Massive Salmon Run Predicted For The Columbia River

Chinook Salmon Courtesy USGS

When the chinook salmon return on the Columbia River next spring, get ready for massive numbers of fish.

Wildlife officials say they’re expecting about 470,000 chinook for the spring run. If that prediction is accurate, it would be the biggest return of spring chinook since 1938.

The announcement by Oregon Fish and Wildlife, Washington Fish and Wildlife and the Columbia River Inter-Tribal Fish Commission, admits that past predictions of salmon runs haven’t always been on target.

So they’re taking extra precautions to get it right for 2010.

Among salmon experts, a “jack” is an immature salmon who thinks he’s ready for spawning. They’re the hormone charged teenagers of the salmon world. Jack doesn’t want to wait around in the ocean to become an adult before returning to his native stream to spawn. So he’ll come back a year or two early. Not surprisingly, almost all jacks are males.

Wildlife experts count the number of returning jacks as one of the factors in predicting how many adult salmon will return the following year. But this method has been unreliable lately. Over the past few years, the forecasts have been too high by an average of 45%. For example, the 2009 spring run of chinook was forecasted at about 300,000. But the actual number was just under 170,000.

What’s also making the prediction for next year especially tricky is that the number of jacks returning in 2009 is way beyond normal. Some 80,000 jacks were counted, that’s 3 to 4 times higher than what the experts would normally expect.

Some of the questions the experts are trying to answer:

• Does the huge number of jacks mean there’s huge numbers of adult salmon waiting to return?
• Or does it mean more salmon are returning early leaving behind fewer adults in the ocean?

Because of the uncertainty, the agencies studied seven different models for forecasting next year’s run. The models produced a range of 366,000 to 528,000 adults for next spring’s chinook run. The committee which produces the forecast agreed on 470,000 fish as an average.

Two members of the committee, Stuart Ellis and Tom Nigro say they don’t really know why these numbers are so high. Both men pointed to changes in how the dams are operated as one possible factor. The federal hydro system on the Columbia River is under orders by a federal judge to adjust the timing of spills, and the amount of water spilled to benefit salmon. They also say we may be seeing the results of better management of hatcheries.  Plus, there have been better conditions for salmon in the Pacific for the past few years.

“We don’t know what 80,000 jacks can produce,” says Nigro, “because we’ve never seen it before.” But whatever the reason, Nigro adds, “Something is fundamentally different.”

As for those jacks who just can’t wait to spawn? They almost never do. The jacks can’t compete with the larger, tougher adult males and are losers in the battles for a mate.

Tags: chinook, columbia river, Columbia River Inter-Tribal Fish Commission, odfw, oregon fish and wildlife, Salmon, washington fish and wildlife, wdfw