Karsten Schneider, Robin W. Baird, Steve Dawson, Ingrid Visser and Simon Childerhouse
Marine Mammal Science 14:316-324. 1998. Download Adobe PDF copy
Summary
In order to study the diving behaviour of bottlenose dolphins in Doubtful Sound, New Zealand, the authors attempted to tag bowriding dolphins with a suction-cup attached time-depth recorder/VHF radio tag. The note describes the immediate reactions of both tagged individuals and other dolphins within the same group, as well as the behaviour of the dolphins when they were encountered on subsequent days. A total of 17 tagging attempts were made between 24 and 29 October 1995. The tag contacted a dolphin in 10 cases, and remained attached for > 10 seconds in five of these. In each of the five cases in which the tag contacted and stuck, the tagged animal immediately began a bout of high-energy behaviours, apparently to dislodge the tag. Tags remained attached on these dolphins for periods of about 10 seconds to about three minutes. Group speed and the number of leaps in the group increased in 5/5 and 4/5 of these cases, respectively. In general, reaction intensity decreased in the order: successful attachments > unsuccessful attachments > misses. Within several days of initiating tagging attempts, the frequency of bowriding behaviour in the population decreased, and slowly returned to "normal" over the next two months. Based on both the reactions exhibited by individual dolphins and those in the surrounding group, and on the inability of the suction-cup tag to remain attached during leaps and high speed swimming, the authors suggest that suction-cup tagging of this population of bottlenose dolphins is not feasible. Reactions of bottlenose dolphins were substantially greater than have been observed for similar studies using these tags on killer whales and Dall's porpoise. Return to homepage of Robin W. Baird