4-43 



Harbor on a fairly regular and essentially year-round basis. Oithona 

 sp(p). was, however, relatively scarce in 1977 collections (Table 4-5). 



Deevey {1952a) reported Oithona sp. as a year round consti- 

 tuent of Block Island Sound plankton which comprised a large percent of 

 the fall copepods (Figure 4-15) . Oithona. sp. was not reported at 

 Millstone Point, probably because of the larger net size used (333pin vs 

 158 ym net at New Haven and Long Island Sound) . 



Important members of the invertebrate meroplankton assemblage 

 in New Haven Harbor included pelagic larvae of barnacles, gastropods, 

 polychaete worms, and bivalve molluscs (Table 4-4) . Among the mero- 

 plankters, barnacle larvae consistently ranked highest in abundance 

 (Table 4-4) . Judging from sessile adult abundance, the species repre- 

 sented have been primarily Balanus eburneus and B. improvisus . A poly- 

 modal pattern of seasonal abiindance is suggested in Figure 4-19 and 

 presumably represents successive spawning episodes. Peaks of repro- 

 ductive activity appeared to be May- July and September-October, with a 

 third, relatively modest, population peak occurring in February-March. 

 In the case of barnacle cyprids (a later developmental stage) , there 

 appeared to be essentially two abundance peaks per year (Figure 4-19) , 

 the first occurring in March or April and the second from June through 

 August. These peaks corresponded to the February-March and May- July 

 naupliar population peaks. There appears to have been no cyprid peak 

 corresponding to the September naupliar peak perhaps due to: 1) onset 

 of winter and consequent scarcity of food, and/or 2) encounter with 

 particular predators, such as ctenophores that have occurred in sub- 

 stantial quantities during the months of August and September (NAI, 

 1978) . Deevey (1952a) reported Balanus sp. larvae in Block Island Sound 

 from January through April. 



Polychaete larvae ranked close to barnacle larvae in overall 

 numerical importance (Table 4-4) particularly in 1973 and 1974 when data 

 were derived from a Clarke-Bumpus net (76ym mesh) . During 1975, 1976 

 and 1977, after a summer peak, there was a decline in abundance (Figure 



