FISHERY BULLETIN: VOL. 73, NO. 1 



larvae should be reared at one set of conditions 

 from fertilization to veliger stage and then 

 transferred to another set of conditions for the 

 late stages. Juvenile clams may have yet another 

 set of optimum conditions different than those of 

 the late larval stage. The larvae and the adults 

 are tw^o distinct morphological and physiological 

 organisms and occupy distinctly different ecologi- 

 cal environments. 



Recent work by Costlow and Bookhout (1971) 

 on the cyclic effect of temperatures on the larval 

 development of an estuarine mud crab, Rhithro- 

 panopeus harrisii, emphasizes the need for more 

 research on the fluctuating environmental var- 

 iables that normally occur in nature. The possible 

 stimulating or inhibiting effect of fluctuating 

 temperatures on bivalve larval survival and 

 grow^th in relation to both pollution and aqua- 

 culture should be investigated in the future. 



ACKNOWLEDGMENT 



This research was supported in part by the 

 National Oceanic and Atmospheric Administra- 

 tion (maintained by the U.S. Department of 

 Commerce) Institutional Sea Grant 2-35187. 



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Alderdice, D. F. 



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