Sports anglers have been ordered to stop catch-and-release fishing for sockeye on the Fraser River after dismal returns that could be the lowest in recorded history.

Department of Fisheries and Oceans area director Barry Rosenberger said anglers can still fish for chinook salmon or other species, but added there were concerns that even catch-and-release fishing could weaken incoming sockeye and reduce their survival rates.

"They're not allowed to fish sockeye and they should be changing their methods so they don't encounter sockeye," he said.

He did not rule out a complete angling ban on the river, which aboriginal leaders had urged to prevent accidental or deliberate catching of sockeye.

"If we still have problems we're going to have to make further changes," Rosenberger said.

The move came Wednesday after new estimates showing 9.5 million sockeye – 90 per cent of the expected run – has failed to materialize.

The current run size estimate of 985,000 doesn't include some of the late-timed runs, so the number could climb somewhat.

But it's far short of the 10.5 million pre-season forecast.

This summer's Fraser sockeye run appears certain to go down as a new record low, worse than the 1.5 million low mark recorded in 2007.

To find a more disastrous year for the embattled species, officials say they'd likely have to point to 1913, when a railway construction rockslide into the Fraser at Hells Gate devastated sockeye runs for decades.

"Everybody is disappointed in the returns coming in," Rosenberger said. "We don't have a specific reason for it."

Detailed study will be required to try to find answers, he added.

"Clearly something has changed in the survival of these fish from the spawning levels to what we've had returned."

Rosenberger noted that while most sockeye runs are doing very poorly, a few have beaten expectations.

The Harrison Lake run, a late summer run, is coming in at twice its forecast – 125,000 sockeye instead of a projected 69,000.

The difference: Harrison Lake sockeye head for salt water earlier than most other runs that spend a year in fresh water.

"They're not reacting the same," Rosenberger said. "We need to study this and understand why. That's a longer term process."

Critics have called for an investigation of the sockeye collapse, and some are demanding a re-examination of the potential impact of sea lice from fish farms on wild salmon.

Rosenberger said sea lice impacts have been primarily a concern for pink salmon, but he said pinks seem to be coming back strongly this year.

Asked whether DFO's forecasting method has failed, he said the model is based on historical returns and may not perform well if conditions change radically.

"There are a number of different studies ongoing," he said. "Hopefully they will deliver a clearer understanding of what the issues are."

No commercial fishing has been authorized this year and none is expected.

Commercial fishermen hoped for an opening based on the promising forecasts, turning the page on the previous two poor years.

About 20,000 sockeye have been caught so far by First Nations for food, social or ceremonial purposes. Another 10,000 have been caught so far in test fisheries that are required to gauge the run size.