8-42 



dance of this species. More likely, increasing abundances of P. polli- 

 caris in the outer harbor are a result of natural variations in Long 

 Island Sound populations. This is further substantiated by a lack of 

 evidence indicating any elevation in bottom water temperatures in the 

 outer harbor attributable to Harbor Station operation (Section 3.0). 

 Unfortunately, however, there are no Long Island Sound studies which 

 provide data on P. pollicaris abundances. 



Sguilla empusa, also in the third category, has been collected 

 most abundantly in the vicinity of the Harbor Station discharge. Annual 

 abundance of this species as indicated by sampling increased from 1974 

 through 1976 and decreased slightly during 1977 (Table 8-3). Because of 

 their burrowing nature, however, mantis shrimp were not effectively 

 sampled by otter trawl and it is therefore difficult to make any accur- 

 ate conclusions concerning variations in annual abundances. Also, 

 because this species has been collected abundantly only during one or 

 two months of the year, it may be that during each year the trawl sam- 

 ples were taken during slightly different phases of the fall peak thus 

 resulting in varying catch sizes from year to year. 



The spider crab, Libinia emarginata, showed a general decrease 

 in abundance from 1974 through 1977 (Table 8-3) . This decrease was not 

 considerable and probably reflected natural variations in catch success 

 of the otter trawl. On a station-to-station basis, variations in annual 

 abundance between preoperational and operational years were not sxibstan- 

 tial except at Station 20. At this station, high abundances (265 indi- 

 viduals) were observed during 1974; there were only 9 individuals ob- 

 served in 1977. The high annual abundance figure for 1974 was primarily 

 the result of a single large catch (265 individuals) of Libinia at 

 Station 20 during June. 



The starfish. Aster ias forbesi, was the only species which 

 showed any major changes in annual abundance. As indicated earlier, the 

 abundance of Asterias decreased consistently from a high of 17,000 in 

 1974 to a low of 600 during the 9-month survey of 1977. Although it is 



