Species composition in the artisanal gillnet fishery of chilean hake Merluccius gayi gayi in central Chile

The species composition in commercial fisheries is important information to establish management measures that contributed to reduce the impact and ensure the sustainability of the activity. A study was conducted to identify and quantify the species caught in the artisanal gillnet fishery of Chilean hake (Merluccius gayi gayi) between January and September of 2010. The capture was registered in 98 fishing sets performed by 45 fishing vessels of 14 artisanal ports distributed between the Valparaíso and Biobío regions. The target specie was the most important species caught in all regions. The presence of 24 taxa as by-catch was registered nevertheless only 4 species had a relative frequency of occurrence higher than 50% of sets performed in some of the regions. These species were lemon crab (Cancer porteri), armed box crab (Platymera gaudichaudii), red squat lobster (Pleuroncodes monodon) and big eye flounder (Hippoglossina macrops), which accounted the highest proportion (>70%) of total by-catch in number. Through classification and ordination methods based on species composition, 4 groups related to geographical regions and bathymetrical range were determined, while the mesh sizes used in the gillnets would have a minor influence on the explanation of the identified groups.