Reproduction of the lion's paw scallop Nodipecten subnodosus sowerby, 1835 (Bivalvia: Pectinidae) from Laguna Ojo de Liebre, B.C.S., México

Knowledge of the reproductive cycle of marine invertebrates of economic importance is essential for management of natural stocks and to initiate aquaculture activities. The reproductive biology of Nodipecten subnodosus from Laguna Ojo de Liebre, B.C.S., Mexico, was studied during a period of 25 mo. N. subnodosus is a functional hermaphrodite in which the follicles contain gametes of only one sex and remain separated from those containing the gametes of the other sex, with female follicles being dominant. Histologic evidence revealed that the lion's-paw scallop may remature at least once during the reproductive season. The temperature, analyzed as a single factor, could be important in the initiation of gametogenesis and/or as a spawning stimulus. The reproductive cycle shows a clear seasonality related to the water temperature, which is supported by the temporal variation of the oocyte diameter and by a significant positive correlation between GSI and temperature. The inactive period occurs from December to March, with low water temperature (16°C to 17.5°C). The gametogenesis started when the water temperature reached 18°C (April). The maximum maturation (90% to 100% of organisms) was reached in August when the temperature was highest (23.5°C). Spawning occurred in September when water temperature decreased. A slight reproductive activity during the cooler months (December to March) was observed. But, during 2002 the reproductive activity in that period was more pronounced and the slight spawning activity was extended to May. This behavior was in accordance with temperature anomalies that occurred in 2002. Then, N. subnodosus is potentially capable of spawning throughout the year if the environmental conditions are favorable. The length at first maturity obtained for N. subnodosus was 135-mmSL.