Studies of the movements and behavior of small odontocetes have been constrained by the limited attachment durations and deployment challenges of remotely-deployed satellite-linked tags. Spinner dolphins (Stenella longirostris) in Hawai‘i provide a clear example, with management measures due to repeated and extensive human interactions limited by incomplete information on spatial use. In 2025 we began using the TADpole tagging system to deploy single-pin finmount satellite-linked tags on spinner dolphins and other species in Hawai‘i to examine movements and dive behavior. Ten tags were deployed on spinner dolphins (nine off the west coast of O‘ahu and one off Lāna‘i), and one each were deployed on a common bottlenose (Tursiops truncatus) off Lāna‘i and a pantropical spotted dolphin (S. attenuata) off Hawai‘i Island. Spinner dolphin tag attachment durations (median=41d, maximum=75d) and transmission durations (median=38d, maximum=60d) were more than three times longer than LIMPET tags deployed on small odontocetes in Hawai‘i (median=12d, maximum=34d, n=121), and the spotted dolphin tag transmitted for 73 days, illustrating the benefits of the TADpole system in increasing tag longevity. Analyses of spinner dolphin tag data revealed strong diel structuring, reflecting daytime resting and nighttime feeding. Daytime resting behavior was characterized by shallower dives and slower speeds, and nighttime dives reached as deep as 352m.Tagged spinners around O‘ahu made extensive movements away from the areas where they were tagged, using all coastal areas around the island with extensive inter-individual variability in spatial use, including brief movements by two individuals to Moloka‘i. The tagged Lāna‘i spinner and bottlenose dolphins utilized coastal areas around multiple islands, while the spotted dolphin remained off the west coast of Hawai‘i Island. These results demonstrate how advances in tagging technology enable longer tag deployments on previously inaccessible species, including the first ever detailed movement data for spinner dolphins over periods of weeks to months.
Citation:
Baird, R.W., R.S. Wells, A.A. Barleycorn, C.J. Cornforth, M.A. Mohler, D.M. Barrios, and A.E. Harnish. 2026. TADpoles and Spinner Dolphins in Hawai’i with Satellite-Linked Tags Reveal Detailed Movement Data Over Weeks to Months. Presentation at the 26th Biennial Conference on the Biology of Marine Mammals, San Juan, Puerto Rico, 19-23 October 2026.
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