As hordes of West Coast salmon continue surging through Mother Nature's floodgates, those with a stake in the once-in-a-lifetime run are tackling a tough question: To fish or not to fish?
Just how many fish can be caught responsibly has rippled like a contentious wave through the anglers, scientists, policy-makers and conservationists who are looking for an answer not available from past records.
With the federal Department of Fisheries and Oceans vaulting British Columbia's Fraser River sockeye run estimates another four million fish to a projected 34 million on Tuesday, experts are looking ahead in attempt to figure out the right moves to make now.
But the facts are murky.
"We don't know what's going to happen. This is beyond anything that's been seen in the times of historic research," said Carl Walters, a professor at the University of British Columbia's fisheries centre.
Prof. Walters has studied Pacific fish for 41 years.
In 2009, plunging returns of only 1.5 million fish prompted a judicial inquiry that begins hearings in late October.
Prof. Walters argues large run sizes have always been rare, but the David Suzuki Foundation contends that in bygone eras, fish once returned in droves of 40- to 50 million, sometimes even beyond 100 million.
The difference in numbers epitomizes the chasm of disagreement on fisheries management, as the people making decisions receive wide opinions on what targets they should be aiming for. While some say 'Let them fish,' environmental advocates warn a cautious approach that ensures biodiversity is required.
"We need to see recovery across different stocks across the Fraser before saying 'We're back, we've rebuilt.' There's more work to be done," said Jeffery Young, an aquatic biologist at the foundation.
A recent retrospective analysis of stock history conducted by Prof. Walters, using data back to 1995, suggests that kind of government policy has let $100-million worth of catch to commercial fisheries and First Nations slip away.
"It's a waste," said Prof. Walters, who is now calling for larger quotas than the 30,000 sockeye currently granted to licensed commercial fishing vessels.
"They could have harvested those fish without impairing future generations."
For decades, Prof. Walters led the charge to rebuild the sockeye stocks through a method he pioneered and convinced Fisheries to adopt in the late 1970s called "adaptive management."
It was an experiment to allow more fish to swim to their spawning beds than had been the case in the past, but it became long-term policy.
Prof. Walters said now that the fish are in bountiful supply, it's time to rethink.
"They're sticking with the same policy even though the data don't support doing so."
Many fishermen argue that allowing copious numbers of salmon to spawn together will result in not enough food and the destruction of eggs in their gravel beds, but a number of experts call that bunk.
But Prof. Walters and Mr. Young both say the science actually supports that at a certain point, no matter how many spawning fish are added to a water body, the same number of hatching will still result.
So in a year like this with a huge return, millions more fish will make it to their intended spawning grounds. But without room to spawn, they'll simply die without reproducing.
For the Adam's River stock, one of the largest that spawns in Shuswap Lake, all those extra carcasses won't be more beneficial to future generations, he said.
Nutrients from their decaying bodies will actually flow downstream, likely only feeding predators, parasites or fish like trout who will battle it out with juvenile salmon a few years down the line.
And bears, eagles and birds only really need some tens of thousands of the millions of fish available this year to sustain their diet, Prof. Walters added, so there's no concern fishermen will deplete that supply.
The Department of Fisheries has maintained a 40-per-cent escapement rate for the largest sockeye stocks since 2004. The theory was that it was the only way to halt overfishing of endangered stocks such as those headed for Cultus Lake.
Barry Rosenberger, area director for Fisheries and Oceans Canada, said the department plans to review the harvest guidelines post-season.
"We were in a period of declining productivity and lower overall returns, and that objective was designed really around ensuring smaller populations that co-migrate with larger ones were getting adequate protection," he said.
"And this year with the very large return we're getting, people are challenging that as an appropriate level to have."
That's raised concern at the David Suzuki Foundation, whose scientists say the 40 or so sockeye stocks - all with unique features, from body size to preferred water temperature - are most resilient and stable as a whole.
"It's like having a diversified investment portfolio, having a lot of different stocks is what gives you the greatest chance of having high returns every year, year-after-year," said Mr. Young, who called on the Department to resist pressures to allow more fishing.
"The reason we're trying to support this and look for rebuilding of diversity actually is to provide long term stability and abundance for the industry, as well as for the fish," he said.
Dennis Brown, a former B.C. fishery adviser and author of Salmon Wars, said the commercial fisheries are not to blame for years of unstable returns. He implored all parties to undergo a serious, non-formulaic examination.
"No one person has got this right," he said. "My only message is what we've been doing for the last 15 years is not working." The Canadian Press