26 



polychaetes present at the sediment surface (Figures 3-7 and 3-8; Table 3-1). Tube-dwelling 

 amphipods (Ampelisca sp), representative of Stage n, were observed at 7 of the 22 stations 

 (Figures 3-7 and 3-9). Stage III activity, evidenced by active feeding voids produced by 

 head-down, deposit-feeding infauna, was predominately noted in the subsurface at Stations 

 lOONE, lOOSW, 150NW, 150S, and 50E (Figures 3-7 and 3-9). Overall, the presence of a 

 diverse mixture of Stages 1, 11 and HI organisms at the stations within the borrow pit indicate 

 that benthic recolonization of this area was occurring as expected at the time of the 

 September 2000 survey. 



Stage I successional status dominated the reference areas, with only a single 

 occurrence of Stage IE activity marked by active feeding voids in one replicate image at 

 Station REF2 (Table 3-2). Dense tube-building Stage I polychaetes, as well as a fecal 

 mound, were noted in one of the replicate images at station REF2. The dominance of Stage I 

 organisms and the notable scarcity of Stage IE at the reference area stations may again be 

 due to periodic physical disturbance experienced in this shallow area. 



Median OSI values for the borrow pit stations ranged from +3 at Stations lOONW, 

 150SW, and lOOSE to +11 at Station lOONE (Table 3-1 and Figure 3-6). This range of values 

 suggests variable benthic habitat quality across the area, ranging from moderately disturbed 

 (OSI values of +3 to +6) to healthy or undisturbed (OSI values >+6). 



Values at the lower end of the scale (+3 to +6) reflect somewhat shallow RPD depths, 

 an absence of Stage n and III infauna, and/or the presence of methane in the sediment. 

 Values greater than +6 generally reflect well-developed RPD depths and the presence of both 

 Stage n and HI recolonizing organisms. Such spatial variability in conditions is typical for 

 an area, like the borrow pit, which had experienced significant physical disturbance related to 

 dredged material placement as recently as 5 months prior to the September 2000 survey. 

 Benthic organisms appeared to have recolonized some areas of the dredged material deposit 

 to a more advanced degree (i.e., Stages n and IH) than others (dominated by Stage I only). 

 This variabiUty in the distribution of recolonizing benthos is normal so soon after the initial 

 disturbance, and it is anticipated that organisms representing more advanced successional 

 stages will become more widely distributed over time. In the absence of additional dredged 

 material disposal, increases in the density of Stage n and EI organisms should be reflected in 

 higher OSI values at the borrow pit stations in the future. 



Shallow mean RPD depths together with only Stage I activity at the Morris Cove 

 reference areas served to diminish the median OSI values to a range of +2 to +7 

 (Table 3-2). The exceptionally low OSI values for Stations REF4 and REF5 reflect very 

 shallow mean RPD depths and the lack of Stage n or HI individuals (Figure 3-5). The 

 northernmost reference areas (REF2 and REF3) appeared to display somewhat healthier 

 benthic conditions than the surrounding stations with deeper mean RPD depths, Stage EU 



Monitoring Cruise at the Morris Cove Borrow Pit 



