Estructura y variación estacional de poblaciones de moluscos asociadas a la pesca artesanal de langosta en el Pacífico Tropical

Abstract

Mollusks associated to the spiny lobster fishery during 1997-1998 in the Tropical Pacific were surveyed. A total of 1 081 specimens of 11 species were collected. The greatest captures were in autumn 1997 (28.16%) and summer 1998 (25.58%). Dominant species were Hexaplex nigritus (Philippi 1845) (83.10%), Chicoreus regius (Swainson 1821) (8.04%), Vasum caestus (Broderip 1833) (2.12%), C. brassica (Lamarck 1822) (1.85%) and C. erythrostomus (Swainson 1831) (1.75%), which have commercial importance. Weight-height ratio, sex ratio and height frequency histograms were done for dominant species. Sex ratio was 1:1, except for C. erythrostomus and H. nigritus (2 males: 1 female); C. regius, C. erythrostomus and V. caestus presented an allometric growth while H. nigritus and C. brassica grew isometrically. Only H. nigritus males were larger than conspecific females. There were significative differences in species distribution in relation with depth; C. erythrostomus occurred in deepest layers while H. nigritus was more superficial; H. nigritus size differed with depth, temperature and locality.