Brown et al.: Simple gear modifications for bycatch reduction in a shrimp trawl fishery 
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Table 2 
Number of port and starboard tows made with control and experimental gears in Pamlico Sound in June and July 2015, 
July-September 2016, and July 2017 and in nearshore waters off North Carolina in August-November 2017. Some of 
the gears had trawl efficiency devices (TEDs) with reduced bar spacing, and bycatch reduction devices (BRDs) included 
the Ricky BRD, Virgil Potter BRD, and state and federal fisheyes. An asterisk (*) indicates that 1 tow made with this 
gear configuration was dropped from analysis. 
Year Gear description 
Net 
Number of tows 
Port Starboard 
2015 Composite panel 
Control 
37 
22 
Experimental 
22 
37 
Reduced-bar TED 
Control 
10 
9 
Experimental 
9 
10 
Reduced-bar TED + square mesh panel + 4.76-cm codend 
Control 
31 
20 
Experimental 
20 
31 
Ricky BRD 
Control 
10 
5 
Experimental 
5 
10 
Double federal fisheyes + 4.76-cm codend* 
Control 
19 
13 
Experimental 
14 
19 
2016 Virgil Potter BRD 
Control 
18 
15 
Experimental 
15 
18 
Double federal fisheyes + 4.45-cm codend 
Control 
20 
3 
Experimental 
3 
20 
Reduced-bar TED + double federal fisheyes + 4.45-cm codend 
Control 
15 
15 
Experimental 
15 
15 
Virgil Potter BRD + 4.45-cm codend 
Control 
11 
14 
Experimental 
14 
11 
2017 Reduced-bar TED 
Control 
5 
5 
Experimental 
5 
5 
Reduced-bar TED + 4.13-cm codend 
Control 
10 
15 
Experimental 
15 
10 
Reduced-bar TED + double state fisheyes + 4.13-cm codend (summer) 
Control 
15 
15 
Experimental 
15 
15 
Reduced-bar TED + double state fisheyes + 4.13-cm codend (autumn) 
Control 
15 
15 
Experimental 
15 
15 
Reduced-bar TED + double federal fisheyes + 4.13-cm codend 
Control 
15 
15 
Experimental 
15 
15 
with double state fisheyes and a 4.13-cm codend that was 
tested in summer, we achieved significant bycatch reduc¬ 
tion (22.8%, P=0.019, and 32.6%, PcO.OOl, respectively), 
although we did not obtain the desired 40% reduction. 
Randomization tests 
In the randomization tests, no significant loss of shrimp 
catch was observed among the 5 gears tested in 2015 
(Table 3). Significant (P<0.05) decreases in finfish catch 
were found in all gears tested in 2015 except for the 
reduced-bar TED and Ricky BRD. Of the gears for which 
a significant reduction in finfish CPUE was detected, only 
the use of the double federal fisheye with a 4.76-cm codend 
resulted in a reduction greater than the target of 40% 
(40.1%, PcO.OOl). 
No significant loss of shrimp catch was detected for 
the 4 gears tested in 2016, on the basis of the results of 
the randomization tests (Table 4). Tests with all 4 gears 
resulted in a significant (P<0.05) decrease in the catch 
of finfish. The use of the double federal fisheye (54.0%), 
the reduced-bar TED with a double federal fisheye and a 
4.45-cm codend (44.9%), and the Virgil Potter BRD with a 
4.45-cm codend (44.3%) all resulted in reductions greater 
than the 40% target. According to the results of the ran¬ 
domization tests, no significant changes were detected in 
the CPUE of invertebrates or elasmobranchs in 2016. 
None of the 5 gears tested in 2017 had a significant loss 
of shrimp catch, on the basis of the results of the random¬ 
ization tests (Table 5). Only when the gear with a reduced- 
bar TED, double state fisheyes, and a 4.13-cm codend was 
tested in summer was a significant decrease in finfish 
catch (32.6%) observed, although the decrease was less 
than the 40% target. Significant decreases in the catches 
of invertebrates (65.1%) and elasmobranchs (57.3%) 
were achieved when the gear with the reduced-bar TED, 
