AN EVALUATION OF TECHNIQUES FOR 

 TAGGING SMALL ODONTOCETE CETACEANS 



A. B. Irvine, 1 R. S. Wells, and M. D. Scott' 



ABSTRACT 



Ninety tags — various combinations of radio tags, spaghetti tags, Roto tags, freeze brands, and tags 

 bolted to the dorsal fin — were placed on 47 Atlantic bottlenose dolphins, Tursiops truncatus, 

 captured near Sarasota, Florida, between January 1975 and July 197(i. In 18 months of field obser- 

 vation, 910 tagged dolphins were sighted; 781 were identifiable, and 129 were not. Twelve naturally 

 marked dolphins were also observed. Radio tagged animals were tracked for as long as 22 days. 

 Repeated observations of tagged animals permitted evaluation of effect on animals and relative 

 merits of the various tags. Freeze brands were most readable from a distance(<30 m ). and most long 

 lived (4.8 years). Other tags were too short lived (bolt tags) or too small to be identified from a dis- 

 tance) Roto tags and spaghetti tags), and all caused tissue destruction. Radio tags caused unexpected 

 dorsal fin damage and were frequently lost prematurely. Taken together, the results suggest that 

 freeze brands are least harmful, and that static tags should be tested on each species to be studied 

 prior to attachment in the field. 



Cetaceans are difficult to study in the field. Most 

 individuals move almost constantly, rise to the 

 surface only briefly to breathe, and are difficult 

 to differentiate from conspecifics. To facilitate 

 individual recognition, researchers have devel- 

 oped several tagging techniques and tested them 

 on small odontocete cetaceans. Nishiwaki et al. 

 (1966) placed streamer tags on captive rough- 

 toothed dolphins, Steno bredanensis, and 

 concluded that none were effective. On the other 

 hand Perrin et al. (1979) recovered spaghetti tags, 

 another type of streamer, from free-ranging 

 dolphins, Stenella spp., in the eastern tropical 

 Pacific up to 1,478 d after attachment. Roto tags 

 were placed on the spotted dolphin, S. attenuata, 

 and one marked individual was repeatedly 

 identified from a semisubmersible over a period 

 of 3^2 y r (Norris and Pryor 1970). Evans et al. 

 (1972) successfully used radio transmitters, 

 large plastic "button" tags, spaghetti tags, and 

 freeze brands on a total of five species in the 

 Pacific Ocean and Gulf of Mexico. Leatherwood 

 and Evans (1979) have recently reviewed devel- 

 opments and uses of radio tags on cetaceans. 

 Irvine and Wells (1972) reported that an 



'Gainesville Field Station, Denver Wildlife Research Center, 

 412 NE. 16th Ave., Gainesville, FL 32601. 



department of Zoology, University of Florida, Gainesville. 

 Fla.; present address: Center for Coastal Marine Studies. Uni- 

 versity of California, Santa Cruz, Santa Cruz, CA 95064. 



department of Zoology, University of Florida, Gainesville, 

 Fla.; present address: Inter-American Tropical Tuna Commis- 

 sion, Scripps Institute of Oceanography, La Jolla, CA 92037. 



improved button tag was sighted 3 mo after 

 attachment to a bottlenose dolphin, Turxiops 

 truncatus, near Sarasota, Fla. Despite all these 

 improvements in tagging technology, however, 

 little information has been available about long- 

 term effectiveness or affect on the wearers of any 

 type of tag. 



The tagging program of Irvine and Wells 

 (1972) was reinitiated in the same area in 

 January 1975, after a 4-yr lapse. Using radio 

 transmitters, visual tags, and natural marks we 

 studied the movements and activities of bottle- 

 nose dolphins. Between 29 January 1975 and 25 

 July 1976, 47 dolphins were captured, tagged, 

 and released a total of 90 times. A summary of 

 the tagging program and an evaluation of the 

 tagging methods used are included below. 

 Detailed analysis of the tagging program results 

 is presented by Irvine et al. (1979, 4 1981). 



METHODS 



The study was conducted along 40 km of 

 coast south from Tampa Bay, Fla. The study area 

 included shallow channels and bays bounded by 

 a chain of barrier islands (NOS Chart No. 



Irvine, A. B., M.D. Scott. R. S. Wells. J. H. Kaufmann, and 

 W. E. Evans. 1979. A study of the movements and activities 

 of the Atlantic bottlenose dolphin, Tursiops truncatus, includ- 

 ing an evaluation of tagging techniques. Available National 

 Technical Information Service, 5285 Port Roval Road, Spring- 

 field, VA 22151 as PB-298042, 54 p. 



Manuscript accepted July 1981. 



FISHERY BULLETIN: VOL. 80. No. 1, 1982. 



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