Hook size selectivity in the artisanal handline fishery of Shimoni fishing area, south coast, Kenya

Abstract

Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissemination of high quality research generated in the Western Indian Ocean (WIO) region, in particular on the sustainable use of coastal and marine resources. This is central to the goal of supporting and promoting sustainable coastal development in the region, as well as contributing to the global base of marine science. The journal publishes original research articles dealing with all aspects of marine science and coastal management. Topics include, but are not limited to: theoretical studies, oceanography, marine biology and ecology, fisheries, recovery and restoration processes, legal and institutional frameworks, and interactions/relationships between humans and the coastal and marine environment. In addition, Western Indian Ocean Journal of Marine Science features state-of-the-art review articles and short communications. The journal will, from time to time, consist of special issues on major events or important thematic issues.

Vulnerability and Decision-Making in Multispecies Fisheries: A Risk Assessment of Bacalao (Mycteroperca olfax) and Related Species in the Galapagos’ Handline Fishery

“…Handline gear is one of the most selective fishing gears used by small-scale fishers, being fairly selective towards large apex predators [64,65]. Larger-sized hooks often increase catch rates and narrow down selection ranges in comparison to smaller-sized hooks [65].…”

“…Handline gear is one of the most selective fishing gears used by small-scale fishers, being fairly selective towards large apex predators [64,65]. Larger-sized hooks often increase catch rates and narrow down selection ranges in comparison to smaller-sized hooks [65]. However, in the Galapagos, where a maximum length in hooks is imposed (70 mm; [57]), a high proportion of the catch (e.g., 0.40 in terms of biomass; [56]) is usually composed of noncommercial species, nonmarketable sizes or regulated species, like sharks.…”

“…This measure would probably result in a benefit to fishers' incomes, as bigger fish generate more revenue, and smaller fish species could still be caught using other gear. However, larger hooks have been proved to have higher catch rates compared to the smaller ones [65]; thus, they could lead to an increased pressure towards large male fish in the population [40], and the incidental catch of large predators, such as sharks, sea lions and dolphins. In addition, it could encourage fishers to shift to other gears equally or more detrimental than handlines (e.g., trawl net, Hawaiian sling) to compensate for the losses.…”