Numerous decades-old sturgeon dying in the Columbia River near the Tri-Cities are prompting a proposal to close catch-and-release fishing for the species.
The proposal is scheduled for consideration today by the Columbia River Compact, the state agencies and tribes that co-manage the fisheries.
“We don’t know the cause for sure, but sturgeon are obviously dying and stressed,” Paul Hoffarth said Wednesday.
The Washington Department of Fish and Wildlife has logged reports of at least 66 dead sturgeon in the Columbia River from McNary Dam to Boardman. More than 20 were reported upstream, from the Hanford Reach downstream to the McNary Dam.
The fish were all in the large category, ranging from 5 feet to 8.5 feet, he said.
They were all feeding heavily on sockeye and their bellies were stuffed with the salmon, he said.
“But we couldn’t find anything obviously wrong with them,” he said.
Theories for the sturgeon deaths include the possibility that the sockeyes they’re eating in this year’s big salmon run could be diseased from migrating upstream in the Columbia’s unusually warm water.
Another theory, Hoffarth said, suggests the sturgeon are stressed by the combination of dramatically lower-than-normal Columbia flows with higher-than-normal July water temperatures.
Biologists still are gathering information and sending tissue samples to labs, Hoffarth said.
“There’s not necessarily a connection with catch-and-release fishing, but we can’t rule that out,” Hoffarth said. “We know we’re having temperature-related mortalities with sockeye. About 200,000 sockeye passed over Bonneville Dam and should have made it up over McNary Dam, but they didn’t. That’s probably temperature-related.”
While fish managers can’t improve river flows and water temperatures, they have the power to end catch-and-release sturgeon fishing until conditions improve, he said.
“We’re scratching for answers,” Hoffarth said. “A similar sturgeon event occurred in Canada’s Fraser River two years back. Scientists have been studying it for two years and they still haven’t figured it out … The sturgeon could just be dying from a horrific confluence of events.”
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