Krieger and Ito: Distribution and abundance of Sebastes borealis and 5. a/eutianus 



271 



Slope (degrees) 



Figure 5 



Four levels of slope observed on the seafloor, and the percent occurrence of habi- 

 tat and percent occurrence of shortraker and rougheye rockfish associated with 

 each level. Observations are from a submersible in the eastern Gulf of Alaska, 

 1992. 



floor in response to the submersible. However, some 

 above-bottom rockfish may not be captured because 

 of their slow rates of descent. Bottom-trawl assess- 

 ment gear is not designed to sample the steep-slope, 

 boulder habitats occupied by these species, and the 



few trawl hauls that are completed in boulder habi- 

 tat likely do not sample rockfish associated with boul- 

 ders. An assessment method is needed that addresses 

 the wide range of habitats, above-bottom distribu- 

 tion, and grouping behavior of shortraker and 



