A new paper was just published on-line in Marine Mammal Science. Subscribers can download a copy at http://www3.interscience.wiley.com/journal/119881066/issue <http://www3.interscience.wiley.com/journal/119881066/issue> A pdf and more information on this research can also be found at www.cascadiaresearch.org/robin/hawaii.htm <http://www.cascadiaresearch.org/robin/hawaii.htm> Baird, R.W., A.M. Gorgone, D.J. McSweeney, A.D. Ligon, M.H. Deakos, D.L. Webster, G.S. Schorr, K.K. Martien, D.R. Salden, and S.D. Mahaffy. Population structure of island-associated dolphins: evidence from photo-identification of common bottlenose dolphins (Tursiops truncatus) in the main Hawaiian Islands. Marine Mammal Science. DOI: 10.1111/j.1748-7692.2008.00257.x Abstract Management agencies often use geopolitical boundaries as proxies for biological boundaries. In Hawaiian waters a single stock is recognized of common bottlenose dolphins, Tursiops truncatus, a species that is found both in open water and near-shore among the main Hawaiian Islands. To assess population structure, we photo-identified 336 distinctive individuals from the main Hawaiian Islands, from 2000-2006. Their generally shallow-water distribution, and numerous within-year and between-year re-sightings within island-areas suggest that individuals are resident to the islands, rather than part of an offshore population moving through the area. Comparisons of identifications obtained from Kaua'i/Ni'ihau, O'ahu, the "4-island area", and the island of Hawai'i showed no evidence of movements among these island groups, although movements from Kaua'i to Ni'ihau and among the "4-islands" were documented. A Bayesian analysis examining the probability of missing movements among island groups, given our sample sizes for different areas, indicates that inter-island movement rates are less than 1% per year with 95% probability. Our results suggest the existence of multiple demographically-independent populations of island-associated common bottlenose dolphins around the main Hawaiian islands. Robin ======================================================== Robin W. Baird, Ph.D. Research Biologist Cascadia Research Collective 218 1/2 W. 4th Avenue Olympia, WA 98501 USA Phone 1-360-943-7325 Fax 1-360-943-7026 e-mail: rwbaird@cascadiaresearch.org www.cascadiaresearch.org/robin/robin.htm