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potentially threatening to the environment occur throughout the Bay but 

 are most concentrated in the region of Portland. 



Casco Bay is characterized by a boreal climate and a large tidal 

 range (3 m) . Sediments range from sand in tidally scoured channels to 

 clay in the inner reaches of the Bay. Interior portions of the Bay have 

 extremely soft bottom sediments which may be described as fluid mud or 

 gel. Stations in these areas are occupied by an aberrant community with 

 low species richness and low density. Further work is needed to fully 

 document this phenomenon. 



Trace metals are not homogeneously distributed throughout Casco 

 Bay. Sandy and offshore stations tend to be low in metal concentration, 

 while Portland Harbor appears to contain anthropogenic inputs. 

 Comparisons with 10 other New England sites confirms that Casco Bay 

 sediments are impacted in terms of the trace metals sampled. 



The fauna of Casco Bay is rich in terms of diversity, density and 

 biomass. These parameters, and others, are positively correlated with 

 bottom depth and negatively correlated with mean grain size and organic 

 carbon content. Most biological parameters are negatively correlated 

 with at least some of the trace metals. We await the hydrocarbon data 

 to complete our analysis. 



Numerical classifications dissected Casco Bay into nine site-groups 

 occupied by 14 species-groups. The site-groups are spatially realistic 

 and differ significantly (>95%) in regard to both physical and 

 biological factors. One species-group is widely distributed and is 

 considered typical, boreal shallow-water fauna. 



