VI-106 



effects of environmental alterations, controlling disposal of waste 

 products, controlling fish diseases and predators, and developing 

 genetic strains of desired species more suited to moderately disturbed 

 habitats might possibly ensue from a sophisticated analysis of the 

 above factors. Certainly we should know more about the effects of 

 any changes in the estuarine environment on the increase or build- 

 up that might be exoected of aquatic weeds, pest species of insects 

 and other arthropods, and diseases and predator species that may 

 reduce populations of desirable organisms or inhibit recreational 

 uses of estuarine areas. 



BIOLOGICAL STUDIES 



Estuarine biological systems are extemaly complex v/hen compared to 

 freshwater or truly marine environments. The areas between the 

 freshwater and the sea remain the biological link betv/een the sys- 

 stems which, if broken, will result in the elimination of many 

 valuable resources. The planktonic stages which are characteristic 

 of life histories of species having commercial or recreational impor- 

 tance are especially vulnerable to environmental changes. 



Sources of Food 



The complicated food chains, associated with the polymorphic life 

 histories of estuarine organisms are poorly understood. For example, 

 the American oyster, which is often called the most thoroughly stu- 

 died of all estuarine organisms, can starve in waters containing 



