Quarterly mean abundance (no./core) at intertidal stations ranged from 4 to 840 and mean species 

 numbers from < 1 to 13. Overall, species abundances and species numbers were highest at Jordan 

 Cove and of similar magnitude at Giants Neck and White Point. In general, intertidal abundance and 

 species number were higher during warmer sampling periods (June and September) than during colder 

 ones (March or December). Multiple regression analyses, which were based on natural abiotic variables 

 were used to identify and remove naturally-induced temporal variations in abundance and number of 

 species. After adjusting for this variation, no significant increasing or decreasing trends in abundance or 

 species number were evident from 1980 to 1985. 



Annual mean species diversity (H') over the study period ranged from 1.2 to 2.3, and evenness (J) 

 from 0.4 to 0.7, and on an annual basis, no consistent spatial or temporal shifts in IV have occurred 

 over the monitoring period. Diversity parameters reflected the spatial differences evident in the structure 

 of intertidal communities throughout the monitoring program. 



l')ata collected during the baseline period characterized the spatial relationships among sampling 

 stations and investigated the extent and direction of temporal fluctuations in the abundance and numbers 

 of species that have occurred from 1980 - 1985. During this period, no changes in intertidal communities 

 could be attributed to operation of Millstone Units 1 and 2 or construction of Unit 3. Data presented 

 here appear representative of natural, undisturbed intertidal communities and will be the basis for all 

 future impact studies performed during 3-umt operating conditions. 



Subtidal 



Sediments at subtidal stations ranged from fme to coarse sands and contained up to 40% silt/clay. 

 Sedimentary characteristics of all stations, except Jordan Cove, have exhibited some temporal shifts 

 during the study. Values for grain size at Giants Neck have generally increased since 1982. At Intake, 

 smaller grain size and more highly variable silt/clay values have been observed since June 1983, when 

 construction activities (dredging and coffer dam removal) resulted in the deposition of fme material at 

 this station. Silt/clay content at Effluent has also become more variable following construction activities 

 in the area of the Unit 3 discharge cut. 



