Winter flounder Pseudopleuronectes americanus reproductive success. I Among-location variability in size and survival of larvae reared in the laboratory

Winter flounder Pseudoplellronectes americanus collected a t selected locations in Long Island 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.