The 1981 study focused on a much smaller geographical area (23 km) using fish from the Connecticut 

 River, Niantic River, Niantic Bay, Jordan Cove, and the Thames River. These areas were thought to be 

 likely sources of winter flounder affected by MNPS operations. Because of the smaller area in which fish 

 were taken, the samples were much more homogeneous than the ones in 1980. Fish from Jordan Cove 

 often misclassLfied into Niantic River or Bay or the Thames River. The Connecticut River winter flounder 

 also misclassified frequently. Upon further examination, most of the latter fish were found to have been 

 sexually immature, which was thought to have caused the failures in discrimination. The seasonal samples 

 taken in Niantic Bay over the year showed substantial variability; summer and fall samples were not 

 significantly different, but other seasons were. 



The major conclusion of the study was that the technique was able to distinguish between stocks or 

 subpopulations of winter flounder found about 5 to 10 km apart. Winter flounder in the area around 

 MNPS appeared to form separate stocks only during the winter and spring spawning season, with inter- 

 mixing greatest during summer and fall. The areas immediately in the vicinity of the plant (Niantic River 

 and Bay and Jordan Cove) appeared to be inhabited by substocks that intermix significantly. Additional 

 interchange took place with stocks from more distant areas, such as the Connecticut and Thames Rivers. 

 Immature fish were impossible to classify using the techniques and analyses employed during the study. 

 They were a heterogeneous group either because they were well-mixed over the geographical range of the 

 study or because juveniles showed a lack of differentiation for the particular proteins examined. As 

 young-of-the-year fish were not examined, this conclusion may not apply to them. 



The fmdings of this study along with tagging data indicated that at certain times of the year the winter 

 flounder impinged at MNPS as well as throughout the study area were a mixture of a number of different 

 spawning stocks. Consequently, the long-term effects of this particular impact on the Niantic River stock 

 are somewhat reduced because of the dilution. Furthermore, the degree of intermixing implies that 

 interchanges frequently occur among local stocks; this would also help to mitigate losses particular to any 

 one of them. 



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