THE COMBINED EFFECT OF TEMPERATURE 



AND DELAYED INITIAL FEEDING ON THE 



SURVIVAL AND GROWTH OF 



LARVAL STRIPED BASS 

 Morone saxatilis (WALBAUM) 



Bruce A. Rogers 



Graduate School of Oceanography 



University of Rhode Island 



Kingston, R.I. 02881 



Deborah T. Westin 



Graduate School of Oceanography 



University of Rhode Island 



Kingston, R.I. 02881 



ABSTRACT 



Rearing temperature and the time of first feeding interact to determine the 

 degree of survival and rate of growth in larval striped bass. Between 15 and 

 27^C, temperature affects the rate of growth and development in fed groups, 

 and the time to death by starvation in unfed lots. Delayed first feeding retards 

 structural development. The 'point-of-no-return' in striped bass is very near the 

 stage of complete mortality due to starvation. Unfed groups survived up to 22 

 days after hatching at 24°C and 32 days at 15°C. Larvae fed late into 

 starvation survived and continued to grow at a rate somewhat higher than that 

 observed in earlier fed groups at all temperatures. Larvae which has survived 

 delayed development were indistinguishable on the basis of external 

 morphology from much younger individuals reared under more favorable 

 conditions. The effects of nutritional and thermally induced developmental 

 retardation are discussed in terms of how they may affect larval growth and 

 mortality rate estimates used in assessing the effects of estuarine power plants. 



INTRODUCTION 



Many estuarine and marine fish species, including the striped bass, Morone 

 saxatilis (Walbaum), produce large numbers of relatively small pelagic eggs at 

 spawning. These smaller eggs contain fewer yolk reserves. After a relatively 

 short incubation period, they hatcn into prolarvae that are, in general, at a 

 more rudimentary stage of structural development than those of species 



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