compared to 1983 and 1984, but similar to the 

 period of 1980-82. Larval abundance at EN dur- 

 ing 1986 was similar to or higher than most other 

 years, except for 1981. ITie fluctuations in Icirval 

 abundance at NB were similar to EN; the 1984 

 abundance was low at both stations. No long 

 term-trends in abundance were apparent for eggs 

 or larvae. 



Patterns of annual abundance of anchovy eggs 

 and larvae in the vicinity of S NFS were not sim- 

 ilar to the Millstone area (Table 12). The low 

 abundances of eggs at Millstone in 1985 and 1986 

 were not found at SNPS, which had high annual 

 egg abundance during this period. Further, the 

 peak that occurred in 1984 at Millstone was not 

 evident at SNPS. During the early 1980s, larval 

 abundance at Millstone was the highest, but at 

 SNPS it was the lowest. These dissimilarities sug- 

 gest that the spatial distribution of anchovies in 

 LIS may differ from year to year. Trawl catches 

 of anchovies at SNPS were variable, but a decline 

 has occurred since the early 1980s, and similar to 

 our trawl data, a majority of the catch was taken 

 in late summer and early fall, probably of young- 

 of-the-year. 



TABLE 12. Annual abundance indices of anchovy eggs 

 and larvae, both expressed as an annual sum of means; 

 and trawl catch as annual CPUE at Shoreham Nuclear 

 Power Station. 



Sums for 1977-82 based on mean density per sam- 

 pling trip (Geomet Tech. 1983) and for 1983-86 based 

 on monthly mean density (EA Eng., Sci., and Tech. 

 1987). 



A comparison of the annual abundance of eggs 

 and larvae at EN indicated two apparent discrep- 

 ancies. First, the index of armual abundance (a) 

 for eggs was generally lower than for larvae, and 

 secondly, there was no relationship between the 

 annual egg and larval abundances. The apparent 

 low abundance of eggs relative to larvae may be 

 related to the length of time that each develop- 

 mental stage was available for capture; the incu- 

 bation period for eggs was only a few days and 

 larvae were available for capture over a period of 

 weeks. In order to make a direct comparison of 

 abundance of eggs to larvae, the abundance index 

 would have to be weighted according to the av- 

 erage developmental time for each respective stage. 

 Another possible explantion for low egg abun- 

 dance, compared to larval abundance, was that 

 Niantic Bay was not a primary spawning area for 

 anchovies and that larvae were transported by 

 tidal currents to the bay from more preferred 

 spawning grounds. 



In either of the above two cases, there should 

 be some relationship between the abundance of 

 eggs (a measure of spawning stock size) and the 

 resulting larvae, unless there were annual fluctu- 

 ations in the mortality rates of eggs and larvae. 

 In some years there appeared to be an inverse 

 relationship between egg and larval abundances. 

 Vouglitois et al. (1987) reported a similar pattern 

 for the bay anchovy in Bamegat Bay, NJ during 

 a 2-year period. This would suggest that com- 

 pensatory mortality occurred during the early life 

 history stages. Density-dependent mortality was 

 examined by comparing annual a values for eggs 

 (E) to the 8-mean density of larvae (L) collected 

 during August at EN. Compensatory mortality 

 was evident, as the slope (P) was negative and 

 significantly different from zero (Fig. 5). This 

 relationship was most evident in 1981 which had 

 relatively low egg abundance and the greatest 

 larval abundance, and in 1984, with the greatest 

 egg and the lowest larval abundance. Compensa- 

 tory mortality can be caused by several factors, 

 including starvation due to competition for prey 

 and increased predatory pressure. Houde (1977, 

 1978a, 1978b) found in laboratory studies that 

 food prey availability affected the survival of the 



Fish Ecology Studies 271 



