Individual biomass and allometry of Mesodesma mactroides from the Southern coast of Buenos Aires, Argentina (Bivalvia, Mactracea).

FIORI, SANDRA MARCELA; CAZZANIGA NÉSTOR JORGE

Sao Pablo (Brasil)

Congreso; V CONGESO LATINOAMERICANO DE MALACOLOGÍA (CLAMA); 2002

Bivalves play an important role in the energy transference between the pelagic and benthic systems, to such an extent that they may regulate primary production directly, and may control secondary production of littoral ecosystems indirectly (Gili & Coma, 1998). In the exposed sandy beaches of the southern Atlantic, the yellow clam (Mesodesma mactroides) generally is the dominant species both in abundance and biomass (Defeo, 1983; Fiori, 1997; Olivier et al., 1971; Penchaszadeh, 1988). Equations to convert molluscan length to weight have been mainly used as a tool for estimating productivity of natural populations of commercially interesting species. These relationships also allow analyzing morphological changes associated to individual growth (Calow, 1975). Owing to their simplicity and relatively simple interpretation, exponential equations are generally used to describe allometric relationships (Gould, 1966; Seed, 1980). In this paper we present an assessment of the individual biomass of yellow clam individuals from the southernmost known population (Jabalí Island, 40º 33' S; 62º 14' W), obtained by equations relating shell length to shell width, and shell length to weight. These relationships were also used to explore morphological changes associated to growth.