548 



Fishery Bulletin 90(3). 1992 



Figure 5 



Average depth (±1 SE) of the eight most distinct 

 bottom type combinations on Heceta Bank, Oregon. 

 Bottom codes and sample sizes are as follows: RR 

 = rock ridge {n 109); FF = flat rock (n 4); BB = 

 boulder (n 29); CC = cobble (n 8); MB = mud- 

 boulder {n 11); MC = mud-cobble (n 45); MP = 

 mud-pebble {n 26); MM = mud (n 55) (see text for 

 a description of bottom type codes), n = number 

 of habitat patches sampled per station. 



Because bottom-type changes were highly correlated 

 with changes in depth (Fig. 5), the CCA did not con- 

 found species associations with bottom types from dif- 

 ferent depths. Each axis measured associations occur- 

 ring within the depth range of 

 the habitat indicated by the vari- 

 able loadings on each axis. 



The first axis described varia- 

 tion in fish abundance associated 

 with mud habitats (160-240m). 

 Variable loadings indicate that 

 thornyheads, zoarcids, poachers, 

 and rex and Dover sole common- 

 ly occur on mud (Table 4). Can- 

 onical variate scores on this axis 

 were significantly different 

 among stations in both the habi- 

 tat and fish scores: station 5, the 

 only pure mud station (Fig. 2), 

 was significantly different from 

 all others (Kruskal-Wallis, p< 

 0.01) (Fig. 6A). 



The second axis contrasted an 

 additional independent fish-habi- 

 tat association. Variables load- 

 ings indicated that ratfish, and 

 rosethorn, sharpchin, yelloweye, 

 canary, and pygmy rockfish were 

 associated with boulder and 

 cobble fields at 75- 100 m depths. 

 Canonical scores for the second 

 axis also differed significantly 

 among stations on both habitat 

 and fish scores: station 6, the 

 station with the highest cover of 

 boulder-cobble (Fig. 2), was 

 significantly different from all 

 other stations (Kruskal-Wallis, 

 p<0.01) (Fig. 6B). 



The third axis indicated an ad- 

 ditional association between fish 

 and habitat. Variables loadings 

 indicated that greenstriped and 

 yellowtail rockfish, lingcod, and 

 cottids were associated with sand 



