Growth and fisheries of the Black Ark Anadara tuberculosa, a bivalve mollusk, in Bahia Magdalena, Baja California Sur, Mexico

Abstract

In order to determine the trends in the landings and growth of the pustulose ark or black ark Anadara tuberculosa (Mollusca; Bivalva) in the Bahía Magdalena – Almejas region, at the Baja California peninsula’s southwestern coast, Mexico, catch statistics recorded by artisan or small-scale fishermen are analyzed from 1992 to 2002, as well as size-frequency distributions of samples taken from commercial catches from November 1998 to December 2000. Catch data reveal considerable fluctuations along with a trend towards decline. No defined seasonal exploitation pattern was observed, but on average the months with the highest catches coincide with the highest reproductive activity. Evidence was found of a decrease in black ark density, which might be accounted for by the fishery. The parameters derived from the von Bertalanffy growth equation confirm that individuals reach the minimum catch size of 60 mm in a little more than one year. Catch sizes ranged between 40 and 80 mm.