6-37 



sity. Due to the degree of variability in the data it is difficult to 

 detect a true seasonal trend of diversity; however, in 1974, 1975 and 

 1977 diversities in Morris Cove reached their greatest values in Octo- 

 ber or December. Thi:; type of seasonal trend is common in natural com- 

 munities as spring recruitment commencing during spring months extends 

 into the summer and fall increasing species richness and density. A 

 slight trend of annually increasing values was also apparent at Morris 

 Cove. The inner harbor diversities were lower and less consistent than 

 those at Morris Cove. The trend of higher late fall values was noted 

 in October 1974 and 1975 but was obscure for other years. The greater 

 variation and lower diversities in the inner harbor may be related to 

 the environmental stresses encountered by benthic organisms due to 

 increased pollutant impact in the inner harbor during late summer. 



Within-Station Variability 



In order to develop an understanding of the variability of 

 three important biological parameters (species richness, density, and 

 diversity) , the coefficients of variation (CV) among three replicates 

 for each parameter were calculated for six stations for 1977 (Table 6- 

 7) . Stations in Morris Cove were selected at random. This was not 

 considered appropriate for inner harbor stations as, in some cases, 

 there were only three or four stations with any macrofauna. Inner 

 harbor stations with the most animals were selected so that the results 

 might in some way represent the "best" case. One might argue that three 

 replicate samples containing no macrofauna show low variance , but we 

 cannot be sure that there were no animals adjacent to the sampling area. 



The mean CV values for the three parameters are presented for 

 the inner harbor and Morris Cove samples separately in Table 6-8. The 

 CV for these parameters range from 20.7 to 74.0% of the mean. The 

 number of individuals in a sample is the most variable of the three. 

 Diversity, which is effectively limited to a range of 0.0 to approxi- 

 mately 4.0, was the most stable parameter among replicates with a CV of 



