Orcas may replace polar bears as top predator. Here's where

Researchers say melting sea ice in Hudson Bay continues to stir a dramatic shift in the food chain, with killer whales eating their way to the top of the predator list.
"We are seeing a lot more killer whale activity in Hudson Bay and they are a top predator," Steven Ferguson, researcher with Fisheries and Oceans Canada and the University of Manitoba told CBC. "They are really a magnificent, interesting predator - highly efficient."
According to Ferguson, sea ice irritates the dorsal fin of an orca. However, because ice is melting earlier each year, the predators are spending more time searching for food in the bay.


Image courtesy: Brian Rundle -- Sooke, British Columbia
Image courtesy: Brian Rundle -- Sooke, British Columbia
"They appear to be eating other whales and seals and, I would imagine, if we lose our sea ice they will replace polar bears as that top predator," the researcher told CBC.
Ultimately, this could have a major impact on other species.
Each summer, nearly 60,000 beluga whales migrate from the Hudson Strait to the southwestern coast of the bay to feed and mate. This is one of the largest concentrations of Belugas in the world. However, Ferguson says they are at risk.
"They are food for killer whales and we've had a few instances where we have recorded attacks by killer whales on the beluga population," he told the news agency. "It probably happens more often than we know because it's not an easy thing to observe."
Image courtesy: Heidi den Haan -- Churchill, Manitoba
Image courtesy: Heidi den Haan -- Churchill, Manitoba
Other predators taking advantage of the melting ice include Greenland sharks. Although, they don't venture into the Hudson Bay as far as other species do because it is shallow, CBC reports.
Ferguson will be presenting his findings at ArcticNet 2016, Canada's largest Arctic scientific conference. It will be held Monday to Friday in Winnipeg, Man. at the RBC Convention Centre, where about 700 scientists from across the country will gather to address the ongoing changes in Canada's Arctic.
It is estimated that within the next 10 to 15 years, we could see an ice-free summer, according to Ferguson.
"That still means we have ice in the winter, and we could have quite a bit of ice, which is important for the arctic ice adapted species like the beluga whale," he said. "But it's hard to know how far the melting will go and whether [we will] have sea ice at all in 100 years."