[7] Botulism Kills Millions Of Fall Chinook At Ringold Hatchery

The Washington Department of Fish and Wildlife reported last week that the agency lost about 20 percent of its upper Columbia hatchery production, most likely to an outbreak of botulism in its huge nine-acre pond at Ringold Hatchery near Pasco, Washington.

The 3.5 million upriver bright smolts affected by the outbreak were raised at Bonneville Hatchery and transported to Ringold in mid-May. They had been scheduled to be released this week.

The pond used by the fall chinook contained waste from spring chinook released earlier this year, part of a one-time contract with the Umatilla Tribes. The waste likely contributed to low levels of dissolved oxygen in the pond's water, which coupled with warm temperatures, gave the natural botulism toxin a chance to grow, said John Kerwin, WDFW hatcheries division director.

He told NW Fishletter that the nine-acre pond at Ringold is the largest in the state and it's tough to manage, being unlined, with no way to keep birds out. He said his agency hopes eventually to be able to build three smaller ponds in place of one large one--that would be lined and able reduce bird predation. "But there's no wiggle room in Mitchell Act funding for hatcheries," he said.

Kerwin said the loss would have an impact on fisheries. As for the dead smolts, they will be covered in lime and buried on site, while the pond will be drained, limed and allowed to dry out for the rest of the summer. -B. R.

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