Anglers puzzled by Snake River steelhead return
Sunday, November 13, 2011
Steelhead anglers are scratching their heads along the Snake River system.
The fish run is slightly below average this year.
Fishing success has been spotty.
And word's out that steelheading could be curtailed in a popular southeastern Washington stream in the next few years.
Let's tackle the issues in that order.
By the end of October, 170,000 steelhead had moved upstream over Lower Granite Dam, compared with about 187,000 on the same date in 2010. The five-year average for that date is just more than 179,000.
Statistically there are plenty of fish in the Snake River system to keep anglers busy, but for some reason fishermen are waiting longer than usual for a tug on their line.
"Catch rates haven't been all that good, yet," agreed Glen Mendel, Washington Fish and Wildlife Department fisheries biologist. "The average is a little slower than usual for this time, especially from the mouth of the Snake up to Lower Granite.
Some anglers have noticed far more fall chinook salmon spawning in Snake tributaries. One fly fisher noted this week that a favorite Grande Ronde steelhead run where he saw one chinook redd last year had salmon on about 15 redds this year.
"I hooked two salmon there incidentally, but no steelhead," he said.
The Lower Snake River Compensation Plan calls for restoration of fall chinook as well as steelhead fisheries impacted by the building of dams.
Chinook smolts have been released in Snake River tributaries for several years. "Now were starting to see the returns (of chinook adults) reaching the full mitigation levels," said John Whalen, WDFW regional fisheries manager.
That explains why anglers in the Grande Ronde are seeing more salmon this year, but it isn't necessarily the reason steelhead seem harder to catch.
Fisheries research literature notes that fall chinook can be aggressive to steelhead, which are smaller, but Whalen is skeptical.
"It's not uncommon for steelheading to have slow periods," Whalen said. "If the steelheading success doesn't start picking up through the end of this month, that will get my interest up."
Mendel tends to think the cool, wet spring and this year's abundance of water is the most significant factor in the differences anglers are noticing.
USGS stream flow charts indicate most southeastern Washington streams are running 40-75 percent above the flows of recent years. "That may be part of the issue," Mendel said.
Clear conclusions are difficult because of myriad variables, including water temperatures, irrigation demands and the wayward ways of steelhead.
December often is the best month for steelheaders upstream in the Tucannon River, while August and September can be good in the Tucannon's lower mile as Idaho-bound fish nose into the tributary to enjoy the cooler water before continuing up the Snake.
"But with more water this year, Snake River temperatures tended to stay lower and the fish may have just gone on," he said.
Wandering steelhead present another challenge to understand.
Tagged fish studies have shown that hatchery fish from the Tucannon return, test the river briefly and then continue up the Snake.
About 50 percent of them go up over four dams - Ice Harbor, Lower Monumental, Little Goose and Lower Granite. About 25 percent of those steelhead succeed in coming back down to the Tucannon through two dams, neither of which was designed for downstream adult migration.
"I don't think they're totally lost," Mendel said. "It's not uncommon for steelhead to come in way before spawning and take trips all over place before going to spawning grounds."
But nobody knows whether they're purposely avoiding the Tucannon for some reason or whether they just miss it.
The rumor that steelhead fishing could be closed in the Tucannon is not unfounded.
WDFW plans to schedule a meeting, probably in Dayton, to explain the possibilities.
The state began a program last year to stock the Tucannon River only with progeny from natural-origin steelhead. Several years will be needed to ramp up production without mining too many of the wild steelhead that return to the stream.
The goal during this transition is to have the number of natural spawners increase while plucking out native spawners for the hatchery component without causing a big gap in the fishing opportunity.
The hatchery-raised fish from native spawners will not be fin-clipped for at least a few years to reduce the chance of them being harvested by anglers if they temporarily bypass the Tucannon.
"The impact to the fishery will begin next year," Mendel said.
Endangered species agreements require the state to have a minimum of 250 natural spawners in the Tucannon.
"If we can't hit that critical threshold, we can't allow fishing," he said. "Even catch-and-release is not allowed because of the mortality associated with it."
Bottom line: Steelhead anglers will be able to fish the Tucannon River next year. After that, the jury is out.