Selectivity of viola Loricariichthys anus (Siluriformes: Loricariidae) fishery in Mirim Lagoon, RS, Brazil

Abstract

Mirim Lagoon is one of the main water bodies of the southern lagoon system in South America, which has water system shared between Brazil and Uruguay. The fishing activity developed in the region has decreased catch levels rates, leading fishermen to intensify continuously the fishing effort. Viola (Loricariichthys anus) is one of the most important native species for artisanal fisheries; therefore, it is necessary to study its natural stocks and the appropriate fishing effort. Thus, the goal of this work was to identify the more efficient mesh size in relation to economic and sustainable perspective for viola fisheries. It was used 10 gillnet of 60 mm, 10 gillnet of 70 mm and 10 gillnet of 80 mm between opposite internodes. Fishing was performed with all mesh sizes in an interleaved array, for a period of 12 hours in the evening, according to the local procedure. Total number of fish caught in each mesh size was distributed by class of total length and the selectivity was determined. The result indicates that 70 mm gillnet is more efficient, catching fish with minimum size higher than that of the first spawning, being, therefore, the most recommended for viola fishing in Mirim Lagoon, RS.