VI: EPILOGUE 



The information presented here confirms certain ideas concerning 

 life history previously discovered by studies in the field. In one 

 aspect it gives a physiological background and an explanation of some 

 ecological phenomena, more specifically the goings and comings, sea- 

 sonal cycles, size and growth, and distribution over an environment 

 with variable salinity and temperature limits, and the seasonal pat- 

 terns and cycles that are preeminent and dominant in life histories. 

 These patterns are not always regular and they undergo perturba- 

 tions that lead to variations close to or even beyond tolerable 

 limits of temperature and salinity at a given time and place. In 

 part this report defines some of these limits and variations. 



When the tolerable environmental limits are reached or trans- 

 gressed the result is catastrophe. These sometimes occur under 

 natural conditions at the margins of the sea, and are usually un- 

 controllable because they are large-scale phenomena connected with 

 weather, climate, etc. The same results sometimes can be obtained 

 locally, and slowly because of the works of man. These works are 

 modifiable and in part their impact on the environment can be seen, 

 if we have the proper understanding. This report adds to the under- 

 standing of the basic environmental factors, temperature and salinity, 

 on shrimp. Brown shrimp were selected for study in part because of 

 their great abundance and commercial importance, which similarly en- 

 hances them as ecologically important representatives of estuarine 

 species. 



Possibly the most worthwhile generalization of this report is 

 that it reveals that a slow gradualism in change of basic environ- 

 mental factors is best for the organisms and permits their adaptation 

 in many ways; therefore, from the standpoint of biological management 

 and fisheries this principle should always be held in mind in the 

 planning of works with hydraulic, hydrological , and hydrographic im- 

 pacts upon the estuaries and the margins of the sea. 



300 



