Reproductive cycle of the bivalve Lima scabra (Pterioida : Limidae) and its association with environmental conditions

We examined the reproductive cycle of a tropical bivalve, the fire scallop Lima (Ctenoides) scabra (Born, 1778), over a 14 months period in the Golfo de Cariaco, Venezuela, and the association of gonadal growth and spawning w ith environmental factors. Most small individuals were males and most large individuals females, indicating the protandrous characteristic of this spe cies. We documented three marked decreases in gonadal mass, from late Octob er to December 1992, from early June to early July 1993 and from late Octob er to early December 1993, and all were associated with drops in temperatur e related to renewed upwelling. This suggested that major synchronized spaw nings were stimulated by drops in temperature or other factors related to t he onset of upwelling. Multiple regression analyses indicated that the majo r environmental factor associated with increases in gonadal mass was phytop lanktonic food availability. Analyses of regressions of mass of somatic tis sues to shell height suggested decreases in reserves in somatic tissues at the end of the November-December spawnings, but not at the end of the June- July spawning. This may be because body reserves are used for reproduction during November and December when phytoplanktonic food availability is low.