308 



Fishery Bulletin 91(2), 1993 



Figure 3 



An adult yelloweye rockfish in a typical "refuge space.' 



of area of rocky habitat inside 

 the 180 m deep edge of the conti- 

 nental shelf. Allowable biological 

 catch (ABC) and TAC can then 

 be set, using known life-history 

 information including estimates 

 of natural mortality. In 1991, the 

 Gulf of Alaska Plan Team of the 

 NPFMC used this approach in 

 recommending an ABC for the 

 demersal shelf rockfish assem- 

 blage in the East Yakutat Dis- 

 trict (O'Connell et al. 1991). 



Acknowledgments 



Funding for the submersible and 

 support vessel was provided by 

 NOAAs West Coast National Un- 

 dersea Research Center, Fair- 

 banks, Alaska. Barry Bracken, 

 Dave Gordon, and Beverly Rich- 

 ardson helped with the field 

 work. Rich Slater and the crews of Delta Ocean- 

 ographies, the M/V Wm. A. McGaw, and the M/V 

 Privateer provided invaluable assistance. Thanks 

 also to Ken Krieger and Paul Skvorc for techni- 

 cal advice, and Gordon Kruse and Terry Quinn II 

 for their input regarding line-transect methods 



and statistical analysis. 



Citations 



panses of soft bottom. This topography may cause ju- 

 veniles to be more closely aggregated than in the Sitka 

 area, where reefs and pinnacles are often linked by 

 hard bottom, e.g., continuous lava flats. Although hard 

 bottom is not ideal habitat, it may promote movement 

 offish between reefs. 



Our ultimate goal is to develop a quantitative pre- 

 dictive model to estimate density of yelloweye rockfish 

 and other DSR species based on one or more param- 

 eters reflective of structural habitat complexity. In the 

 interim, the use of line transect-derived density esti- 

 mates can be directly applied in fisheries management. 

 In the absence of a fishery-independent biomass esti- 

 mate, the total allowable catch (TAC) currently in use 

 for demersal shelf rockfish had previously been based 

 on historical catch information. In contrast, the transect 

 data allowed us to estimate biomass/km 2 and to ex- 

 pand this estimate to a larger area using an estimate 



Buckland, S. J. 



1985 Perpendicular distance models for line transect 

 sampling. Biometrics 41:177-195. 

 Burnham, K. P, D. R. Anderson, & J. L. Laake 



1980 Estimation of density from line transect sampling 

 of biological populations. Wildl. Monogr. 72, 202 p. 

 Hayes, R. J., & S. J. Buckland 



1983 Radial distance models for the line transect 

 method. Biometrics 39:29-42. 

 Larson, R. J. 



1980 Competition, habitat selection, and the bathymetric 

 segregation of two rockfish (Sebastcs) species. Ecol. 

 Monogr. 50:221-239. 

 Love, M. S. & A. W. Ebeling 



1978 Food and habitat of three switch-feeding fishes in 

 the kelp I'oR'sts i iff Santa Barbara. California Fish. 

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 Love, M. S., M. H. Carr, & L. J. Haldorson 



1991 The ecology of substrate-associated juveniles of the 

 genus Sebastes. Environ. Biol. Fishes 30:225-243. 



