Photo ID Catalog of Killer Whales in the Nemuro Strait (Rausu), Hokkaido, Japan (2010‒2025)

This catalog is an updated version of our Photo ID Catalog of Killer Whales in the Nemuro Strait (Rausu), Hokkaido, Japan (2010–2018), published in 2025. This catalog was compiled by the University Alliance for Hokkaido Orca Research Project (Uni-HORP) and is publicly released to support the identification of killer whales (Orcinus orca) in the Nemuro Strait (off the coast of Rausu, Hokkaido, Japan). It presents photographs of individuals observed between 2010 and 2025. A total of 495 killer whales have been individually identified and cataloged. This total includes calves and juveniles; however, these individuals are not formally registered and are not assigned identification numbers with the prefix “RA_oo”. Individuals are grouped using cluster analysis based on the half-weight association index, derived from 105 observations collected between 2012 and 2023. Photographs of many individuals have been updated to the most recent and highest-quality images, allowing growth to be observed through comparison with earlier photographs.