CULTURE PARAMETERS, GROWTH AND MORTALITY OF HALIBUT (HIPPOGLOSSUS-HIPPOGLOSSUS L) YOLK-SAC LARVAE IN UPWELLING INCUBATORS

Halibut yolk sac larvae were raised in upwelling incubators with different rates of continuous flow. Rate of mortality increased with increasing rate of flow, but in a stagnant incubator there were no surviving larvae beyond Day 12 after hatching. Larval dry weight decreased with increasing rate of flow, whereas yolk sac dry weight did not differ significantly. Hence, yolk sac utilization efficiency was higher with lower flows. The number of bacteria in the stagnant incubator increased rapidly from Day 3. In the incubators with flow, the accumulation of bacteria was delayed, and did not exceed 10(6) bacteria per ml before Day 16.