
CONTENTS 
Summary « » « » «© © © © © «© © © © © © ew oe wt et tlt ll 
INCPOGMCETOR. “we <6", Mace Corded © cal GD caberae ete tery whe ete A 
Sources and methods . .. «e+. + -«»s © e «© «ee 
Counts and measurements of seals .... .« « « « « 
Age determinations .«. + « » «© » «© © © © © © we eo 
Components of the herd .... 6 6 « « © © © © © ww 
Bulls .... F SUC eUe ee. acme Zim es hie wee See 
Counts of pulls te a ee ee 
Fecundity of bulls . «© « «6 «© «© ww wp ww wo 
Bachelors ... nanan one b's 
Statistics of the outnereial: “eALL ee ee 
Escapement of bachelors from the Kill ee eo oe 
PUDS: 0 ee PT we we ee a ae Bed eee yl es 
Size of the pup class in 1947 as derived from 
tag recoveries in 1950 and 1951 ....4... 
Sample counts and rapid field estimates of 
living pups, and counts of dead pups. .... 
Estimate of the number of pups born annually, 
from the trend of the commercial harvest... 
Estimate of the number of pups born annually, 
from the trend of the harem bull count... 
COWS. peter <4 cen ‘elra- Ae vaabl gy pacman oat ce leercne. een ye Mee fa 
bach lis Balsa Ge ee er Pe ke ae oe a ane nee 
Present size of the herd ... «+s. 86 «© «e » © © © @ ® 
Type Gee sy ate Sy fe el es Teas 8 PP lcs: bee eae eo ketal 
Estimate of the size of the herd from the trend 
of the commercial harvest... . vt eo ee on Le 
Estimate of the size of the herd vom the 
trend of the harem bull count .......e = « 
Appendix A.--Effect of sealing on fluctuations in herd 
size 1786-1951 ..... ee, ee ee ee 
Appendix B.--Fecundity of males ee ee eee 
Appendix C.--Size of the average harem .. . = tS alee 
Appendix D.--Age criteria for bachelor fur dente ee 
Appendix E.--Escapement of bachelors from the 
commercial kill . .. 2. 6 «© « © « é ee eres 
Appendix F.--Calculations for the sive of the ue class 
in 1947 from tag recoveries . .. «1. ee see eee 
Appendix G.--Aerial photography on the Pribilofs eo +8 8 
Literature cited . . « «© «© + © es © se ee ww wee es 
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