Size structure and sexual maturity of the golden crab (Chaceon chilensis) exploited off Robinson Crusoe Island, Chile

Abstract

Golden crab ( Chaceon chilensis ) specimens were analyzed after being caught with traps by artisanal fishermen off Robinson Crusoe Island, Juan Fernandez Archipelago, Chile. Of the 13,027 individuals caught between 300 and 1,000 m depth, 97.9% were male (12,754) and the rest female (273). The carapace length (CL) of the sampled crabs was measured and, on average, the males (CL: 118.9 mm) were larger than the females (CL: 94.3 mm). On the north side of the island, the specimens presented lower average sizes (112.2 mm) whereas, in the remaining zones, the average carapace lengths were similar (CL: 117.1-119.5 mm). In bathymetric terms, an increasing trend was seen between average size and depth, with sizes over 123 mm CL found beginning at 750 m depth. A comparison of linear regressions between the carapace length and chela length of males revealed physical maturity at 100 mm CL, whereas a numerical analysis showed the size at first sexual maturity (SSM 50% ) to be 109 mm CL.