Figure 9. — Freeze-branded pup, Zapadni Reef Rookery, St. Paul Island, 11 October 1967. 



Tables A-26 and A-27 show the recovery 

 locations of males and females given tags or 

 other marks as pups. 



during the first year following application for 

 lS-series tags and 0.39 in 2 years after appli- 

 cation for lR-series tags. The 2S-series tags 

 had a loss of 0.30 in 1 year. 



Probability of Tag Loss 



We calculated the rate or probability of tag 

 loss from tags recovered and from checkmarks 

 identified in 1967 (table 12). The rate of tag loss 

 observed on St. George Island was somewhat 

 less than that for St. Paul Island for Q-, P-, 

 and O-series tags. Observers recovering tags 

 on St. George Island believed that the check- 

 marks were less clear there than on St. Paul 

 Island. Uniformity of checkmarks should be 

 achieved in the future by using at least part of 

 the same tagging crew on both islands. On 

 St. Paul Island the rate of loss for R-series 

 tags was about twice that for Q- andP-series 

 tags. There is no apparent reason for this 

 difference, but it may be a sampling error . 



The probability of loss observed for tags 

 applied to animals older than pups was 0.25 



Effects of Time of .Tagging 



In 1963 and 1964, half the tags used on pups 

 were applied 12-21 August and half 20-25 

 September to determine if time of application 

 was related to rate of recovery. Recoveries 

 from the 1963 experiment are nearly complete; 

 the recoveries through age 4 for tags applied 

 in September show a significantly higher rate 

 of recovery (P<0.01) than for tags applied in 

 August (table 13). The recoveries for the 1964 

 year class, though incomplete, show the same 

 trend. We attached the tags applied in 1963 and 

 in August 1964 at the hairline of the front 

 flipper, and those applied in September 1964 

 between the fourth and fifth digits. The dif- 

 ference in site of application may affect the 

 results of the experiment. 



13 



