Local experts are warning this year's flourishing sockeye return does not mean the fish are in the clear, although more than 34 million of the salmon are expected to come back to the Fraser - the highest return in nearly a century.

"To see this is incredible. It's great news, and it's very, very exciting," said Mark Angelo, chair of BCIT's Rivers Institute. "(But) we have to refrain from getting overly optimistic because we're not out of the woods yet."

Angelo called this year's run an amazing contrast to 2009. Last year's was the lowest in 52 years, with 1.7 million sockeye finally returning to the Fraser to spawn when Fisheries and Oceans Canada was expecting 10.6 million. No one knows exactly what happened, but theories include disease and sea lice from fish farms, pollution and warming waters.

The federal government called for a judicial inquiry on the declining stock, and the commission is scheduled to report back with recommendations in 2011.

The commercial sockeye fishery has been mostly closed on the Fraser since 2006, but Fisheries and Oceans Canada is allowing fishermen to catch up to 13.3 million sockeye this year.

And while this year's sockeye run is in good shape, Angelo said it's too early to tell if this marks the beginning of a major turnaround. Some species - such as coho, chum and steelhead trout - are still struggling, he said, adding that two to four consecutive years of strong sockeye returns would indicate recovery. Angelo said we still have to manage the fishery and protect habitat.

Angelo guessed the conditions for fish from this year's return were likely more favourable as they headed out to sea as young, vulnerable juveniles.

SFU fish biologist John Reynolds holds the Tom Buell B.C. Leadership Chair in salmon conservation. The salmon cycle peaks ever four years, Reynolds said, and that's part of why this year's run is so record-breaking. But why sockeye returns from the past two years are so radically different is still a bit of a mystery.

"The best information we have is the Pacific Ocean was cooler when they went to sea in 2008 than it was when the fish from the previous year went out in 2007," Reynolds said.

Cooler water means it's easier for young sockeye to find food, and there were likely fewer predators around.

"Juvenile salmon's world only involves two things: eating and not getting eaten," he added.

While this year's numbers are high, Reynolds said we're not out of the clearing yet.

"This is the peak of the cycle," Reynolds said, explaining the Fraser sockeye numbers reach a high point every four years. "It's a new roll of the dice next year."

Last year, Burnaby-New Westminster MP Peter Julian called on the federal government to conduct an inquiry into declining Fraser sockeye stocks.

"This is a welcome respite from the collapse we've been seeing, but it doesn't in any way mean we're out of the tunnel," he said. "It deepens the mystery about the overall issues around the collapse of the fisheries because this year has been so abundant."

Julian suspects sea lice from fish farms may have played a role in last year's dismal return, and he wants the government to investigate more.

"We don't really know, and the federal government hasn't invested to do the monitoring," he said.

Julian also wants more government resources to protect wild salmon and for fish farms to move into closed containment systems on land.

For more, see Jennifer Moreau's blog, Community Conversations, at www.burn abynow.com.