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

Summary: 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.