LONG-TERM SURVEY ON WILD AND CULTURED MUSSELS (MYTILUS-GALLOPROVINCIALIS LMK) REPRODUCTIVE-CYCLES IN THE RIA DE VIGO (NW SPAIN)

The gonadal development of cultured and wild mussels (Mytilus gallopro vincialis) was studied in several localities of the Ria de Vigo (NW Sp ain) from December 1987 to June 1993. In the mussel populations examin ed, a stable reproductive pattern, with minor variations, was found. G ametogenesis takes place in late autumn and early winter. In late wint er, gonad follicles are full of ripe gametes and some spawns may occur . However, the peak of the spawning season occurs in spring, coincidin g with an increase in temperature in the area. After the first spawns, the gametogenesis begins again, quickly reaching new spawning conditi ons. Several spawns may occur until early summer. During late summer a nd autumn, there is a storage of reserves that will be used for the ne xt gametogenesis. (C) 1998 Elsevier Science B.V.