About 10% of their food as well as their shrinking habitat
Killer whales have found a bonanza of new prey in the Arctic as melting ice forces fish to move northward.
During their winter prowls, the huge – and increasingly vocal – whale animals venture out more than 30km (19 miles) in search of food.
In addition to fish, they will sometimes venture far from the pack to find sea eagles and seals, researchers say.
The breakthrough comes as the United Nations heads to a landmark summit to discuss ending climate change.
Antarctica’s polar regions are under acute pressure from climate change, while the Arctic is becoming more and more warming.
The northern part of the Arctic is expected to hit “carbon dioxide neutral” status by 2050, an international panel of scientists says.
Ample food for the whales
North of Newfoundland, the thin and brittle Arctic ice disappears year after year.
The entire permafrost – a frozen layer at the bottom of the ocean – on the ice sheet gradually thaws as the ice melts.
The melt is causing more and more small fish to swim to the surface looking for water and the easiest places to spawn.
“The transition in the top of the water column from sea ice habitat to open ocean is one of the most important changes that drivers will see in their lifetimes,” said lead author and science editor for the Arctic Network at the Zoological Society of London, Nick Smithers.
This barren area – where brown algae and anemones used to grow – is now filled with fish-eating seals, eagles and whales.
But large concentrations of these animals can be a health hazard.
Many of the whales are dying, either as the result of collisions with other whales or by sickened by the open water.
“The whales’ food needs are growing along with their prey resources,” he added.
The winter months, from September to November, are when they are most active, approaching ships on gill nets as they hit the open water.