Maturation and induced spawning of the mangrove red snapper (Lutjanus argentimaculatus) reared in a floating net cage in the Philippines

Abstract

Wild-caught mangrove red snapper (Lutjanus argentimaculatus) were reared in a floating net cage at SEAFDEC/AQD's Igang Marine Substation at Guimaras Island, Central Philippines. In 1993, monthly samplings and induced spawning trials were conducted as part of a project on seed production. Gonadal development began in February for males and April for females, reached a peak in September and declined in December. Males and females had ripe gonads for up to 5-6 consecutive months. Spawning occurred in the evening (2000 to 2300 hours), 32-36 hours after a single intramuscular injection of 1,500 IU human chorionic gonadotropin kg^-1 body weight (BW). About 0.53-2.14 million eggs were collected per female (2.5-4.4 kg BW) with fertilization rates of 21-97% and hatching rates of 42-80% resulting in 30-85% normal larvae (straight and without deformities). The results strongly suggest the feasibility of breeding mangrove red snapper in floating net cages.