An Evaluation of Bycatch Reduction Technologies in the North Carolina Shrimp Trawl Fishery

Home , Bycatch reduction device, Spot (fish)

Kevin Brown, Blake Price, Laura Lee, Scott Baker, and Sara Mirabilio

Final Report

to the

National Fish and Wildlife Foundation Fisheries Innovation Fund

and the

National Oceanic and Atmospheric Administration

for the study period

August 2016 and July-November 2017

North Carolina Department of Environmental Quality Division of Marine Fisheries Morehead City, NC

March 2018

This project was conducted under the National Fish and Wildlife Foundation Fisheries Innovation Fund under Grant Award 47988 and the Atlantic Coastal Fisheries Cooperative Management Act (ACFCMA) and funded by the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, under Grant Award NA13NMF4740243. ABSTRACT

The purpose of this project was to identify gear modifications that could potentially be implemented by the commercial shrimp trawl fishery in North Carolina to reduce bycatch in the fishery. Gear comparisons were made using six modified shrimp (otter) trawls in Pamlico Sound, North Carolina during October 2016 and July 2017 and in nearshore ocean waters of North Carolina from August to November 2017 to determine methods of reducing bycatch while maintaining acceptable shrimp harvest. Six experimental otter trawls were tested against a control net consisting of a federally certified turtle excluder device with 4-inch bar spacing, one state fisheye bycatch reduction device, and a 1 ½-inch stretch mesh tail bag. Various combinations of gear modifications including turtle excluder device bar spacing, mesh size, and additional fisheyes were tested. Three gear configurations reduced finfish bycatch relative to the control; however, only one gear met our goal of 40% mean bycatch reduction. Our results indicate that continuation of the industry workgroup and further testing is necessary, especially on smaller vessels (< 45 ft). Recommendations include; continued experimentation of gear modifications in inshore and nearshore areas of North Carolina, potential implementation of gear regulations based on experimental designs, and continual improvement of collaboration and outreach with the industry to develop and implement gear to reduce bycatch in the shrimp trawl fishery of North Carolina.

ACKNOWLEDGMENTS

This project was made possible by financial support from the National Fish and Wildlife Foundation Fisheries Innovation Fund (Grant Award 47988) and by Atlantic Coastal Fisheries Cooperative Management Act (Award NA13NMF4740243) as well as considerable in-kind contributions from the shrimp trawl industry.

The authors would like to thank the members of the industry workgroup including John Broome, Mikey Daniels, Stevie Davis, Brent Fulcher, David Jarvis, Robbie Metcalf, Kenny Midget, Clyde Phillips, Clyde Potter, Kenny Rustic, Doug Todd, and Gordon Winfree. Numerous technicians including Cayce Harburg, Nick Harris, Sean Morrison, Josh Paylor and Linus Stoltz for their assistance collecting and verifying data and conducting field work. Pingguo He, Steve Eayrs, Dan Foster, Gary Graham, and Frank Helies for their guidance and consultation in study design and BRD development. Captains Stevie Davis, Robbie Metcalf, John Broome, and Clyde Phillips and their crews for graciously hosting us aboard their vessels and their assistance in conducting the testing, switching gear, risking a catch reduction and loss of income to contribute to this effort.

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TABLE OF CONTENTS

ABSTRACT ...... ii ACKNOWLEDGMENTS ...... iii TABLE OF CONTENTS ...... iv LIST OF TABLES ...... v LIST OF FIGURES ...... vi BACKGROUND ...... 7 METHODS ...... 9 GEAR PARAMETERS ...... 13 RESULTS ...... 13 Virgil Potter BRD, 4-inch TED, 1 state fisheye, and 1 ¾-inch tail bag (fall 2016) ...... 14 3-inch TED, 1 state fisheye, and 1 ½-inch tail bag (summer 2017) ...... 14 5 3-inch TED, 1 state fisheye, and 1 ∕8-inch tail bag (summer 2017) ...... 14 5 3-inch TED, 2 state fisheyes, and 1 ∕8-inch tail bag (summer 2017) ...... 15 5 3-inch TED, 2 state fisheyes, and 1 ∕8-inch tail bag (fall 2017) ...... 15 5 3-inch TED, 2 federal fisheyes, and 1 ∕8-inch tail bag (fall 2017) ...... 16 DISCUSSION ...... 16 RECOMMENDATIONS ...... 18 LITERATURE CITED ...... 20 Tables ...... 23 Figures...... 29

LIST OF TABLES

Table 1. Number of tows (n), average catch (kg) in control and experimental nets, and percent (%) change in catch by year, season, gear, and species. Note that negative values indicate a reduction. Data in this table (randomization test) were derived from all tows that were considered reliable...... 23 Table 2. Number of tows (n), average catch (kg) in control and experimental nets, and percent (%) change in catch by year, season, gear, and species. Note that negative values indicate a reduction. Data in this table (t-test) were derived from a subset of the reliable tows such that the number of tows taken on each side of the vessel were equivalent...... 24 Table 3. Percent change in catch and results of the randomization tests comparing catches between the control and experimental nets by year, season, gear, and species. Values in bold indicate significant p-values, i.e., a significant difference was found (α = 0.05). Data in this table were derived from all tows that were considered reliable...... 25 Table 4. Percent change in catch and results of the t-tests comparing catches between the control and experimental nets by year, season, gear, and species. Values in bold indicate significant p-values, i.e., a significant difference was found (α = 0.05). Data in this table were derived from a subset of the reliable tows such that the number of tows taken on each side of the vessel were equivalent...... 26 Table 5. Number of tows (n), average catch (kg) in control and experimental nets, and percent (%) change in catch by year, season, gear, and species. Note that negative values indicate a reduction. Data in this table (randomization test) were derived from all tows that were considered reliable. Tows that caught mostly anchovies were excluded...... 27 Table 6. Number of tows (n), average catch (kg) in control and experimental nets, and percent (%) change in catch by year, season, gear, and species. Note that negative values indicate a reduction. Data in this table (t-test) were derived from a subset of the reliable tows such that the number of tows taken on each side of the vessel were equivalent. Tows that caught mostly anchovies were excluded...... 27 Table 7. Percent change in catch and results of the randomization tests comparing catches between the control and experimental nets by year, season, gear, and species. Values in bold indicate significant p-values, i.e., a significant difference was found (α = 0.05). Data in this table were derived from all tows that were considered reliable. Tows that caught mostly anchovies were excluded...... 28 Table 8. Percent change in catch and results of the t-tests comparing catches between the control and experimental nets by year, season, gear, and species. Values in bold indicate significant P values, i.e., a significant difference was found (α = 0.05). Data in this table were derived from a subset of the reliable tows such that the number of tows taken on each side of the vessel were equivalent. Tows that caught mostly anchovies were excluded...... 28

