104 



occurrences and abundances, dissected Casco Bay into ecologically 

 meaningful components. Analysis of variance also demonstrated that the 

 site-groups were significantly different in regard to four of the trace 

 metals, cadmium, chromium, nickel and zinc. 



The data was subjected to Duncan's multiple range test to determine 

 which site-groups differed in the measured parameters. Results of this 

 procedure are presented in Table 12. Zinc is not included because 

 Duncan's test is not powerful enough, in this case, to break out the 

 dissimilar site-groups. Groups represented by the same letter in the 

 table are not different. For instance, by comparing Tables 11 and 12 we 

 can conclude that site-group A is significantly deeper than all the 

 others which do not differ significantly among themselves. Likewise, 

 site-group 9, located on a mussel reef, has a significantly greater 

 density than site-groups 1 and 3 which are in turn significantly denser 

 than the remainder of the groups. Some of the other results are not so 

 straightforward. In terms of biomass site-groups 1 and 3 are 

 significantly richer than site-groups 4, 5 and 6, but the intermediate 

 groups cannot be statistically differentiated from either the high or 

 low biomass stations. 



We are extremely encouraged that the chosen classification 

 techniques produced groupings that are statistically valid. We are 

 confident that once all of the data are available we will be able to 

 provide a comprehensive analysis and benchmark of the present state of 

 the benthic environment of Casco Bay. 



SUMMARY AND TENTATIVE CONCLUSIONS 

 Casco Bay is a major coastal resource heavily utilized for 

 commerce, commercial fishing and recreation. Facilities and activities 



