Effects of broodstock diets on growth of larval Atlantic cod ( Gadus morhua L.)

A previous study using two commercial pelleted diets (broodstock and on-growing diets) and a baitfish diet to feed hatchery-reared Atlantic cod ( Gadus morhua ) broodstock revealed higher growth and size of spawners as well as higher fertilization and hatch success in the group fed the baitfish diet, but no differences in egg diameter or blastomere normality. In the present study, we explore differences in condition and growth of cod larvae to assess the effect of the abovementioned broodstock diets on offspring using protein-specific growth rates and RNA/DNA ratios (RNA/DNA). Changes in RNA/DNA with time (after 7 days post-hatch) were significantly lower in the broodstock diet group compared with the other two groups, suggesting a lower feeding condition and growth potential. However, our results show no differences in growth and survival up to 49 dph between the larvae originating from broodstock fed the three diets. Contrary to other authors’ findings, we found no correlation between the RNA/DNA and instantaneous growth rates possibly due to the variability in growth observed within diet groups. Our results provide information about the effects of broodstock diets on early larval growth and survival of Atlantic cod.