0 591 52 122 C Cc 80.5 83.0 76.5 16.0 9.0 572 573 43493E4511 53 122 E Lk 45.0 46.5 46.0 7.0 3.0 592 54 125 C Cc 67.0 69.0 65.0 8.5 3.0 544 545 436A177A13 55 125 C Cc 92.0 94.0 85.5 33.0 7.0 593 56 131 C Cc 74.0 75.0 76.0 10.0 3.0 594 595

36

Appendix 1, Table 4. Catch data other than sea turtles. Number of individuals captured for the dominant species in the catch (greater than 6% in both control and experimental trawls). A complete list of all species captured is available as an electronic file in Appendix 2.

Control Trawl Experimental Trawl

Haul Skate/

Ray Kingfish Banded Drum

Atlantic Croaker

Atlantic Bumper

Blue Runner

Skate/ Ray Kingfish

Banded Drum

Atlantic Croaker

Atlantic Bumper

Blue Runner

1 6 2 0 0 0 0 4 0 0 0 0 0 2 45 1 1 0 0 0 16 1 0 0 0 0 3 5 16 11 4 0 0 0 0 0 10 0 0 4 10 0 0 8 0 0 1 0 3 3 10 0 5 4 0 5 7 6 0 5 0 0 0 0 0 6 5 0 0 0 10 0 2 0 0 0 1 0 7 14 1 2 0 6 0 8 1 3 0 4 0 8 0 6 0 0 4 0 2 0 0 0 2 0 9 0 4 1 0 8 0 0 0 0 0 0 0

10 1 0 0 0 0 0 11 0 0 0 0 0 11 3 2 0 0 0 0 3 1 1 2 0 0 12 3 15 4 0 0 0 12 9 10 1 0 0 13 0 3 0 0 0 0 0 18 0 0 0 0 14 1 7 0 0 0 0 0 6 0 1 0 0 15 1 1 4 0 0 0 1 0 3 0 0 0 16 1 1 2 1 0 0 1 1 4 0 0 0 17 0 22 0 2 0 0 0 8 0 0 0 0 18 1 0 6 3 0 0 2 1 1 0 0 0 19 0 0 0 0 1 0 0 0 0 0 0 0 20 3 0 0 1 0 0 0 0 0 0 6 0 21 1 0 0 0 0 0 0 0 0 1 1 0 22 0 0 0 0 0 0 1 0 0 0 0 0 23 4 0 0 0 0 8 2 0 0 0 0 0 24 2 0 0 0 0 6 1 0 0 0 0 0 25 2 0 0 0 0 3 0 0 0 0 0 26 0 0 0 0 0 1 1 0 0 0 0 0 27 3 0 0 0 4 50 2 2 0 1 0 4 28 4 0 0 0 0 8 1 1 0 0 0 0 29 2 0 0 1 0 0 1 0 0 0 0 0 30 1 3 0 1 0 6 3 0 0 1 3 1 31 15 0 0 0 0 0 6 0 0 0 1 0 32 6 1 0 1 3 0 3 0 0 0 0 0

37

Appendix 1, Table 4 (continued).

