Rogers et al.: Effectiveness of bycatch reduction devices in Louisiana inshore waters 
559 
ences in species composition and length-frequency 
distributions. 
Discussion 
The Authement-Ledet, Lake Arthur, and Cameron 
BRD’s significantly reduced bycatch, but also the 
catch of shrimp. Excluded shrimp were primarily in 
the smaller size classes. The Eymard BRD caught 
significantly more fish and shrimp than the corre- 
sponding control nets. 
The Lake Arthur and Cameron BRD’s were de- 
signed with a similar opening, but the Lake Arthur 
BRD did not release as many fish. Because the weight 
of the aluminum frame of the Cameron BRD caused 
the device to sink slightly, the bottom of the Cameron 
opening was only about 15 cm from the bottom of 
the trawl net. In contrast, the floats of the Lake 
Arthur BRD raised the opening to about 30 cm above 
the trawl bottom. A design somewhat similar to the 
Lake Arthur BRD and placed 1.7 m from the end of 
the net did not significantly reduce bycatch in inshore 
waters of Alabama (Wallace and Robinson, 1994). 
Reductions with the Cameron BRD (16% shrimp, 
51% fish) were similar to those found by Watson et 
al. (1993) for the fisheye top position excluder in off- 
shore waters (17% shrimp, 70% fish). Inshore fish 
are typically smaller and less able to escape by swim- 
ming; this may account for the lower reductions with 
the Cameron BRD. This BRD also released shrimp 
of most size classes; Watson and McVea ( 1977 ) found 
that the fish escape device, a somewhat similar de- 
vice, also lost shrimp over the entire size range. 
Changing the location of the Cameron shooter may 
affect performance, although Watson et al. (1993) 
noted that the top position appeared to have the best 
effectiveness for fish reduction and shrimp retention. 
A bottom-mounted Florida fish shooter, placed 1.7 m 
from the end of a 4.9-m trawl, reduced bycatch 26% 
by weight and 46% by number and caught 14% fewer 
shrimp than an unmodified net (Wallace and 
Robinson, 1994). McKenna and Monaghan 4 reported 
that the efficiency of the Florida fish excluder de- 
pended on the size of the escape opening, placement 
of the excluder in the net, and the number of devices 
installed. 
4 McKenna, A., and J. P. Monaghan Jr. 1993. Gear development 
to reduce bycatch in the North Carolina trawl fisheries. 
Completion report to Gulf and South Atlantic Fisheries Develop- 
ment Foundation Cooperative Agreement No. NA90AA-H-SK052. 
North Carolina Div. Mar. Fish., Morehead City, NC, 79 p. 
