Gonadal development in males of Notocrangon antarcticus (Decapoda: Caridea) from the Weddell Sea, Antarctica

Our knowledge on reproductive traits of marine decapods is mainly based on studies concerning reproductive features of females, while the description of trends in reproductive cycles for males are scarce. Here, we analyzed the gonad development and the seasonal variation of the gonadosomatic index (GSI) of male Notocrangon antarcticus (N = 106; collected between 1986 and 1992; Weddell Sea), one of the most common caridean shrimp inhabiting the Antarctica. Male size ranged from 10.2 to 17.7 mm CL (carapax length), and individuals were significantly larger in autumn. The length of appendix masculina increased with male size, and there was no evidence for sex reversal, corroborating the assumption of dioceism in N. antarcticus. The average dry weight of the males was highest (mean 0.39) in autumn. The highest and lowest gonad dry weights were obtained from summer samples; however, we did not detect significant differences among seasons. The highest mean GSI was calculated for individuals collected in summer, and mean GSI was significantly different between summer-autumn and summer-spring, but not in autumn-spring. The GSI remained practically constant, independent of male CL. The size at sexual maturity was 13.8 mm CL, a size smaller than previously reported for N. antarcticus. The results obtained demonstrate that peak reproductive productivity of male N. antarcticus is during the summer months, when abundant nutritional resources are available.