Movements and spatial use of false killer whales in Hawai‘i: satellite tagging studies in 2009
Baird, R.W., G.S. Schorr, D.L. Webster, D.J. McSweeney, M.B. Hanson and R.D. Andrews. 2011. Movements and spatial use of false killer whales in Hawai‘i: satellite tagging studies in 2009. Report prepared under Order No. AB133F09SE4132 from the Pacific Islands Fisheries Science Center, Honolulu, HI.
Movements and spatial use of Hawaiian insular false killer whales was examined using data from nine individuals satellite-tagged in 2009; five tagged off the island of O‘ahu in October and four tagged off the island of Hawai‘i in December. A total of 3,782 locations were available after filtering, over periods up to 104.8 days (median = 70.7 days), more than doubling the location data available from this population. Assessment of distance between pairs of individuals with overlapping data indicated we obtained movement information from at least five and possibly seven different social groups of false killer whales. All tagged individuals remained in association with the main Hawaiian Islands. While movements of one individual extended up to 112.8 km from shore, into a water depth of approximately 5,400 m, the average distance from shore ranged from about 11 to 23 km, in depths averaging about 500 to about 1,200 m. Four of the five individuals tagged off O‘ahu moved west to Kaua‘i and Ni‘ihau, providing evidence the Hawaiian insular population uses the waters around the westernmost of the main Hawaiian Islands. There were no significant differences in the proportion of time spent using windward versus leeward sides of the islands. One individual that had been tagged previously (in 2008) showed very different spatial use patterns in 2008 versus 2009. Overall the data provides a more robust assessment of spatial use and movements of Hawaiian insular false killer whales that can be used in helping assess critical habitat if this population is listed under the Endangered Species Act.