SPAWNING OF THE SILVER SEA BREAM, SPARUS-SARBA, IN CAPTIVITY

Spawning of the silver sea bream, Sparus sarba, in captivity was studi ed at ambient temperature and photoperiod during one breeding season. Broodstock were divided to two groups (A and B) of 6 and 7 individuals , respectively. They were caught in the sea and acclimatized to labora tory conditions for about seven months prior to spawning. Spawning las ted 65 days from April 8 to June 11 in group A, and 43 days from April 10 to May 22 in group B, within the temperature range between 13.5 an d 21.3 degrees C. Numbers of buoyant and sunken eggs, fertilization ra te of buoyant eggs and percentage of abnormally developed eggs were es timated daily. There was no correlation between water temperature at s pawning and viable hatch, and between spawning period and viable hatch , at the same incubation temperature in all cases. The total number of eggs released during the spawning period was estimated at 18.1 millio n in group A and 10.8 million in group B. Mean egg diameter tended to decrease during the spawning season along with increasing water temper ature. Mean egg diameter ranged from 0.952 to 1.001 mm and from 0.962 to 1.015 mm in groups A and B, respectively.