LIST OF FIGURES

Figure 1. Location of commercial shrimp trawl gear testing (Virgil Potter BRD, 1 state fisheye, 1 ¾-inch tail bag) tows made in Pamlico Sound, North Carolina, October 2016...... 29 5 Figure 2. Location of commercial shrimp trawl gear testing (3-inch TED and 1 ∕8-inch tail bag) tows made in Pamlico Sound, North Carolina, July 2017...... 30 Figure 3. Location of commercial shrimp trawl gear testing (3-inch TED, 2 state fisheyes, 5 and 1 ∕8-inch tail bag) tows made in near shore ocean waters of North Carolina, August 2017...... 31 Figure 4. Location of commercial shrimp trawl gear testing (3-inch TED, 2 state fisheyes, 5 and 1 ∕8-inch tail bag) tows made in near shore ocean waters of North Carolina, October-November 2017...... 32 Figure 5. Location of commercial shrimp trawl gear testing (3-inch TED, 2 federal fisheyes, 5 and 1 ∕8-inch tail bag) tows made in near shore ocean waters of North Carolina, October 2017...... 33 Figure 6. 4-inch TED (industry standard, left) compared to a 2-inch TED (right). (Image source: Broome et al. 2011) ...... 34 Figure 7. Ricky BRD. (Image source: Helies et al. 2012)...... 34 Figure 8. Hummer Line BRD. (Image source: Crowley 2014) ...... 35 Figure 9. Diagram of Hum Line BRD. (Image source: Lionell Laforce, NOAA-HSU) ...... 36 Figure 10. Photo of a single green Lindgren-Pitman Electralume light (left) and same light in relation to groundline of trawl (right) currently being tested in the Oregon Pink shrimp fishery (Image source: Hannah 2014)...... 37 Figure 11. Port-side and bottom view of the NOAA Fisheries TED-BRD combo showing fish excluder panels under the TED grid above (Image source: Crowley 2014)...... 37 Figure 12. Depiction of a shrimp vessel equipped with quad trawls (Image source: Scott- Denton et al. 2012)...... 38 Figure 13. Virgil Potter BRD as tested in Pamlico Sound, NC...... 39

BACKGROUND

In 2016, North Carolina’s commercial shrimp fishery was valued at over $28 million with landings over 13 million pounds (NCDMF 2017). The fishery targets brown Farfantepenaeus aztecus, pink F. duorarum, and white Litopenaeus setiferus shrimp. All three species are considered annual crops, which means they are short-lived and the annual abundance of each stock is a function of the strength of the incoming year class. Although all three commercially important shrimp species in North Carolina are considered viable (NCDMF 2006, 2015), a formal stock assessment has not been completed due to environmental conditions influencing population size more than fishery pressure.

Otter trawls are the predominant gear used to harvest shrimp and account for 92% of landings in North Carolina (NCDMF 2015). Most landings are from the Pamlico Sound (56%), Atlantic Ocean (24%), and Core Sound (6%). No other waterbody contributed more than 4% of the state’s landings (NCDMF 2014). Otter trawls are cone shaped nets constructed of twine webbing of various materials (nylon, spectra, and polyethylene). The net is opened horizontally by water pressure forcing the doors (planers) on either side of the net to spread apart. The bottoms of the doors are typically rounded along the leading edge, with a metal runner protecting the typically wooden door and providing weight. A single float in the center of the top line and weights (sections of chain) that run along the bottom line are used to vertically open the mouth of the trawl. The nets are equipped with tickler chains, which are attached to the doors and drag along the bottom, just in front of the footrope to disturb shrimp resting on the substrate. The nets terminate in a tailbag (or cod end) where the catch is concentrated and retained during the tow. Double-seamed nets are constructed from two body sections fish low in the water column and are used to target brown shrimp, while four-seamed nets, consisting of four webbing panels, also target brown shrimp, they fish higher in the water column (Watson et. Al 1984). Tongue nets fish higher in the water column, and are used to target white shrimp.

The shrimp trawl fishery in North Carolina is controversial due to the amount of finfish bycatch and the subsequent discard of commercially and recreationally valuable fish species such as; flounder spp. (Paralichthys lethostigma, P. dentatus, and P. albigutta), weakfish (Cynoscion regalis), spot (Leiostomus xanthurus), and Atlantic croaker (Micropogonias undulatus). Bycatch remains an important and controversial topic in fisheries management and marine conservation both in the United States, and around the world (Alverson et al. 1994; Alverson and Hughes 1996; Crowder and Murawski 1998; Diamond 2003; Kelleher 2005; Davies et al. 2009).

In 1992, North Carolina became the first state to require Bycatch Reduction Devices (BRDs) in shrimp otter trawls. During the spring and summer of 1999 and 2000, Johnson (2003) characterized the bycatch of inshore commercial shrimp trawlers working in Core, Southern Pamlico, and Back sounds and found that spot accounted for 17%. All nets sampled were fitted with BRDs and Turtle Excluder Devices (TEDs); the Florida Fish Eye Excluder (SH-2-2015) was cited as the most commonly used type of BRD. Brown (2009) characterized the nearshore commercial shrimp trawl fishery from Carteret to Brunswick counties from 2007 to 2008. All observed trips used Florida Fish Eyes in combination with a Super Shooter, Straight Bar, or Inshore Hard TEDs (50 CFR 223). Over 100 species were observed throughout the study with Atlantic croaker (25%) and spot (7%) being the most abundant finfish bycatch in all net types (Brown 2009).

Since TEDs and BRDs were first implemented, many variations have been tested by state and federal agencies. The National Oceanic and Atmospheric Administration (NOAA) Fisheries has developed a protocol by which BRDs must be evaluated (NOAA 2008). Many of the most relevant TED and BRD research findings are described in detail elsewhere (Holland 1989; Mckenna and Monaghan 1992; SAFMC 1996; NCDMF 2006, 2015; Brown 2010). Until recently, there were five BRDs certified for use in North Carolina. Recently, two management strategies that were included in Amendment I to the N.C. Shrimp Fishery Management Plan (FMP) have taken effect allowing any federally certified BRD to be used in state waters and requiring a second BRD to be installed in all shrimp trawls (NCDMF 2015).

Despite the growing number of available BRDs, fishery managers and fishermen continue to face the issue of bycatch and regulatory discards within the commercial shrimp trawl fishery. NCDMF issues stock status reports yearly and the stock status of many of these incidental and discarded fish species are listed as “unknown”, “concern”, or “depleted”. Two examples are summer flounder and weakfish; summer flounder are listed as concern with overfishing occurring, and weakfish are listed as depleted but overfishing is not occurring). Discards impact fishery yields and fishery managers’ ability to accurately assess fish stocks.

In 2012, the North Carolina Marine Fisheries Commission (NCMFC) voted to amend the Shrimp FMP, and to limit the amendment to focus on finfish bycatch issues in the commercial and recreational shrimp fisheries. In early 2014, the NCMFC selected preferred management strategies. One of the primary management strategies selected was to:

Convene a stakeholder group to initiate industry testing of several BRDs to reduce bycatch to the extent practicable with a 40% target reduction. Upon securing funding, testing in the ocean and internal waters will consist of three years of data…. Results should minimize shrimp loss and maximize reduction of bycatch of finfish. Promising configurations will be brought back to the NCMFC for consideration for mandatory use.

The NCMFC also provided additional guidance concerning group representation, the specifications of control nets to be used in BRD testing, and the review process for possible implementation of mandatory use of promising configurations.

