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11-13-2003, 11:07 AM
Salmon Choke On Silt
Thursday, November 13, 2003
By ERIK ROBINSON, Columbian staff writer
Scores of fall chinook and coho salmon suffocated in a "river of liquid quicksand" sloughing off the southeast flank of Mount Adams over the past three weeks.
Many died before they had a chance to spawn.
Yakama Nation biologists who regularly monitor spawning beds and fish counts in the Klickitat River said hundreds of spawning beds, known as redds, have been smothered with sediment. Bill Sharp, a tribal fisheries biologist for the past 15 years, attributed the deaths to unusually warm weather that eroded the Rusk and Klickitat glaciers on Mount Adams on Oct. 20.
"I've never seen adult fish die as a result of an event," he said.
Though glacial silt running off the mountain is a common event in the Klickitat basin, it usually occurs over relatively short periods during the late summer. This time, Sharp described a sustained "river of liquid quicksand" occurring right in the middle of the spawning period for fall chinook and coho.
"This seems to be much more persistent," said Willie Scott, scientist in charge of the U.S. Geological Survey in Vancouver.
Geologists haven't concluded what triggered the event Scott said they're planning to examine the glaciers from the air this week but it coincides with a blast of warm, soggy air from the South Pacific.
Although rainfall in Southwest Washington didn't measure up to the deluge of floodwaters that hammered Puget Sound and British Columbia in mid- to late October, the unusually warm temperatures apparently took a toll on the meager snowpack on Mount Adams.
Although specific weather records weren't available for the mountain for Oct. 20 or 21, temperatures clearly would have been much warmer than typical.
Vancouver, for example, recorded an overnight low temperature as toasty as it's been all year 67 degrees.
By midday on Oct. 20, tribal biologists in Top*****h began hearing reports of Big Muddy Creek and the Klickitat River running chocolate brown. In later days, workers found one juvenile fish trap clogged with sand 18 inches thick 10 miles downstream from the Klickitat's confluence with Big Muddy Creek.
Sharp said tribal biologists are continuing to conduct stream surveys, so it's too early to assess the effect of the glacial melt on overall salmon survival.
But he said preliminary surveys show as many as half the carcasses discovered in the river still contained eggs or milt meaning the salmon were only hours or days away from completing their cycle of life, from the river to the ocean and back, spawning and dying.
"They could not escape," Sharp said. "They could not seek refuge anywhere."
Even the fish that show up afterward will be affected, he said. The mass of sediment now tumbling down the Klickitat will smother eggs the salmon lay in gravel.
Joe Hymer, a biologist with the Washington Department of Fish and Wildlife in Vancouver, expected about 20,000 coho and fall chinook returning to spawn in the Klickitat basin to be killed by the glacial outwash. It's rare for rivers to become lethal for spawning adults.
"Other than Mount St. Helens, I haven't seen anything that extreme," Hymer said.
Even so, he expects the fish will recover. Even in the Toutle River, below Mount St. Helens, salmon have managed to recolonize a river choked with an entire mountaintop. Hymer figures Klickitat basin salmon stocks will endure a little mud this year.
"Nature can heal itself fairly quickly," he said.
Thursday, November 13, 2003
By ERIK ROBINSON, Columbian staff writer
Scores of fall chinook and coho salmon suffocated in a "river of liquid quicksand" sloughing off the southeast flank of Mount Adams over the past three weeks.
Many died before they had a chance to spawn.
Yakama Nation biologists who regularly monitor spawning beds and fish counts in the Klickitat River said hundreds of spawning beds, known as redds, have been smothered with sediment. Bill Sharp, a tribal fisheries biologist for the past 15 years, attributed the deaths to unusually warm weather that eroded the Rusk and Klickitat glaciers on Mount Adams on Oct. 20.
"I've never seen adult fish die as a result of an event," he said.
Though glacial silt running off the mountain is a common event in the Klickitat basin, it usually occurs over relatively short periods during the late summer. This time, Sharp described a sustained "river of liquid quicksand" occurring right in the middle of the spawning period for fall chinook and coho.
"This seems to be much more persistent," said Willie Scott, scientist in charge of the U.S. Geological Survey in Vancouver.
Geologists haven't concluded what triggered the event Scott said they're planning to examine the glaciers from the air this week but it coincides with a blast of warm, soggy air from the South Pacific.
Although rainfall in Southwest Washington didn't measure up to the deluge of floodwaters that hammered Puget Sound and British Columbia in mid- to late October, the unusually warm temperatures apparently took a toll on the meager snowpack on Mount Adams.
Although specific weather records weren't available for the mountain for Oct. 20 or 21, temperatures clearly would have been much warmer than typical.
Vancouver, for example, recorded an overnight low temperature as toasty as it's been all year 67 degrees.
By midday on Oct. 20, tribal biologists in Top*****h began hearing reports of Big Muddy Creek and the Klickitat River running chocolate brown. In later days, workers found one juvenile fish trap clogged with sand 18 inches thick 10 miles downstream from the Klickitat's confluence with Big Muddy Creek.
Sharp said tribal biologists are continuing to conduct stream surveys, so it's too early to assess the effect of the glacial melt on overall salmon survival.
But he said preliminary surveys show as many as half the carcasses discovered in the river still contained eggs or milt meaning the salmon were only hours or days away from completing their cycle of life, from the river to the ocean and back, spawning and dying.
"They could not escape," Sharp said. "They could not seek refuge anywhere."
Even the fish that show up afterward will be affected, he said. The mass of sediment now tumbling down the Klickitat will smother eggs the salmon lay in gravel.
Joe Hymer, a biologist with the Washington Department of Fish and Wildlife in Vancouver, expected about 20,000 coho and fall chinook returning to spawn in the Klickitat basin to be killed by the glacial outwash. It's rare for rivers to become lethal for spawning adults.
"Other than Mount St. Helens, I haven't seen anything that extreme," Hymer said.
Even so, he expects the fish will recover. Even in the Toutle River, below Mount St. Helens, salmon have managed to recolonize a river choked with an entire mountaintop. Hymer figures Klickitat basin salmon stocks will endure a little mud this year.
"Nature can heal itself fairly quickly," he said.