By William Mccall
Associated Press
PORTLAND, Ore. – Salmon on both sides of the Pacific Rim need protection more than ever as scientists learn more about their diversity and their effect on other species, even trees, top fisheries experts said Monday.
Dan Bottom of the National Marine Fisheries Service opened a two-day conference of experts from four countries warning the Pacific Northwest is “experiencing an aquatic biodiversity crisis.”
Conservation principles have changed from trying to simply improve the production of salmon to understanding the web of environmental factors that shape their lifecycle, Bottom told the Pacific Rim wild salmon and steelhead conference, where scientists from Russia, Japan and Canada joined their U.S. counterparts.
Bottom said more than 200 salmon stocks are at risk of extinction or threatened, a decline that roughly follows the level of development along the Pacific Rim. In more populated and industrialized areas, the fish decline is more apparent than in remote areas.
“The picture is not pretty,” he said.
Bottom was a biologist for the Oregon Department of Fish and Wildlife for more than 20 years before he joined the federal fisheries agency. He said evidence is mounting that salmon survival depends on the diversity of wild stocks, which in turn depends heavily on keeping their environment as natural as possible.
Biologists once believed they could protect fish populations by controlling one area, such as river migration, estuary protection or ocean harvest levels.
But he said that biologists now understand that all cycles of the salmon migration are linked and interwoven with changes in the environment, from the deep ocean all the way to spawning grounds in the shallow river and creek beds of inland mountain ranges.
Jack Stanford, a University of Montana biologist, said studies of the Flathead Lake area in Montana provide a smaller model of the biodiversity needed to maintain wild fish populations, and the role fish have in maintaining other species, including plants.
Stanford said alluvial flood plains in the rivers feeding the lake show tremendous biodiversity because they are not dammed and flood on a regular basis.
The flooding supports cottonwood trees, which in turn form sheltering habitat for salmon when the trees die and fall into wetlands and riversides. The salmon, in turn, provide much of the nutrients the trees and other plants need when they spawn and die, decaying along the stream beds that water the woods and forest.
Stanford noted that most rivers populated by salmon are loaded with gravel that flushes water underground, carrying a rich load of microscopic life that supports forests and wildlife.
“It’s a complex world out there,” Stanford said, “and these fish are living in that complex world.”
The heavily dammed rivers of the Northwest interrupt the natural cycle, he said.
“Flooding drives biodiversity,” Stanford said, while dams “have very much changed the way rivers do their work.”
He urged the Army Corps of Engineers to consider restoring natural flood plains, and even moving freeway lanes that block them in some lowland areas along the I-5 corridor.
“We’ve got to be adaptive, and we’ve got to be radical,” Stanford said.
The conference is sponsored by the Portland-based Wild Salmon Center.
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