In the fall of 2014, the NCMFC awarded a Conservation Fund Grant to the project team to convene a stakeholder group and initiate industry testing of three BRDs. The first meeting occurred 31 March 2015. The industry workgroup consists of 12 members representing a wide geographic range of shrimpers, net makers, and industry leaders in North Carolina. Testing continued in 2016 through the Bycatch Reduction Engineering Program (BREP), which allowed testing of three BRDs (Brown et al. 2017).

This project advances the NCMFC 2014 request by establishing a representative industry workgroup, conducting formal workshops prior to industry-led testing, evaluating BRDs aboard commercial trawlers, and conducting an outreach workshop to communicate the most promising configurations to the industry. Should optimal BRDs be identified in this process, fishery managers

8 and the commercial industry will have additional tools to maintain this economically and culturally significant fishery.

METHODS

This study was conducted from 2 October 2016 to 13 October 2016 and 12 July 2017 to 25 July 2017 in Pamlico Sound, North Carolina (Figures 1 and 2), and from 3 August 2017 to 20 November 2017 in the near shore ocean waters (from Carolina Beach to Oak Island) of North Carolina (Figures 3-5). This study addressed six specific initiatives, as described below.

1. Continue an industry workgroup comprised of commercial shrimp industry representatives, state and federal gear specialists and outreach coordinators (i.e., Sea Grant extension personnel).

The North Carolina Division of Marine Fisheries (NCDMF) and North Carolina Sea Grant (NCSG) collaborators convened an industry workgroup composed of select commercial fishermen, net makers, and shrimp fishing industry representatives from North Carolina on 31 March 2015. Members were selected based on knowledge of the gear and the fishery as well as geographic representation. This workgroup remained intact throughout the project period as their knowledge and feedback was integral to the success of the project. Workgroup members learned about the most recent advancements in BRD gear technology, prioritized new gears or broad technological solutions that should be field tested to achieve significant bycatch reduction over existing levels, and provided recommendations as to what percentage of shrimp loss is acceptable with new BRDs. The workgroup was comprised of 12 people and included six fishermen with extensive knowledge of both small (<45-ft) and large (>45-ft) shrimp vessel operations, four net- makers, and two other industry stakeholders. Care was taken to ensure that a geographically diverse workgroup was formed for this project.

2. Host a series of collaborative workshops to identify and prioritize existing or new bycatch reduction gears or broad technological solutions that can be tested to achieve a target of 40% finfish bycatch reduction in the North Carolina shrimp trawl fishery and build off the results of the NCMFC Conservation Fund Grant and the NOAA BREP grant.

The NCMFC suggested management recommendations for testing that included tailbags with a larger mesh size, T-90 panels, skylight panels, and reduced bar spacing in TEDs (Figure 6; Hataway 2010; Broome et al. 2011). However, this project was designed to be adaptive and considered a broader range of BRD prototypes including, but not limited to: the Ricky BRD (Figure 7; Helies et al. 2012 and 2015), hummer line (Figures 8 and 9; Crowley 2014), light sticks placed in the mouth of the trawl (Figure 10; Hannah 2014), square-mesh panels/rings (Arkley 2001), bycatch deflector device (Broome 2014), and the NOAA Fisheries TED-BRD combo (Figure 11; Crowly 2014) with the hum line.

At the first workgroup meeting on 31 March 2015, an overview of existing and previously completed BRD research efforts were provided to workgroup members. Dr. Pingguo He, associate professor of fisheries at the School for Marine Science and Technology, University of Massachusetts Dartmouth, attended the first workgroup meeting and provided an update on fish

behavior in response to fishing gears and his study involving an additional option, the topless trawl. Mr. Frank Helies, project director with the Gulf and South Atlantic Fisheries Foundation (GSAFF), provided an update of recent BRD research conducted by GSAFF. Gary Graham, fisheries specialist at Texas Sea Grant, attended and provided insight to BRD testing in the Gulf of Mexico. Steve Eayrs, research scientist at the Gulf of Maine Research Institute, presented information on how to choose and test BRDs. Dan Foster, research fishery biologist at the NOAA Harvesting Systems Unit (NOAA-HSU), Pascagoula, MS provided an overview of BRD testing methodology and criterion, as defined in the NOAA testing manual (NOAA 2008). Workgroup members then had the opportunity to present for consideration, any new or additional BRD designs or broad technological solutions for consideration by the members. Three designs were selected for field testing by participating fishing vessels. Two additional BRD designs were also selected, by consensus of the workgroup, as “backups” in case one of the three primary approaches failed to yield satisfactory results during any early “calibration trips” prior to data collection.

The second workgroup meeting was held 25 January 2016. Researchers from the NCDMF and the NOAA-HSU gave overviews on the NCMFC directive and reviewed the results from 2015 testing. Workgroup members discussed and recommended BRD options for testing in 2016. The workgroup also discussed and recommended acceptable shrimp loss with new BRDs of between 3% and 5% depending on the reduction of finfish that is accomplished. The workgroup decided to forgo any contract monies to allow a second observer to be hired to conduct whole haul sampling. The workgroup felt that if everything was weighed, it would remove any potential sample bias due to non-random subsamples.

The third workgroup meeting was held 9 January 2017. Results from 2016 testing were reviewed by researchers from NCDMF and the NOAA-HSU. The workgroup discussed and recommended BRD options for testing in 2017. The workgroup again decided to forgo any contract monies to allow a second observer to be hired to conduct whole haul sampling.

A fourth workgroup meeting was held 22 January 2018. NCDMF and NOAA-HSU researchers reviewed the NCMFC directive and reviewed preliminary results from 2017. The workgroup also discussed how to make recommendations to the NCMFC and planned a follow-up meeting for 8 March 2018 to finalize those recommendations. The future of the workgroup was also discussed.

3. Conduct comparative tows in North Carolina waters aboard commercial vessels to field test technological solutions identified by the group.

During the fall of 2016, two commercial shrimp (otter) trawl vessels committed to conduct initial installation and “trial-run tows”, in addition to conducting formal comparative tows (experimental versus control), with a minimum target of 30 successful paired tows to test three BRDs (Table 1). One vessel began testing and conducted 25 comparative tows before testing was disrupted by Hurricane Matthew (8-9 October 2017) and its aftermath. That test was discontinued as well as the tests scheduled for the two other BRDs. A no-cost extension was granted which allowed those monies to be directed to the summer 2017testing. During 2017, four commercial shrimp trawlers committed to conduct similar testing with a minimum target of 30 successful tows per experimental gear (Table 1; NOAA 2008). The fall 2016 vessel and one of the 2017 vessels were quad rigged trawlers and so to eliminate bias associated with use of a try net the control and

experimental nets were tested in the “one” and “four”, or outside positions (Figure 12; Eayrs 2012). A try net is a small trawl that is used to by fishermen to estimate the quantity of shrimp available both before and during the tow. The three small vessels which conducted testing in 2017 were double rigged vessels and either did not use a try net, or it was determined that the try net was not affecting the test net’s catch. A successful tow was defined as both the control and experimental nets fishing without an indication of problematic event (i.e., crab pots in net) occurring during the tow to impact or influence the fishing efficiency (catch) of one or both nets. The control net for this project consisted of a typical commercial shrimp otter bottom trawl with a Florida Fish Eye BRD, a TED with 4-inch bar spacing, and a 1 ½-inch, stretched mesh tail bag. Field testing occurred in October 2016 and July through November 2017 to coincide with peak shrimp season. One large vessel (2016) and one small vessel (2017) operated in Pamlico Sound while one large vessel (2017) and two small vessels (2017) operated in nearshore ocean waters (Figures 1-5).

