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Survival, growth, and starvation times were studied in summer flounder Paralichthys dentatus larvae hatched in the laboratory at 12.5 and 21*C. The observations spanned the time interval from hatching throughout the period of feeding on rotifers. Survival and growth in length and weight were strongly dependent on water temperature and delay of the initial feeding. At either temperature, the percentage of summer flounder larvae surviving beyond the rotifer phase increased if food was made available at the time of mouth opening. At 12.5*C, hatching started 85 h after fertilization. All feeding delays resulted in 2 separate periods of mortality, which caused low final survival. The point of no return ranged from 11 to 12 d after hatching. Larvae fed at mouth opening showed a maximum survival of 40%. No significant growth in length or weight was evidenced by any group at 16 d after mouth opening. At 21*C, hatching started 60 h after fertilization. Larvae fed at mouth opening showed 90% survival and significant growth in length and weight in 10 d. A delay of 48 h in initial feeding led to a final survival of 36%, but also resulted in significant growth. Time to the point of no return was 6 to 7 d from hatching. These results illustrate the interdependence of temperature and food availability and their effects on survival and growth of summer flounder larvae. These observations provide crucial information for the development of a culture system for this species and demonstrate the strong influence of the temperature-food relationship on larval survival and growth, suggesting that this relationship is a determinant of recruitment in certain areas of the ocean


David A. Bengston is from Department of Zoology (University of Rhode Island)