m 



n 



1 



Figure 22. — Technician drawing blood from shrimp heart. 



the blood may indicate a requirement .'or 

 continuous feeding to supply energy. 



Zoula P. Zein-Eldin, Project Leader 



GROWTH AND SURVIVAL OF 

 ESTUARINE -MARINE ORGANISMS 



This project is concerned primarily with 

 determining the short-term tolerances of post- 

 larval penaeid shrimp to salinity and tem- 

 perature, and the optimum conditions for 

 shrimp growth. During the year, we studied 

 the survival of postlarval white and brown 

 shrinnp exposed to selected con-ibinations of 

 temperature and salinity, and completed growth 

 experiments with two species of laboratory- 

 hatched shrimp. Studies also were made to 

 determine the effect of container size on 

 growth and survival of postlarval brown shrimp. 



Survival 



Three 24-hour experiments were made to 

 define the 80-percent survival limit of post- 

 larval white shrimp. Test temperatures ranged 

 from 7.5° C. (46° F.) through 37.5° C. (99° F.), 

 and salinities ranged from Z through 45 p.p.t. 

 Connbinations of salinity and temperature re- 

 sulting in 80-percent survival are shown in 

 table 9. 



We compared results of these experiments 

 with results of past experiments with brown 

 shrimp. Postlarval white shrimp withstood 

 higher temperatures and lower salinities than 

 postlarval brown shrimp. Conversely, young 

 brown shrinnp withstood lower temperatures 

 than did white shrimp. Most postlarval white 

 shrimp enter the estuaries later in the year 

 than brown shrimp and are normally subjected 

 to warnner water. In the Galveston area, juve- 

 nile white shrimp frequently penetrate the 



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