Helping juvenile salmon migrate out to sea has long been difficult and controversial. Barging is a common way to get the fish around dams.
The salmon are hauled around eight dams in the Columbia and Snake rivers. Idaho Conservation groups say this practice harms fish — and needs to stop now.
Seven groups sent a letter to NOAA Fisheries and the U.S. Army Corps of Engineers, asking the agencies to this spring stop sending salmon along their migration route in barges.
"When it comes to endangered sockeye salmon, the science shows that it's particularly detrimental for sockeye salmon to be barged," said Zack Waterman, Idaho Sierra Club director.
The groups say barging Snake River sockeye can make them more vulnerable to warm water conditions, like the 2015 drought and heatwave that killed 95 percent of the run. One reason: In barges, the fish can't develop their homing abilities that help them return to spawning habitat as adults.
"It takes the fish that were barged longer to make it back to where they were originally spawned at, than their counterparts that went through the river system," Waterman said.
NOAA officials say it's long been known that it takes barged salmon a longer time to reach spawning grounds, but, they say, 2015 was a highly unusual year.
By their math, excluding 2015 and 2014, it's more beneficial to both barge juvenile salmon around dams and to allow others to fall over spillways. Every year isn't going to be as hot as 2015, said Ritchie Graves, a fisheries biologist with NOAA Fisheries.
He said barging is a way to increase your odds when gambling with Mother Nature.
"If you're playing on the roulette wheel in Las Vegas and you have to make a bet every year, the smartest bet to make most of the time is still to at least bet some of your (juvenile salmon) on the transport strategy," Graves said.
Right now the federal government barges about 50 percent of Snake River sockeye salmon. Graves says the federal agencies are "diversifying risk."
"The problem with all this is we don't know what the temperature is going to be like two years out," Graves said. "Essentially we're working under spread-the-risk advice. … We're watching these numbers very carefully, and we'll be thinking about how or if we need to change transport operations in the future."
The fish are collected above Lower Granite Dam in southeast Washington, along with other species that depend on barging, like steelhead. They're then released below Bonneville Dam, about 50 miles east of Portland.
Stopping barging, conservation groups said, would mean juvenile salmon would be spilled over the tops of dams.
Ultimately, the groups would like to see the removal of the four Lower Snake River dams — this barging request, they say, is an important interim step to saving wild runs.
"Removing the Lower Snake River dams — that's what's going to solve the problem," said Kevin Lewis, Idaho Rivers United executive director. "Everything up to that point is a stopgap measure."
The conservation groups say juvenile mortality is the most problematic part of salmon recovery — that's why how they get to the sea is important. David Cannamela is a retired fisheries biologist, now with Sierra Club.
"We have 10,000 years of data that essentially prove that the river will work, and so for the long-term, anything that we can do that makes the system more like a river is going to be more successful to juvenile and adult [salmon] survival," Cannamela said.
Dam removal on the lower Snake has been consistently opposed by those who rely on the dams and impounded water for agriculture, hydroelectricity and commerce.