Yoklavich et al : Habitat associations of deep-water rockfishes 



639 



complex rock habitats that harbor the larger, more valu- 

 able species, such as S. ruherrimiis. Sebastes helvomacu- 

 latus ranked third in overall abundance both in Soquel 

 Canyon and on Heceta Bank, Oregon (Stein et al., 1992). 

 This was one of the dominant species in the complex rock 

 habitats on Heceta Bank, as well as on site 2 (the area 

 with the most fishing activity in Soquel Canyon). Interest- 

 ingly, abundance of S. helvomaculatus was significantly 

 lower in this same habitat at those sites having high num- 

 bers of larger species and less fishing activity in Soquel 

 Canyon (i.e. sites 3-5; Fig. 6). 



It is generally understood, especially in the broad litera- 

 ture on artificial and tropical reefs, that complex rock out- 

 crops of high relief provide shelter and protection to reef 

 fishes (Bohnsack. 1989; Potts and Hulbert, 1994, among 

 others). O'Connell and Carlile ( 1993) noted that the occur- 

 rence of adults, ruberrimus was higher in areas with more 

 voids or refuge spaces, and that "extremely high" densi- 



ties of this and other species were associated with isolated 

 abrupt pinnacles comprising boulders and overhangs. This 

 type of habitat, surrounded by fields of mud as is the case 

 at Site 5 in Soquel Canyon, likely functions as a natural 

 aggregating device for structure-oriented species such as 

 many of the benthic rockfishes. Moreover, in seeking shel- 

 ter near these rock outcrops in Soquel Canyon, large rock- 

 fishes may be excavating the semiconsolidated mudstone 

 (Yoklavich, pers. obs. ), thereby creating more of their own 

 habitat (not unlike the construction of burrows in soft sed- 

 iments by tilefish [Lopholatiliis chamaeleoriticeps: Able et 

 al. 1982] ). The extraordinary abundances estimated for 

 several large species (S. paucispinis, S. levis, S. rosenblatti, 

 O. elojjgatus) in a relatively small area of the canyon pro- 

 vide an insight into considerations of design and location 

 when establishing protected areas as a management tool. 

 In addition to high abundances of valuable species on 

 those rock outcrops in Soquel Canyon with little or no 



