Table 23. --Forecast of the kill of male seals in 1970, by age, 

 Pribilof Islands, Alaska 



Table 24. --Forecasted and actual kill of male seals, by age, 

 Pribilof Islands, Alaska, 1969 



Island 



2 and 5 



3 



Total 



Age 



2 and 5 



Total 



St. Paul 



St. Georg 



Total 



3, 500 

 900 



Number 



27,800 11.600 



7, 000 2, 900 



4, 400 



34, 800 



14. 



42, 900 

 10, 800 

 53, 700 



George Island is based on the assumption that 

 the kill on St. Paul Island will be 80 percent 

 of the total (average of 1955-64 year classes 

 was 79 percent). 



Table 24 compares the forecast for 1969 with 

 the actual kill. As noted in the introduction 

 to this section, this forecast was very poor, 

 erring in overestimating the kill of 3- and 4- 

 year-olds. Actually the forecast of the kill at 

 age 3 erred by only 1.23 times the standard er- 

 ror, which unfortunately is to be expected oc- 

 casionally. The forecast for the kill of 4-year- 

 olds on St. Paul Island, however, erred by 7.7 

 thousand, or about 4.2 standard errors of our 

 estimate in the forecast for 1968. Apparently 

 our knowledge of basic biological factors is in- 

 adequate with regard to forecasting the sur- 

 vival of fur seals, or, as mentioned earlier, 

 we are not measuring the appropriate variables 

 with required accuracy. 



Douglas G. Chapman 



SPECIAL STUDIES 



This section includes studies of fur seal biol- 

 ogy that are carried on in addition to continuing 

 studies described in the main body of this 

 report. 



Activity of Young Male Seals on 

 Land 



Studies of the activity of young males while 

 they are on the hauling grounds of the Pribilof 

 Islands will provide information useful for ef- 

 ficiently harvesting the population. Marking 

 individual seals with tags and radio transmit- 

 ters (telemetry) can furnish this information. 



Tagging. — We marked male seals ^ 2 years 



St. Paul 

 Actual 

 Forecast 



St. George 

 Actual 

 Forecast 



Combined 

 Actual 

 Forecast 



4, 109 

 3, 300 



1, 091 

 900 



5, 200 

 4, 200 



17, 826 

 23, 600 



2, 645 

 5, 900 



20, 471 

 29, 500 



10, 565 

 18, 300 



204 

 600 



12, 769 

 2.1, 900 



32, 500 

 45,200 



5, 940 

 11, 400 



38, 440 

 56,600 



old (most were 3 and 4 years old) on St. Paul 

 Island with paired but uncoated X-series tags 

 in 1968 and XA-series tags in 1969. The tags 

 were attached to the front flippers of these seals 

 (fig. 9) on 24-25 June and 10-11 and 18 July 

 in 1968, and on 20-24 June and 1-5 and 14-17 

 July in 1969. We drove some seals especially 

 for tagging, but selected most of the animals 

 from among seals routinely driven for killing. 

 These tagged seals were killed when they ap- 

 peared in drives subsequent to tagging, and the 

 age of each was determined from a canine tooth 

 collected at death. 



We also tagged 40 seals on St. Paul Island 

 with paired, white-coated (fuse-bond plastic) 

 X-series tags 30 June to 3 July and 14-17 July 

 in 1969. If these seals appeared in subsequent 

 drives, their tag numbers were to be recorded, 

 but they were not to be killed until near the 

 end of the season. Some of the animals, how- 

 ever, were taken prematurely. 



Male seals tagged in 1968 and recovered in 



1968 and 1969.— Of 334 males ^ 2 years old 

 tagged on St. Paul Island in 1968, 67.7 percent 

 were recovered in 1968 and 12.8 percent in 



1969 (table 25). The recovery rates of seals 

 tagged on inaccessible hauling grounds in June 

 and on accessible hauling grounds in July were 

 lower (70.7 and 77.0 percent, respectively) 

 than a rate of 87.3 percent for seals tagged 

 in June on accessible hauling grounds. 



All of the seals tagged in 1968 and recovered 

 in that year had retained both tags; 8 of 43 

 recovered in 1969 had lost 1 tag. Tag loss, 

 therefore, was 1.5 percent. 



25 



