Abundance and distribution of the deep-sea crab Chaceon ramosae (Decapoda: Geryonidae) in southern Brazil: Contribution to the fishing regulation

Abstract

The deep-sea crab Chaceon ramosae occurs at 350-1200 m depth in the southeast and south of Brazil. Here we evaluated the latitudinal, bathymetric, and seasonal abundance of C. ramosae in southern Brazil obtained during several research cruises. We also obtained populational data to evaluate the effectiveness of the fishing regulations for C. ramosae. Five sampling cruises were carried out in 2009-2010 and the sampling effort comprised 32 fishing hauls with four pots per mainline. In total, 195 individuals were caught, 128 males and 67 females, of which 17 were ovigerous. The highest catch per unit effort occurred between 29°03’ and 29°05’S at 800-1000 m in depth. The highest abundance occurred in winter, and almost all ovigerous females were captured in this season. The size at the onset of sexual maturity was estimated at 120 mm carapace width. Depth was the most critical environmental factor explaining C. ramosae distribution. The largest individuals, as well as the mature ones, were mainly captured in shallower regions (400-600 m). Our results confirm the need for prohibiting the fishing for C. ramosae at depths lesser than 500 m.