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Ecology and salmon related articles

Spring Chinook Numbers Rebound

by Jonathan Brinckman
The Oregonian, November 24, 1999

Biologists expect the biggest run in more than a decade next year,
but the vast majority will be hatchery fish

State biologists predict that 50,000 Snake River spring chinook will enter the Columbia River next year, the biggest run in 13 years.

But the vast majority will be hatchery fish, and biologists cautioned that the number of wild spring chinook, a threatened species, is expected to rise less dramatically.

"You shouldn't get your hopes up," said Jeff Curtis, Western conservation director of Trout Unlimited, a conservation group. "You are going to have ups and downs in this thing, but the trend line is going down."

About 5,000 of the returning fish are expected to be wild spring chinook, up from the 2,700 wild Snake River spring chinook that entered the Columbia River this year. About 4,600 Snake River hatchery spring chinook entered the Columbia this year.

The fact that wild spring chinook are not expected to bounce back as dramatically as their hatchery cousins illustrates one of the toughest problems in salmon recovery: Salmon populations can plunge too low to recover quickly when conditions in their habitat improve.

Four wild Snake River salmon and steelhead trout runs have fallen so precipitously that the federal government is considering breaching four dams on the lower Snake to aid the fish.

Biologists cite two key factors for the increase in the number of hatchery fish: Heavy spring runoff in 1995 and 1996 helped young salmon reach the ocean safely, and colder ocean water produced more nutrients for the small fish that salmon eat. That helped more salmon than usual survive to adulthood.

But 1995 and 1996 were record poor years for wild Snake River spring chinook: Only 745 fish made it to Idaho in 1995. Biologists theorize that so few young fish hatched that the wild population was unable to rebound even under much improved conditions.

Ray Beamesderfer, an Oregon Department of Fish and Wildlife biologist, said anglers should not expect the states to lift sportfishing restrictions. The tribal commercial fishery for spring chinook, closed in 1977, probably also will remain shut down. Sportfishing targeting hatchery stocks will remain restricted to avoid accidental catches of wild fish.

"The bottom line is, we aren't going to fish," Beamesderfer said.

The Snake River spring chinook are part of a larger population of spring chinook that return to the upper Columbia and Snake rivers. About 134,000 spring chinook are expected to enter the Columbia next year, nearly 100,000 more than the 38,574 this year and the most since 1977.

Willamette River spring chinook also are expected to show improvement, for the fourth straight year, but the Department of Fish and Wildlife has not completed projections.

Forecasts for stronger salmon runs are linked directly to improved ocean conditions. National Marine Fisheries Service biologists report that ocean temperatures and plankton counts show that a seven-year period of nutrient-poor seas has ended, at least temporarily.

Bill Peterson, a fisheries service oceanographer, said the plankton he caught in sampling nets this summer and fall was uniformly characteristic of cold ocean waters, like those off Alaska's coast.

If the oceans are shifting to more nutrient-rich upwelling, salmon numbers should continue to improve. Ocean conditions will affect all Northwest salmon stocks, including Oregon coastal coho, listed as threatened last year under the Endangered Species Act.


Jonathan Brinckman
Spring Chinook Numbers Rebound
The Oregonian, November 24, 1999

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