03/21/2026
Understanding Killer Whale Photo-Identification Catalogs
Over the past few days we’ve received several questions from followers about the photo-identification of the recently documented unidentified killer whales in the Salish Sea. In particular, people have asked why our research team sometimes uses non-“T” identification codes for whales, while other individuals are identified using established “T” IDs.
Photo-identification has been used for over five decades to study killer whales. Individual whales can be identified by the unique shape of their dorsal fin, saddle patch, and scars, allowing researchers to track whales across years and even decades.
Across the North Pacific, multiple photo-identification catalogs exist, developed by different research programs working in different regions and habitats. These catalogs are scientific tools used to document sightings and track individual animals; they are not centralized registries, and no single organization maintains a complete record of every whale encountered throughout the species’ range.
Many long-term studies have focused on killer whales that regularly use the coastal waters of British Columbia, Washington, and Alaska. These efforts have produced extensive catalogs of whales frequently encountered in those regions.
However, research along the outer coast and in offshore environments has shown that many whales encountered in these areas cannot be matched to individuals in existing coastal catalogs, suggesting that a portion of the population remains poorly documented.
Because of this, researchers studying whales in different habitats often maintain parallel or region-specific catalogs. When whales cannot be matched to previously identified individuals, they are temporarily assigned new identification codes so sightings can be tracked and analyzed until their identity and associations are better understood.
At the ORA - Oceanic Research Alliance, our research focuses on mammal-eating killer whales occurring in offshore and open-ocean environments, which remain one of the least studied components of the west coast transient population. When whales encountered during our research cannot be matched to published catalogs, we assign temporary identifiers so these individuals can be documented scientifically and included in future analyses. As additional sightings accumulate, whales from different catalogs are often linked together through photographic matches, allowing researchers to better understand how animals move between regions and habitats.
Scientific progress depends on open data, collaboration, and continued documentation of whales across their full geographic range. Encounters with previously unidentified whales provide valuable insights into the ecology, movements, and population structure of these remarkable predators.
At the ORA - Oceanic Research Alliance, we continue to use the west coast transient (Bigg's) alphanumeric "T ID system" for known whales (i.e., T011A, T101), but for us to publish papers on poorly known aspects of transient ecology, behavior, and natural history, we have had to create additional catalogues for unidentified or unpublished individuals.
In 2021 we published a NOAA Technical Memorandum summarizing unpublished data and photographs of transient killer whales frequenting offshore waters of the California Current System.
Here is a link to a free PDF of our published catalog: https://repository.library.noaa.gov/view/noaa/30740
