these, 67 had been previously tagged as pups, 

 3 had been tagged as yearlings, and 1 had been 

 tagged as a pup and again as a yearling. A tag 

 was attached to the rear edge of each front 

 flipper at the hairline (fig, 1 3). Ideally, 2-year- 

 old males only would have been tagged. This 

 was not possible, however, because 2- to 

 4-year-old animals overlap in body length. 

 Age at the time of tagging, therefore, will be 

 determined from subsequent recoveries of 

 tags and canine teeth. 



Body lengths of selected males were not 

 actually measured because of the extra time 

 required, a factor that contributed to distress 

 and some deaths from overheating, especially 

 on warm days. 



Experimental Marks 



Several tags and other kinds of marks have 

 been tried as substitutes for the cattle-ear tag. 

 Tags tested included coded wire, plastic roto, 

 button ear, Monel ear (size 4), and Monel 

 butt-end bird leg band (fig. 16). Cryogenic or 

 freeze branding was also tested. Other marks 

 tried included V-notches cut into the leading 

 edges of front flippers and excisions such as 

 removal of the tips of front flippers and of the 

 tips of various digits on hind flippers. Not all 

 of the tests were extensive, and quantitative 

 data are yet to be collected from those that 



Figure 16. — Experimental tags used on pups, St, Paul 

 Island, 1964-65: plastic roto (A), small cattle ear (B), 

 button ear (C), bird leg band (D), and spaghetti (E). 



were. The general effectiveness of each type 

 of mark, however, was examined. 



Coded wire . --This tag, which has been used 

 for marking salmon (Jefferts, Bergman, and 

 Fiscus, 1963), was cut from type 302 stainless 

 steel wire of two sizes, 0.058 and 0.10 cm. 

 (0.023 and 0.04 inch). In 1963, five pups were 

 marked by using a hypodermic syringe to 

 implant tags 0.16 by 0.058 cm. (1/16 by 0.023 

 inch) next to the cartilage in the leading edge 

 of each front flipper, so that the tags were 

 perpendicular to the long axis of the flipper. 

 The syringe had been modified by attaching to 

 the plunger a wire of sufficient length to bring 

 it to the tip of the needle whenthe plunger was 

 fully depressed. In use, a wire tag was placed 

 in the tip of the needle, the needle was inserted 

 into the flipper, and the tag was implanted into 

 the cartilage by depressing the plunger. Six 

 days after tagging, only 6 of the 10 tags im- 

 planted could be found. The tissue did not react 

 to the tag. 



Since the syringe as used in 1963 was un- 

 satisfactory, it was further modified in 1964 

 by attaching a larger diameter wire to the 

 plunger. Correspondingly larger wire tags, 

 0.32 by 0.10 cm. (1/8 by 0.04 inch), were 

 inserted into the flippers of 100 pups at the 

 same site used in 1963. Guard hair was sheared 

 from the head of each pup to permit later 

 identification. Twenty-three days after tagging, 

 48 of the 100 pups were found; tags were re- 

 covered from 18 by making a small incisionat 

 the tagging site (an unsatisfactory method of 

 recovery). The tags did not irritate the tissue. 

 Of the 30 pups from which tags were not re- 

 covered, some had obviously lost their tags 

 and others had either lost their tags or the 

 technique of application or recovery was at 

 fault. Though the wire was compatible with 

 seal tissues, development of a tag applicator 

 and detector would require considerable effort 

 and expense. A disadvantage of this type of tag 

 is that it cannot be seen externally. 



Plastic roto rag . --This tag is usedprimarily 

 on domestic animals and is available in at 

 least two sizes. In 1965, 99 large and 100 

 small roto tags were fastened between the 

 second and third digits of the right hind flipper 

 just above the nails. These tags were easily 

 applied and seen, and caused no tissue reac- 

 tion. Many tags were lost within a month after 

 tagging but no quantitative data are available. 



Button-ear tag . --This is an aluminum tag 

 used primarily on small domestic animals. In 

 1965, 158 pups were tagged betweenthe second 

 and third digit of the right hind flipper. These 

 tags were easily seen after attachment to the 

 animal but difficult to apply. Some were lost 

 within a month after application, but one found 

 on a male recovered during tagging of yearlings 

 in 1966 was in good condition. This tag will not 



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