Observers were hired and trained to collect data under NCDMF protocols, which meet the requirements of federally funded observer projects and largely coincide with NOAA Fisheries guidelines (NOAA 2016). North Carolina Division of Marine Fisheries staff and personnel with NOAA Fisheries Beaufort Laboratory, NC, trained observers to handle, transport, identify, resuscitate, tag, and release sea turtles in accordance with federal Endangered Species Act standards.

The prototype field testing closely followed the NOAA Bycatch Reduction Device Testing Manual (NOAA 2008). Prior to formal field trials and data collection, the experimental nets were calibrated to minimize any potential net bias. The effects of any bias associated with the use of a try net were mitigated by using the outside nets of four-barrel (quad) rigs, or in the case of the small double rigged vessels, the try net was not used or was determined not to be affecting the catch of the test nets. Experimental and control nets were switched from side to side ensuring an equal number of successful tows were made with the BRD prototype on each side of the vessel to reduce the potential for side bias. Gear specification data were collected for both experimental and control nets and included head rope length, mesh size of wing and tail bag, TED type, TED bar spacing, BRD type, location, and duration (tow time).

Two observers were assigned to each trial. Following each paired tow, the catches from each net (experimental and control) were sampled separately. During testing, the total weight (kg) of four categories of catch (Penaeid shrimp, finfish, non-shrimp invertebrates, and elasmobranchs) were recorded, except in 2016 when only finfish and shrimp were recorded.

4. Analyze data and compare results to finfish bycatch levels currently observed in the North Carolina shrimp trawl fishery.

Following the completion of all trips, data were entered into the NCDMF biological database and tows were coded as to whether they would be included in the analyses based on comments provided by the observers. Tows were omitted from analyses if a problematic event (i.e., crab pots in net) was experienced. Observed weights were standardized to the target two-hour (2016) or one-hour (2017) tow time to adjust for differences in tow times, a standard practice in analysis of fisheries data. The analyses described here were applied to these adjusted weights. The average weight of each net (control and experimental) was computed for each gear and species combination along

11 with the difference in average weight and percent change (percent reduction). Two types of analyses described below were used to evaluate the differences in catches between the control and experimental nets: t-tests and randomization tests.

The first approach used to compare catches between the control and experimental nets was the paired t-test. Paired t-tests (alpha = 0.05) were used to determine the average percentage of shrimp and bycatch differences with the use of an experimental BRD compared to control nets during comparative tows. While calibration tows were made prior to testing, some side bias was still assumed in testing. To account for side bias, test gears were switched between the sides of the vessel throughout testing with the goal of having an even number of tows with the experimental gear on each side of the vessel. When this was not achieved, an even number of tows was randomly so the comparisons would be made with an equal number of tows (with the experimental gear) on each side of the vessel.

The second approach used to compare catches between the control and experimental net was the randomization test (Manly 2007). Unlike the paired t-test, the randomization test does not assume the data are normally distributed, and catch data are frequently found to be non-normally distributed. The data was tested for normality and the majority of the data differences were not normally distributed. Another advantage of the randomization procedure is that it does not require tows to be dropped from the analysis. The null hypothesis for the randomization test is that there is no difference in catch between the control and experimental nets. The test statistic evaluated was the difference in average catch between the control and experimental nets. The randomization procedure was written and conducted in the R statistical programming language (R 2017, version 3.4.3). Data were randomized and resampled 10,000 times for each gear/species/net combination. The randomization test “p-value” for a two-tailed test is the proportion of test statistics (including that computed from the original data) that are as large or larger in absolute value than the absolute value of the statistic computed from the original data.

5. Conduct follow-up outreach to the commercial industry with a final workshop to present results and to discuss best performing conservation gear(s) and fishing practices.

After data analysis has been completed, a final industry workgroup meeting will be held (scheduled for April 4, 2018) and will be open to the public and widely advertised, so that project investigators can share the results of the research with the greater industry and interested members of the public. In addition, investigators Baker and Mirabilio will prepare a summary of the research results in a format appropriate for general audiences. The summary will likely follow the format previously used to successfully communicate BRD testing results with industry (Baker 2010). Research summaries will be mailed to all North Carolina commercial fishermen that landed shrimp within the last year (via NCDMF Trip Ticket records). Finally, research results will be shared with other appropriate state and federal management agencies in the Southeast United States, industry associations (e.g., North Carolina Fisheries Association (NCFA), GSAFF)), as well as relevant trade publications (e.g., National Fisherman).

6. Present findings to the N.C. Marine Fisheries Commission for potential use in better state shrimp fishery management.

With the completion of the third year of field trials in 2017, project investigators will provide a presentation of the findings to the NCMFC at their May 2018 Business Meeting. Findings may be used to make decisions in state shrimp fishery management. Results will be applicable to shrimp trawl fisheries in the greater southeastern United States and findings will be shared with other appropriate state and federal management agencies in the Southeast United States and Gulf of Mexico via industry associations (e.g., NCFA, Southern Shrimp Alliance (SSA)) as well as relevant trade publications (e.g., National Fisherman).

GEAR PARAMETERS

Six configurations of experimental otter trawls were tested throughout this study (Tables 1 and 2). Headrope length, footrope length, and net bodies were identical on both the experimental and control nets. All control nets were equipped with a federally certified TED with 4-inch bar spacing, one state fisheye BRD, and a 1 ½-inch stretch mesh tail bag.

The first gear modification tested in the fall of 2016 was the Virgil Potter BRD, 4-inch bar spaced TED, one state fisheye, and 1 ¾-inch tail bag (Figure 13). The Virgil Potter BRD consisted of a radial escape section constructed of 8 ½-inch stretch mesh and was five meshes long. A funnel constructed of 1 ½-inch stretch mesh was part of the design.

In the summer of 2017, three experimental gears were tested that included a TED with 3-inch bar spacing, one state fisheye, and 1 ½-inch tail bag. Following five comparative tows with less than 5 desired reductions of finfish observed, the experimental gear was modified to include a 1 ∕8-inch stretch mesh tail bag.

The next tested gear, in the summer of 2017, was a TED with 3-inch bar spacing, two state fisheyes, 5 and 1 ∕8-inch stretch mesh tail bag.

In the fall of 2017, two experimental gears were tested which included a TED with 3-inch bar 5 spacing, two state fisheyes, and 1 ∕8-inch stretch mesh tail bag. Finally, a modification consisting 5 of a TED with 3-inch bar spacing, two federal fisheyes, and 1 ∕8-inch stretch mesh tail bag was tested.

