An Examination of Movements of Bottlenose Dolphins Between Islands in the Hawaiian Island Chain

Information on population size, residency and movements of bottlenose dolphins (Tursiops truncatus) around oceanic islands is extremely limited. We photo-identified bottlenose
dolphins around the islands of O‛ahu, Maui/Lana‛i, and Hawai‛i, in April and May 2002, and compared photographic identities with dolphins identified off Maui/Lana‛i in 2000 and 2001.
Seventeen bottlenose dolphin groups (mean group size of 8.5 individuals) were encountered during 28 days of field effort, and 58 individuals with long-term markings were documented in the three areas. Of the 18 individuals identified off Maui/Lana‛i, 11 of these had been documented in that area in 2000/2001, indicating that individuals show some residency to the area. Of the 40 individuals identified off the islands of O‛ahu (29) and Hawai‛i (11), none had been previously documented. Combined with an apparent preference for shallow (<200 m deep) areas, these data suggest that movements between islands are limited. Concurrent biopsy sampling for collection of genetic samples may provide evidence of differentiation between islands, however sample sizes off the islands of O‛ahu (6) and Hawai‛i (4) are currently insufficient for such testing.

Citation:

Baird, R.W., A.M. Gorgone, and D.L. Webster. 2002. An Examination of Movements of Bottlenose Dolphins Between Islands in the Hawaiian Island Chain. Report prepared under contract #40JGNF110270 to the Southwest Fisheries Science Center, National Marine Fisheries Service, La Jolla, CA.