Abstract

The present study aims to describe the population dynamics and state of the fishery of the mud cockle Anadara tuberculosa (locally know as piangua) in three harvesting areas along the Pacific coast of Costa Rica (Chomes, Purruja and Rincón) and to put the results in context with this species in other Costa Rican areas as well as with other Anadara spp. around the globe. The study is based on a five-month sampling period from October, 2003 through April, 2004 during which monthly length frequency measurements and tagging experiments were carried out. Von Bertalanffy growth parameters, K and L∞, (0.14 and 63.15, respectively) revealed a growth performance (f’= 2.75) which is in the range of reported values for this family of bivalves, indicating the accuracy of these values. Estimated exploitation rates range from 0.62 (Rincón) to 0.76 (Purruja) and exceed sustainable levels at all study sites. The strong overharvesting in these areas, also mirrored by the low average harvested cockle sizes relative to less exploited areas of Costa Rica and elsewhere, is due to the relatively small clam populations in each fishing area, the easy accessibility and the high economic importance of the species to the local resource users. If conservation measures are not implemented it is probable that A. tuberculosa may follow its formerly abundant and bigger sister species, Anadara grandis (chucheca), on its way to local extinction. Rev. Biol. Trop. 54 (Suppl. 1): 87-99. Epub 2006 Sept. 30.
Keywords: Anadara tuberculosa, bivalve, Costa Rica, Golfo Dulce, Gulf of Nicoya, mangrove, phi prime, small scale fishery, von Bertalanffy