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Fishery Bulletin 90(3). 1992 



fish assemblage, followed by 

 boulder, rocky ridge, mud and 

 cobble, and mud and boulder 

 habitats. In contrast, habitats in- 

 volving combinations of boulder, 

 mud, sand, and cobble had com- 

 paratively similar fish assem- 

 blages. 



The results of the cluster anal- 

 ysis provide information relevant 

 to the interpretation of the PCA 

 results (Figs. 3,4). Stations that 

 displayed little among-transect 

 variability in fish assemblages 

 were composed primarily of rocky 

 ridge (stations 1 and 3), and mud 

 (station 5): habitats that had 

 relatively distinct fish assem- 

 blages. In contrast, stations with 

 high among-transect variability 

 (primarily stations 2 and 6) were 

 composed of mixtures of mud, 

 cobble, and boulders: habitats 

 sharing relatively similar fish 

 assemblages. 



There were additional habitat 

 patterns evident in the distribu- 

 tion of the most abundant rock- 

 fish species (Table 3). Comparing 

 abundances of the four most 

 abtmdant species within subhabi- 

 tats, pygmy rockfish dominated 

 all except mud, mud and cobble, 

 and flat rock. Sharpchin domin- 

 ated mud and cobble; rosethorn, 

 the flat rock (Table 3). Compar- 

 ing abundances for each subhabi- 

 tat within species, it is clear that 

 each species, even though it 

 might not be numerically domi- 

 nant overall, was most abundant 

 in a particular habitat. Thus, 

 pygmy rockfish were most abun- 

 dant on mud and boulder; sharp 

 chin and greenstriped rockfish on mud and cob- 

 ble; rosethorn rockfish on boulder; and yellowtail 

 rockfish on rock ridges. 



Figure 3 



Ordination of first and second principal component 

 scores for 36 transects sampled at six stations on 

 Heceta Bank. The analysis is based on the relative 

 abundances of 30 fish taxa observed (see Table 2 

 for species list). 



