PORTLAND, Ore. – For the straight second year, the spring chinook salmon that normally leap by the thousands up the fish ladders of Bonneville Dam toward spawning grounds are virtually absent.

Fishery experts say the run has been late before, thus they aren’t hanging out the crepe just yet. But it’s off to such a weak start that a Columbia River Indian tribe had to haul some of last year’s salmon out of the freezer last weekend for its traditional “First Foods” ceremony that marks the return of the fish.

As of Tuesday, only 135 adult chinook had been counted at the dam. The 10-year average at this point, which includes a couple of bumper years, is about 19,000.

The tribal share of this spring run has been calculated at 6,188 fish. As of last weekend’s ceremony at Celilo Village near The Dalles, tribal fishermen had caught only about 20.

The 140 miles of river below the dam will close to salmon, steelhead and shad fishing effective Friday. It could reopen if more fish pass the dam.

“There are ups and downs in the fish world,” said Cindy LeFleur of the Washington Department of Fish and Wildlife. “Last year was one of the latest runs we’d seen and this year is shaping up that way.”

She said a late surge remains possible and more should be known in late April, when about half of the run normally would have passed the dam.

She said the sport fishery below the dam has told scientists the fish are in the river. “But we’re not seeing movement over the dam.”

For reasons not well understood, salmon don’t spawn until they return to the places where they were hatched. Then they die. Some spawn below the dam but most spawning grounds extend as far as Idaho and into numerous Columbia River tributaries above Bonneville Dam.

Preseason estimates for last year were for 254,100 salmon to make it past Bonneville Dam. Only 106,900 did so.

This year’s prediction is 88,400 – still a fairly healthy run if it shows up. In recent years, the run has been as low 42,000 in 1999 and as high as 438,000 in 2001.

As with last year, the salmon are apparently waiting for some biological trigger to send them up the stairstep-like ladders, past a counting window and on their way upriver. The spring run is described as famously finicky about water conditions and other factors.

Data from the count are used to predict future runs and have been fairly accurate until last year.

“Scientists are taking into account ocean temperatures and conditions, sea lions, ocean fishing and out-migrating conditions,” said Charles Hudson of the Columbia River Intertribal Fish Commission. “It still doesn’t make up for the gap” between last year’s predictions and actual returns.

He said tribes worry that a return to the days of persistently low runs will eliminate ceremonial and subsistence fishing.

Federally protected sea lions, who gather in increasing numbers at the base of the dam to snag salmon as they amass at the fish ladders, take an estimated 3.5 percent of the run and are blamed by many.

There is a move to seek permission to shoot the worst offenders, some of whom return year after year.

But Hudson said that has to be kept in perspective. “Spring chinook for the last 40 years have been in deep, deep distress,” he said.

Spring chinook in the Columbia generally have been off-limits to tribal and nontribal commercial fishermen since 1977.

Brian Gorman of the National Marine Fisheries Service in Seattle said the spring run tapers off in late May or early June, when the summer run begins. The summer and fall runs are thought to be in better shape.

Problems are not limited to the Columbia.

Last week, the Pacific Fishery Management Council voted to close commercial salmon fishing on 400 miles of the Pacific Coast and to heavily restrict it along 300 more miles to protect dwindling stocks of chinook from Northern California’s troubled Klamath River.

Reasons are more evident in the Klamath. The river was overfished in the 1980s and since 1917 dams have cut off some 300 miles of spawning habitat.

In 2002 some 70,000 adult chinook died in the river from diseases linked to low and warm water.