Control Trawl Experimental Trawl

Haul Skate/

Ray Kingfish Banded Drum

Atlantic Croaker

Atlantic Bumper

Blue Runner

Skate/ Ray Kingfish

Banded Drum

Atlantic Croaker

Atlantic Bumper

Blue Runner

33 3 0 0 0 0 0 4 2 0 0 0 0 34 1 4 2 2 0 0 0 2 2 5 0 0 35 6 18 13 4 0 0 5 2 0 0 0 1 36 1 15 8 14 0 0 0 3 1 1 0 0 37 2 16 12 6 0 0 1 6 4 4 0 0 38 3 5 0 3 0 0 0 4 2 1 0 0 39 3 19 17 3 0 0 0 2 6 0 0 0 40 1 4 13 0 0 0 0 7 9 2 1 0 41 2 48 35 0 0 0 1 15 17 1 0 0 42 7 0 0 3 5 36 0 1 0 2 0 7 43 3 2 0 8 15 1 2 1 0 1 1 0 44 4 7 0 7 0 19 6 4 0 0 0 8 45 8 6 0 1 0 12 3 0 0 0 0 1 46 6 14 0 2 0 10 2 1 0 0 0 0 47 3 1 0 3 0 0 2 4 0 7 0 17 48 3 1 0 6 53 0 1 2 0 3 2 0 49 0 1 0 0 15 11 0 0 0 0 0 7 50 3 1 0 1 7 8 5 1 0 0 0 0 51 6 2 0 4 12 4 1 1 0 0 0 4 52 4 0 0 4 46 5 5 0 0 0 2 0 53 10 13 0 1 0 0 2 0 0 0 1 0 54 3 2 42 0 0 0 4 2 14 0 0 0 55 22 0 0 1 0 0 19 0 0 0 0 0 56 15 3 4 2 0 0 1 1 1 0 0 0 57 6 9 6 0 0 0 5 0 1 0 0 0 58 4 16 11 0 0 0 4 1 0 0 0 0 59 7 1 2 1 0 0 7 0 0 0 0 0 60 50 2 0 0 0 0 46 1 0 0 0 0 61 1 4 6 3 0 0 3 2 14 3 4 0 62 7 5 19 1 4 0 1 16 11 0 7 0 63 5 6 0 4 10 4 3 0 0 0 0 0 64 9 6 9 34 0 20 1 4 2 33 0 3 65 0 0 0 3 0 5 1 0 0 5 0 1 66 2 0 0 0 0 2 2 0 0 6 1 0 67 1 0 0 2 3 21 0 0 0 2 4 0 68 6 0 0 1 1 6 6 0 0 2 1 0 69 2 0 0 1 6 4 1 0 0 3 1 3 70 5 6 35 5 2 8 4 0 9 1 0 0

38

Appendix 1 Table 4 (continued)

Control Trawl Experimental Trawl

Haul Skate/

Ray Kingfish Banded Drum

Atlantic Croaker

Atlantic Bumper

Blue Runner

Skate/ Ray Kingfish

Banded Drum

Atlantic Croaker

Atlantic Bumper

Blue Runner

71 17 0 15 1 0 0 7 1 0 0 0 0 72 3 0 0 0 6 0 3 0 0 0 0 0 73 3 1 15 0 0 0 3 2 22 0 0 4 74 9 1 3 0 0 0 12 0 0 0 2 0

75 No Data

76 13 0 0 0 1 0 6 0 0 0 4 0 77 11 0 0 0 15 3 8 0 0 0 0 0 78 19 1 0 0 3 0 20 0 0 0 0 1 79 3 0 0 1 0 0 1 0 0 0 0 0 80 5 21 66 5 0 0 0 5 0 1 0 0 81 12 4 4 0 0 0 8 0 3 0 0 0 82 1 28 0 18 0 0 1 9 0 5 0 0 83 0 26 5 30 0 0 4 0 1 0 0 0 84 7 3 1 0 0 0 1 11 0 1 0 0 85 1 4 0 2 0 0 1 4 0 0 0 0 86 1 6 3 2 0 0 2 0 2 0 0 0 87 4 2 2 0 0 0 0 5 5 0 0 0 88 0 0 0 1 0 0 0 1 0 1 0 0 89 1 7 1 3 0 0 3 0 0 1 0 0 90 3 5 0 9 0 0 0 3 0 1 0 0 91 2 0 0 2 0 0 0 0 0 0 0 0 92 2 0 0 0 0 0 1 1 0 0 0 0 93 4 0 0 1 0 0 1 0 0 0 0 0 94 3 2 0 1 0 0 1 0 0 0 0 0 95 5 0 0 0 2 0 8 0 0 0 0 0 96 5 5 2 2 0 3 3 1 0 0 0 0 97 16 0 0 0 0 0 5 0 0 0 0 0 98 4 14 19 3 0 7 2 1 7 0 0 0 99 16 6 3 1 0 0 6 0 0 0 0 0

