as the one taken immediately after dredging and the two taken in winter during 

 the presumed period of least faunal diversity and abundance. 



The next group is the first cluster and has five samples (1 April 1977- 

 experimental to 2 May 1977-experimental) . These are related by season (spring), 

 and consist of a base-line sample and control and experimental samples collected 

 8 to 9 months after dredging. This mixture, and close correspondence between 

 control and experimental samples suggests that community recovery has occurred 

 within the borrow pit at station 1. 



Then there is a single, odd sample with no close associates (1 November 1977- 

 experimental) , followed by the second cluster which contains eight samples 

 (4 October 1976-experimental to 3 October 1977-experimental). Except for the 

 two control samples, this group represents the experimental samples in the fall 

 during the first 3 months after dredging. 



Cluster three is considered the opposite of cluster two. It has seven 

 samples (10 August 1976-control to 2 August 1977-control) ; five are post-dredging 

 late summer and fall control samples; one a preconstruction control sample from 

 July; and one a winter experimental sample. 



Cluster four is the largest grouping and contains the next 15 samples (1 

 September 1977-control to 1 November 1977-control) ; 8 of these are fall control 

 samples and closely associated with experimental samples taken as soon as 2 

 weeks after dredging, as well as in various other months. Here, the indication 

 is that recovery at station 1 began very quickly after dredging. 



The fifth and last cluster contains six samples (1 June 1977-control to 

 11 July 1977-experimental) , which are equally divided among summer control and 

 experimental samples taken about 1 year after dredging. Similarities between 

 clusters one and five provide substantial evidence of faunal recovery over a 

 postconstruction period of 8 to 11 months. 



For the one-time sampling at six stations, control and experimental 

 collections all show a high level of faunal affinity and therefore support 

 cluster data from station 1 showing a recovery time of 1 year or less. At the 

 time these samples were taken, the diagram shows that station location east to 

 west along the coast was a greater clustering factor than whether or not a 

 sample came from a dredged or undredged bottom. This is not surprising 

 considering the daily discharge of estuarine water through West Pass and into 

 nearshore waters at the eastern end of the study area. 



e. Stability Analyses . In the first analysis, control and experimental 

 samples are represented along the x-axis according to the number of days before 

 and after dredging (see App . F) . The y-axis is a scale of increasing distance 

 from a statistically determined centroid, or midpoint within a community clus- 

 ter represented mathematically and calculated from all available base-line and 



26 



