Photographs are analyzed following protocols developed by Bigg (1982)* in Pacific Northeast, using pigmentation and scarring patterns of the dorsal fin and the saddle patch for identification of individuals. Each identified individual gets allocated a unique ID-number and is added to the ID-Catalogue. Further re-sightings of individuals overtime enable building sighting histories, essential to understand life-history of killer whale groups.
The ID-Catalogue currently gathers all individual killer whales identified from 2007 to date. For each distinctive whale, the best ID-photograph showing distinctive features and a unique associated ID-number are shown.
Ideally, an ID-photograph should show both the dorsal fin and the entire saddle patch, with best sharpness, and optimal light and contrast in order to unambiguously discern distinctive natural markings. Poor light conditions, rough seas or difficulties to approach the whales on certain occasions can challenge photographers, leading to a few medium-to-poor quality ID-photographs.
By convention, and for sake of simplicity, only left sides of the dorsal fin and saddle patch are available in this catalogue. The catalogue does not provide any information about individuals.
As killer whales may give birth, die, exit or enter the study area, the ID-project requires a consistent survey effort over the years and the catalogue needs to be regularly updated with the latest identified individuals.
Whales identified in Norwegian waters from 1986 through 2005 are in process of being matched to the current ID-Catalogue. Already multiple re-sightings lead to available sighting histories of several decades for some whales!
Sampling areas and time period
The ID-Catalogue currently includes individual killer whales that were photographed in Norwegian waters since 2007. Norwegian Orca Survey has been collecting pictures since 2013 on a year round basis in northern Norway. In addition, colleagues, friends, whale watching companies and members of the general public provided substantial amounts of photographs from diverse years and areas. Main regions where individual killer whales were photographically identified are shown on the map.
*Bigg, M.A. 1982. An assessment of killer whale (Orcinus orca) stocks off Vancouver Island, British Columbia. Report of the International Whaling Commission, Special Issue 32: 655–666.