By SHANNON DININNY
YAKIMA, Wash. (AP) -- Steelhead are swimming upstream in southwest Washington's upper White Salmon River, marking the first upstream fish migration since a dam was built there nearly a century ago.
Biologists from the Yakama Nation's fisheries program and the U.S. Geological Survey documented multiple adult fish jumping at Husum Falls and BZ Falls, which are both upstream of the breached shell of Condit Dam, in the past week. The dam was breached in October.
"We are able to witness the first salmon returning to the White Salmon River," Virgil Lewis, chairman of the Yakama Nation's Fish and Wildlife Committee, said in a statement Monday. "We see these salmon as leaders that are creating a path for other salmon to come back."
USGS fish biologist Brady Allen said the migrating fish are likely adult hatchery steelhead.
The 125-foot dam, built in 1913, blocked passage for native species of Pacific salmon and other anadromous fish that mature in the ocean and return to rivers to spawn, confining them to the lower 3.3 miles of the river. But Portland,Ore.-based utility PacifiCorp, elected to remove the dam rather than install costly fish passage structures that would have been required for relicensing.
The White Salmon River winds from its headwaters on the slopes of Mount Adams through steep, forested canyons to its confluence with the Columbia River, the largest river in the Pacific Northwest.
In late April, surveys showed that no spawning salmon had returned to Rattlesnake Creek, one of the major tributaries of the White Salmon River, about 50 miles east of Vancouver.
"We were sort of disappointed," said Jeanette Burkhardt of Yakama Nation Fisheries. "It was a vindication to actually see them jumping at Husum and BZ."
The 90-feet-thick dam has a big hole in the bottom where it was breached, but the fish still must swim through a long tunnel to migrate upstream.
"There wasn't any certainty about the speed of water going through the tunnel, or whether there were debris jams, or how passable it is," she said. "Evidently, it's possible."
Burkhardt said biologists are now waiting to see if fall chinook will return to the area to spawn in September.
Meanwhile, workers are laboring 12 hours a day, six days a week to remove the concrete structure of the dam to meet an Aug. 31 target date.
Copyright 2012 The Associated Press.