8-10 



temperature, salinity, and dissolved oxygen, as well as biological 

 factors such as available food source, predator-prey relations, and 

 interspecific and intraspecific competition for available habitat 

 resources. As is the case in most estuarine systems, physical and 

 chemical parameters varied from one area to another resulting in dif- 

 ferences in species composition and relative abundances. In New Haven 

 Harbor, low salinities in the inner harbor, particularly during winter 

 and spring, restrict many stenohaline species such as the common star- 

 fish, Asterias forbesi, from the area. In contrast, euryhaline species 

 such as Palaemonetes vulgaris , a caridean shrimp, and the mud snail, 

 Ilyanassa obsoleta can tolerate fluctuating salinities and are abundant 

 in this area. The inner harbor is characteristically a highly variable 

 environment. Physical/chemical parameters such as temperature, dis- 

 solved oxygen and salinity fluctuate widely. During summer, dissolved 

 oxygen drops considerably (4.0 ppm and lower) and temperatures are high 



(22-24°C) . During winter the opposite occurs: temperatvires may drop to 

 near freezing and dissolved oxygen increases to supersaturation levels. 

 As a result, many organisms move in and out of the area in response to 

 the changing environmental conditions, and species composition and 

 abundances fluctuate widely over the course of a year. 



Inner harbor Station 5 has consistently ranked among the top 

 three stations in annual abiondance (Table 8-2) , Characteristic epi- 

 benthic species in this area have been Crangon septemspinosa , Ilyanassa 

 obsoleta, Limulus polyphemus and Palaemonetes vulgaris , and to a lesser 

 degree, Nassarius trivittatus and Ovalipes ocellatus (NAI, 1978a). 



The epibenthic invertebrate community in the deeper water of 

 the main shipping channel in the vicinity of the Harbor Station dis- 

 charge (Station 8) and middle harbor (Station 11) was composed of a 

 somewhat different array of epifa\inal species (NAI, 1975a, 1976a, 1977 

 and 1978a) . Both stations were similar in terms of species composition 

 and abundance, and typically ranked either first or second in total 

 annual abundance (Table 8-2) . Salinity at these areas does not fluc- 

 tuate to as large a degree as at Station 5. Bottom dissolved oxygen 



