Gear-based species selectivity and potential interactions between artisanal and aquarium fisheries in coastal Kenya: implications for reef fisheries management

Abstract

Multivariate and ecological approaches were used to investigate potential interactions in species selectivity between artisanal and aquarium fisheries on the south coast of Kenya. Aquarium fishery landings were monitored from September 2010 to March 2013, while artisanal landings were monitored over 1 year from January to December 2014. Target aquarium species constituted approximately 12% of the artisanal catches by weight and 8% by relative abundance, and was comprised of 17 fish families and 58 species dominated by wrasses. Handlines and spearguns had the highest potential interaction with the aquarium fishery. Pair-wise comparisons of Pianka’s overlap index revealed basket traps and monofilament gillnets as having the strongest overlap. The index further showed that aquarium snorkel fishers had a higher overlap in species selectivity with artisanal gears; while DCA ordination also showed a high overlap in the shared fishing grounds. DCA ordination further revealed the ornamental angelfishes, Pomacanthus imperata and Pomacanthus semicirculatus as strongly associated with spearguns, while the wrasses Halichoeres hortulanus and Thalassoma hebraicum, and the surgeonfish Acanthurus leucosternon were strongly associated with handlines. Spatial regulation of fishing effort will be most appropriate in minimizing the cumulative effects of fishing on vulnerable species resulting from interactions between the two fisheries.