recently-deposited (i.e., since November 1987) dredged material 

 occurred at two stations in the immediate vicinity of the "B" mound. 

 This correlates well with the acoustically-determined changes in 

 depth noted in this location. Likewise, relict dredged material was 

 noted at stations at and in the vicinity of the "C" and "A" mounds, 

 consistent with the results of both the 1988 bathymetric and 1987 

 REMOTS® surveys. The indistinct, low-reflectance horizons noted at 

 some stations away from the three mounds (Figure 3-9) serve as 

 indirect evidence of disposal which might have occurred anytime in 

 the past, probably well before the 87-88 disposal season. 

 Apparently these errant disposal events were not all that common, 

 because the resulting relict dredged material layers present at 

 these locations appeared relatively thin and are widely-spaced. 



A second objective of the REMOTS® survey at WLIS was to 

 assess environmental impacts related to dredged material disposal. 

 The lack of significant differences between reference and disposal 

 site stations in such REMOTS® parameters as RPD depths, percentage 

 of Stage III organisms, and OSI values indicated a rapid recovery 

 by the ambient benthic community; the seafloor disturbance caused 

 by dredged material disposal was apparently rather transient as 

 detected at the benthic population level. This disturbance 

 primarily was physical in nature and limited to the immediate 

 vicinity of the active "B" disposal mound, where stations 3-C and 

 5-E exhibited OSI values +6. The low OSI values at a small number 

 of stations elsewhere at the site were caused by variable RPD layers 

 or within-station patchiness in the distribution of Stage III 

 infauna. At each reference site, apparent between-station 

 variability in such parameters as the RPD, OSI and infaunal 

 successional stage was most likely due to the fact that only one 

 REMOTS® image was obtained at the individual stations. Because of 

 the patchy distribution of benthic organisms, and in some cases RPD 

 depths, it is recommended that additional replicate photographs be 

 obtained at each individual reference site station in future 

 surveys. This would match the level of replication employed at the 

 disposal site and would allow a better assessment of any apparent 

 variability or sampling artifact caused by using the cross-shaped 

 station pattern at the reference sites. 



In November 1987, significantly greater RPD depths coupled 

 with a slight increase in the number of Stage III organisms at both 

 reference and disposal site stations lead to the conclusion that 

 overall benthic habitat quality at WLIS had improved relative to the 

 stressed conditions noted during a period of near-bottom hypoxia in 

 August 1986. This was reflected in the significantly higher OSI 

 values in 1987 compared to 1986. The 1988 results suggested a 

 continuation of this trend. While RPD depths and OSI values were 

 not significantly different in 1988 compared to 1987, there was an 

 increase in the percentage of replicate photos showing evidence of 

 head-down, deposit-feeding Stage III organisms. This serves as one 

 indication that relatively healthy benthic conditions continued to 

 exist both at the site and in the general area outside the site 



8 



