Warmer temperatures have put chinook salmon — and a way of life — in grave danger

At the home James MacDonald shares with his wife and their two kids, it's approaching dinnertime. His five-year-old son, Sye, is helping MacDonald open a can of salmon.

As a citizen of the Ta'an Kwäch'än Council — one of several First Nations known as "salmon people" — MacDonald's ancestors have been fishing chinook salmon for millennia. 

But that way of life couldn't feel further away than it does right now.

"My wife and I were down at Costco a couple of weeks ago in Vancouver … and we bought $300 worth of canned sockeye. And, you know, it's the only way at this point that we can have salmon in our house," said MacDonald, a member of the federally appointed Yukon salmon sub-committee.

In an effort to preserve dwindling chinook stocks, MacDonald says he hasn't fished on the Yukon River since he was a young boy. 

"Culture doesn't come from a can, but when we prepare it with the kids we can still talk to them and tell them about what salmon means to us." 

CBC Radio's What on Earth travelled to Yukon this summer to explore how a warming climate has threatened chinook salmon, endangering not just the species but a cultural keystone for these Indigenous communities. There, it found that an unprecedented seven-year moratorium on fishing mandated by Canada's federal and Alaska's state governments, combined with other conservation efforts, may be netting some success.

This summer about 24,000 chinook were counted moving up the Yukon River at the border with Alaska. That's compared to historic lows of 12,000 and 15,000 the last two seasons, says Elizabeth MacDonald, a biologist and fisheries manager for the Council of Yukon First Nations. 

The fishing moratorium has only been in place for five months.

"I don't want to sound too joyous, because if we were talking about the run like we're having right now, five years ago, we would have been devastated by the numbers," said MacDonald, who lives in Whitehorse. "But it is better than the last few years. I'm really grateful for that." 

When data on the salmon run was first collected in the 1980s, between 100,000 and 200,000 chinook would enter the Yukon River, MacDonald said. Anywhere from a quarter to more than a third were destined to make that crossing into Canada.

Canada's North is warming faster than the rest of the country. Temperatures there have risen an average of two to four degrees since 1950, compared to an average of 1.9 C from 1948 to 2021 in Canada as a whole, according to Environment and Climate Change Canada.

Those hotter temperatures have a number of negative impacts on the chinook, MacDonald said.

The migration they make to return to their spawning grounds is the longest salmon run in the world, stretching to around 3,000 kilometres. The journey takes two months, during which time the chinook eat nothing — all while performing what MacDonald calls the fish equivalent of running a marathon uphill.