Catch dynamics of set net fisheries in Israel

Abstract Artisanal fisheries are globally common, providing almost 50% of total world landings. However, due to overfishing, they are worldwide on the verge of collapse. Fisheries in the eastern Mediterranean Levantine Basin must additionally cope with extreme thermal conditions, meaning that fish are typically smaller relative to other regions. In Israel, mesh size restriction has been suggested as a means to rebuild stocks, but data on artisanal fishing landings across mesh size are extremely sparse. The aim of this study was to quantify set net catches across different mesh sizes in order to identify fishing methods that can benefit both fish populations and fishers. We hope to identify which mesh size provide the highest ratio of commercial to non-commercial fished biomass, the lowest variance in fisher’s revenues and benefits the reproductive potential of the resource by targeting mature individuals. We found that across the range of mesh sizes examined, smaller mesh sizes (i.e. 25, 28, 30) did not catch a larger proportion of individuals below reproductive size but, rather, smaller species. The 43 mm mesh, caught larger individuals with lower total biomass but of larger species, with similar proportions of individuals below reproductive size to smaller mesh sizes. Net mesh size was not associated with fisher revenue. Trammel nets were found to be the least selective in relation to non-commercial by-catch, although the proportion of mature individuals in the catch was larger than for the other nets examined. These findings suggest that mesh size restrictions, across the range of mesh sizes examined, will not result in a decrease in catch of individuals below reproductive size but rather shift the species composition of the catch towards large-bodied, often high trophic level, species. Thus, mesh size restrictions are unlikely to rebuild fish stocks of high-value commercial species nor increase fisher revenue. We suggest that artisanal fisheries management in the Levantine Basin should evaluate new management measures and consider reducing overall fishing pressure along with implementing ecosystem-based fisheries management, such as the closure of fish reproduction and recruitment areas and establishment of marine protected areas.