Effects of starvation at the first feeding stage on the survival and growth of walleye pollock Gadus chalcogrammus larvae

The effects of starvation at the first feeding stage on the survival and growth of walleye pollock Gadus chalcogrammus larvae were examined in rearing experiments performed in the laboratory. Newly hatched larvae grown at 2 °C, 5 °C, and 8 °C that commenced feeding at 3, 2, and 1 days post-hatching (dph) exhibited yolk exhaustion at 8, 8, and 5 dph and reached the point-of-no-return (PNR) at 15, 14, and 10 dph, respectively. Larvae kept at 5 °C were starved for 2–16 dph and then reared to examine the effect of delayed initial feeding on growth and survival. The larvae that were fed earlier grew better and showed higher survival rates. The time thresholds after which delayed feeding would prevent the larvae from growing and surviving were 2–3 and 0–1 days, respectively, before the PNR. Walleye pollock larvae have a long mixed endogenous and exogenous feeding period and relatively high starvation tolerance, as is typically observed in cold water fishes. Delayed initial feeding affects their survival and growth, even during the mixed feeding period. The availability of prey at the first feeding stage would have a critical effect on the stock size of this species.