RESULTS

The results provided varying trends among the gear types tested. Over the two years of testing 145 comparative tows were made on six experimental gears, with three dropped because they were considered unreliable for analyses. Testing occurred on 24 trips across 39 fishing days (days where fishing occurred), over the course of 41 sea days (days on the vessel was on the water). Observers sampled and weighed over 36,000 kilograms of fish, shrimp, and other marine organisms. The following sections discuss findings from gear types tested in Pamlico Sound, N.C. October 2016 and July 2017 and in nearshore ocean waters from August to November 2017.

One large (>45 ft) commercial shrimp trawl vessel conducted comparative BRD testing on one device throughout Pamlico Sound, N.C. during October 2016. One small (<45 ft) commercial shrimp fishing trawl vessel conducted comparative BRD testing on two devices throughout Pamlico Sound, N.C. during July 2017. One small vessel (<45 ft) tested one device in nearshore ocean waters during August 2017. One small vessel (<45 ft) tested one device in nearshore ocean waters from October to November 2017 and one large (>45 ft) vessel tested one device in nearshore ocean waters in October 2017. All control nets including TEDs, bags, and fisheyes were standardized on each vessel.

Approximately 98% of tows were considered reliable tows and were included in the analyses and a summary of the observed data for 2016 and 2017 is presented in Tables 1 and 2. Tows were considered unreliable if a problematic event (i.e., crab pots in net) was experienced.

Virgil Potter BRD, 4-inch TED, 1 state fisheye, and 1 ¾-inch tail bag (fall 2016)

There were 25 tows made testing the Virgil Potter BRD with one state fisheye and 1 ¾-inch stretch mesh tail bag. The goal of 30 tows was not reached due to disruptions in the season caused by Hurricane Matthew. A total of 20 matched pairs were used for t-test analysis comparing the Virgil Potter BRD (Tables 1 and 2).

Data collected from all 25 tows were included in the randomization test (Table 1). The average catch of finfish in the experimental net (96.1 kg) was 44.3% lower than the average catch in the control net (172 kg; Table 1). This difference was found to be significant based on the randomization procedure (p < 0.001, α = 0.05; Table 3). The difference in average shrimp catch between the control (31.3 kg) and experimental (29.5 kg) nets (Table 1) was not found to be significant based on the randomization test (p = 0.691, α = 0.05; Table 3).

Data from 20 matched pairs were used for t-test analysis. Based on the results of the t-test, the mean weight (kg) of the target species (shrimp) in the experimental net was not significantly different from the control net (p = 0.055; Table 2). Differences in shrimp catch between the control net and the experimental net ranged from a gain of less than 1% to a loss of 11%, with an average of 5.5% shrimp loss (Table 2). The mean weight (kg) of finfish bycatch in the experimental net was significantly reduced (p < 0.001; Table 4) from the control net, averaging a 43.2% finfish reduction, and ranging from 22.8% to 63.7%.

3-inch TED, 1 state fisheye, and 1 ½-inch tail bag (summer 2017)

There were five tows made with the 3-inch TED included in the randomization test (Table 1). The differences in the average catch between the control and experimental nets for finfish, non-shrimp invertebrates, elasmobranchs, and shrimp were not significant (all p-values > 0.05, α = 0.05; Table 5). A t-test was not performed on these five tows due to low sample size and all five tows were made with the experimental gear on the same side of the vessel.

5 3-inch TED, 1 state fisheye, and 1 ∕8-inch tail bag (summer 2017)

There were 25 tows made with this gear. Three tows were dropped from the randomization test as they were considered unreliable due to problematic events (i.e. crab pots in the nets). The differences in the average catch between the control and experimental nets for finfish, non-shrimp invertebrates, elasmobranchs, and shrimp (Table 1) were not significant (all p-values > 0.05, α = 0.05; Table 3) based on the randomization procedure.

There were 20 tows used for a t-test analysis with this gear. While finfish were reduced on average by 22.8%, with shrimp losses less than 8%, the percent reductions in finfish, non-shrimp invertebrates, elasmobranchs and shrimp (Table 2) were not significant (all p-values > 0.05, α = 0.05; Table 4) based on the t-test procedure.

5 3-inch TED, 2 state fisheyes, and 1 ∕8-inch tail bag (summer 2017)

Data collected from all 30 tows were included in the randomization test. The average catch of finfish in the experimental net (98.5 kg, Table 1) was 32.6% lower than the average catch in the control net (146 kg; Table 1). This difference was found to be significant based on the randomization procedure (p = 0.002, α = 0.05; Table 5). The differences in average catch between the control and experimental nets for non-shrimp invertebrates, elasmobranchs, and shrimp (Table 1) were not significant (all p-values > 0.05, α = 0.05; Table 3) based on the randomization procedure.

Similar to the randomization test, the t-test analysis found the reduction in finfish to be significant (p <0.001; Table 4). Shrimp catch reductions averaged 6.8% (Table 2), and were significant (p = 0.039; Table 4). Non-shrimp invertebrates and elasmobranchs were minimally reduced with this BRD configuration, but were not significant with the t-test procedure (Tables 2 and 6).

5 3-inch TED, 2 state fisheyes, and 1 ∕8-inch tail bag (fall 2017)

5 There were 30 tows made with the 3-in TED, 2 state fisheyes, and 1 ∕8-inch tail bag, and all tows were analyzed with the randomization and t-test procedures.

Based on data from all 30 tows, the randomization test detected no significant difference in the average catch between the control and experimental nets for either finfish or shrimp (Tables 1 and 3). The average catch of non-shrimp invertebrates in the experimental net (2.86 kg) was 65.1% lower than the average catch in the control net (8.20 kg; Table 1). This difference was found to be significant based on the randomization procedure (p < 0.001, α = 0.05; Table 3). The average catch of elasmobranchs in the control net (4.26 kg; Table 1) was significantly different (p = 0.014, α = 0.05; Table 3) than the average catch in the experimental net (1.82 kg; Table 1).

The t-test analyses depict similar trends in catch differences in each of the species groups (Table 2). However, while finfish reductions (5%) were not significant (p = 0.670; Table 4), reductions in the other species groups were found to be significant (p < 0.009 for all; Table 4). Shrimp losses were increased 14.9% on average with this gear compared to the control net (Tables 2 and 4).

There were five tows in which an unusually large number of anchovies were observed. The randomization test and the t-test were applied to the same data for this gear except that these five

tows were excluded. The results of the randomization test were similar to those in which all 30 tows were included. That is, there was no significant difference in the average catch between the control and experimental nets for finfish or shrimp (p – 0.790; Tables 5 and 7). There were significant differences detected between the average catches in the control and experimental nets for non-shrimp invertebrates and elasmobranchs (p = 1.00E-04, 0.0456; Tables 5 and 7).

There were 20 tows used for the t-test analyses, excluding tows with anchovies (5 pairs). Finfish reductions decreased on average to 2% (p = 0.901), while shrimp loss was significant and remained approximately 15% (p = 0.006; Tables 6 and 8). Non-shrimp invertebrate reductions (66%) and elsmobranch reductions (61%) were significant (p = 0.015, 0.020, respectively; Tables 6 and 8).

