The migration of marine predators could alter food webs in their newly adopted ecosystems
Far from their usual tropical waters, some 200 bottlenose dolphins and about 70 false killer whales have been spotted off the western coast of Canada’s Vancouver Island. Over on the Atlantic coast, bull sharks have turned a North Carolina estuary into a nursery — a sight more familiar in Florida, until now.
Two new studies highlight the unusual northern sightings of these three ocean predators.“Alone, these sightings could be seen as accidental, or vagrancies,” says marine ecologist Luke Halpin of Halpin Wildlife Research in Vancouver and part of the team tracking the dolphins sighting. “But we're seeing a lot of warm-water species ranging into historically cold North Pacific waters.” Those include dwarf sperm whales (Kogia sima), pygmy sperm whales (Kogia breviceps) and short-finned pilot whales (Globicephala macrorhynchus) documented by other researchers.
The results suggest that these marine