STEVENSON — It's a bit of a mystery, but 40 percent of the tagged Wind River summer steelhead tallied at Bonneville Dam never show up at Shipherd Falls, just 11 miles away.
Shipherd Falls is at river mile 2.0 up the Wind River. The fish ladder at the falls has a PIT (passive integrated transponder) tag reader, as does the Bonneville Dam fish ladder.
A percentage of wild steelhead originating from the Wind River have transponders inserted when they are young for monitoring and research purposes.
"It's a little scary,'' said Dan Rawding, a Washington Department of Fish and Wildlife biologist. "Sixty-five percent of the PIT-tagged steelhead at Bonneville Dam get to Lower Granite Dam on the Snake River. We're losing more fish in 11 miles than to Lower Granite in 300 miles.''
Rawding said there could be several reasons for the loss.
Wind River steelhead may wander about the Bonneville pool of the Columbia for six to nine months before heading up the stream to spawn.
"When they hold in the Columbia, they are exposed to warm water (above 70 degrees), which can be lethal to steelhead,'' he said.
Summer steelhead are well known to duck in to cold-water refuges such as Drano Lake, the White Salmon River and the Deschutes River to get relief from the hot temperature in the Columbia.
Wind River summer steelhead also are subject to catch-and-release mortality in the spring chinook, summer chinook, fall chinook, coho and winter steelhead sport fisheries plus retention in the tribal chinook, coho, steelhead and sockeye commercial fisheries and tribal ceremonial and subsistence fisheries, Rawding said.
Wind River steelhead also may stray. The next PIT tag detector on the Columbia River is at McNary Dam. There are detectors on the John Day and Hood River.
But other streams such as the Deschutes and White Salmon rivers, or Rock Creek in Klickitat County, do not have detectors.
Even with the 40 percent loss, wild Wind River steelhead are in decent shape.
The fish were listed as threatened under the federal Endangered Species Act in 1998. Fishing closed beginning in 1997.
Stocking of hatchery fish stopped in 1998 to give wild steelhead a better chance to recover.
John Weinheimer, a WDFW district biologist, said the return of wild steelhead to the Wind has varied, but hit a high of 1,500 in the 2010-11 spawning year.
Summer steelhead fishing in the Wind upstream of Shipherd Falls eventually resumed in 2006 with a catch-and-release season from Sept. 16 through Nov. 30. Catch-and-release fishing is allowed as long as the run is at least 500 fish.
The watershed appears to meet the minimum seeding level of 500 summer steelhead since 2002. At that number, on average, about 25,000 smolts are produced.
A watershed planning process for the Wind is expected to begin in September and October, said Pat Frazier, regional fish program manager.
An advisory group will be formed and a six-month planning process will follow, attempting to develop a watershed plan that balances fishing opportunity with protection of wild steelhead.
Among the topics to be reviewed in the planning process could be a harvest season on wild steelhead or the reintroduction of hatchery fish.