Robichaud et al.: Selection of Chionoecetes opilio and Hyas spp. by Gadus morhua and Raja radiata 



679 



strongly with crab density, is secondary to substrate 

 type. Studies by Robichaud (1985) and Robichaud et 

 al. (1989) have shown that snow and toad crab densities 

 were not significantly different over a wide depth range 

 for a given substrate and crab species. A study by Scott 

 (1982) on selection of bottom type by 25 species of 

 groundfish, including cod and skate, concluded, even 

 for species like skate which were not strongly associ- 

 ated to bottom type, that depth was not a specific deter- 

 minant of distribution. 



Previous studies on the impact of cod on snow crab 

 recruitment have not taken into account the behavioral 

 and ecological aspects of the two species (Waiwood et 

 al. 1980, Waiwood 1981, Bailey 1982, Waiwood and 

 Elner 1982). The dynamics of benthos:fish trophic 

 interrelationships are complex, and models based on 

 simple expansion of predator abundance and feeding 

 rate data cannot adequately express the "real world" 

 situation. 



Acknowledgments 



We express our thanks to B. Best and J. Hurley for 

 typing, to F. Cunningham and B. McMullon for illustra- 

 tions, and to G. Lilly and K. Waiwood for helpful com- 

 ments on this paper. 



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