high values obtained in the March and June 1983 (Fig. 13 0), Seasonal 

 peaks also occurred in 1981 and 1982 at these stations; moderately large 

 numbers were collected at GN in 1977. This species apparently peaks in 

 June, although its recent appearance makes interpretation of any long-term 

 seasonal trends difficult. Of all population changes that occurred at 

 subtidal stations, the increased abundance of Polydora caulleryi throughout 

 the Millstone area during 1983 was most notable. 



Ampelisca verrilli 



Ampelisca verrill i is a suspension feeding arthropod that is 

 frequently found in dense aggregations where their fine sand tubes can form 

 sediment stabilizing carpets over the bottom. Large fluctuations in their 

 abundance however can occur as the food resources in the area are depleted. 

 Reductions in density have also been attributed to pollution, wave induced 

 bottom scouring, and siltation. Ampelisca was the most abundant species 

 collected at the IN station during 1983, and was among the top ten only at 

 IN and EF. Since 1980 this species has been consistently among the top ten 

 dominant taxa at IN and rare or absent at the other stations. Distinct 

 seasonal peaks have generally occurred in September at all stations (Fig. 

 13 P). At EF, the high annual densities of this species during 1983 were 

 due to very high values obtained in September 1982; all other quarterly 

 density estimates were comparable to previous years. 



Species Diversity 



Annual mean species diversity (H') of the subtidal communities ranged 

 from 4.59 at EF to 3.01 at JC (Table 9). High EF diversity was due to high 

 evenness (J) and number of species (S) relative to the other stations. All 

 subtidal communities exhibited seasonal variation in diversity with the 

 number of species varying most over the sampling stations and evenness 

 varying least. Relative to measures of diversity in previous years, those 

 at EF were higher or equal to the three year average; at IN and GN all 

 measures were below the three year average; at JC , H' and J were lower than 

 the three year ranges. Although diversity measures at some subtidal 



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