METHODS FOR TAGGING SMALL CETACEANS 



W. E. Evans,'- ^ J. D. Hall,- A. B. Irvine,^ and J. S. Leatherwood^ 



ABSTRACT 



Four types of tags have been used on four species of delphinids. These include a circular plastic button 

 tag that is attached to the dorsal fin by a nylon bolt, a highly visible dart-type spaghetti tag that is 

 placed near the base of the dorsal fin, a radio transmitter tag, and a freeze brand. 



Use of button tags has been discontinued due to high shedding rate. The dart-type spaghetti tag has 

 proved best for tagging large numbers of animals without capturing them. The radio tag provides 

 very detailed information on behavior and movements, while freeze branding provides a permanent 

 mark, though both require capturing the animal. 



The importance of marking commercially valu- 

 able species of whales (primarily the larger 

 baleen whales and the sperm whale) has long 

 been recognized. Since their development in the 

 mid-1920's, "Discovery-type" tags have been 

 used to mark large numbers of these animals 

 (Rayner, 1940; Brown, 1962; Clark 1962). Re- 

 turns from these tags have provided valuable in- 

 formation on the species' distribution, migration, 

 and abundance and on such basic aspects of their 

 biology as relative growth rates and the timing 

 of the events in their lives (Mackintosh, 1965). 



The relationship of several small delphinid 

 species to commercial fish populations and the 

 potential of these cetaceans as a major economic 

 resource has renewed interest in their stocks 

 during the last decade (Perrin, 1970). Early 

 attempts to study these populations in the wild 

 have been hampered by the difficulty of posi- 

 tively identifying an animal or a population from 

 one encounter to the next. Therefore, develop- 

 ment of a reasonable method for marking these 

 animals for identification would facilitate studies 

 of their life histories. 



Although several investigators have tried tag- 

 ging small cetaceans, only three have had even 

 moderate success. In a program conducted by 



^ Authors are listed in alphabetical order. 

 '^ Marine Life Sciences Laboratory, Naval Undersea 

 Research and Development Center, San Diego, CA 92132. 

 ' Mote Marine Laboratory, Sarasota, FL. 33581. 



the Oceanic Institute, Oahu, Hawaii, plastic cat- 

 tle eartags were placed on two Steno hredanensis 

 and one Stenella attennata (Evans, 1967) . This 

 program was continued by Norris and Pryor 

 (1970), and at least one of the tags was still 

 on a Stenella attennata when it was resighted 

 after 3i/4 years. 



Sergeant and Brodie (1969) tagged 812 be- 

 lugas, Delphi napteriis leucas, in Hudson Bay, 

 Canada, over a 2-year period. Six hundred and 

 ninety-four of these animals were tagged with 

 a spaghetti tag originally designed by Mather 

 ( 1963) for use in tagging pelagic fishes and man- 

 ufactured by Floy Tag Company,' Seattle, Wash. 

 The remaining 118 belugas were tagged with 

 Petersen disc tags, similar to the button tags 

 we used. Of the 812 animals tagged, 2 with 

 spaghetti tags were recovered by the beluga fish- 

 ery. A third spaghetti tag was observed in a 

 live animal temporarily stranded by the ebbing 

 tide 1 year after the original tagging. 



Perrin and Orange (1971) tagged 21S, Ste7iella 

 spp. in 1969 and approximately 1,000 in 1970 in 

 the eastern tropical Pacific with spaghetti-type 

 dart tags. Five tags have been recovered; max- 

 imum time at liberty was 138 days (916 km net 

 movement) , 



Since 1968, personnel of the Naval Undersea 

 Research and Development Center's Marine Bio- 

 science Division at San Diego, Calif., have been 



* Reference to commercial products does not imply 

 endorsement by the National Marine Fisheries Service. 



Manuscript accepted September 1971. 

 FISHERY BULLETIN: VOL. 70, NO. 



1, 1972. 



61 



