4. To evaluate whether variations in the abundance estimates in 



the current year are within the normal variation as determined 

 from historical data and to interpret such variations in 

 relation to power plant operations. 



To ensure that these objectives were met, study methods have been 

 modified when necessary (NUSCo 1983a). Offshore ichthyoplankton and 

 entrainment fish egg methods have been consistent since 1979; trawl, 

 seine, impingement and entrainment larval programs have been consistent 

 since 1976. 



Observed changes in finfish abundance may be natural or power plant 

 induced, so an understanding of fluctuations representing natural 

 variability is important. Historical observations through 1982 provided 

 a basis for predicting the kinds and relative numbers of organisms that 

 might occur in a given area at a certain time of the year. We used 

 harmonic regression analysis to model the observed abundance fluctuations 

 and to forecast expected fluctuations for 1983. We compared the actual 

 data collected to those values predicted and interpreted the differences 

 relative to power plant impact. Model results and interpretations are 

 included in this report. 



MATERIALS AND METHODS 



Trawl sampling 



Demersal f inf ishes were sampled west of Twotree Island (TT) , 

 southwest of Bartlett Reef (BR) , in Niantic Bay (NB) , Jordan Cove (JC) , 

 Niantic River (NR) and in front of the intake structures (IN) (Fig. I). 

 Specimens were collected using a 9.1-m otter trawl with a 0.6-cm mesh 

 cod-end liner. Triplicate tows, each covering 0.69 km of the bottom as 

 measured by RADAR, were made biweekly at each station from October 1977 

 through September 1983. Prior to October 1977, the unit-effort was 15 

 min per tow. Although time is traditionally the unit-effort for trawls, 

 it was felt that the demersal finfish abundance would be better 



