Top predators in a changing ecosystem

Top predators in a changing ecosystem: occurrence and implications of specialisation in killer whale

Understanding the effects of climate change on marine ecosystems and food web dynamics requires knowing the foraging ecology of top predators, particularly those that can have large impacts through top-down control. Killer whales can cause cascading effects in food webs, however these effects depend on the occurrence and degree of prey specialishaation . Specialist populations can, in turn, be affected by prey availability through bottom-up control.

In Iceland killer whales are thought to feed on herring, although some observations have suggested a wider dietary niche. Variability in movement patterns also suggests variations in foraging ecology. This project aims to understand the role killer whales play in the Icelandic marine ecosystem by investigating the occurrence of specialisation and potential inter- and intra- individual variations in diet.

This will be accomplished by combining boat and land-based observations with tissue and prey sampling. Prey availability will be related to killer whale occurrence by concurrent observations with herring surveys and linkages to other areas in the North Atlantic will be investigated by comparing photographs collected at wider spatial scales. Together these data will provide an assessment of the potential implications of environmental changes on this population as well as contribute to our global understanding of top predator dietary specialisation and the ecological factors that may drive it.