An assessment of bycatch reduction devices in Kuwait's shrimp trawl fishery

Three bycatch reduction devices (BRDs), i.e. the Turtle Excluder Device (TED), Square Mesh Codend (SMC) and Fisheye (FE), were tested to evaluate their feasibility in the Kuwait shrimp-trawl fishery. All three BRDs could be fitted to a shrimp trawl and normal fishing activities could be conducted both on an industrial trawler and an artisanal dhow boat. The comparisons of the catch from a net equipped with a BRD on one side and a standard net (exact same net configuration but without a BRD device) on the other side of a double-rigged shrimp trawler (steel boat) showed different results in the three BRD types. The net fitted with a TED performed well without capturing any turtles or large animals, and did not significantly reduce shrimp catch or fish bycatch (124.4: 117.0 and 852.0: 905.8, both P > 0.05). Although the SMC reduced both shrimp catch and bycatch in general, the Wilcoxon's signed rank test showed a significant difference only among bycatch (1034.2: 1147.3, P < 0.05). Chi-square tests showed that a net fitted with SMC caught significantly larger shrimp (more large and fewer small sizes) than a standard net for all three major shrimp species (33.5: 32.5; 26.9: 25.0; 20.3: 19.3, all P < 0.01). This indicates that the SMC reduced the catch of small size shrimps as well as smaller size fish. A net fitted with a fisheye significantly reduced both the shrimp catch and bycatch (137.4: 174.6; 997.5: 1377.8, both P < 0.01); the shrimp loss was probably due to an inappropriate location of the FE in the trawl.