Table 21. — Checkmarks overlooked compared to the number available, 1 

 Pribilof Islands, Alaska, 1961-63 



1 These data are from male seals taken from 2 July to 15 August in 

 1961 and from 2 July to 5 August in 1962 and 1963. 



a half to three-quarters of an inch from the 

 rear edge of the front flipper where furred 

 skin ends and bare skin begins. Tags attached 

 this close to the edge, however, are vulnerable 

 to loss because there is only a narrow strip 

 of skin holding them in place. Tags clinched 

 through muscle tissue are held more firmly 

 in place, but shock, infection, slowed growth, 

 and death of the pups may result. 



In 1963, application of fewer tags and use 

 of a small tagging crew improved quality of 

 tagging. Preliminary results of post mortem 

 examinations indicate that most of the tagged 

 pups found dead died from causes other than 

 tagging. 



Application of checkmarks .-- The veining 

 chisels formerly used to make the "V" notch 

 checkmark were replaced in 1961 with 

 veterinary ear notching instruments. The latter 

 tool is superior because it remains sharp 

 through thousands of "cuts" and makes uni- 

 form checkmarks. Quality of checkmarks made 

 with the ear notching instrument will be ap- 

 praised when pups from the 1962 year class 

 return as 2-year-olds in 1964 and as 3-year- 

 olds in 1965. 



For making the slice type of checkmark, 

 knives were replaced with sheep shears in 

 1963. Although satisfactory checkmarks can 

 be made with knives, use of sheep shears 

 avoids the need for a wooden surface to cut 

 against. Also, the sheep shears do not dull as 

 easily as knives. 



Quality of tags .-- The new style 49M tags 

 supplied by the manufacturer for pup tagging 

 in 1963 were very satisfactory. Less than 



50 of 25,000 tags failed to be clinched when 

 first used. In I960, several hundred of 60,000 

 tags used could not be clinched. Although 

 most of these clinched after straightening, the 

 entire I960 lot of tags was generally unsatis- 

 factory. 



Recovery of tags and checkmarks . --Since 

 1960, all carcasses have been re-examined 

 on St. Paul Island in a search for tags and 

 checkmarks overlooked by the tag-recovery 

 crew. While less than 0.5 percent of the 

 available tags have been overlooked, check- 

 marks are most difficult to detect. Some 

 comparisons of recovered and overlooked 

 checkmarks are made in table 21. Carcasses 

 were first re-examined on St. George Island 

 in 1962. 



Tagged seals without checkmarks .- - Table 

 22 shows the results of some appraisals on 

 the number of tagged seals without check- 

 marks. Replacement of veining chisels and 

 knives with veterinary ear-notching instru- 

 ments and sheep shears is expected to elimi- 

 nate vague checkmarks. 



Results of Double Tagging 



In 1958 (K-series tags), 5,000 seal pups 

 were double tagged on St. Paul Island to pro- 

 vide a basis for determining the rate of tag 

 loss. Recoveries of survivors in 1961, 1962, 

 and 1963 are listed in table 23. 



20 



