Canada's West Coast was home to an orca baby boom this past year, with eight calves born to J-Pod, a group of killer whales living in the Georgia Strait and Puget Sound.

It's been almost 40 years since that many calves were born into the southern resident killer whale population.

Hussein Alidina, senior specialist of oceans at World Wildlife Fund Canada, says the spate of births is a surprise when three calves per year is the norm.

"Typically with this population, when their primary food, chinook salmon, is available in abundance, their survival rates and birth rates are higher," he told The Early Edition guest host Stephen Quinn.

"The last few years, 2013, 2014 and perhaps even this year, there's been relatively more chinook salmon availability."

Alidina says while this year has been a relatively good one for the orcas, climate change and habitat destruction over the decades has reduced the number of salmon available to the whales.

And while he said it was good to see so many whales born this year, each calf only has a 50 per cent chance of surviving into adulthood.

The orcas remain endangered, counting only about 84 individual whales. To lose their endangered status, they would need to number 120 whales.

To hear the full story, click the audio labelled: 2015 brought baby boom to West Coast orcas