EFFECTS OF EGG DISINFECTION ON YOLK-SAC AND 1ST FEEDING STAGES OF HALIBUT (HIPPOGLOSSUS-HIPPOGLOSSUS L) LARVAE

Halibut eggs were treated with the disinfectant glutaric dialdehyde in two regimes, 400 ppm for 10 min and 800 ppm for 2.5 min. Treatment effects were evaluated by analyses of egg mortality, performance of deformed larvae, survival during the yolk-sac period, and growth and survival during first feeding. To evaluate effects of disinfection on the first feeding stage, two separate feeding regimes, Artemia salina and wild zooplankton, were tested. No significant differences in survival or percentage of deformed larvae were found between the larval groups during the yolk-sac period. Differences in survival appeared during start feeding where eggs exposed to 400 ppm glutaric dialdehyde showed significantly higher survival than did the 800 ppm and control (untreated) group on both food types. The 400 ppm group also showed higher growth, which was most pronounced with wild zooplankton.