100 6 14 3 0 0 0 7 0 0 0 0 0 101 10 15 5 0 0 0 4 7 5 0 0 0 102 6 18 18 3 0 0 0 9 0 0 0 0 103 2 25 7 5 0 0 4 7 4 3 0 0 104 8 1 1 4 0 0 7 2 2 1 0 0

39

Appendix 1, Table 4. (continued)

Control Trawl Experimental Trawl

Haul Skate/

Ray Kingfish Banded Drum

Atlantic Croaker

Atlantic Bumper

Blue Runner

Skate/ Ray Kingfish

Banded Drum

Atlantic Croaker

Atlantic Bumper

Blue Runner

105 2 12 2 2 0 0 2 3 2 0 0 0 106 2 22 0 1 0 0 5 8 1 0 0 0 107 10 6 7 4 0 0 7 4 6 2 0 0 108 10 10 23 21 0 0 8 4 7 4 0 0 109 7 33 4 6 0 0 4 4 0 0 0 0 110 8 1 0 1 0 1 16 0 0 0 0 4 111 22 0 0 0 4 3 7 0 0 0 0 0 112 9 0 0 1 0 1 17 0 0 0 0 0 113 6 0 0 0 0 1 12 0 0 0 0 0 114 12 0 0 0 0 0 5 0 0 0 0 3 115 4 0 0 0 0 1 5 0 0 0 0 0 116 9 0 0 0 0 1 9 0 0 0 0 11 117 3 0 0 0 0 17 3 0 0 0 0 0 118 6 0 0 0 0 14 5 0 0 0 0 0 119 13 0 0 0 0 0 9 3 0 0 0 0 120 5 3 0 0 0 0 4 2 1 0 0 0 121 5 7 1 0 0 0 3 0 0 0 0 0 122 6 0 0 0 0 0 6 0 0 0 0 0 123 6 6 1 0 0 0 6 0 0 0 0 0 124 33 2 1 0 0 0 17 1 5 0 0 0 125 8 3 2 0 0 0 15 0 1 1 0 0 126 10 1 12 0 0 3 5 1 0 0 0 127 2 3 17 1 0 0 1 2 4 0 0 0 128 9 1 2 0 0 0 4 2 2 0 0 0 129 10 2 2 15 0 0 2 2 2 0 0 0 130 7 0 4 0 0 0 2 5 0 0 0 0 131 9 0 0 0 1 3 4 0 0 0 0 5 132 6 0 0 0 0 10 6 0 0 0 0 7

Total 808 643 521 305 253 320 556 248 201 123 59 92 % 21.8 17.4 14.1 8.2 6.8 8.7 36.1 16.1 13.0 8.0 3.8 6.0

40

Appendix B

41

1.   Summer Flounder Capture (June-August 2013) •  The experimental topless trawl was tested against a traditional trawl

during 41 90-minute paired tows (28 paired tows with an optimal float configuration) aboard the F/V Darana R for fish capture.

•  Catch was sorted and weighed by species and analyzed using a one tailed paired T-Test with α=0.05 to compare the catch efficiency.

2. Sea Turtle Exclusion (October 2013) •  The experimental topless trawl was tested against the traditional trawl

during 132 30-minute paired tows aboard the F/V Karen Elizabeth, a twin-trawl vessel, for sea turtle exclusion off of Brunswick, GA.

•  When the nets were hauled and the cod ends emptied, if sea turtles were present they were measured and tagged following NMFS protocol.

REDUCING SEA TURTLE MORTALITY IN THE U.S. NORTHEAST AND MID-ATLANTIC SUMMER FLOUNDER TRAWL FISHERY

Meghan Gahm1, Joseph DeAlteris1, Christopher Parkins2, Henry Milliken3, Eric Matzen3 1. University of Rhode Island, Kingston, RI, USA 2. Coonamessett Farm Foundation, East Falmouth, MA 3. NMFS, NEFSC, Woods Hole, MA

1. Summer Flounder Capture (June-August 2013) •  Using a one tailed paired T-Test, there was a significant loss of summer

flounder with the experimental topless trawl with an average of 22.7% loss of target species (p=0.008).

