CONICET | Buscador de Institutos y Recursos Humanos

In Southern South America, fishing for king crabs began in the 1960s, basic management rules were put in force in the 1980s, which were supported by studies done in the 1990s. Although size and sex selection, and a limited season were imposed to the mixed fishery for Lithodes santolla and Paralomis granulosa of the Beagle Channel, the fishery for the more valuable L. santolla has collapsed, closed, and is recovering very slowly. One of the solutions for the recovery of wild stocks is the population restocking. We have studied larval biology and settlement, as bases for restoring natural population with small crabs by using techniques of cultivation and release. Lithodes santolla larvae hatch once a year and their development is completed in fully lecitotrophy, without ingestion of external food. Development to crab I stage is strongly dependent on temperature and lasts from 20 to 120 days at 15ºC and 3ºC, respectively. Survival to megalopa is also dependent on temperature, with higher survivals at 6 and 9ºC. The highest molting frequency is attained at higher temperatures, and after 180 days individuals reach the crab III and VII stages of about 3 and 6 mm CL at 6 and 15ºC, respectively. Artificial collectors gather young-of-the-year crabs at <40 m depth. In cultures in 1,4 l-containers, the best survival to megalopa of 35% was obtained at the lowest tested density of 71 larvae·l-1. A survival to megalopa of 65% was attained in aerated containers of 10 l with inspections only at the molting time. Recently molted megalopae avoid sandy bottoms, and prefer mussel shells and rocks which provide three-dimension substrata. The next phase of crab enhancement research needs to include cultivation at a large scale, costs, releasing procedures (what stages, where, when and who), techniques for identification of released crabs, and effectiveness of such a program.

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