1. Effects of oil spills and chronic oil contamination. 



2. Effects of dredging and pipeline burial. 



3. Effects of support facilities such as harbors. 



4. Secondary effects of increased population, recreation use, and 

 food supply. Demands on fisheries. 



5. Effects of loss of habitat due to secondary spin-off developments. 

 Specific fisheries information were presented earlier in this section, thus a 

 more generalized impact analysis is given here. 



Fish and shellfish populations could be adversely affected if oil 

 spills, continuous small leaks from pipelines or harbors, cause lethal ef- 

 fects on eggs and/or fry in spawning areas. This effect could occur at 

 continuous exposure to concentrations of soluble hydrocarbons derivates 

 in excess of 0.1 ppm (1 ,Vol .1 ,p.!07) . These concentrations of soluble 

 hydrocarbons occur in areas near unweathered spills of crude oil offshore 

 or spilled refined oil nearshore. 



Anadromous fish such as shad, striped bass, or menhaden may be particu- 

 larly vulnerable to a spill occurring in a critical or shallow estuarine 

 waterway during migration periods. Shrimp and sessile shellfish are also 

 particularly subject to injury by nearshore spills. A local estuarine 

 breeding population of an important species could be lost due to contamination 

 of spawning or nursery grounds. Less obvious effects may also ensue, among 

 them, loss of planktonic o.^ benthic food supplies. The degree of impact, of 

 course, depends on the time of year of the spill, type of oil, duration of 

 spawning and breeding, the type of organisms affected, the areal extent of the 

 spill, and weather conditions at the time (1 , p. 107-108) . 



Shellfish communities may be affected directly by the laying of pipe 



69 