•  Using a Kolmogorov-Smirnov test, there was a significant difference in the length frequency distribution of summer flounder between the two net types.

•  According to the National Marine Fisheries Service (NMFS), sea turtle interactions, mainly loggerhead sea turtles (Caretta caretta) in the U.S. northeast and mid-Atlantic summer flounder (Paralicthys dentatus) trawl fishery have increased.

•  Gear modifications have been suggested as an attempt to reduce these interactions.

•  Because previous studies on catch retention in trawl nets with TEDs showed an unacceptable loss of commercially important species ( Lawson et al. 2007), the topless trawl design was developed(DeAlteris et al. 2013, DeAlteris and Parkins 2012 ).

•  A topless trawl has a longer headrope length compared to a traditional trawl, which provides sea turtles sufficient time to escape before being captured and entering the cod end of the net.

•  To decrease the incidental capture of sea turtles within the U.S. northeast and mid-Atlantic summer flounder fishery while maintaining target species catch by using an experimental topless trawl.

Hypotheses •  The experimental topless trawl and control trawl will have the same mean

catch weight for summer flounder. •  The experimental topless trawl and control trawl will have the same

capture of number of sea turtles.

2. Sea Turtle Capture (October 2013) •  A total of 56 sea turtle individuals (N Control=37 and N Experimental=19)

were captured in the 132 30-minute tows with an estimated 48.6% overall reduction of sea turtle capture.

•  52 of the turtles captured were loggerhead sea turtles (Caretta caretta) and 4 were Kemp’s Ridley sea turtles (Lepidochelys kempii) and 4 of the loggerhead species were recaptures (sea turtles that were tagged after the first capture, and then subsequently recaptured).

All Paired Tows •  Overall, it was seen that there was a significant loss of summer flounder

for the experimental topless trawl with 22.7% loss of target species. •  Performance sensors on the trawl gear indicated that the headline height

and starboard wing height decreased throughout the duration of the tow for the experimental trawl, but not the control trawl.

•  When testing for sea turtle exclusion, preliminary analysis indicates that the experimental topless trawl had an overall average of 48.6% reduction of sea turtle capture with a total of 37 sea turtles captured in the control trawl and 19 sea turtles captured in the experimental trawl.

Day Paired Tows •  For all paired tows completed during the day (N=21) there was a 16.0%

average loss of summer flounder and summer flounder made up a smaller portion of the total catch when compared to night tows (control = 9.3% of total catch: experimental =8.7%)

•  For all paired tows completed during the day (N=77) there was a 30.4% reduction of sea turtle capture on average with 23 sea turtles captured in the control trawl and 16 sea turtles captured in the experimental trawl.

Night Paired Tows •  Overall, for all paired tows completed during the night (N=7) there was an

average of 30.5% loss of summer flounder, however summer flounder made up a greater portion of the catch for night tows (23.6% of total catch for both net types) when compared to day tows.

•  For all paired tows completed during the day (N=55) there was a 78.6% reduction of sea turtle capture on average with 14 sea turtles captured in the control trawl and only 3 sea turtles captured in the experimental trawl.

•  Funding was provided by the NMFS NEFSC Protected Species Branch and NMFS Office of Sustainable Fisheries through a grant to the Gulf and South Atlantic Fisheries Foundation, Inc.

•  Joseph DeAlteris, University of Rhode Island •  Christopher Parkins, Coonamessett Farm Foundation •  Henry Milliken, Eric Matzen , and Heather Haas, NMFS NEFSC •  Captain Jim Ruhle and F/V Darana R Crew •  Captain Chris Roebuck and F/V Karen Elizabeth Crew •  Mary O’Rourke, Trawlworks and Jon Knight Superior Trawl

Results Introduction

Methods

Discussion and Conclusion

Future Directions

Acknowledgements

Figure 1: Expected sea turtle interactions for a traditional summer flounder trawl net (headrope length < footrope length ) and the experimental topless trawl (headrope length >footrope length).

