13-16 



EPIBENTHIC INVERTEBRATES 



During the course of the New Haven Harbor Station Ecological 

 Monitoring Studies, 44 epibenthic invertebrate taxa were collected. In 

 general, abundance was highest during periods of moderate water temp- 

 eratures, from late spring to early summer and fall; it was lowest 

 during periods of extreme water temperature, during winter and, more 

 notably, mid-summer. Seasonal abundance patterns may have reflected 

 local inshore-offshore movements or changing degrees of organism activ- 

 ity and thus exposure to capture by sampling gear. 



The most abundant trawl organisms were sand shrimp (Crangon 

 septemspinosus) , common starfish {Asterias forbesi) , rock crabs {Cancer 

 irroratus) , lady crabs [Ovalipes ocellatus) and mantis shrimp (Sguilla 

 empusa) . Sand shrimp comprised from over 50 to 90% of the total annual 

 catch. Densities were highly variable but tended to be lowest at outer 

 harbor stations and generally lower in the harbor during summer months. 

 Starfish annual abiindances declined steadily at all stations during the 

 monitoring program with no seasonal or spatial trends evident. Rock 

 crab and lady crab annual abundances varied widely, and both crabs had 

 distinct seasonal abundance patterns. Rock crabs were well-represented 

 during all seasons except siommer. For lady crabs, annual abiondance 

 differences were particularly high, with total number captured ranging 

 from 60 individuals in 1974 to 3200 in 1977. Largest numbers were 

 consistently collected during late summer and early fall in the inner 

 harbor and Morris Cove. The deep-burrowing stomatopod shrimp, Sguilla, 

 was captured almost exclusively in fall trawls in channel stations. 

 Lobsters {Homarus americanus) are the only commercially important trawl 

 invertebrates in New Haven Harbor and comprised about 1% of the trawl 

 catch in each year of the sampling program. Lobster abundances peaked 

 regularly in spring and, occasionally, in the fall. Summer and winter 

 lobster catch was characteristically low. Catch was highest in the 

 channel near the Harbor Station discharge throughout the program and 

 lowest in the shallow inner harbor and outer harbor areas. 



