where bottom currents are higher (Biembaum 1979). After construction, the infaunal community 

 responded to bottom disturbances in a highly predictable manner. As in other areas subjected to 

 disturbance, (i.e., dredging) the initial decrease in species numbers and abundance was followed by the 

 rapid invasion of opportunistic species (e.g., Polydora ligni, Capitella Mediomastm amhisela), (Grasste 

 and Grassle 1974; McCall 1977; Swartz et al. 1980; Flint and Younk 1983; Nichols 1985). Following 

 these species, ampeliscid amphipods, more traditionally found at the IN station, settled and became very 

 abundant. These species can stabilize the sediment surface (Dlumer et al. 1970; Sanders et al. 1972) 

 and thus allow recolonization and recruitment of other species to the area. 



Power plant related impacts at EF, even during the period immediately following construction 

 activities, were less dramatic than those at IN. Levels of silt/clay were only slightly elevated and 

 apparently enhanced colonization of species that rely on fine material as a food source. In 1985, densities 

 of deposit feeding species such as oligochaetes, T/iary-^ spp., Tellina agilis, Lumbrineris tenuis and 

 Polyc.lmis eximius remained higher than most previous years (except 1984). Although these species 

 were present at this station in the past, their relative abundances were much lower before construction. 

 The FF community also exhibited a significant increase in the average number of species. Although 

 relatively high numbers of species have been collected at this station, the most dramatic increase occurred 

 after construction. This increase probably reflected the influx of deposit-feeding species, which utilized 

 the higher silt/clay content found after construction began. However, since the opening of the second 

 discharge cut, silt/cIay content decreased and the numbers of amphipod and mollusc species increased 

 in the three quarters during the 1986 sampling period. Despite these changes, the structure of the FF 

 community has exhibited a higher degree of year-to-year similarity than that at IN. 



Generally, the GN and JC communities have been more similar to each other in terms of species 

 composition, abundance and diversity. Species comprising these communities and their abundances are 

 more similar to other studies of near-shore areas (e.g., Watling 1975) than those of IN. During the 

 baseline period, an area-wide increase and decline was seen in the abundance of Mediamaslus amhiseta 

 at GN and JC. This species was the most abundant organism at both stations during 1984, and 

 accounted for 25% (GN) and 43% (JC) of the total organisms collected. In 1985, the relative abundance 

 of Mediomaslus amhiseta declined to 7% and 12% at GN and JC, respectively (lower densities of this 

 taxon were also evident at EF and IN in 1985). The decreased abundance of Mediomastus amhiseta at 



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