Traditional Trawl Experimental Trawl

Figure 2: The net designs for the control trawl and experimental topless trawl to be used to test summer flounder capture and sea turtle exclusion.

•  The control trawl design was designed with a 19.8-m headrope, 24.4-m footrope, and 16 plastic floats and the experimental trawl had a 48.7-m headrope, 24.4-m footrope, two restrictor lines, and 30 plastic floats.

Control Trawl Experimental Trawl

Figure 3: The average catch in kg for summer flounder for all paired tows (N tows=28), all paired day tows (N day tows=21), and all paired night tows (N night tows=7).

Figure 4: The number of individual sea turtles captured for all tows (N tows=132), day tows only (N day tows=77), and night tows only (N night tows=55).

Purpose

Figure 5: The overall average % reduction of catch for summer flounder and sea turtles for the experimental topless trawl for the test performed in the summer flounder fishery and the test performed in the wild sea turtle population.

Gear Modifications •  Modifications to address performance issues could be tested in the flume

tank with the goal of making the headrope more stable. Behavioral Studies •  Understanding the behavior of flat fish and sea turtles with trawl gear are

crucial in optimally designing fishing gear that will retain the catch of flatfish while reducing sea turtle capture.

•  It would be beneficial to identify how these behaviors change in a 24-hour period because of the catch and capture differences between night and day.

Figure 6: A model of the experimental topless trawl with the 48.7 m headrope, 24.4 m footrope, 30 floats, and two restrictor lines in the flume tank at the Memorial University in St. John’s, Newfoundland.

References •  DeAlteris J., Parkins, C., Hasbrouck, E., Scotti, J., Froehlich, T., and J. Costanzo, 2013.

Evaluation of a topless bottom trawl design with a 160 foot headrope for fish capture. [NOAA NMFS Contract Number: EA 133F-10-SE-2491, Mod. 002]

•  DeAlteris, J. and C. Parkins. 2012. Field and data report; Evaluation of a topless bottom trawl designs with regard to excluding sea turtles.[NOAA Contract No. EA 133F-10-SE-2491, Mod. 002].

•  Lawson D., J. T. DeAlteris and C. Parkins. 2007. Evaluation of the catch efficiency of the NMFS certified Turtle Excluder Device (TED) in the Mid-Atlantic summer flounder trawl fishery Summary report; 26 p + appendix] NOAA Contract No. EA133F-05-SE-6561.

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0

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Summer Flounder

Sea Turtles

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Appendix C

43

Reducing Sea Turtle Mortality in the U.S. New England and Mid-Atlantic Summer

Flounder Trawl Fishery

Meghan Gahm1, Joseph DeAlteris1, Christopher Parkins2, Henry Milliken3, Eric Matzen3

1. University of Rhode Island, Kingston, RI 2. Coonamessett Farm Foundation, East Falmouth, MA 3. NMFS, NEFSC, Woods Hole, MA

44

Background •  1996: Summer flounder

TEDs seasonally required south of Cape Charles, VA

•  Sea turtle bycatch has increased in northeast trawl fisheries – Fishery of focus for this

study: Summer Flounder (Paralicthys dentatus)

•  Gear modifications proposed as an attempt to decrease these mortalities

Karp et al. 2007, National Bycatch Report

45

Results: TED •  2006-2010: Tested the catch

effectiveness of TEDs in New England and mid-Atlantic trawl fisheries

•  Results: Summer flounder TEDs reduce targeted finfish catch – NMFS Certified TED &

Experimental TED •  Significant loss of target

species • Reported as difficult and

dangerous to operate Photo: Christopher Parkins

46

Background: Topless Trawl •  Proposed use of a topless bottom trawl net

–  Increased length of headrope would give sea turtles time to escape net

Control Trawl Headrope < Footrope

Topless Trawl Headrope > Footrope

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Methods: Fishing Gear Topless Trawl: 48.7-m. headrope Control: 19.8-m. headrope

48

Background: Topless Trawl •  2010-2013: Studies on the catch effectiveness

of a topless trawl in the U.S. New England and mid-Atlantic summer flounder fishery. •  2010: Evaluation of a topless bottom trawl with a

32.3-m headrope for fish capture. •  2011: Evaluation of a topless bottom trawl with a

32.3-m, 39.6-m, 45.1-m, and 48.7-m headrope for sea turtle exclusion.

