average of 2,200, with a range between 324 (immediately after dredging), and 

 4,037 1 year following dredging. 



Results of periodic sampling at station 1 showed that numbers of individuals 

 within the borrow pit first reached control sample abundance in December 1976, 

 or about 3 months after dredging had been completed. From that time through the 

 next four sampling periods, individuals in experimental samples were more 

 numerous than in control samples. In May, abundance values were reversed, then 

 again favored the experimental sample in June but remained higher in controls 

 until collecting terminated in November 1977. Thus, a pattern of abundance 

 indicative of faunal recovery within 3 months did not occur the following sum- 

 mer and fall seasons. 



At stations 1 to 6, one-time sampling in July neither confirmed nor refuted 

 evidence of recovery from time-sequence sampling at station 1. Numbers of 

 individuals were higher in control samples at stations 1, 3, and 4, while 

 abundance values were higher in experimental samples at stations 2, 5, and 6. 

 A comparison of averages and ranges showed that the average number of individuals 

 per square meter was higher for experimental samples. The low for experimental 

 collections was well above that of control samples, and the high for experimental 

 samples was comparable to the high for control samples. In summary, abundance 

 values demonstrated rapid initial faunal recovery in the borrow pits that was 

 practically complete after about 12 months. 



c. Diversity (H') and Equitability (J') . For comparable pairs of control 

 and experimental samples, species richness and abundance data were converted 

 statistically to provide an index of diversity (H') that was used to numerically 

 determine degrees of difference between faunal communities in undredged bottom 

 and borrow pits. Observed differences were validated for each sample set by 

 calculating equitability (J'), which is a mathematical measurement of how evenly 

 organisms in a sample are divided among the various species represented (Pielou, 

 1975). Used in combination, values of H' and J' for base-line and control samples 

 were regarded normal. For experimental samples, lesser values of H' and J' were 

 attributed to dredging effects, and equal or higher values were considered 

 evidence of faunal recovery. In base-line samples, values for both parameters 

 were slightly higher in summer months, but control samples at station 1 showed no 

 seasonal trend. 



Average values for H' and J' in base-line samples were 2.6 and 0.7 

 respectively, with H' ranging from 1.9 to 3.5 and J' ranging from 0.6 to 0.8. 

 Average H' in control samples was a little higher than base-line but J' was the 

 same and ranges of both were within base-line limits. Among experimental 

 collections, average H' was 2.8 and ranged between 1.8 and 3.7. The average for 

 J' was the same as for base-line and control samples, but the low was 0.5 and the 

 high was 0.8. Lowest values for H' and J' were recorded in January and February, 

 and may have been a result of low water temperature as well as dredging. 



When H' and J' values for control and experimental samples taken on the same 

 data were compared, the results showed little regularity. In the series from 



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