5 3-inch TED, 2 federal fisheyes, and 1 ∕8-inch tail bag (fall 2017)

5 There were 30 tows made with the 3-inch TED, 2 federal fisheyes, and 1 ∕8-inch tail bag. All tows were used for both the randomization and t-test analyses. The differences in the average catch between the control and experimental gears for finfish, non-shrimp invertebrates, elasmobranchs, and shrimp (Table 1) were not significant (all p-values > 0.05, α = 0.05; Table 3) based on the randomization procedure applied to all 30 tows.

Based on the t-test procedure finfish increased by 29% on average with this gear; this increase was significant compared to the control net (p = 0.020; Tables 2 and 4). Shrimp catches were reduced by 9% on average with this gear, and was found to be significant with the t-test (p = 0.002; Table 4). Non-shrimp invertebrates showed an increase of 22% on average with the test gear, while elasmobranchs were reduced by 24% on average. However, t-test results indicated that differences in the average catch between the control and experimental gears were not significant for these catch categories (p = 0.276, 0.271; Tables 2 and 4).

Tows made by this vessel also encountered excessive anchovy catches on some tows and these tows were dropped from a further randomization and t-test. Specifically, the randomization procedure was applied to these data a second time except that 11 tows in which an unusually large number of anchovies were observed were excluded. No significant differences in average catches between the control and experimental gears were detected for any of the species (Tables 5 and 7).

For the t-test, 16 tows were analyzed following dropped tows with anchovies. By doing so, finfish catches were reduced by 9% on average, while shrimp catches were reduced by 6% (p = 0.246, 0.0728; Tables 6 and 8). However, non-shrimp invertebrate catches were increased by 69% though this was not significant (p = 0.055), and no significant differences in elasmobranch catches were detected (p = 0.439; Tables 4 and 8).

DISCUSSION

While the methodology followed the NOAA protocols (NOAA 2008), it should be noted that the establishment of a 40% bycatch reduction goal over the current industry standard (control net equipped with federally certified TED, one state fisheye BRD, and 1 ½-inch stretch mesh tail bag) is unprecedented. Federal certification of a BRD prototype requires the BRD to demonstrate a consistent reduction of total finfish bycatch of at least 30%, by weight, when compared to a control

net. However, the control net defined in the federal protocols does not have a BRD and is often called a ‘naked net’. Assuming our control net with a BRD is achieving a 30% reduction of finfish and we achieve our goal of 40% reduction of finfish by weight, we will achieve the equivalent of 58% reduction over a ‘naked net’ or nearly twice the federal requirement. For example, it is assumed the control net with a BRD will reduce 30 kg of every 100 kg of bycatch. The 40% reduction goal is then applied to the remaining 70 kg for a further reduction of 28 kg, for a total of 58 kg reduction from a ‘naked’ net.

In addition, previous tests with industry in the Gulf of Mexico have indicated that a 10% shrimp loss may be acceptable, if bycatch is greatly reduced by the gear (Crowley 2014). In this study, the determination of acceptable shrimp loss for new gears in North Carolina was an agenda item for the second workgroup meeting, and the workgroup indicated a shrimp loss between 3% to 5% is acceptable, depending on the level of discards achieved.

Much of this work focused on smaller vessels (<45 ft) and nearshore ocean waters of North Carolina. Unlike previous testing in 2015 and 2016 (Brown et al. 2017), the results from this study fell short of achieving the additional 40% reduction in finfish bycatch with the BRD combinations used. It should be noted that one of the industry workgroup’s recommendations was to test the larger 1 ¾-inch tail bag as one of the parts of the BRD for the large vessel, but this was not 5 completed during this testing, as only 1 ∕8-inch tail bags were used in the test BRD combinations. This testing has required multiple gear combinations to be tested simultaneously, so direct impact (or lack thereof) of any one part of the gear (e.g., TED, number of fisheyes, tail bag mesh size) is difficult to discern. However, previous testing does point to a significant reduction in finfish 7 bycatch when the larger (1 ¾-inch or 1 ∕8-inch) tail bags have been used (Brown et al. 2017). To achieve the target of 40% finfish reduction, testing with the use of a larger tail bag size is necessary in the small boat fleet, and as part of this process.

While the mean finfish reductions were not achieved with the gears tested here, the use of a 3-inch TED in conjunction with two state fisheyes did show promise during summer testing (2017) on a small vessel. This BRD combination showed an average finfish reduction of nearly 33% with upper and lower confidence intervals ranging from a finfish loss of 21% to 44%. Shrimp loss associated with this test was relatively minimal averaging 7%, but ranged from less than 1% to 13%. Based on previous results, it is likely that testing a 3-inch TED with two state fisheyes and the use of a larger mesh tail bag (1 ¾-inch) would result in finfish reductions greater than the 40% target. Further testing with this gear combination is needed in the small boat fleet to accurately assess this claim.

The entire catch on several tows with two of the vessels were unexpectedly comprised of small anchovies in 2017. Discussion among industry workgroup members during a January 2018 initial meeting indicated this may not represent normal catches and could have skewed the results to some degree. Analyses where tows comprised of anchovies were removed before re-analyzing with a randomization and t-test do indicate that the increased anchovy composition influenced mean 5 finfish losses. In particular, testing with a 3-inch inch TED, 1 ∕8-inch tail bag and two federal fisheyes, indicated a gain in finfish bycatch of over 29% on average. However, when anchovy tows were removed, finfish catches were reduced to an 8.5% loss, similar to the result from gears

using two state fisheyes. Thus, it is necessary to test the gear combinations that incorporate two federal fisheyes with a larger tail bag on the small boat fleet.

5 Collectively, it does not appear that gears using a 1 ∕8-inch tail bag, 3-inch TED, and two fisheyes (state or federal), will achieve the additional 40% finfish reduction in the small boat fleet. A number of other BRDs (e.g., composite panel, Virgil Potter) and BRD combinations (e.g., two fisheyes and larger tail bags) that proved successful in large vessel testing should be tested on smaller vessels (< 45 ft) to see if the previous observed reductions in finfish can be achieved.

Discussion among the industry workgroup and panel members at previous meetings have related the importance of repeatability in these tests. This applies to not only being able to observe the same results on similar vessels in the same region, but also to observe finfish reductions from successful BRD combinations elsewhere, regionally. This group was tasked with a high target of finding gears that can reduce finfish catches an additional 40% beyond the already 30% achieved from the control TED, 1 ½-inch tail bag and one BRD (state fisheye).

Testing in 2015 and 2016 was able to identify potential gear combinations (Brown et al. 2017), but these observations need to be repeated, and further testing is needed in the small boat fleet. Therefore, it is the goal of the industry workgroup and panel members to continue this process through the workgroup collaboration, and further testing. By doing so, it is likely that an array of options for both the large and small boats in NC can be made available, and allow managers to continue the viable and critical commercial shrimp fishery in NC.

