no 



CTR, 75E, 150N, 150W, 300WSW, and 300SE). Organisms retained on a 500-micrometer 

 sieve were identified and enumerated (Appendix C). Based on knowledge of their life 

 histories and feeding habitats, particularly the polychaetes (Fauchald and Jumars, 1979), a 

 significant number of the collected infauna were assigned to a successional stage as defined 

 in the REMOTS® successional paradigm (Table 4-1). The following comparisons between 

 the grab sample and REMOTS® results therefore are based mainly on the taxa and their 

 associated successional stage classifications listed in Table 4-1 and in Tables 2 through 4 of 

 Appendix C. In the following comparisons, the generic and species names and abundances 

 come from traditional benthic grab analyses. The successional designation(s) come from 

 REMOTS® image interpretation based on between one and three replicate images per station. 

 Not all replicates provided useful data. 



The numerically dominant species at Station CTR (mound apex) was the protobranch 

 bivalve Nucula annulata followed by the tube-dwelling amphipod crustacean Ampelisca 

 vadorum. Nucula spp. are known to appear on other disposal sites in Long Island Sound (an 

 infrequently used sandy Guilford, CT site [Rhoads pers. comm.]) and in the vicinity of the 

 former New York Mud Dump on relict dredged material (Valente 1998, Chang et al. 1992). 

 The same bivalve is an important component of the Nephtys incisa I Yoldia limatula 

 assemblage (sensu Sanders 1960) in both Long Island Sound and Buzzards Bay. The 

 appearance of N. annulata at Station CTR is unusual because of its co-occurrence with a 

 well-known Stage II species, A. vadorum. Nucula annulata is considered a late Stage II 

 species due to its relatively conservative reproduction, relatively slow growth rate, and long 

 life span (several years). All of the Nucula were small, i.e., within the range of 0.75 to 1.5 

 mm. None of these protobranchs showed annular growth bands suggesting that they were a 

 single age-class (cohort) that settled as larvae during the spring to early summer of 1997. 

 Alternatively, these small juvenile bivalves may have been passively transported to the 

 station from the ambient bottom by means of turbulence and resuspension. Small N. 

 annulata have been recovered from sediment traps located decimeters above the bottom in 

 Buzzards Bay (Rhoads pers. comm.). 



Based on the dominance of Nucula annulata and Ampelisca vadorum, as well as the 

 presence of the Stage II amphipod Leptocheirus pingus and the Stage n/m polychaete 

 Spiochaetopterus costarum among the dominants (Appendix C, Table 2), the species found 

 in the grabs would identify Station CTR as being a late Stage II or early Stage HI 

 assemblage. However, REMOTS® images did not show any evidence of macrofaunal 

 organisms and so the successional status was not assigned. The presence of the highly 

 plastic, relic gray Gardiner's clay had the apparent effect of retarding infaunal succession 

 relative to dredged material of more recent age. The apparent absence of macrofauna from 

 the profile camera images is explained by the low density of macrofauna recovered from the 

 grab samples (50 individuals per 0.04 m 2 ). At this density of organisms, a random vertical 

 cut of the botto m by the camera presents a low probability of imaging an organism. 



Monitoring Cruise at the New London Disposal Site, Seawolf Mound 1995 - 1998 



