Reproductive Cycles in Atlantic and Mediterranean Populations of Venus nux Gmelin, 1791 (Bivalvia: Veneridae), from Southern Spain

ABSTRACT The recent reduction of catches of common shellfish in southern Spain has pointed out an overexploitation of these resources. For this reason, new shellfish resources have been investigated—among them, the venerid Venus nux Gmelin, 1791. To provide information to managers for a better regulation of this new fishery, we studied the reproductive cycle in the Atlantic (Huelva) and Mediterranean littoral (Malaga) of southern Spain from June 1999 to May 2000 using histology and changes in flesh dry weight. Histological examination of the gonads showed a long and asynchronous reproductive period. Spawning occurred throughout the year in both populations. Two different spawning peaks were observed: April/May for the Mediterranean population and June/July for the Atlantic one. These peaks correspond to the highest percentage of population in spawning stage, together with the greatest loss of tissue weight. During the annual reproductive cycle, new activation of the gonads from postactive stages occurred ...