Industry involvement and collaboration in this bycatch reduction initiative has been substantial and productive. Meeting facilities were provided by the NCFA and were scheduled to coincide with their annual meeting to maximize industry involvement and outreach. For the gears tested during this study, the industry donated 41 sea days for testing. The shrimp industry also provided culling tables to keep the control and experimental catches separate, donated use of supplies, assisted with catch sorting, installed and switched nets and experimental BRDs, and responded quickly and efficiently to the needs of the project in modifying experimental BRDs for follow-up testing.

The importance of gear studies designed to reduce bycatch cannot be overstated. The results of this study provide effort, catch, and discard information that can be used in current and future management decisions in shrimp trawl fisheries throughout North Carolina. In addition, information gathered from this study will guide future BRD testing in North Carolina. These efforts will not just benefit North Carolina fishermen but will potentially benefit all commercial shrimp fishermen in the South Atlantic and Gulf of Mexico.

RECOMMENDATIONS

• Continue the industry workgroup and make recommendations for gears to be tested for repeatability on large vessels, and implement small boat (< 45 ft) gear combinations for testing to begin as early as summer 2018.

• Continue to collaborate with the commercial industry to identify and test gear modifications in the commercial shrimp trawl fishery to aid in the reduction of finfish bycatch while maintaining acceptable shrimp harvest. This should be conducted throughout the state, across all seasons, and with various size vessels to determine differences associated with area, season, or vessel size.

• Managers should consider implementing some of the gear modifications into the commercial shrimp trawl fishery following the completion of this 3-year initiative and summarization of results.

• Generate better lines of communication between fishery managers, the commercial fishing industry and the public. This will increase understanding and allow increased inclusion of commercial knowledge into fishery management.

• Continued partnership between the commercial fishing industry, fishery managers, and researchers to develop technological solutions and trawling methods to reduce finfish bycatch.

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Tables

Table 1. Number of tows used for analysis (n), average catch (kg) in control and experimental nets, and percent (%) change in catch by year, season, gear, and species. Note that negative values indicate a reduction. Data in this table (randomization test) were derived from all tows that were considered reliable.

Year Season Gear Species n Control Experimental % Change Virgil Potter, 4” TED, 1 ¾” tail bag, 1 Finfish 25 172 96.1 -44.3 2016 Fall state fisheye Shrimp 25 31.3 29.5 -5.78 Finfish 5 12.3 12.9 5.06 Invertebrates (non-shrimp) 5 4.90 6.80 38.8 2017 Summer 3" TED, 1 ½” tail bag, 1 state fisheye Elasmobranchs 4 0.200 0.350 75.0 Shrimp 5 18.7 17.3 -7.79 Finfish 22 34.9 27.8 -20.4 Invertebrates (non-shrimp) 22 2.07 2.06 -0.439 2017 Summer 3" TED, 1 5/8" tail bag, 1 state fisheye 1 Elasmobranchs 3 0.333 0.0667 -80.0 Shrimp 22 11.6 10.6 -9.04 Finfish 30 146 98.5 -32.6 Invertebrates (non-shrimp) 30 17.2 15.9 -7.59 2017 Summer 3" TED, 1 5/8" tail bag, 2 state fisheyes Elasmobranchs 30 2.87 2.39 -16.7 Shrimp 30 2.86 2.67 -6.64 Finfish 30 57.5 54.9 -4.58 Invertebrates (non-shrimp) 30 8.20 2.86 -65.1 2017 Fall 3" TED, 1 5/8" tail bag, 2 state fisheyes Elasmobranchs 29 4.26 1.82 -57.3 Shrimp 30 9.75 8.31 -14.8 Finfish 30 75.6 97.7 29.3 Invertebrates (non-shrimp) 30 2.29 2.87 25.1 2017 Fall 3" TED, 1 5/8" tail bag, 2 federal fisheyes Elasmobranchs 28 0.904 0.682 -24.5 Shrimp 30 17.3 15.1 -12.5

1 Three tows that were considered unreliable were dropped from analysis 23

Table 2. Number of tows used for analysis (n), average catch (kg) in control and experimental nets, and percent (%) change in catch by year, season, gear, and species. Note that negative values indicate a reduction. Data in this table (t-test) were derived from a subset of the reliable tows such that the number of tows taken on each side of the vessel were equivalent.

Year Season Gear Species n Control Experimental % Change Virgil Potter, 4” TED, 1 ¾” tail bag, 1 Finfish 20 189 107 -43.2 2016 Fall state fisheye Shrimp 20 33.1 31.3 -5.46 Finfish * - - - 2017 Summer 3” TED, 1 ½” tail bag, 1 state fisheye Invertebrates (non-shrimp) * - - - Shrimp * - - - Finfish 20 34.6 26.7 -22.8 5 2017 Summer 3" TED, 1 ∕8" tail bag, 1 state fisheye Invertebrates (non-shrimp) 18 2.25 2.11 -6.06 Shrimp 20 12.1 11.2 -7.82 Finfish 30 146 98.5 -32.6

5 Invertebrates (non-shrimp) 30 17.2 15.9 -7.58 2017 Summer 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs 29 2.96 2.48 -16.3 Shrimp 30 2.87 2.67 -6.80 Finfish 30 57.5 54.9 -4.57

5 Invertebrates (non-shrimp) 30 8.19 2.86 -65.1 2017 Fall 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs 28 4.38 1.88 -57.1 Shrimp 30 9.76 8.30 -14.9 Finfish 30 75.6 97.7 29.3

5 Invertebrates (non-shrimp) 25 2.24 2.73 21.9 2017 Fall 3" TED, 1 ∕8" tail bag, 2 federal fisheyes Elasmobranchs 15 1.30 0.988 -24.3 Shrimp 30 17.3 15.7 -9.04

* No T-test conducted due to small sample size

Table 3. Percent change in catch and results of the randomization tests comparing catches between the control and experimental nets by year, season, gear, and species. Values in bold indicate significant p-values, i.e., a significant difference was found (α = 0.05). Data in this table were derived from all tows that were considered reliable.

Year Season Gear Species % Change p-value Finfish -44.3 0.00140 2016 Fall Virgil Potter Shrimp -5.78 0.691 Finfish 5.06 0.732 Invertebrates (non-shrimp) 38.8 0.281 2017 Summer 3" TED Elasmobranchs 75.0 0.487 Shrimp -7.79 0.827 Finfish -20.4 0.341

5 1 Invertebrates (non-shrimp) -0.439 0.993 2017 Summer 3" TED, 1 ∕8" tail bag, 1 state fisheye Elasmobranchs -80.0 0.397 Shrimp -9.04 0.556 Finfish -32.6 0.00200

5 Invertebrates (non-shrimp) -7.59 0.505 2017 Summer 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs -16.7 0.425 Shrimp -6.64 0.598 Finfish -4.58 0.890

5 Invertebrates (non-shrimp) -65.1 1.00E-04 2017 Fall 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs -57.3 0.0138 Shrimp -14.8 0.365 Finfish 29.3 0.250

5 Invertebrates (non-shrimp) 25.1 0.455 2017 Fall 3" TED, 1 ∕8" tail bag, 2 federal fisheyes Elasmobranchs -24.5 0.360 Shrimp -12.5 0.234

Table 4. Percent change in catch and results of the t-tests comparing catches between the control and experimental nets by year, season, gear, and species. Values in bold indicate significant p-values, i.e., a significant difference was found (α = 0.05). Data in this table were derived from a subset of the reliable tows such that the number of tows taken on each side of the vessel were equivalent.

