Author Identifier (ORCID)
Abstract
Aim: Killer whales, Orcinus orca, are cosmopolitan top predators showing highly variable ecology and behaviour across populations. In the Indo-Pacific, baseline knowledge in general remains scarce, limiting the assessment of their vulnerability to the accelerated environmental changes, including expanding fisheries this region is undergoing.
Methodology: This review synthesises 170 sources found between 2000–2025 to evaluate the current knowledge on distribution, population structure, and feeding ecology (including depredation) of killer whales in the Indo-Pacific, and to identify priorities for future research and management.
Results: Occurrence was highly variable, from sporadic sightings in most tropical sectors to seasonal and year-round presence at temperate and sub-Antarctic hotspots, reflecting ecological heterogeneity and sampling bias. Seven distinct populations or forms have been confirmed in sub-Antarctic and temperate regions, but observation and photo-identification data suggest additional populations. Their connectivity and the presence of putative ecologically and genetically distinct forms remain unresolved. Sixty-eight prey species were confirmed as taken naturally, notably elasmobranchs, cetaceans, and fish. Generalist diets emerged as a possible dominant pattern although robust dietary inference was concentrated at a few sites. Sixteen species were confirmed as taken through depredation on 17 fisheries, with highly variable rates of interaction with fishing vessels being possibly explained by varying overlaps with killer whale occurrence and diet. Major gaps were identified in killer whale photo-identification data, genetic sampling, and reporting of interactions with small-scale fisheries and should be addressed to improve management and conservation of killer whales in the Indo-Pacific.
Keywords
connectivity, depredation, distribution, feeding ecology, Indo-Pacific, killer whale Orcinus orca, population structure
Document Type
Journal Article
Date of Publication
9-1-2026
Article Number
e70046
E-ISSN
13652907
ISSN
03051838
Volume
56
Issue
3
Publication Title
Mammal Review
Publisher
Wiley
School
Centre for Marine Ecosystems Research
Funding Information
We acknowledge salary support from the Minderoo Foundation OceanOmics centre for I.M.R., and support their mission to protect and restore natural ecosystems for future generations.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
Lacetera, P., Tixier, P., Reeves, I. M., Terrapon, M., Barnes, A., Guinet, C., Elwen, S. H., Totterdell, J., Tucker, J., Cross, P., Bisset, G. K., Dickie, J., & Arnould, J. P. Y. (2026). Killer whales (Orcinus orca) in the Indo-Pacific: A review of their distribution, population structure, and ecology. Mammal Review, 56(3), e70046. https://doi.org/10.1111/mam.70046