5-9 



with most species settling from June through October (Figure 5-3) . 

 Species richness values were greatest in July, August and September for 

 all years (Table 5-2) . Species richness was usually lower at Long Wharf 

 than Fort Hale or Harbor Station, reflecting decreased water quality in 

 the inner harbor. 



Species richness on long-term panels showed annual increases 

 from 1971 through 1976 and a decrease in 1977 (Figures 5-4, 5-5). As 

 already indicated, however, this parameter is influenced by taxonomic 

 refinements, panel losses and length of sampling period. Table 5-3 was 

 constructed to assess the effect of 1975 and 1976 taxonomic changes on 

 the data. Species are included in the highest taxon that could have 

 been used at any time. For example, in some years barnacles were 

 identified to Balanus spp. , consequently more specific taxa, B. ebur- 

 neus , B. crenatus and B. improvisus are grouped under Balanus spp. 

 and times of occurrence noted. Many of the polychaete species have been 

 grouped in families as the lowest meaningful taxon, while in some cases 

 the class designation Polychaeta was used. Taxa are marked to indicate 

 changes in identification resulting from the 1975 personnel change, as 

 well as changes instituted with the new contractor in 1976. The latter 

 have a limited impact on Table 5-3 data because the changes are largely 

 refinements of previously identified taxa. Figure 5-4, however, shows a 

 large 1976 species richness increase reflecting an increase in more 

 specific taxa, accompanying the previously used general classifications, 

 but this increase is not a true indication of an actual species richness 

 increase. The 1977 decrease is related to long-term panel loss at Fort 

 Hale, and the shortened sample period (10 months) as well as taxonomic 

 refinements . 



Seasonal trends in long-term panel species richness were 

 variable in New Haven Harbor. High summer richness occurred in the 

 summer of 1977, but not in 1975 and 1976, and was probably a function of 

 recruitment from spawning populations (Osman, 1977) . The general trend 

 of unpolluted estuaries is toward high summer richness (Calder and 

 Brehmer, 1967; NAI, 1975b; NUSCO, 1977), but this trend may be vari- 



Text continued on page 5-16. 



