Vital statistics and embryo and larval viability were determined for winter flounder Pseudopleuronectes americanus spawning in Narragansett Bay, Rhode Island, USA, over the course of the spawning season. Fish approaching spawning condition were collected throughout the spawning season and hand-stripped in the laboratory. Larvae were reared through the first month of life. Female size affected most of the reproductive parameters examined, including both absolute and relative measures of total reproductive output (reproductive rate and gonadosomatic index), e g g size, fecundity, and viability. Spawning time was found to affect e g g size, fecundity, and viability, but not reproductive rate or gonadosomatic index. Egg size increased with increasing female size and decreased as the spawning season progressed. Spawning time and female size explained 61 O/ O of the observed variability in egg size among females. Female size explained 95 % of the variability in reproductive rate and 90 % of the variability in fecundity. Female size and spawning time combined explained 9 4 % of the variability in fecundity. The effects of female size and spawning time on both fertility and hatch rate were non-additive. Embryos produced earlier in the spawning season appeared to have a survival advantage over those produced later in the spawning season. Embryos produced by small, latespawning fish appeared to be at a pronounced disadvantage.

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Winter flounder Pseudoplellronectes americanus collected a t selected locations in LongIsland Sound (LIS). New York, and Narragansett Bay (NB). Rhode Island, USA, were spawned in the laboratory and the larvae reared for a month after hatching. In 1987 the average size of yolk-sac larvae varied widely among locations. Moreover, a direct correlation was observed between size of yolk-sac larvae and survival for the first month of life. Fish from NB produced the smallest larvae with the lowest survival rate. The Madison site In LIS produced the largest ydlk-sac larvae with the highest survival rate. Size and biochemical composition (~t g larva-') of yolk-sac larvae were correlated. Dry weight and RNA content were the best predictors of survival potential among the variables considered (protein, DNA, lipid content, and RNA/DNA ratio). In 1988 little difference was observed in viable hatch or welght of yolk-sac larvae among locations. While no signlflcant difference in larval survival was observed between NB and LIS fish, survival was higher in the Madison group than the Morris Cove group from LIS. These data suggest that when differences in size among newly hatched larvae are sufficiently large, survival potential can be affected.