LOBSTER POPULATION DYNAMICS 



INTRODUCTION 



The American lobster, Homarua americaniis, is the most valuable commercially harvested species in 

 I^ng Island Sound (I.,IS). Annual landings since 1977 have ranged between 600,000 and 2,000,000 pounds 

 with a value ranging between 1.3 and 6.2 million dollars. The landings for New London county, which 

 include Millstone Point, were between 28% and 45% of the total LIS catch from 1977 to 1985 (Blake 

 and Smith 1984; CT DEP personal communications). Fxploitation rates in LIS are high and over 90% 

 of marketable lobsters are newly recruited from the sublegal size class (Smith 1977; Keser et al. 1983). 

 Therefore the strength of the legal catch is highly dependent on the number of lobsters in the prerecruit 

 size class (one molt from legal size). 



The lobster monitoring program at the Millstone Nuclear Power Station (MNPS) was designed to 

 assess the impacts of plant operations by evaluating year-to-year, seasonal, and between station changes 

 in selected population characteristics such as catch per unit effort, size frequencies, growth rates, sex ratios, 

 female size at sexual maturity, characteristics of egg-bearing females and lobster movements. L,obster larvae 

 enfrainment studies are also conducted to assess impacts on the larval stage of lobsters. The results of all 

 these studies arc often compared to other studies conducted throughout the range of the American lobster. 



Potential effects of MNPS operations on the lobster population are impingement of lobsters on the 

 intake traveling screens, entrainment of larvae through the cooling water systems, and thermal effects of 

 the discharge. These power plant impacts may reduce survival of lobster larvae and juveniles or alter the 

 behavior of adults which may result in a decline in the local inshore fishery. 



The purpose of this report is to summarize the results of the lobster population studies conducted 

 during 2-unit operation from 1975 to 1985. These results will be compared to data collected under 3-unit 

 operating conditions to assess the possible impacts on the local lobster population associated with MNPS 

 operations. 



