Bathymetric distribution of Thaisella chocolata (Duclos) in Guañape Norte Island - La Libertad, Peru. March 2016

Abstract

Thaisella chocolata chocolate rock shell, whose indicators suggest taking measures to avoid overexploitation, is one of the most important resources for extraction in La Libertad Region. The aim is to know its distribution in the North Guañape Island, to determine the type of distribution, size structure, sex, stage, and sex ratio. Information from the survey carried out in March 2016 by the Huanchaco Coastal Laboratory was used. Dispersion indices, density (ind/m2), biomass (g/m2), sex ratio, and gonadal maturity stages were calculated. The chocolate rock shell was recorded up to a depth of 20 meters with minimum densities. High percentages of individuals below the minimum catch size (MCS) were recorded at all depth levels. The space distribution showed an aggregated pattern, higher densities and biomasses were located in the range of 10 to 15 m of depth. The sex ratio was equal at 5 m and between 10 and 15 m was favorable to females; the predominant stage was maximum maturity.