Induced spawning of sea bass, Lates calcarifer, and rabbitfish, Siganus guttatus, after implantation of pelleted LHRH analogue

Abstract

Captive Lates calcarifer broodstock at Tigbauan, Iloilo (Philippines) were implanted with cholesterol-based pellets of the LHRH analogue D-Trp⁶-desGly¹⁰-LHRH ethylamide or D-hArg(Et₂)⁶, Pro⁹-NHet-LHRH at doses between 9.0 and 23.5 μg/kg body weight. In May, one of ten LHRH-treated females released partially hydrated ova into the tank 4 days after implantation. In July, at least one (and probably four) of five LHRH-treated females spawned in the tank 2 days after implantation; 2.6 million hatchlings were collected. In August, both LHRH-treated females spawned in the tank 2 days after implantation; 978 000 hatchlings were collected. None of the sham-operated control fish spawned in any of the experiments.

Captive Siganus guttatus broodstock implanted with silastic-based pellets of the LHRH analogue D-Nal (2)⁶LHRH spawned 1–2 days earlier than sham-operated controls.