Factors affecting catch, fishing power and trappability in the Barbados trap fishery

Factors affecting catch, trap fishing power and reef fish trappability were investigated by experimental fishing with Antillean fish traps on west coast fringing reefs in Barbados. Commercial (small mesh) traps caught significantly more fish (by number and weight), caught significantly smaller fish, and caught a higher proportion of immature fish, than large mesh traps. Fishing power was significantly higher for commercial traps than for large mesh traps. These catch differences between trap types have serious implications for the management of the reef fish resource by the imposition of larger mesh sizes in the commercial fishery.The squeezability hypothesis and the visual image hypothesis were investigated as explanations for the lower fishing power of large mesh traps. The lower fishing power of large mesh traps results primarily from lower catch rates of fish in the 5.5-6.0 cm body depth size class. This result is strong support for the squeezability hypothesis as an explanation for the lower fishing power of large mesh traps. Differences in the visual images of traps created by structural differences and biotic differences did not produce definitive differences in ingress rates to traps, suggesting that the visual image hypothesis is an inadequate explanation for the lower fishing power of large mesh traps.The trappability of reef fish differed substantially between species, but trappability differences were not correlated with species mobility, activity of the species in traps, gregariousness, or capacity of the species to squeeze through meshes. Predator-prey effects on trappability were negligible, but trappability was negatively correlated with percent reef cover of the substratum and with substratum rugosity. This suggests that traps are more attractive to fishes in areas where natural structural complexity is lower. (Abstract shortened by UMI.