176 



A. McLaren 



same age-specific rates of hunting mortality as seals in southern Baffin Island. 

 Fig. 2 depicts the characteristics of such a balanced population. 



The original assumption that the population of southern Baffin Island was 

 indeed being subjected to maximum possible hunting should now be 



16.000- 



6,000- 



.28 

 >.25 



«.20 



.15- 



.05 



h L 



5-! Hypotheticol Age Structure when No Hunting 

 LnEquilibrium Population of Southern Baffin Island 

 *%, Age -specific Pup Production 



-^ 



• • • • Percentage QQ Pupping 



Rote of Hunting Mortolity 



Rate of Natural Mortality 



o'lVaVs'eV'e'a'io' " "15" " '20' 



AGE- GROUP 



^ 



-w 



35 



T? 



100 

 90 I 

 80 « 

 70 I 

 60 I 



40 g 



< 



•30 g 

 u 



.20 £ 

 •10 



Fig. 2. — The age structure (above) of an equilibrium population of ringed seals in southern Baffin 



" Island from which 7,000 seals (about 7 per cent of the population at the beginning of the 



seal-year) are removed armually. Smoothed curves (below) are drawn through the annual 



rates underlying this equilibrium, although in calculation the annual mortality rates were 



applied to the nearest per cent. 



re-examined. This would imply that all suitable 'sites' in the fast ice were 

 being used by pupping females, that age-specific birth rates were maximal, 

 and that no emigration from the overall area was occurring. Nothing 

 quantitative can be said about the last of these at present, but the existence of 



