During the past few years, including the flood year of 1973, 

 the shrimp catch statistics of the north central Gulf of Mexico, 

 the area of greatest production in North America, have reflected 

 the influence of an above average supply of fresh water. The total 

 hydrographic data may be available for a broad analysis of this 

 general question, although it had not been made, but at least with 

 the present data we are in a much better position to give some ex- 

 planation of how populations of this abundant fishery species, the 

 brown shrimp, are influenced by salinity and temperature changes. 

 We may even see the hope of an approach to a predictive situation 

 of some reliability, which in a sense is a major goal of fisheries 

 and wildlife management, as set forth in the broader view by John 

 Stuart Mill (1848), who said, "Of all truths relating to phenomena, 

 the most valuable to us are those which relate to their order of 

 succession. On a knowledge of these is founded every reasonable 

 anticipation of future facts, and whatever power we possess of in- 

 fluencing these facts to our advantage." 



The above remarks concern large general or regional phenomena; 

 but there is another approach to the effects of temperature and 

 salinity changes and that concerns the more local changes of river 

 basins. Some studies have been made by the Louisiana Department of 

 Wildlife and Fisheries (White 1975) in individual estuarine drainage 

 basins . 



It would seem, for instance, that an examination of the Tennessee- 

 Tombigbee project as a local work, in the light of some of the above re- 

 sults, may yield information of value for operation of this project 

 within the General Design Memorandum. After all it sits on the 

 fourth largest drainage basin of North America and Mobile Bay is a 

 productive fishery area. In fact we may suggest, in the light of these 

 results that any large project within the shrimp productive area of the 

 southeast coast of the United States might be examined with some profit 

 in the planning stage. 



301 



