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 ef fects were evaluated by analyses of egg mortality, performance of defo rmed larvae, survival during the yolk-sac period, and growth and survi val during first feeding. To evaluate effects of disinfection on the f irst feeding stage, two separate feeding regimes, Artemia salina and w ild zooplankton, were tested. No significant differences in survival o r percentage of deformed larvae were found between the larval groups d uring the yolk-sac period. Differences in survival appeared during sta rt feeding where eggs exposed to 400 ppm glutaric dialdehyde showed si gnificantly higher survival than did the 800 ppm and control (untreate d) group on both food types. The 400 ppm group also showed higher grow th, which was most pronounced with wild zooplankton.