FISHERY BULLETIN: VOL. 70. NO. 1 



The fourth method, freeze branding, consists 

 of applying a supercooled branding iron, usually 

 copper, to the epidermal surface of the dolphin 

 for 5-30 sec. Evidence from freeze branding 

 cattle indicates that the branding process is pain- 

 less to the animal and has no lasting effect other 

 than leaving a permanent mark (Farrell, Lais- 

 ner. and Russell, 1969) . Though evidence of the 

 branding usually becomes indistinct shortly after 

 application, after about 2 months the animal will 

 display a highly legible brand (Figure 4). We 

 have used this method on eight wild T. ti-uncatus 

 near Sarasota in conjunction with either a but- 

 ton tag or a spaghetti tag. The number on a 

 freeze branded animal was clearly visible, from 

 a distance of 40 yards, when the animal was 

 resighted 10 weeks after tagging. 



FiGi.RE 4. — A Tumiops truncatus with the freeze brand 

 on the dorsal fin. 



DISCUSSION 



We have discontinued use of the button tag 

 in favor of the spaghetti and radio tags. In- 

 cidence of loss of button tags from animals has 

 been exceptionally high among the T. truncatus 

 around Sarasota, and the few resightings of but- 

 ton-tagged dolphins off southern California lead 

 us to believe that button tag loss is high in this 

 area also. A major disadvantage of the button 

 tag is that the animal must be captured in order 

 to be tagged. The spaghetti tag, on the other 



hand, is normally placed in the animal while it 

 is free swimming and thus does not require cap- 

 ture. Using this method we have placed over 50 

 spaghetti tags in one herd of D. delphis in less 

 than 2 hr. When spaghetti tags are placed 

 in the fibrous tissue at the insertion of the dorsal 

 fin, incidence of tag loss appears to be lower for 

 spaghetti tags than for the button tags (Nishi- 

 waki, Nakajima, and Tobayama, 1966). In 

 either case, the numbered information on the tag 

 is so small that it cannot be read on a moving 

 animal at sea. Unless the spaghetti tags are 

 color-coded, resighting at sea can give no in- 

 formation on the original tagging location. Spa- 

 ghetti tags may also be placed in an animal that 

 has been captured. 



The radio tags can be placed only on captured 

 animals but provide very detailed information 

 concerning exact movement and diving patterns 

 of the animal. 



While freeze branding involves capture of the 

 animal, it appears to provide permanent and 

 highly legible identification of cetaceans. Tom- 

 ilin (1962) reported taking a Black Sea D. 

 delphis in 1953 which bore a brand posterior 

 to the eye. The brand was quite legible and 

 contained numbered information. The source 

 and nature of the brand were not known. 

 In the future, we plan to freeze brand all the 

 dolphins we capture for radio tagging and to 

 continue to use the spaghetti tags for free-swim- 

 ming delphinids. 



An advertisement was placed in the July issue 

 of National Fisherman requesting that any in- 

 formation on sightings of tagged delphinids in 

 the Eastern Pacific be forwarded to the Marine 

 Bioscience Division of the Naval Undersea R&D 

 Center, San Diego, Calif. (Evans, Leatherwood, 

 and Hall, 1971). Copies of this advertisement 

 have been placed at sportfish landings and com- 

 mercial docks from Santa Barbara to San Diego, 

 Calif. 



LITERATURE CITED 



Brown, S. G. 



1962. A note on migration in fin whales. Nor. 

 Hvalfangst-Tid. (Norw. Whaling Gaz.) 51(1): 

 13-16. 



64 



