However, there were some differences with respect to the dominant 

 species. With a few exceptions, the stations studied here were 

 characterized by high relative abundances of the polychaete 

 Mediomastus ambiseta , followed by the less abundant polychaete 

 Aricidea catherinae , oligochaetes, ascidians, and occasionally the 

 polychaete Spiophanes bombyx . High abundances of Mediomastus are 

 also found in Cape Cod Bay but are unusual for Massachusetts Bay 

 where spionids and Aricidea predominate, although Mediomastus is 

 generally present. Mediomastus is an opportunist, and its 

 occurrence on the disposal mound may suggest that the community is 

 stressed by disturbance or organic enrichment; however, due to the 

 relatively unpolluted condition of the disposal site this is 

 unlikely. It is possible that a Mediomastus -dominated community is 

 a natural phenomenon in Buzzards Bay as it is in Cape Cod Bay. 

 Results of the REMOTS® survey indicated a Stage I community at the 

 disposal site. The reference station Rl had a very similar 

 infaunal community even though the station was clearly away from 

 the disposal site. The benthic community at reference area 1 

 consisted of Stage I, Stage III, and Stage I on Stage III taxa 

 (Figure 3-15) . 



Species richness was slightly higher at the reference 

 stations than at the disposal site stations, but both groups of 

 stations were well within the range usually observed in soft-bottom 

 shallow-water environments (see Blake et al. , 1987 for 

 Massachusetts Bay data) . Total densities were similar at the 

 disposal mound and reference stations; in comparison to other 

 adjacent areas, such as Massachusetts Bay, the densities found in 

 Buzzards Bay were relatively low. This may be in part a seasonal 

 effect, because the samples were taken in March when juveniles were 

 either not yet present or were still too small to be retained on 

 0.5 mm mesh screen. Detailed information on the relative 

 abundances of juveniles in 0.5 mm and 0.3 ram fractions of the same 

 sample can be found in Blake et al. , (1987) . 



The assessment of the number of dominant species shared 

 among stations revealed that the disposal site stations were very 

 similar. Only station 22 differed somewhat, due to the presence of 

 molluscs and nemerteans, rather than polychaetes and oligochaetes, 

 among the highest ranked species. Reference stations differed more 

 from each other than the disposal site stations. This was 

 especially true of reference area 3, where the top ranks were 

 occupied by molluscs rather than polychaetes (except for 

 Mediomastus ) . Reference area 1 was most similar to the disposal 

 site stations, followed by reference areas 2 and 3. A relatively 

 high similarity existed between reference area 3 and station 22. 

 The very different character of reference area 3 is also documented 

 in the great difference in the mean apparent RPD depth in this 

 location as compared to the other reference areas (Figure 3-12) . 

 Results of the benthic grab analyses correlate well with results 

 obtained from REMOTS® for infaunal successional stages, OSI, and 

 RPD depths. 



11 



