FISH ECOLOGY 

 INTRODUCTION 



Finfish are an important marine resource and are found in a variety of habitats in the vicinity of 

 Millstone Nuclear Power Station (MNPS) in eastern Ixjng Island Sound (LIS). The construction and 

 operation of MNPS could affect fish assemblages inhabiting the site environs (Fig. 1) by increasing 

 mortality rates of various life stages and by altering spatial distributions. Populations may experience 

 higher than normal mortality rates due to either impingement of young and adult fish on the intake screens, 

 or entrainment of larvae in the cooling water system. The effect of increased mortality rates on these 

 populations can be very different depending on the size, age structure and life span of the affected 

 populations, and on the existence of compensatory mechanisms. Further, the spatial distribution of local 

 fish populations may change in response to alterations in the thermal or chemical regime of the effluent 

 or modifications to the physical habitat. Warmer water temperature can attract or exclude fish from areas 

 affected by the thermal plume. Physical alterations caused by construction, dredging or bottom scouring 

 could also attract or exclude fish from affected habitats. Because of these potential effects, Northeast 

 Utilities Service Company (NUSCo) established several finfish sampling programs to provide baseline data 

 for assessing the impacts of construction and operation of MNPS on local fish populations. 



The objectives of the fish ecology programs are as follows: 



1. To sample, identify, and enumerate fish found in the Millstone Point area; 



2. To determine which fish species may be susceptible to impact from entrainment, impingement, or 

 exposure to the heated effluent; and 



3. To describe the fluctuations in abundance of life history stages of species that are potentially impacted 

 and evaluate whether these fluctuations are within the expected historical range or have been effected 

 by power plant operation. 



