INDUCED SPAWNING IN BREAM, ABRAMIS-BRAMA (L), USING CARP AND BREAM PITUITARY EXTRACT AND HCG

Induced spawning in bream, Abramis brama (L.), was studied using aceto ne-dried common carp pituitary (CP) and bream pituitary (BP) with or w ithout the addition of human chorionic gonadotrophin (hCG). The total dose administered to fish was of 5.0 mg kg(-1) BP or 4.0 mg kg(-1) CP with or without 2000-2200 IU hCG kg(-1) for females and 2.5 mg kg(-1) BP or 2.0 mg kg(-1) CP with or without 1000-1100 TCT HCG kg(-1) for ma les. In all male treated groups 100% of spermiation was observed; in f emales the most effective method was a triple injection with hCG and c arp pituitary, resulting in 79% of females ovulated (over 68% of eyed eggs). Biological quality of eggs, expressed as a percentage of eyed e ggs, was negatively correlated with time elapsing between resolving (f inal) injection and ovulation. Spawning success, expressed as a value of S-e (spawning effectiveness coefficient), was higher in fish treate d with triple injection.