The federal government is looking into why there is an increased number of killer whale sightings in Nunavut waters.

Eric Kan, an area director for the Department of Fisheries and Oceans, said the increase in whales migrating north in the summer could be attributed to the longer ice-free season in the summer.                        

Kan said the department is keeping close watch.

"We're concerned, they may have been damaging or have some impact to other marine mammals. Killer whales have been known and we have some reports they do kill other marine mammals, so certainly it's a concern from our perspective," he said.

Hunters also report seeing more killer whales than they used to. The whales are being seen near the mouth of Frobisher Bay in Cumberland Sound and in Foxe Basin.

Kan said they are fierce predators that go after marine mammals such as beluga and narwhal.

He added that the department has been monitoring the killer whale activity in the area for six years but, so far, there is no real data on the numbers.