Reproduction of the sea urchin Pseudechinus magellanicus (Echinoidea: Temnopleuridae) from Golfo Nuevo, Argentina

Pseudechinus magellanicus (Philippi, 1857) is a common and abundant sea urchin along the Argentinean coast. Gonad index cycle was studied for this species in Golfo Nuevo, Patagonia, from May 2001 to March 2003. Comparative studies of gonad index and gonad histology were performed for the year 2002. Gonad index reflects gonadal stages, showing two spawning peaks for the studied period. Major spawning occurred in winter and a second spawning event occurred during summer. Males and females spawned synchronously. Male gonads recovered faster than females after spawning, suggesting that females invest more time and energy in gametogenesis. Gonads were resorbed by both sexes. Gonad index was negatively correlated with photoperiod and water temperature with a lag period of 3 mo.