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III. BIOLOGICAL ISSUES 



The Assessment Community 



Recent emphasis upon interspecies relationships has forced the assess- 

 ment community to design systems and models that serve to analyze the total 

 marine environment. Recognizing that budget limitations produce severe con- 

 straints on project design, and recognizing as well that many of the issues 

 now under consideration are extremely time-consuming and expensive, several 

 basic assumptions appear necessary in order to understand interrelationships. 



1. The Relationship of Inshore Marine Ecosystems to Offshore Systems 

 Very little is presently known concerning the relationship of inshore 



marine ecosystems to offshore stocks. NMFS has budgeted a research vessel 

 for this task; the vessel should be operating in 1977. The effects of 

 estuary degradation on breeding grounds and lower trophic forms may have 

 severe impacts on offshore species, particularly those that spend part of 

 their life cycle in shallow nearshore waters. 



2. Behavior Characteristics and Other Life Patterns Occurring in Mid- 

 v.'ater Depths 



All fish spend a portion of their life cycle in pelagic form; that is, 

 drifting or swimming in the midwater zone between the surface and the bottom. 

 For groundfish, this period is short and occurs directly after the hatching 

 of eggs. Pelagic species, such as herring, spend their entire life cycle in 

 this zone. Although hydroacoustics can generally assess concentrations of 

 midwater fish, adequate knowledge of this region has not been developed. 



