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Fishery Bulletin 98(1) 



canary rockfish we noted tended to associate with 

 vermilion rockfish. Halfbanded rockfish were almost 

 always seen in schools, sometimes containing hun- 

 dreds of individuals (Fig. 4C). 



In the greenling family, Hexagrammidae, both ling- 

 cod and painted greenling, were common; together 

 they represented about 5.3% of all fishes seen. Larger 

 lingcod were solitary and tended to remain near 

 the bottom of the platform (Fig. 4D). They were usu- 

 ally seen sitting motionless on the bottom or slowly 

 swimming just above it. Juvenile lingcod rarely came 

 within a meter of the platform, they were usually 

 seen Ijdng among the mussel shells away from the 

 structure (Fig. 4E). Painted greenling sat on the 

 crossbeams, along the pilings and on the mussel 

 shells, always found as solitary individuals. 



Among platform comparisons The bottom fish as- 

 semblages around each platform were all different 

 (Tables 4 and 5). Pairwise percent similarity indices 

 (PSD for each combination of platforms ranged from 

 OVc (platforms Gail and Holly) to 70.1% (platforms 

 Grace and Hidalgo) (Table 4). The average percent 

 similarity was 20.0%. Despite a low average sim- 

 ilarity value, rockfishes, as measured by number, 

 density and biomass, dominated the bottom assem- 

 blages around all of the platforms (Table 5). Ling- 

 cod were the only nonrockfish species among the top 

 four most common species at any platform. 



Around platform Irene, subadult and adult copper 

 and vermilion rockfishes were most abundant. Irene 

 also was unique among the platforms in having large 

 numbers of juvenile lingcod. Halfbanded rockfish, 

 painted greenling, and pile perch were also com- 

 monly seen. Halfbanded and greenspotted rockfish 

 were most common at platform Hidalgo, along with 



flag rockfish, lingcod, bocaccio, and vermilion rock- 

 fish. Similar to that around Hidalgo (PSI=60%), the 

 bottom fish assemblage around platform Hermosa 

 was characterized by greenspotted and halfbanded 

 rockfish, with lesser numbers of flag rockfish and 

 lingcod (Table 4). Vermilion, calico, widow, copper, 

 and squarespot rockfishes were most often seen at 

 Holly, along with lesser numbers of halfbanded rock- 

 fish, pile perch, rosy rockfish, and painted green- 

 ling. Very large schools of halfbanded rockfish were 

 observed at Grace, along with some flag, greenspot- 

 ted, and vermilion rockfishes. The dominance of half- 

 banded rockfish at Hidalgo and Grace resulted in 

 the highest PSI among platform pairs (70.1% ). Mem- 

 bers of the rockfish subgenus Sebastomus, primar- 

 ily gi'eenblotched and greenspotted rockfishes and 

 bocaccio were most abundant at platform Gail. Gail 

 had by far the highest number and density of bocac- 

 cio of any of the platforms. 



We observed between 8 and 21 species around 

 the bottom of the platforms (Fig. 5A). We found 

 no significant relationship between species number 

 or diversity (H') and platform bottom depth (linear 

 regression: species richness vs. depth, r^^O.SS, 

 P=0.07, diversity (H') vs. depth, r2=0.19, P=0.37, 

 Fig. 5A). Although neither relationship was signif- 

 icant, there was a tendency for platforms in shal- 

 lower water to have both higher species richness and 

 species diversity. Location of the platforms within 

 the Santa Barbara Channel and Santa Maria Basin 

 also did not explain the differences among plat- 

 forms. There was no correlation between northwest 

 to southeast orientation and either species richness 

 or diversity (Spearman rank correlation: species rich- 

 ness vs. orientation, /•,,=-0.26, P=0.6, diversity (H') 

 vs. orientation, r^.=-0.6, P=0.2). In fact, the two most 



