Large-scale habitat segregation of fish-eating and mammal-eating killer whales ( Orcinus orca ) in the western North Pacific

摘要: Top predators strongly impact the structure of ecosystems through top-down cascading effects on prey species. Killer whales (Orcinus orca), top in marine ecosystems, are increasing their presence Arctic following ice cover loss. The killer differs dramatically across ecotypes: ‘resident’ R-type feed mostly large fish, while ‘transient’ T-type mammals. We analyze differences geographical distribution whale ecotypes western North Pacific order to predict potential climate change range and consequential ecosystems. show that prevail coastal waters eastern Kamchatka, Commander Kuril Islands central Okhotsk Sea, dominate Chukotka Sea. most prominent difference between these areas is depth: regions where prevail, deep occur close shore, dominated by represented wide shallows covered with winter. propose several hypotheses explain this large-scale segregation, including species cover. Habitat preferences suggest expansion induced will likely involve consequently increase predation pressure mammals a greater extent than fish stocks. This should be considered further studies prediction models highlighting change.