6-41 



Classification Analysis 



Results of the cluster analyses are presented as dendrograms 

 in Figure 6-8 and 6-10 and mapped in Figure 6-9. Analysis of the dendro- 

 grams by strictly objective methods is difficult because of the temporally 

 and spatially irregular appearances of a number of opportunistic and 

 eurytopic species. Station similarities are inconsistent and generally 

 low. In order to attempt to identify some objective station groupings 

 in the harbor, the normal (Q-type) dendrograms were examined for linkages 

 between stations at a level above 0.5. These were recorded for each 

 sampling period and subsequently arranged in a trellis diagram (not 

 presented) showing number of linkages >0.5 over the entire program for 

 all possible pairs of stations. Because the NAI stations did not occur 

 in all of the dendrograms, the number of such linkages for these sta- 

 tions was increased proportionately. Station-pairs that had four or 

 more pairings >0.5 in common were relatively rare and formed four rather 

 discrete groupings. Their spatial distributions are shown in Figure 6- 

 10. Examination of the inverse (R-type) dendrograms (Figure 6-10) and 

 the species frequency lists, identifies the component species groups 

 which are responsible for the described clusters (Table 6-9) . 



A three-station cluster comprising Stations 5, 10 and 6N 

 occupies a small band of the inner harbor reaching from City Point to 

 the channel opposite the New Haven Harbor Station (Figure 6-9) . This 

 was the only cluster to appear in the inner harbor. The formation of 

 clusters in this type of analysis requires some consistency, or at least 

 congruent variation, in the species composition at the stations in 

 question. This is clearly difficult to find in New Haven inner harbor. 



The species which dominates the inner harbor cluster is 

 Nereis succinea (Table 6-9) . Though nodal analyses are not presented in 

 this report, some results are reported that are useful to provide an 

 objective and simple way to consider the relationships of species and 

 station groupings. Constancy of Nereis was high for the inner harbor 

 station group, particularly for Station 10 (i.e., proportion of Nereis 



(Text continued on page 6-50) 



