Spawning of Red Snapper (Lutjanus campechanus) in Response to Hormonal Induction or Environmental Control in a Hatchery Setting

Abstract

Red snapper (Lutjanus campechanus) is a popular marine sportfish and is a significant part of the commercial fisheries in the Gulf of Mexico. It can be reproduced under hatchery conditions by induced spawning of wild-caught adults or by conditioning wild-caught adults to spawn naturally under controlled conditions. Mature females (Gondosomatic Index ω 1) occur in the northern Gulf of Mexico from May to September. When such females were collected off the Alabama coast and induced to spawn with HCG, 56 ± 17.3% of the females ovulated. Fecundity (ovulated floating eggs) varies, for 60 spawns averaged 197,212 ± 173,349 eggs/kg female. Percent hatch averaged 42.1 ± 3.44%. Wild-caught adult red snapper can be held in confinement and natural spawning obtained when temperature and photoperiod are controlled. Adult snapper held in 13.2-m3 tanks (8–10 fish/tank), where photoperiod and temperatures were adjusted, spawned naturally 63 times over a 105-day period, with a mean egg production/tank of 4.2 million eggs. Mean fertilization rate, hatch rate, and survival at 36–40 hph were 90.5%, 83%, and 49%, respectively. Natural spawns produce better quality seed, but the occurrence of fertilized spawns is unpredictable. Hormone-induced spawns are easier to schedule but egg quality can be variable.