respectively, from stations 300SE and 300WSW; faunal abundances were also greater (1118 animals from 

 300SE and 5 1 8 animals from 300WSW). The number of taxa, including unidentified and juvenile 

 specimens, ranged from 17 at station CENTER to 66 at station 300SE. Densities ranged from a low of 

 1 .25 x 10 3 individuals/m 2 at the CENTER station to 2.795 x 10 4 individuals/m 2 at station 300SE. 



The ten most abundant species at each station are listed in Tables 2-4. The most ubiquitous dominant 

 species were the bivalve Nucula annulata and the polychaete Prionospio steenstmpi which were among 

 the top six dominants at all six stations. The polychaete Mediomastus ambiseta was among the ten most 

 abundant species at all stations, ranking within the top three species at five stations. The amphipod 

 Ampelisca vadorum and the gastropod Crepidula plana were among the top ten dominants at five stations. 

 The polychaete Tharyx acutus was represented among the top ten dominants at four stations. 



Overall, polychaetes with 12 species, belonging to nine different families, constituted the largest 

 taxonomic group to be found among the top ten dominants at the six New London stations. The second 

 largest groups were bivalves (4 species), with Nucula annulata extremely abundant and amphipods (4 

 species) mostly belonging to the genus Ampelisca. Two gastropod taxa, Ilyanassa trivittata and Crepidula 

 plana, one decapod, Pagurus spp., and oligochaeta spp. complete the list of dominant species; Ilyanassa 

 was among the dominants at two stations, while Pagurus spp. and oligochaeta spp. were among the 

 dominants at one station. 



Diversities (FT) ranged from a low of 2.65 at station 150N to a high of 4.10 at station 150W (Table 5). 

 The low value at station 150N may not be too surprising, since the sample was dominated by Nucula 

 annulata. These stage II deposit-feeding bivalves stir up the surficial layers of the sediment thus 

 decreasing the availability of suitable benthic habitat for colonization (Don Rhoads, pers. comm.). The 

 diversity at the CENTER station was relatively high, considering the very low abundance of individuals 

 (50) present in the sample. This is a situation where diversity is high when the number of species is low 

 and the community is in an early stage of succession (Pearson and Rosenberg, 1978). Evenness (J') ranged 

 from a low of 0.48 at station 150N to a high of 0.82 at the CENTER station (Table 5). 



Density measures (Figure 1) show increasing numbers of species and individuals as stations are located 

 further from the center of the site. Other community parameters tend to show three pairs of stations. The 

 CENTER station and 75E combine low numbers of species and individuals with similar low diversity 

 (3.27 and 3.16) and high to moderate evenness (0.82 and 0.68); rarefaction curves for these stations are 

 well below those of the 150m and 300m stations. Stations 150N and 300SE combine high numbers of 

 species and individuals with very low to moderate diversity (2.65 and 3.66) values and low evenness 

 values (0.48 and 0.63); rarefaction curves for these stations lie between the central and western stations. 

 The more westerly stations, 150W and 300WSW, combine moderate to high numbers of species and 

 individuals with the highest diversity values (4.10 and 3.91) and similar moderately high evenness (0.76 

 and 0.70); rarefaction curves for these stations lie slightly above those for 150N and 300SE. 



4.0 References 



Pearson, T.H. and R. Rosenberg, 1978. Macrobenthic succession in relation to organic enrichment and 

 pollution of the marine environment. Oceanogr. mar. Biol. Ann. Rev., 16:229-31 1. 



Sanders, H.L. 1968. Marine benthic diversity: a comparative study. Am. Nat., 102:243-282. 



