Scientists begin study of green sturgeon
Thursday, September 15, 2011
Washington and Oregon scientists are tagging green sturgeon in Northwest estuaries hoping to learn more about the life cycle of the threatened and poorly understood fish.
Using commercial fishing boats and 600-foot gillnets, the scientists will collect and tag green sturgeon at the mouths of the Columbia and Umpqua rivers plus in Grays Harbor and Willapa Bay.
As many as 525 green sturgeon will be tagged and tracked for the next two years as they move up and down the West Coast. The tags will be implatned surgically and not visible to plain view.
The researchers want to learn when the fish enter the river from the ocean, how far up the rivers they move, how long they stay in fresh water and when they leave.
It is known that green sturgeon spend time in the brackish water of the river mouths, but at some point move upstream to spawn. Scientists know the green sturgeon spawn in the Sacramento, Klamath and Rogue rivers, but suspect they might use other waters including the Umpqua River.
"There's not a lot of population information about green sturgeon,'' said Erick Van Dyke, project leader for the Oregon Department of Fish and Wildlife.
Green sturgeon are listed as threatened under the federal Endangered Species Act. They inhabit waters from northern California to Alaska.
If caught by fishermen, green sturgeon must be released. Unlike white sturgeon, greens are much less likely to bite traditional fishing baits, thus the use of gillnets to collect a sample population.
The National Marine Fisheries Service has provided a green to pay for the research. Green sturgeon are found only along the Pacific coast of North America.
Green sturgeon used to e caught incidentally in white sturgeon seasons.
The commercial catch in the lower Columbia peaked at 6,000 green sturgeon in 1986 and 4,900 in 1987.