relation to quantitative and qualitative changes in salinity 

 in their natural environment. 



To conduct laboratory studies on the survival or mortality 

 of "most important species" in a range wide enough to in- 

 clude lethal extremes. Rates of respiration in different 

 salinities and other physiological evidence of stress should 

 certainly be studied, as should rates of growth and repro- 

 duction in various nonlethal salinities. Adaptability to 

 changing salinity should be included in laboratory experi- 

 mentation (Ref. Effects of Engineering Activities on Coastal 

 Ecology, U.S. Army Corps of Engineers, August 1971), 



During the first phase of the studies carried out at this labora- 

 tory, the survival, growth, ionic regulation, and metabolic rates of 

 brown shrimp were determined in relation to salinity and temperature 

 changes. The present project is a continuation of phase one. Brown 

 shrimp were selected as the experimental species because of their 

 euryhalinity, their abundance in the commercial fisheries, and their 

 biological importance in the food chain of the estuarine community. 

 Their wide distributional range enhances their value as a key species. 

 They extend southward along the Atlantic coast from North Carolina to 

 Florida and westward to the Yucatan Peninsula in the Gulf of Mexico, 

 with the exception of the southwest Florida estuaries. They are now 

 the most abundant commercial shrimp. Selection of this species for 

 study has definite advantages over others with a more localized dis- 

 tribution. 



It should be noted, however, that the data obtained for brown 

 shrimp may not be applicable directly to the white and pink shrimp 

 except in a broad sense. This is because of the apparent differences 

 in the salinity and temperature requirements within the three species. 

 Gunter et al. (1964) have shown the presence of a positive correlation 

 between the salinity concentration and the abundance of three species 

 in the Gulf of Mexico. The authors found that the greatest amount of 

 white shrimp are produced in the low saline waters of Louisiana, the 

 greatest amount of brown shrimp in the saltier bays of Texas and the 



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