Table 2. --Estimated mortality of pups from birth to about 25 August, by rookery, year classes 



1963-66, Pribilof Islands, Alaska 



Island total 



5/, 



264, 372 

 (246, 380) 



32,598 21,572 39,124 23,536 



1^0. 12 



4/ 

 -0. 08 



4/, 



0. 14 



0. 08 



St. George Island 



East Reef 2, 645 



East Cliff 10,208 



North 26, 507 



Sou'.h 7, 574 



Staraya Artil 8, 854 



Zapadni 8, 970 



105 



397 

 2, 525 



162 

 1, 041 



542 



Island total 



64,758 



4,772 



1,631 



3.716 



4,648 0.07 



0. 03 



0. 07 



Total both 

 islands 



329, 130 



37 370 23,403 42,840 28,184 



0. 11 



0.07 



0. 13 



0. 07 



0. 08 



l7 Mean of estimates at time of shearing obtained for year classes 1963-66 from samplong for marked-to- 

 unmarked ratios. 



2/ Obtained by adding the number of dead pups counted to the mean estimated pup population and dividing 

 by^the latter. 



3/ Mean of complete counts. 



4/ Calculated from estimate for St. Paul Island excluding Sea Lion Rock. 



5/ Total for St. Paul Island excluding Sea Lion Rock. 



in 



§20 



< 

 Z) 



o 



UJ 



o 



<" 10- 

 </) 



0. 



a. 



o 

 < 

 iij 

 o 



o 

 to 



■^ 

 o 

 o 



Y=I322+0.II502X 

 r = 0.90 



Figure 5. — Least squares line and 95 percent confidence 

 limits for a comparison of counts of dead pups, Pribilof 

 Islands, Alaska, 1953-54 and 1956-66. 



50 



100 



COUNTS OF DEAD PUPS, ST PAUL I. (THOUSANDS) 



