False Killer Whales: Energetics and Survival

Background

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False killer whales around Hawai‘i represent one of the most endangered and least understood odontocete populations in U.S. waters. The Main Hawaiian Islands Insular Population is genetically distinct, exhibiting strong site fidelity and long-term social clustering that differentiate them from pelagic populations in the broader Pacific. Despite decades of dedicated research, major gaps remain in understanding their energy requirements, how they meet those needs in an ecosystem with declining prey availability, and how nutritional stress contributes to ongoing population decline.

Recent studies have revealed declining trends, with the population currently estimated at approximately 139 individuals. Prey size and abundance have diminished over time, commercial fisheries overlap heavily with the whales’ foraging habitat, and the population continues to decline at roughly 3-5%/year. These whales require large, energetically rich prey to sustain high metabolic costs, and emerging evidence suggests that some individuals experience nutritional stress. Understanding the bioenergetic demands of false killer whales, how those demands vary across age and sex classes, and how much prey these whales must consume to maintain health is essential for effective management and recovery planning. This research integrates drone photogrammetry, long-term sighting histories, and metabolic measurements to build the first comprehensive energetic framework for this endangered population.