5-34 



Corophiwn i-nsidiosiffn 



Corophium insidiosum, a tube-dwelling amphipod, increased in 

 abundance throughout the study, with maximum numbers at Long Wliarf . 



Corophium Insidiosum has been classed as an opportunistic 

 species and an indicator of slight organic pollution (Anger, 1977) . C. 

 insidiosum spawns within its burrows from February through April, the 

 females retaining the larvae in their brood pouch. Females may have 4-5 



broods per year, the offspring of which reproduce in the same season. 



2 

 Densities may reach 63,000/m (TRIGOM, 1973). C. insidiosum is a com- 

 mensal of P. ligni , utilizing the polychaete tubes to provide suitable 

 habitat as well as feeding on microorganisms living in the tubes (Daro 

 and Polk, 1973) . The similarity in distribution between C. insidiosum 

 and P. ligni has been documented in a number of areas: Maine (Fuller, 

 1946) , Chesapeake Bay (Cory, 1967) , California (Graham and Gay, 1945) , 

 North Sea (Daro, 1970) , and the Baltic Sea (Anger, 1977) . 



Corophium insidiosum distribution patterns in New Haven Harbor 

 were similar to other areas. Percent occurrence values of 62, 46 and 33 

 percent at Long Wharf, Harbor Station and Fort Hale, respectively, in 

 conjunction with Figure 5-12, indicate maximum numbers and occurrence at 



Long Wharf, a silty, inner-harbor station. Highest abundances, exceed- 



2 

 ing 250,000/m , in 1977 were reported during July and August following 



juvenile settlement (NAI , 1978a). The 1976 abundance peak was also 



during the summer, but 1974, 1973 and 1972 showed spring maxima with 



smaller numbers settling in the fall. Studies at the Piscataqua River, 



New Hampshire showed C. insidiosum settling mainly in the spring and 



summer (NAI, 1977c) . C. insidiosum at Niantic Bay settled primarily in 



August (1973) on short-term panels and showed highest long-term panel 



densities in July; it was present in high numbers all months of 1973 



except May (Battelle, 1978). 



