605 



individuals must originate from undisturbed populations in nearby 

 bays. Ths process usually requires that larval or juvenile forms from 

 the undisturbed population find their way into the ocean, survive there, 

 and thence migrate into the modified bay. It also requires that the 

 modified bay be once again a suitable habitat for the original inhabi- 

 tants. Probability of such a sequence of events may be low, explaining 

 the long periods generally required for recolonization of a despoiled 

 area. 



This particular study would seek to develop methods for facilitating 

 this process. The ultimate climax communities in the modified bay 

 would thus be enhanced both in terms of species diversity and the pro- 

 duction of organisms useful to man. 



The case study selected here is Newport Bay, Calif., because of the 

 plans being made to develop this area within the next few years. 



Bay development typically involves replacing shallow marshland 

 with navigable open water (usually 10 to 30 feet deep). Entirely ter- 

 restrial islands and peninsulas may be left in the bay or built up by 

 filling. Organic productivity by marsh vegetation is eliminated, and 

 the food base remaining for animal communities are either phyto- 

 plankton or dimly illuminated (and hence sparse) bottom vegetation. 

 Populations dwelling in shallow zones find their habitat greatly re- 

 duced. Deep-waiter animals have an expanded habitat, but cannot 

 multiply faster than their basic organic food resources. 



If deep-water attached plants existed in the bay, and if they survive 

 the construction activities, they can colonize the newly created deeper 

 bottoms. As plant cover develops, habitats and food resources become 

 available for animal communities. If the proper plants are absent or 

 lost, or if bottom illumination is low, attached vegetation may never 

 gain a foothold. Bay life then depends totally on phytoplankton 

 productivity. Many species, including animals soug'ht by man, cannot 

 utilize planktonic food resources. These forms dwindle or vanish. 



Whatever the course of events, results add up to biological imx)ov- 

 erishment for years or even indefiniteily. Man could intervene in several 

 ways. Most importantly, stands of suitable attached vegetation must 

 be created to provide food bases for animal communities. If desirable 

 fauna and flora totally perish during bay modification, seed stock 

 populations could 'be introduced to strategic areas. Last, but by no 

 means least, ecological comisel could be provided to planning engineers 

 to insure that the best possible decisions are made before bay modifica- 

 tion commences. 



The proposed plan of study consists of several interrelated studies. 

 Objectives can best be achieved by developing information in all these 

 lines of work, more or less concurrently. 



1. The important plant and animal species of southern Califor- 

 nia bays would be identified and their ecological requirements 

 determined. 



2. Various types of construction used in bays (i.e., riprap bulk- 

 heads, pilings, artificial islands, etc.) would be evaluated for 

 suitaibility as substrata for colonizing organisms. Criteria of suit- 

 ability are diversity and abundance of species associated with the 

 substrates. Evaluations take account of hydrographic conditions, 

 age of the particular construction, and other modifying factors. 