•  2012: Evaluation of a topless bottom trawl with a 48.7-m headrope for fish capture

•  2013: Flume tank work to evaluate the performance and rigging of the topless trawl.

•  2013: Evaluation of a topless bottom trawl with a 48.7-m headrope and restrictor lines for fish capture 49

Results: 2010 Topless Trawl

•  2010: Evaluation of 32.3-m headrope in summer flounder fishery – Paired testing against a control trawl with a

19.8-m headrope – No Significant loss of target species

50

33.30%

0%

71.40%

96%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90%

100%

32.3 m 39.6 m 45.1 m 48.7 m

% R

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of S

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s

2011 Topless Trawl Average % Reduction of Sea Turtle

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N T

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s C

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Experimental Headrope Length

2011 Topless Trawl Study Results

Control Experimental

Results: 2011 Topless Trawl

•  2011:Evaluation of a topless bottom trawl design in regards to excluding sea turtles –  32.3-m, 39.6-m, and

45.1-m headrope did not significantly decrease sea turtle capture

–  Headrope length of 48.7-m had a significant reduction of sea turtle capture

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Results: 2012 Topless Trawl •  Evaluation of a topless bottom trawl with a

48.7-m headrope for fish capture – Paired testing against control trawl with a

19.8-m headrope – Results: Significant loss of target species

•  F/V Darana R: 51% loss of summer flounder •  F/V Caitlin and Mairead: 74% loss of summer

flounder

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Results: 2013 Flume Tank •  Original 48.7-m headrope topless trawl

– Net design that reduced capture of sea turtles and catch of summer flounder

Note: Wings are laying flat 53

Results: 2013 Flume Tank

Restrictor lines

•  Optimally Reconfigured topless trawl •  48.7-m Headrope, 2 restrictor lines, and 30

floats

54

Results: 2013 Field Study 1) Summer flounder •  A 48.7-m

headrope with 2 restrictor lines had a significant loss of summer flounder –  2 float configurations

tested •  Optimal float

configuration had an average of 22.7% loss of target species (p=0.008).

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Results: 2013 Field Study 2) Sea Turtle Capture •  A total of 132 30-

minute tows were completed

•  For all tows, 37 turtles were captured in control trawl and 19 turtles were captured in experimental trawl

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Experimental

•  52 loggerhead (C. caretta) and 4 Kemp’s Ridley sea turtles (L. kempii)

56

Discussion

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Summer Flounder

Sea Turtles

•  Overall with a 48.7-m headrope topless trawl with 2 restrictor lines, there was a 22.7% reduction of summer flounder catch and a 48.6% reduction of sea turtle capture

57

Discussion

•  Topless trawl with a 48.7-m headrope and 2 restrictor lines is preferred by fishermen over the TED for the summer flounder fishery – Lower target species loss, safer, and easier to

operate •  However topless trawl still has loss of

target species and still captures sea turtles

58

Further Directions •  Gear Modifications

– Test the 48.7-m. experimental trawl with 2 restrictor lines in a flume tank to help stabilize the headrope height and wing height.

•  Behavioral Studies –  Behavioral studies on flatfish and sea turtles

would help to optimally design fishing gear –  Identify how these behaviors change in a 24-

hour period

59

Acknowledgements Joseph DeAlteris Christopher Parkins Henry Milliken Eric Matzen Heather Haas Captain Jim Ruhle F/V Darana R crew

Captain Chris Roebuck F/V Karen Elizabeth crew Mary O’Rourke Jon Knight

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For More Information

•  Poster # 0108 •  Reports Available:

– http://www.nefsc.noaa.gov/read/protspp/PR_gear_research/

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