Variaciones temporales en la composición y abundancia de cuatro especies de Cancer (Decapoda: Brachyura: Cancridae) capturadas con trampas en bahía San Vicente, Concepción (Chile central)

Abstract

This study analyzes the composition and distribution of the main brachyuran decapod crustacean species caught by small-scale fishermen in the coastal area off the Hualpen Peninsula (Concepcion). These patterns were then compared and related to variations in temperature and extraction depth. The catches throughout the year were basically represented by four Cancer species, especially in autumn 2003, when C. porteri was most abundant. This species was under-represented during the rest of the year and dominant again the following summer. C. coronatus, C. setosus, and C. edwardsi were not very abundant in summer, but appeared in greater quantities during the rest of the year. This variation in species composition and spatial distribution of the catches was related to seasonal migrations, which were associated with the occurrence of bad weather fronts that affect the area in winter. The significant relationships between abundance and temperature support the occurrence of these migrations. Moreover, experiments (catch, marking, re-catch) were done to determine the population parameters of the species under study. Although the general re-catch rate was very low, the results suggest a high degree of mobility.