La pesquería de vieira tehuelche, Chlamys tehuelcha (d'ORB., 1846), del golfo San José (Argentina): abundancia de clases anuales
Néstor F. Ciocco, Diana A. Aloia

THE FISHERY OFTEHUELCHE SCALLOP, Chlamys tehuelcha (D’ORB., 1846) FROM SAN JOSE GULF(ARGENTINA): YEAR CLASS STRENGTH. - Three exceptionally strong year-classessettled at regular intervals (1970-1975-1980) on one of the main grounds of San Jose Gulf (San Roman). Density dependence of larval settlement has been suggested as ahypothesis to explain this phenomenon. The aims of this work were: a) to renewthe monitoring of the main populations (interrupted in 1983), adding data onpostlarval settlement on artificial collectors, and b) to discuss the consistencyof the year-class strength pattern with the density-dependent larval settlementhypothesis. Five grounds were explored in February 1988; the only two groundswith significant scallop abundance (San Roman, N, and Tehuelche, SE) wereperiodically monitored until April 1989. Polyethylene monofilament collectorswere employed at San Roman, Tehuelche and Logaritmo (S-SW) during the 1988 and1989 settlement periods. The San Roman mean density (x = 5.60 scallops m-2,s = 3.68)was similar to that of Tehuelche (x = 4.53 scallops m-2, s = 3.01.San Roman ground was mainly constituted by scallops settled in 1987, while onTehuelche ground scallops 1+ to 5+ were equally represented. In both kinds ofyear, the mean numbers of larvae captured were distributed as follows:Tehuelche San Roman Logaritmo. The abundance of larvae was greater in 1988 thanin 1989 at all 3 localities. The multi-year cycle of San Roman (1970-1975-1980) continued with a strong year-class, probably settled in 1984, and another onesettled in 1987. The density-dependence of larval settlement should operate ona local scale at each ground, and should explain only a small fraction of thevariability of each population. The data suggest that larval availability isgoverned at a larger comprising the whole Gulf.

Keywords: Pectinidae, fishery, year-class strength, density-dependent larvalsettlement, metapopulation, southwest Atlantic, Argentina
Contents of this volume Sci. Mar. 55(4) : 569-575 Back PDF
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