Wild salmon advocates expressed relief Thursday after Prime Minister Stephen Harper announced that the federal government will stage a judicial inquiry into the collapse of sockeye salmon runs on the Fraser River.

Details will be announced Friday in Vancouver by Stockwell Day, federal Trade Minister and regional minister for British Columbia.

Day is expected to name a judge to head the inquiry and to announce terms of reference. The inquiry will have the legal power to compel witnesses to testify — meaning that federal scientists will have the freedom to discuss their concerns about sockeye without fear of repercussion.

Sockeye runs spawning in the Fraser drainage have been in a two-decade decline after years of spectacular abundance in the 1980s, and hit a 50-year low in summer 2009.

That has prompted concerns, as detailed in a recent book by B.C. author Alex Rose, that sockeye are heading for a population failure on the scale of the collapse of Atlantic cod.

In his book, Who Killed the Grand Banks, Rose suggests that sockeye are beset by the same conflicting political agendas that enabled East Coast fishermen to push cod to the brink of extinction.

“Mr. Harper deserves credit for this decision. It’s long overdue,” Rose said in an interview. “After seeing the denial and obfuscation of DFO and its regime on the East Coast with the collapse of the Grand Banks cod, I’m convinced that we need to get these people on the stand and under oath.”

Documents show that while the Department of Fisheries and Oceans was officially predicting strong sockeye returns and a commercial fishing opportunity for Fraser sockeye in 2009, others at DFO were warning of a probable collapse based on grim results in ocean test fishing programs dating back to 2007.

B.C. New Democrat and Liberal MPs, first nations, commercial and sport fishing groups, conservation groups and local governments have all been calling on the government for action but until Harper’s announcement there was no evidence that the Tories intended to respond.

The reason for the decline remains a mystery, although poor marine survival rates among juvenile salmon migrating into the ocean for the first time appear to be the principal culprit.

Climate change effecting ocean temperature, declining ocean salinity, dwindling food resources and health threats from fish farms along salmon migration routes have been suggested as possible explanations — but the official position of the Department of Fisheries and Oceans is that no specific cause is known.

Chief Bob Chamberlin, secretary treasurer of the Union of B.C. Indian Chiefs, called Harper’s announcement “excellent news.”

“I think it’s crucial that they release a complete understanding of what happened with the sockeye collapse here on the West Coast,” Chamberlin said.

He wants the inquiry to look at potential for sea lice infestations and disease transfer from salmon farms to juvenile wild salmon.

“I would urge the Prime Minister to make the necessary resources available for intervenors to participate — if not, you’ll have well-resourced industries like fish farms participate and put their spin on things, and other people who could inform the whole process will be excluded.”

Craig Orr, executive director of Watershed Watch Salmon Society, wants the inquiry to look at the “disconnect” between DFO researchers who warned in 2007 of the pending collapse based on an absence of juvenile 2009-class Fraser sockeye in ocean test fishing, and DFO’s “rosy” pre-season forecasts for the 2009 sockeye Fraser return.

“An inquiry should allow them to compel testimony from the managers and the scientists, which is good,” Orr said.

Commercial gillnetter and troller Rick Burns, who abandoned the Fraser in favour of fishing the north B.C. coast four years ago, said he’s “all for” the inquiry and said it needs to be a “far ranging inquiry because there are so many factors that affect salmon.”

Phil Eidsvik, spokesman for the BC Fisheries Survival Coalition, said the inquiry is “great news for B.C. salmon.

“I couldn’t be more pleased – we have been asking for a full judicial inquiry into the management of Fraser salmon since 1992,” Eidsvik said.

“Harper has shown that he understands how important salmon is to B.C. and is putting his government under a microscope to ensure that B.C. salmon don’t go the way of Atlantic cod.”

ssimpson@vancouversun.com