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REMOTS® results suggest that there was high spatial patchiness at this station. The 

 population of N. annulata showed a diverse range of size (0.75 to 3.75 mm) suggesting that 

 more than one age class (cohort) may have been present. The larger specimens showed 

 growth annuli in the shells indicating that they were >1 year old. At least two cohorts 

 appeared to be present in the larger specimens. 



At Station 150N (mound plateau nearest apex), Nucula annulata (Stage II) 

 represented over one half of the individuals sampled. Small specimens (0.75 mm) appeared 

 to be the 1997 cohort, while individuals approaching 3.75 mm were probably over one year 

 old based on the presence of growth annuli within the shell. Another bivalve, Tellina agilis, 

 represented by four juvenile individuals is known to be a Stage II species. Their small size 

 suggested that they comprised a 1997 cohort. Mediomastus ambiseta and Prionospio 

 steenstrupi are Stage I polychaetes that were moderately abundant, and there were also a few 

 individuals collected representing Stage HI polychaete taxa (e.g., Nephtys incisa and 

 Levinsenta gracilis). Two sediment profile images provided useful successional 

 information. Both replicates indicated a Stage II successional designation, mainly reflecting 

 the presence of Nucula annulata. This inference is supported by the ground-truth sampling. 

 The presence of low densities of both Stage I and Stage HI polychaetes was apparently 

 missed in the sediment profile images. 



Faunal dominants at Station 150W (mound plateau) included two Stage I polychaetes 

 (P. steenstrupi and M. ambiseta) and the Stage II bivalve N. annulata. Juvenile Tellina 

 agilis (Stage U) were also present (n=l), along with two Stage HI polychaetes (Maldanidae 

 sp. and Nephtys incisa). The overall designation of this station as being in a Stage I-U sere 

 was based on one sediment profile replicate showing Stage I; a second replicate, Stage U; 

 and a third replicate, Stage I-JH. This inference is supported by the benthic grab sample 

 data. A low density of Stage HJ polychaetes apparently was present along with the surface- 

 dwelling Stage I and II taxa. A range of sizes (0.75 to 4.0 mm) was present in the N 

 annulata population. The largest specimens appeared to have at least two shell growth 

 annuli, suggesting that several age classes may have been present. 



Several species were present at Station 300WSW (mound plateau) that represented a 

 mixture of successional stages. Stage I taxa included the polychaetes P. steenstrupi and M. 

 ambiseta. Stage U taxa were represented by N. annulata and A. vadorum. Stage HJ taxa also 

 were present (maldanid polychaetes). Sediment profile images showed the following 

 successional development: I-U, I-HJ, and I-HJ. This station therefore was assigned a mixed 

 successional status, suggesting that it was in an advanced state of recolonization. Individuals 

 ranging from 0.75 to 3.0 mm were present in the N. annulata population. The size 

 distribution was skewed toward small specimens suggesting a successful 1997 recruitment. 



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



