Seasonal variations in condition, reproductive activity, and gross biochemical composition of two species of adult clam reared in a common habitat: Tapes decussatus L. (Jeffreys) and Tapes philippinarum (Adams & Reeve)

Abstract

The condition, reproductive activity, and gross biochemical composition of an indigenous and an introduced adult clam population raised in acommon habitat of the French Atlantic coast were examined over a 74-wk period. The indigenous species, Tapes decussatus L. (Jeffreys) and the introduced species, T. philippinarum (Adams & Reeve) were raised together on the south Finistère coast of Brittany. The gross biochemical composition of a standard animal of each population was significantly correlated with the population condition indices. During the winter, no reproductive activity was observed in either population, and the contribution of protein, glycogen, and lipids to the maintenance energy was calculated. Protein formed the main reserve, while lipids contributed as much as glycogen in T. decussatus, and twice as much in T. philippinarum. Although some species differences were noted in the mean levels of biochemical components, the overall seasonal variations were similar in both populations.