Population Dynamics
Monitoring the demography of Norwegian killer whales to evaluate their vulnerability to rapidly changing marine ecosystems.
Population size, mortality and reproduction rates, and geographic range are key parameters in the assessment of species and populations’ extinction risk (IUCN). We monitor these parameters for Norwegian killer whales by conducting photo-identification surveys all year round and by applying mark-recapture models to individuals’ sighting histories. Results in 1988-2019 estimated that about 2,000 killer whales frequented Norwegian coastal waters. We are currently working on estimating reproduction rates and calf survival. Combining citizen-science (ID photos contributed by the public) with our dedicated research surveys allows us to ‘follow’ individual killer whales along the entire Norwegian coast. Over the years, we have built a comprehensive dataset on individuals’ geographic range and seasonal movements, providing insights into immigration and emigration rates as well in relation with dynamic prey resources. Our results will inform evaluations of killer whales’ conservation status and predictions on the future of the Norwegian population.