IMPROVED SEED PRODUCTION OF GOLDSTRIPED AMBERJACK SERIOLA-LALANDI UNDER HATCHERY CONDITIONS BY INJECTION OF TRIIODOTHYRONINE (T-3) TO BROODSTOCK FISH

Survival of the seed of goldstriped amberjack Seriola lalandi was cons istently enhanced by intramuscular injection of triiodothyronine (T-3) to the broodstock fish at a dose of 20 mg/kg body weight. Survival ra tes at the time of transfer to net cages (35 d after hatching) were 2. 6-5.0% for the T-3 treatment while only 0.3-2.1% for the control. Surv ival rates 36 mo after hatching was estimated to be 12 times higher in the T-3-treated group (1.1%) than in the control (0.09%), T-3 concent ration in newly spawned eggs increased from control levels of 0.3-1.0 ng/g to 68-127 ng/g 2 d after injection and subsided with successive s pawns. T-3 concentration in the treated larvae was about 360 times hig her than in the control upon hatching (29 ng/g vs 0.08 ng/g), but beca me indistinguishable from the control 6 d after hatching. These result s indicate injection of T-3 to the broodstock of S. lalandi to be of p ractical value in aquaculture of the species.