318 



Fishery Bulletin 92(2), 1994 



by wall habitat (3.5 fish-lOOm" 2 ) (Fig. 4). Only four 

 quillback rockfish were observed over sand-mud 

 habitat. Quillback rockfish densities, whether in 

 complex or wall habitat, did not differ among depth 

 intervals <100 m (P=0.52 and P-0.64 respectively) 

 (Fig. 4). 



Tiger, copper, yellowtail, and yelloweye rockfish 

 were observed only over complex or wall habitats, 

 whereas greenstriped rockfish occurred mostly over 

 sand-mud habitat (Table 3). Tiger rockfish tended 

 to occur in both complex and wall habitats, whereas 

 copper, yellowtail, and yelloweye rockfish were seen 

 mostly in complex habitat. 



Activities 



Quillback, copper, and greenstriped rockfish did not 

 appear to be attracted to or obviously repelled by the 



Table 3 



Numerical abundance of rockfish (Sebastes spp.) 

 observed in densities of <1 fish- 100m" 2 over com- 

 plex, wall, and sand-mud habitat in Saanich Inlet. 



Species 



Complex 



Wall 



Sand-Mud 



S. nigrocinctus 

 S. caurinus 



S. flavidus 

 S. elongatus 

 S. ruberrimus 



13 



2(1 



2] 







t 



15 



•1 

 2 

 1 

 1 



E 

 o 



I 



CO 



z 



LU 

 Q 



20- 



18- 

 16" 

 14 - 



12- 



10 

 8 

 6 

 4 

 2 

 



1 



M 



1 



□ COMPLEX 



□ WALL 



21-40 



41-60 61-80 



DEPTH ( m ) 



81-100 



Figure 4 



Median densities of quillback rockfish, Sebastes maliger, 

 in complex and wall habitats among depths. Vertical 

 bars represent interquartile ranges (Q 02 5 to Qo7s)- 

 Median densities of quillback rockfish over sand-mud 

 habitat were zero. 



presence of the submersible and its lights. At times, 

 rockfish actively finned to maintain station after the 

 submersible had produced currents. Any observed 

 movements away from or towards the submersible 

 were always relatively slow and, at times, hovering 

 quillback rockfish would move slightly away from 

 the path of the submersible, stop, and then resume 

 hovering. Tiger and yelloweye rockfish appeared to 

 have a delayed response to the submersible, in that 

 it was possible to observe them prior to their actu- 

 ally moving into a shelter hole or crevice. In con- 

 trast, some spotted ratfish, Hydrolagus colliei, and 

 a sixgill shark, Hexanchus griseus, were obviously 

 attracted to the Pisces. These fish swam back-and- 

 forth around the front of the submersible, repeatedly 

 approaching the viewing ports near the external lights. 

 Activities were determined for a total of 662 quill- 

 back rockfish and the majority were observed hov- 

 ering or perched on substrate in the open (Fig. 5), 

 regardless of depth interval (all P>0.10). Copper 

 rockfish were also observed primarily hovering and 

 perched in the open, but were seen swimming more 

 frequently than quillback rockfish. Both species 

 were observed infrequently in crevices and rarely in 

 shelter holes. Tiger rockfish were also observed most 

 frequently perched in the open or occupying crevices. 

 Yellowtail rockfish were all observed either hover- 

 ing or swimming close to the substrate. All eight 

 greenstriped rockfish were observed perched on the 

 substrate. Of the five yelloweye rockfish observed, 

 one was in a shelter hole, three were in crevices, and 

 one was hovering. 



Species associations 



The majority of quillback rockfish (94% occurrence) 

 were observed within 3 m of at least one other 

 quillback rockfish (Fig. 6). Quillback rockfish were 

 almost never observed alone (2%) and were ob- 

 served in the presence of other species relatively 

 infrequently (-20% occurrence or less). Quillback 

 rockfish formed loose conspecific aggregations that 

 were distinctly different from the conspecific 

 schools of yellowtail rockfish observed from the 

 Pisces. When schooling, yellowtail rockfish formed 

 tight groups of fish that orientated and moved to- 

 gether in the same direction, whereas in the ag- 

 gregations of quillback rockfish, individual fish 

 were orientated in various directions and engaged 

 in various activities. Small groups of quillback 

 rockfish (2-5 fish) observed from the submersible 

 were interspersed between larger aggregations of 

 more than 15 fish. Copper rockfish occurred within 

 3 m of quillback rockfish 92% of the time (Fig. 6), 

 but also tended to occur near other copper rockfish 



