6-31 



In addition to these fluctuations there is a seasonal pattern 

 of change in faunal density which has been noted in previous reports. 

 Figure 6-6 shows these density changes at 1) two Morris Cove deep-water 

 (fine sediment) stations, 2) two Morris Cove shallow-water (coarse-grained 

 sediment) stations and 3) two inner harbor deep-water stations, respect- 

 ively. All three areas exhibit the same general trend. Seasonal den- 

 sity minima tend to occur in late-sxommer, with the densest populations 

 generally occurring in late fall. This is particularly evident in the 

 inner harbor, although somewhat less clear at the shallow-water Morris 

 Cove stations, and again readily discernible at the deep Morris Cove 

 station although the radical changes in density characteristic of the 

 other areas are not so apparent (Figure 6-5) . 



The pattern of seasonal density minima occurring in the late- 

 summer is somewhat unusual as most natural benthic populations, if they 

 exhibit pronounced seasonality, tend to develop maximum densities during 

 this period and into the early fall. In an unpolluted bottom area, 

 particularly one exposed to storms, the late fall/early winter period is 

 marked by low densities. The pattern observed in New Haven Harbor tends 

 to confirm the conclusions offered in earlier reports that pollution- 

 related stresses, which are most evident during the summer, are the 

 primary controlling factor for the New Haven benthos. In light of these 

 data on faunal density it is possible to place the hypothesis of an 

 "August effect" in its proper perspective. 



From Figure 6-6 we see that Station 5 shows a precipitous 

 decrease in faunal density during August for each of the four years of 

 the program. This pattern is somewhat less evident at Station 10 and at 

 shallow stations in Morris Cove, and quite marked, though without such 

 precipitous declines, in the deeper Morris Cove stations. These obser- 

 vations , combined with the fact that August declines were not apparent 

 at the NAI inner harbor stations tend to indicate that the occurrence of 

 dramatic faunal declines in August depends upon station location and 

 water depth. Dissolved oxygen data (Normandeau Associates, Inc., 1975- 

 1978) indicate that dissolved oxygen values generally decrease with 



