considered the poorest indices of abundance. 



In spite of such inadequacies of proper sampling and analysis, the 

 SHL produced interesting qualitative and semiquantitative data for 

 zooplankton populations endemic to the Bight. In these studies SHL 

 emphasized copepods, which are present in the Bight the year round, and 

 are usually the principal constituent of zooplankton. Copepods are small 

 shrimp-like animals, which because of their abundance, are important in 

 t\).e marine food chain. This was the only taxonomic group fully 

 analyzed by the SHL. 



The survey showed a general increase in total number of copepods from 

 January until late June, then a decrease from July until October, after 

 which, the numbers again increase. The average number of copepods per 

 cubic meter ranged from a high of 41,000 to a low of 700. The largest 

 number found was 87,000 copepods/m^ and the lowest 100 copepods/m^, with 

 most counts between 1,000 and 10,000/m^. The numbers of copepods/m^ 

 found by SHL were within the ranges reported by other investigators for 

 other middle Atlantic coastal areas (Table 17) . The numerical abundance 

 of six copepod species and the total copepod numbers for each of the six 

 stations and three depths sampled throughout the year, are given in 

 Figures 43 to 48. Figure 49 gives the average zooplankton population in 

 the water column for the dumping sites and adjacent areas. These data 

 confirm the known seasonal variation of copepod distribution. 



A significant observation of SHL was that copepod counts in the sewage 

 sludge disposal area were not different from other areas. Throughout the 

 year the counts of copepods were different only five times. Two of these 

 times the counts were higher than expected, and three times were lower. 

 For the rest of the 93 samples that were analyzed, the counts fell within 

 the expected range. 



Besides copepods, other zooplankton organisms were found by SHL in 

 the area of the dumping grounds in significant numbers. These included 

 chaetognaths , polychaete larvae, bivalve larvae and pelagic gastropods. 

 Seasonal zooplankters found in abundance were cladocerans, nauplii and cy- 

 prid stages of barnacles, siphonophores, salps and echinoderm larvae. 

 Although important constitutents of zooplankton, these meroplankton 

 organisms are seasonal visitors in the waters of the area, and of limited 

 value in zooplankton studies. Their occurrence however is useful in 

 predicting the potential benthic communities. Bivalve larvae were 

 abundant from January to April and from August through November in 1969, 

 while in January through March of 1970 they were not as abundant. The 

 highest concentration, 8,400/m^ was measured in a bottom sample from an 

 area southeast of the dumping grounds. Counts almost as high of bivalve 

 larvae were taken by SHL in the sewage dumping grounds. The low adult 

 population on the bottom suggested to SHL that settlement of larvae is 

 inhibited. 



Polychaete larvae were found in the Bight in densities up to 600/m^, 

 with highest concentrations near the bottom, from January to early June 



96 



