4-28 



ellates (including H. triquetra) , unspecified flagellates and Skele- 

 tonema costatum (June 1975 through 1977; July 1974 through 1977) were 

 dominant. August's community was usually dominated by flagellates and 

 Thalassiosira/Cyclotella species (including T. pseudonana) ; Skeletonema 

 costatum (1976 and 1977) , Chaetoceros sp. (1976 and 1977) , and pennate 

 diatoms (P. tricornutum in 1974, unspecified Pennales in 1975 and 1976, 

 C. closterium in 1976 and 1977, and A. glacialis in 1976) were also 

 dominant in August. During September, flagellates continued to dominate 

 with diatoms such as Skeletonema costatum (1974 through 1977) , Chae- 

 toceros spp. , C. curvisetus in 1974 and 1975 and Chaetoceros sp. in 1976 

 and 1977, Thalassiosira/Cyclotella sp. (1974 through 1977) , and Lepto- 

 cylindrus minimus (1975 through 1977) . 



A comparison of maximum cell densities recorded for seven of 

 the dominant species during the present study compared with literature 

 records for Long Island Sound and Great South and Moriches Bays, is 

 presented in Table 4-3. Similar order-of -magnitude densities were found 

 for all but Thalassionema nitzschoides whose peak New Haven Harbor 

 densities were higher than those reported for Long Island Sound, and 

 Thalassiosira pseudonana which was less dense in New Haven Harbor than 

 in Great South and Meriches Bay. 



Characterisation of the New Haven Harbor Zooplankton 



Characterization of the New Haven Harbor zooplankton in this 

 study relies on data produced by two different methods of sampling and 

 laboratory analysis. Further, because the second method was instituted 

 just several months prior to the plant going on line, understanding of 

 the differences in density estimates based on the two different methods 

 is vital to analysis of impacts. 



Results of a 13-month comparability study are presented in 

 detail in Appendix 4-1. The foremost observation is that the two methods 

 yielded radically different density estimates. Of the two methods, the 



