Reproductive biology of Lithodes santolla in the San Jorge Gulf, Argentina

Reproductive biology of Lithodes santolla in the San Jorge Gulf, Argentina

J.H. Vinuesa and P. Balzi

Reproductive biology of Lithodes santolla in the San Jorge Gulf, ArgentinaThis is part of Crabs in Cold Water Regions: Biology, Management, and Economics
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Description

The southern king crab (SKC) or "centolla" (Lithodes santolla) is a common crab throughout the southeastern Pacific Ocean (southern Chile), Fuegian Archipelago and the southwestern area of the Atlantic Ocean. The reproductive biology of SKC in the San Jorge Gulf (45-48ºS) was studied on a bimonthly sampling basis during 1994-1996 and on a monthly basis during 1998-1999. Samples were obtained with trawling bottom nets at depths between 26 and 90 m, about 0.5 to 12 miles offshore.

The reproductive activities are annual in all mature females. These begin in November and extend until late December, but there are differences between years. Mating normally occurs between a recently molted female and an intermolt male of larger size. Timing of reproductive events is the same in females reproducing for the first time and those that have brooded eggs previously.

Larval hatching was observed mainly between September and October indicating that embryo genesis lasts nearly 10 months. Fecundity increases with carapace length (CL) ranging from 1,965 to 29,100 eggs, but is variable in crabs of similar size. These females are less fertile compared with other areas of the SKC distribution, due to the smaller proportion of ovigerous females and a smaller clutch size. Maturity was observed in females as small as 60 mm of carapace length.

Seasonal and daily movements of males and females occur. Mature crabs appear in aggregations in shallow nearshore waters between late October and November for female molting and mating. After fertilization crabs began to migrate again to deeper waters.

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