8-45 



period the number of Cancer individuals impinged has been small (average 

 of to 6 per 24 hours) . The decrease in the impingement of Cancer 

 since December 1975 does not appear to reflect any decrease in the pop- 

 ulation abundance of this species since, during 1977, Cancer was col- 

 lected in trawls in relatively high abundances. Maximum impingement of 

 the calico crab, Ovalipes ocellatus , and the mantis shrimp, Squilla 

 empusa, occurred during October and November. During periods of peak 

 impingement the average number of animals impinged per 24 hours ranged 

 from 50 to over 250 for Ovalipes and 100 to 1200 for Squilla. Ovalipes 

 was also impinged in lesser numbers during April, May and June when the 

 average number of animals impinged per 24 hours ranged from 5 to 200. 

 The magnitude of impingement of Ovalipes and Squilla has generally been 

 consistent with trawl data. Ovalipes was collected in highest abun- 

 dances in otter trawls during 1975 and 1977 while relatively few were 

 collected during 1976. Similarly, highest numbers of Ovalipes were 

 impinged during 1975 and 1977, while only moderate nvimbers were impinged 

 in 1976. Squilla was collected in highest abundances during 1976 and 

 impingement was also high during this year. Comparison of preopera- 

 tional with operational trawl data shows no trends of decreasing catch 

 abundance of Cancer, Ovalipes or Squilla as might be expected if exces- 

 sive impingement had occurred. 



In conclusion, with one exception, no major changes in epi- 

 benthic species abundance and distribution within New Haven Harbor have 

 been apparent since the New Haven Harbor Station began operation (29 

 August 1975) . Variations observed in species composition, distribution 

 and abundance during all operational years appear to be well within the 

 range of variability established by preoperational monitoring. The 

 starfish, Asterias forbesi, was the only species that showed any major 

 change in abundance; there has been no evidence to date that suggests 

 that the observed annual decrease in catch abundance of this species was 

 attributable to the operation of the New Haven Harbor Station. The 

 operation of New Haven Harbor Station appears to have had no detectable 

 influence on the epibenthic invertebrate community in New Haven Harbor. 



