POPULATION DYNAMICS AND EXPLOITATION OF SEALS 169 



Fig. I.— The eastern Canadian Arctic, showing localities mentioned in the text. 



planktonic, nektonic or benthonic food and varies its diet considerably, 

 generally turning from inshore feeding on the epibenthic Mysis, prawns, or 

 polar cod{Boreogadns), to strictly macroplanktonic feeding in deeper, offshore 

 waters. Food may be chosen from many points on the food web and from 

 at least two trophic levels, and it is consequently unhkely to Umit the 

 distribution and abundance of this species. Indeed, the seal is scarce where 

 its food is apparently abundant and is common in regions of low productivity. 



