TABLE 1. The seasonal 5-mean (CPUE) of the abundant fish taxa caught in trawls during each report period (June- 

 May). 



Data seasonally restricted to June-October for Stenotomus chrysops, to August-October for Anchoa spp. , to 

 October-February for Menidia spp. , and remaining taxa year-round (June-May) 



data for this analysis were limited to their season 

 of occurrence: June through October for scup, 

 August through October for anchovies and Oc- 

 tober through February for silversides. The 

 5-mean catch for all of the dominant species has 

 fluctuated and during three-unit operation the 

 catches were within or above historical ranges 

 with some of the highest abundances for scup, 

 anchovies, and silversides. 



Seine monitoring 



Approximately 40 different taxa have been 

 caught by seine during the past 1 1 years of mon- 

 itoring (Appendices IV and V). Silversides dom- 

 inated the shore-zone catches and accounted for 

 over 80% of the total. About 80% of the total 

 seine catch was collected at JC. This station is 

 a productive nursery area, and hundreds of juvenile 

 silversides are routinely caught at this site during 

 the summer months (June through September). 

 Because silversides dominated all the annual 

 catches, total catches were largely a function of 

 silverside catches. Total catches for all shore-zone 

 taxa were higliest during the 1976-77 and 1977-78 

 report periods and were dominated by juvenile 

 silversides at JC (NUSCO 1987b). Because the 

 silversides dominated the shore-zone area of Jor- 

 dan Cove, which may be thermally impacted by 

 the condenser cooling water discharge, 't was se- 

 lected as a potentially impacted taxon and is dis- 

 cussed in further detail later. 



Impingement monitoring 



Impingement has been monitored at Millstone 

 Unit 2 since it began operating in September 

 1975. The objective of the monitoring program 

 was to quantify total annual species-speciftc loss 

 due to impingement. Because impingement losses 

 have been well-documented and measures to mit- 

 igate impingement losses have been investigated, 

 a request was vSubmitted to the Connecticut DEP 

 in July 1987 to discontinue impingement moni- 

 toring at Unit 2 (NUSCO 1987a). The DEP 

 accepted our request and sampling was discontin- 

 ued on December 11, 1987. 



Annual impingement estimates were calculated 

 from January 1, 1976 through December 11, 1987. 

 Over 100 fish and invertebrate taxa were impinged 

 during the past 12 years (Tables 2 and 3). Sand 

 lance accounted for over 60% of the total because 

 an estimated 480,000 were impinged during the 

 week of July 18, 1984. Impingement of sand 

 lance during that week accounted for over 98% 

 of the 12-year total for that species. The sand 

 lance is a schooling species (Leim and Scott 1966) 

 and a large school encountered the intake struc- 

 ture. Excluding sand lance, six fish taxa dominated 

 the collections: winter flounder, anchovies, 

 grubby, silversides, sticklebacks, and Atlantic 

 tomcod (Table 4). These taxa were selected as 

 potentially impacted species and discussed in fur- 

 ther detail later, except for winter flounder (see 

 Winter Flounder Studies section). 



Fish Ecology Studies 261 



