Murie et al.: Distribution and activities of Sebastes spp. 



319 



(64% occurrence) and tiger rockfish 

 (32%). Copper rockfish, while usually 

 near quillback rockfish, were also ob- 

 served in conspecific aggregations and 

 they were seldom seen alone (4%). Ti- 

 ger rockfish were almost always ob- 

 served near quillback rockfish (96% 

 occurrence) and, to a much lesser ex- 

 tent, near other tiger rockfish (21%) 

 (Fig. 6). The majority of yellowtail rock- 

 fish were observed in proximity to 

 quillback rockfish (96%) and other yel- 

 lowtail rockfish (91%). All five of the 

 yelloweye rockfish seen were near quill- 

 back rockfish. Six greenstriped rockfish 

 were observed near quillback rockfish 

 whereas two were alone. 



Discussion 



COPPER (n=24) 



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HOLE CREVICE PERCH HOVER SWM 



HOLE CREVICE PERCH HOVER SWM 



Quillback rockfish are the numerically 

 dominant rockfish species at depths of 

 21-100 m in nearshore areas of south- 

 ern British Columbia, based on sub- 

 mersible observations in a fjord (this 

 study) and in relatively open coastal 

 areas (Richards, 1986). Based on both 

 of these submersible studies, the main 

 depth distribution of quillback rockfish is between 

 41 and 60 m, and their density at this depth is more 

 than eight times greater than that of any other rock- 

 fish species observed at 41-60 m (Fig. 3A; Richards, 

 1986). As in Saanich Inlet, greenstriped and 

 yelloweye rockfish were also observed in relatively 

 low densities in the northeastern Strait of Georgia 

 (means of <2 fishlOOm -2 in various habitat types) 

 (Richards, 1986), as well as tiger and copper rock- 

 fish (Richards and Cass, 1985). Yellowtail rockfish 

 were not seen during submersible dives in the north- 

 eastern Strait of Georgia (Richards and Cass, 1985). 

 In Saanich Inlet, complex habitat dominated by 

 broken rock and boulder fields appears to be a com- 

 mon feature for the occurrence of the majority of 

 these rockfish species. Based on Pisces surveys in 

 the northeastern Strait of Georgia, Richards (1986) 

 also observed that quillback and yelloweye rockfish 

 were most abundant in complex habitat. Similarly, 

 densities of copper and quillback rockfish were high- 

 est in complex habitat or in areas of highly irregu- 

 lar relief in Saanich Inlet in <40 m depth (Murie, 

 1991) and in the northern Strait of Georgia in <18 

 m depth (Richards, 1987). In SCUBA surveys, 

 Matthews (1990) found the greatest densities of 

 large copper and large quillback rockfish on high- 

 relief rocky reefs in Puget Sound, Washington. Ad- 



ACTIVITY 



Figure 5 



Percent occurrence of behavioral activities for quillback rockfish, 

 Sebastes maliger; copper rockfish, S. caurinus; tiger rockfish, S. nigro- 

 cinctus; and yellowtail rockfish, S. flavidus, observed in Saanich Inlet from 

 the Pisces submersible. 



ditionally, submersible observations in the vicinity 

 of Heceta Bank, Oregon (Pearcy et al., 1989), sug- 

 gested that tiger, yelloweye, and yellowtail rockfish 

 were most frequently encountered over rock and 

 rubble habitat. The densities of these near-bottom 

 species may be greatest in this type of habitat be- 

 cause of increased protection from predators or in- 

 creased density of prey due to the increase in mi- 

 crohabitat and vertical structure. 



Stein et al. (1992) observed fish from a submers- 

 ible at Heceta Bank and determined that the occur- 

 rence of fish species was related to specific sub- 

 strates. Given the propensity of quillback rockfish 

 to aggregate over complex habitat, differences in 

 their density among sites surveyed in our study was 

 not surprising. Sheppard Point, which had more 

 sand-mud areas and a shallower slope, was notice- 

 ably different from Elbow Point and McKenzie 

 Bight. It was also the only site where greenstriped 

 rockfish were observed, which is consistent with the 

 apparent habitat distribution of this species (Richards, 

 1986; Pearcy et al., 1989; Stein et al., 1992). 



The overlap in the depth ranges, as well as the 

 similarity in the median depths and the occurrence 

 of fish over complex and wall habitats, suggested 

 that quillback, copper, tiger, and yellowtail rockfish 

 do not segregate in Saanich Inlet within the range 