Year Season Gear Species % Change p-value Finfish -43.2 1.06E-04 2016 Fall Virgil Potter Shrimp -5.46 0.0545 Finfish -22.8 0.0187 5 2017 Summer 3" TED, 1 ∕8" tail bag, 1 state fisheye Invertebrates (non-shrimp) -6.06 0.692 Shrimp -7.82 0.294 Finfish -32.6 1.41E-07

5 Invertebrates (non-shrimp) -7.58 0.0865 2017 Summer 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs -16.3 0.184 Shrimp -6.80 0.0394 Finfish -4.57 0.670

5 Invertebrates (non-shrimp) -65.1 0.00138 2017 Fall 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs -57.1 0.00904 Shrimp -14.9 3.15E-04 Finfish 29.3 0.204

5 Invertebrates (non-shrimp) 21.9 0.276 2017 Fall 3" TED, 1 ∕8" tail bag, 2 federal fisheyes Elasmobranchs -24.3 0.271 Shrimp -9.04 0.00231

Table 5. Number of tows (n), average catch (kg) in control and experimental nets, and percent (%) change in catch by year, season, gear, and species. Note that negative values indicate a reduction. Data in this table (randomization test) were derived from all tows that were considered reliable. Tows that caught mostly anchovies were excluded.

Year Season Gear Species n Control Experimental % Change Finfish 25 58.2 52.4 -9.94

5 2 Fall 3" TED, 1 ∕8" tail bag, 2 state fisheyes Invertebrates (non-shrimp) 25 9.36 3.19 -65.9 2017 Elasmobranchs 24 4.50 2.07 -54.0 Shrimp 25 10.9 9.18 -15.7 Finfish 20 69.5 49.6 -28.7

5 3 3" TED, 1 ∕8" tail bag, 2 federal fisheyes Invertebrates (non-shrimp) 19 2.17 3.44 58.4 2017 Fall Elasmobranchs 17 1.00 0.865 -13.5 Shrimp 19 19.2 17.4 -9.08 Table 6. Number of tows (n), average catch (kg) in control and experimental nets, and percent (%) change in catch by year, season, gear, and species. Note that negative values indicate a reduction. Data in this table (t-test) were derived from a subset of the reliable tows such that the number of tows taken on each side of the vessel were equivalent. Tows that caught mostly anchovies were excluded.

Year Season Gear Species n Control Experimental % Change Finfish 20 48.1 47.1 -2.12

5 2 Invertebrates (non-shrimp) 20 8.69 2.94 -66.2 2017 Fall 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs 19 5.16 2.00 -61.3 Shrimp 20 9.56 8.09 -15.4 Finfish 16 51.6 47.2 -8.54

5 3 Invertebrates (non-shrimp) 12 2.16 3.64 69.0 2017 Fall 3" TED, 1 ∕8" tail bag, 2 federal fisheyes Elasmobranchs 10 1.40 1.07 -24.0 Shrimp 16 19.0 17.8 -6.22

2 Five tows for which most of the catch was anchovies were dropped from analysis 3 Eleven tows for which most of the catch was anchovies were dropped from analysis 27

Table 7. Percent change in catch and results of the randomization tests comparing catches between the control and experimental nets by year, season, gear, and species. Values in bold indicate significant p-values, i.e., a significant difference was found (α = 0.05). Data in this table were derived from all tows that were considered reliable. Tows that caught mostly anchovies were excluded.

Year Season Gear Species % Change p-value Finfish -9.94 0.790

5 Invertebrates (non-shrimp) -65.9 1.00E-04 2017 Fall 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs -54.0 0.0456 Shrimp -15.7 0.333 Finfish -28.7 0.186

5 Invertebrates (non-shrimp) 58.4 0.229 2017 Fall 3" TED, 1 ∕8" tail bag, 2 federal fisheyes Elasmobranchs -13.5 0.689 Shrimp -9.08 0.476

Table 8. Percent change in catch and results of the t-tests comparing catches between the control and experimental nets by year, season, gear, and species. Values in bold indicate significant P values, i.e., a significant difference was found (α = 0.05). Data in this table were derived from a subset of the reliable tows such that the number of tows taken on each side of the vessel were equivalent. Tows that caught mostly anchovies were excluded.

Year Season Gear Species % Change p-value Finfish -2.12 0.901

5 Invertebrates (non-shrimp) -66.2 0.0149 2017 Fall 3" TED, 1 ∕8" tail bag, 2 state fisheyes Elasmobranchs -61.3 0.0199 Shrimp -15.4 0.00590 Finfish -8.54 0.246

5 Invertebrates (non-shrimp) 69.0 0.0552 2017 Fall 3" TED, 1 ∕8" tail bag, 2 federal fisheyes Elasmobranchs -24.0 0.439 Shrimp -6.22 0.0728

Figures

Figure 1. Location of commercial shrimp trawl gear testing (Virgil Potter BRD, 1 state fisheye, 1 ¾-inch tail bag) tows made in Pamlico Sound, North Carolina, October 2016. 29

5 Figure 2. Location of commercial shrimp trawl gear testing (3-inch TED and 1 ∕8-inch tail bag) tows made in Pamlico Sound, North Carolina, July 2017.

5 Figure 3. Location of commercial shrimp trawl gear testing (3-inch TED, 2 state fisheyes, and 1 ∕8-inch tail bag) tows made in near shore ocean waters of North Carolina, August 2017.

5 Figure 4. Location of commercial shrimp trawl gear testing (3-inch TED, 2 state fisheyes, and 1 ∕8-inch tail bag) tows made in near shore ocean waters of North Carolina, October-November 2017.

5 Figure 5. Location of commercial shrimp trawl gear testing (3-inch TED, 2 federal fisheyes, and 1 ∕8-inch tail bag) tows made in near shore ocean waters of North Carolina, October 2017.

Figure 6. 4-inch TED (industry standard, left) compared to a 2-inch TED (right). (Image source: Broome et al. 2011)

Figure 7. Ricky BRD. (Image source: Helies et al. 2012)

Figure 8. Hummer Line BRD. (Image source: Crowley 2014)

Figure 9. Diagram of Hum Line BRD. (Image source: Lionell Laforce, NOAA-HSU)

Figure 10. Photo of a single green Lindgren-Pitman Electralume light (left) and same light in relation to groundline of trawl (right) currently being tested in the Oregon Pink shrimp fishery (Image source: Hannah 2014, personal communication).

Figure 11. Port-side and bottom view of the NOAA Fisheries TED-BRD combo showing fish excluder panels under the TED grid above (Image source: Crowley 2014).

Figure 12. Depiction of a shrimp vessel equipped with quad trawls (Image source: Scott-Denton et al. 2012).

Figure 13. Virgil Potter BRD as tested in Pamlico Sound, NC.