Sexual maturity of the deep-sea red crab Chaceon notialis Manning & Holthuis, 1989 (Brachyura: Geryonidae) in southern Brazil
The red crab Chaceon notialis is one of the three deep-sea crab species currently exploited in Brazil. The red crab fishery started in 1998 with foreign vessels that, as of 2000, have been extensively moni-tored by observers and tracked by satellite. A management plan implemented in 2005 was based only on bio-mass dynamics, as biological knowledge of the resource was limited at that date. Samples taken aboard were used to determine size at first sexual maturity for males and females by studying the allometric growth of the chelae and abdomen in relation to the carapace width (CW), the proportion of females with opened vulvae and eggs in the pleopods, and males showing copula marks on the first ambulatory legs. Morphometric maturity was attained, on average, at 8.9 cm CW (males) and 8.8 cm CW (females). The CW5% was estimated to be 6.9 and 9.7 cm CW for females, considering the vulva condition and eggs in the pleopods, respectively, and 8.4 cm CW for males. The maximum estimated proportions of ovigerous females and males with copula marks by size class were 0.8 and 0.7, respectively, suggesting an annual reproductive cycle for the species, both at the populational and individuals levels. The size composition analysis showed that up to 97% of the females caught in the fishery were immature. Given these results, enhancing trap selectivity and minimizing the mortality of ovigerous females should be considered as new and immediate goals for the management of the resource.