tagging process caused no overt reaction from the animal; 3) the animal was resighted 

 four to fourteen months after tag loss without holes or scarring on its dorsal fm; and 5) 

 the dolphin was still in the company of her five-year-old calf whenever it was resighted 

 (Wells, pers. comm.). 



RESULTS AND DISCUSSION 



Transmitter Attachment and Effects 



1989 



In 1989 we attempted to tag 37 animals during 22 days at sea. Thirty of the 

 attempts were with the dart-pulley-deployment-vehicle system and resulted in three 

 misses, nine darts bouncing off the animal, six darts pulling out, five lines being broken, 

 and assorted failures of swivels and latches (Mate et al.,in prep.). None of the dart- 

 pulley-deployment-vehicle system attempts were successful in attaching a tag, but we did 

 learn a great deal about the holding power of various dart configurations as a result of 

 these attempts. 



The first darts, which were similar to straightened fishhooks, had been tested 

 extensively on samples of gray whale skin and blubber, as no right whale samples were 

 available. In carcass tests, these darts withstood a 45 kg straight pull. When, in the field, 

 these darts pulled easily out of right whales, we revised a folding barb design which we 

 had also tested prior to the field season. This dart used a sharpened blade at its tip to 

 ease penetration and provide some initial purchase for a folding barb. These darts 

 held well enough to break lines rated at 240 kg and provided the basis for our confidence 

 in redesigning the 1990 attachments. 



Field studies revealed a number of areas in which our modelling of the situation 

 had been inadequate. The two-stage attachment technique proved to be totally 

 unsuccessful largely due to turbulence from tail flukes and drag which caused lines and 

 swivels to break. The 1989 tag was relatively large and thus had considerable 

 hydrodynamic drag. It might have been easier and possibly more successful to have 

 eliminated the flotation of the deployment vehicle to reduce the drag. Because they 

 were so easy to approach, we attempted to tag animals in surface active groups (SAGs). 

 However, because multiple animals were rolling next to one another, lines became 

 entangled and broke. 



The pole technique was more successful. We tagged seven animals in seven 

 attempts. A major factor in our late season success was the addition of Scott Kraus to 

 our crew. His experience in maneuvering around right whales proved invaluable. 

 However, none of the seven pole-deployed tags were attached well, and we observed tag 

 losses one, two and three days after tagging. There were actually three versions of the 

 subdermal attachment which evolved during the 1989 season as the result of the poor 



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