based on medians, could not be calculated. The 

 seasonal 5-mean densities were used as an abun- 

 dance index (Table 23). Larval densities have 

 been consistently higher at NB than at EN, but 

 similar annual trends were evident at both stations; 

 abundance increased from the late 1970s to early 

 1980s and then declined to levels comparable to 

 those in the mid-1970s. This decline was not 

 evident in annual egg abundances. 



TABLE 23. The seasonal 5-mean density (no. per 500 

 m ) of tautog larvae collected at stations EN and NB by 

 year. 



Data seasonally restricted to June through August. 



Comparison of annual egg to larval abundances, 

 based on the 8-mean (see Table 5 for egg 5-mean), 

 indicated that egg to larval survival was low; gen- 

 erally the larval index was less than 2% of of the 

 corresponding egg index. Similar low annual 

 larval to egg ratios were evident for collections at 

 SNPS (Table 20). Further discussion of this low 

 survival for the wrasses (tautog and cunner) is 

 provided in the following section on cunner. This 

 apparent low natural egg survival would reduce 

 the potential impact of the large numbers of eggs 

 entrained by three-unit operations. A comparison 

 of annual larval and egg abundances did not reveal 

 a density-dependent relationship, as was found 

 for anchovies. Because the tautog takes 2 to 4 

 years to reach maturity, the possible impact of 

 entrainment by three-unit operation on the adult 

 stock size (best measured by annual egg abun- 

 dance) will not be evident for several years. 



Cunner 



The cunner is a coastal marine fish that prefers 

 rocky habitats (Bigelow and Schroeder 1953; 

 Serchuk 1972; Olla et al. 1975, 1979; Dew 1976; 

 Pottle and Green 1979). It ranges from northern 

 Newfoundland to the mouth of the Chesapeake 

 Bay (Leim and Scott 1966). Most cunner have 

 limited home ranges (less than 4 km) and probably 

 stay within several meters of their nighttime shel- 

 ter. Adults generally display highly localized 

 abundance in areas they inhabit and their numbers 

 greatly decrease only a short distance from cover 

 (Gleason and Recksiek, in preparation). They are 

 active only during the day and activity declines 

 in cold weather as individuals become dormant 

 at temperatures below 8°C and lie torpid among 

 and under rocks (Green and Farwell 1971; Green 

 1975; Dew 1976; Olla et al. 1979). Individuals 

 mature in 1 to 2 years and the maximum reported 

 age is 10 years (.lohansen 1925; Dew 1976). 

 Cunner spawn primarily in June through August 

 and the pelagic eggs hatch in 2-6 days depending 

 on water temperature (Williams 1967; Dew 1976; 

 Fritzsche 1978). Metamorphosis of larvae is com- 

 plete by 10 mm and juveniles move to the bottom 

 (Miller 1958). 



All life stages of the cunner were collected in 

 the Millstone area. Eggs and larvae were found 

 in ichthyoplankton collections, primarily from 

 June through August. Juveniles and adults were 

 caught at aU six trawl stations and in greatest 

 abundance during the spring through fall. Cunner 

 were rarely collected by seine (Appendix IV). As 

 cunner prefer the rocky habitats that surround 

 MNPS, the species was among the top dozen of 

 those impinged (Table 2). Annual impingement 

 estimates at Unit 2 decreased from a high of 1,787 

 in 1983 to a low of 57 in 1987. This decrease 

 followed the general decline in total impingement 

 of all species. 



Cunner eggs predominated in entrainment col- 

 lections and were abundant during May through 

 July; the date of peak abundance consistently oc- 

 curred during the first half of June (Table 24). 



Fish Ecology Studies 283 



