Effect of Gonadotropin Releasing Hormone (Ovaplant-L) Dose on Induced Spawning of Female Striped Bass (Morone saxatilis)

Abstract

To identify the lowest effective dose to achieve spawning in striped bass, three doses of sGnRHa (Ovaplant-L; Syndel) were compared: 10, 30 and 70 µg kg-1, in triplicate. An experimental unit was a 1500 L tank stocked with 1 female and three male striped bass; with nine tanks total. Broodstock were ‘cold-banked’ at 12°C starting 24 May with increase to 18°C over 14 (Trial 1) and six (Trial 2) days. Oocyte maturation was slower than predicted, confounding effect of Ovaplant dose. Ovaplant-L injection resulted in 33.3% (6 of 18) females spawning. Seven required follow-up injection of hCG (350 IU kg-1; hCG). Remaining five failed to oviposite fertile oocytes. Three of four females who received 70 µg kg-1 Ovaplant-L and whose eggs were matured (≤15 Bayless hours) successfully spawned, compared to other treatment groups’ (3 of 5; 10 µg kg-1) (0 of 5; 30 µg kg-1) spawning success.