6-40 



50% or less of the mean. Variability of species richness was inter- 

 mediate between the other two parameters. 



In all cases, variability between replicates was greater in 

 the inner harbor than in Morris Cove. This is to be expected as even a 

 cursory examination of the raw data reveals greater differences among 

 replicates from the inner harbor than from Morris Cove. 



As a comparison, Michael et al . (1978), in summarizing the 

 results of a subtidal sampling program at Plymouth, Massachusetts where 

 three replicates were collected, foiind the variation reported in Table 

 6-8. 



The Plymouth data are from an area that is not subject to pol- 

 lution stress, although it experiences a fair degree of natural distur- 

 bance by wave action. The Morris Cove results are closer to the lower 

 CV values of the Plymouth data, whereas the inner harbor represents a 

 more variable environment with higher CV values . 



Species which were designated as characteristic were also 

 examined for variability among replicates. Two sampling periods from 

 1977 were chosen at random and the data from stations that the par- 

 ticular species characterized were tested for variation among repli- 

 cates. In general the CV for individual characteristic species ranges 

 from 50% to 100% of the mean. This parameter is therefore less pre- 

 dictable than species richness, diversity, or total number of individ- 

 uals. 



