Evaluating Small Cetacean Tags by Measuring Drag in Wind Tunnels
M. Bradley Hanson, National Oceanographic and Atmospheric Administration, National Marine Fisheries Service, National Marine Mammal Laboratory, 7600 Sand Point Way NE, Seattle WA 98115 USA, Andrew J. Westgate, and Andrew J. Read, Duke University Marine Laboratory, 135 Duke Marine Lab Rd., Beaufort, NC 28516
The attachment of satellite-linked transmitters and time-depth recorders are important techniques for obtaining information on the movements and diving behavior of small cetaceans. Drag caused by these telemetry and data logger packages may influence the longevity of attachment and possibly induce changes in the behavior of tagged animals. To quantify the drag caused by these tags, a life-size fiberglass model of a harbor porpoise was mounted in a wind tunnel and fitted with various tag designs. The proportional increase in drag caused by three tag designs varied from 0.27 to 0.66. The tag design with the least increase in drag exhibited the longest attachment on wild porpoises (212 days). Research is required to investigate the energetic costs of this increase in drag to tagged dolphins and porpoises.
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