Propulsion-gear-based characterisation of artisanal fisheries in the Malindi-Ungwana Bay, Kenya and its use for fisheries management

摘要

In Kenya, like other tropical countries, coastal artisanal fishery is multispecies, multigear and multifleet in nature with many management challenges. The Malindi-Ungwana Bay in particular, supports both the artisanal fishery and the semi-industrial bottom trawl shrimp fishery presenting a management challenge. Recent stock assessment surveys have identified catch composition of the semi-industrial bottom trawl fishery in the bay but artisanal catches remain barely described. This study describes, the artisanal fish catch composition (total number of species caught, sizes and trophic levels), and catch-per-unit-effort (CPUE) for each of the most popular propulsion-gear categories used in the bay. We make a case that the use of specific propulsion-gear categories can be dynamically managed to encourage the recovery of selected fish groups and thus support fisheries management. A total of 4 269 finfish belonging to 177 species and 66 families were sampled by the 5 most popular propulsion-gear categories between 2009 and 2011. The total number of species caught was highest for canoe-gillnet, mashua-gillnet and foot-seine net, and lowest for foot-handline and mashua-handline. Significant differences in catch composition existed between the different propulsion-gear categories. The CPUE was not significantly different between propulsion-gear, although this was on the average highest for canoe-gillnet and mashua-gillnet, and lowest for the foot-handline. The highest trophic level of 4.0 was recorded for mashua-gillnet and the lowest 3.4 and 3.2 for canoe-gillnet and foot-seine net respectively. The use of specific combinations of propulsion-gear categories, give an alternative approach in management recommendation of the coastal artisanal fisheries in the tropics, from the traditional gear-based management initiative. This study, singled out the mashua-gillnet, canoe-gillnet and foot-seine net as suitable units for monitoring the artisanal fisheries in Malindi-Ungwana Bay since mashua-gillnet lands the highest mean trophic level and largest sized individuals, and canoe-gillnet and foot-seine net land the highest number of species caught and smallest sized individuals.