6-50 



occurrences in samples from this group were high compared to the total 

 number of possible occurrences or the total number of samples) . Because 

 Nereis was ubiquitous, its fidelity for the group was found to bo low 

 (i.e., its constancy with the inner harbor cluster was not particularly 

 higher than its constancy harborwide) . Nereis was the sixbdominant at 

 Station 5 where Crangon was dominant. However, Crangon , a motile epi- 

 benthic species, appears to have even lower fidelity than Nereis, 

 occurring throughout the harbor in approximately the same frequency. 

 Streblospio benedicti and Capitella capitata, two opportunistic poly- 

 chaetes, also appear as subdominants in this grouping at two stations 

 each. Streblospio occurs at high levels in one of the other groupings 

 as well as this one, but Capitella exhibits high fidelity and appears as 

 a dominant species in this grouping only. As might be expected, this 

 cluster exhibits the best example of a stressed environment populated by 

 several opportunistic species, primarily polychaetes. 



A second cluster of three stations (A, C, G) also became 

 apparent from the trellis diagram. These stations occupy a horseshoe- 

 shape area around the northern and western periphery of Morris Cove. 

 Although no sediment grain-size data were analyzed by either study, 

 field sampling personnel have identified this area of Morris Cove as 

 consisting of a coarse-grained usually muddy sand. This area is dis- 

 tinct from the very soft silt-clay sediments which are typical of the 

 deeper central portions of Morris Cove. Station D, however, which is 

 spatially contiguous to this cluster, and apparently consisting of a 

 similar substratum, showed no particular affinity to this, or any other, 

 cluster. 



This second, well-defined cluster, occupying the shallower 

 portions of Morris Cove is characterized by a somewhat more complex and 

 diverse faunal assemblage (Table 6-9) . Nereis succinea again occurs as 

 the dominant species at two of the stations and as a subdominant at the 

 third. Here, however. Nereis is accompanied by a n\imber of codomi- 

 nants, some of which were not dominant in the inner harbor cluster. 

 These include Tellina agilis , Glycera americana, Streblospio benedicti 

 and Pagurus longicarpus . Of these, Tellina and Pagurus exhibit somewhat 



