Seven Idaho environmental organizations have appealed to NOAA Fisheries and the U.S. Army Corps of Engineers to stop barging endangered Snake River sockeye this spring.
In an April 2017 letter, the conservation groups, led by Idaho Rivers United, said juvenile sockeye that are transported are more vulnerable to overly-warm water when they return as adults in June and July than the sockeye that have migrated through the system on their own as juveniles.
The groups cite a NOAA Fisheries’ appraisal of the disastrous 2015 sockeye migration, in which most of the returning adult sockeye died in overheated waters of the Columbia and Snake rivers before they reached Idaho.
The NOAA report shows survival of 2015 adult Snake River sockeye between Bonneville and Lower Granite dams was zero for fish that were collected and transported as juveniles, and eight percent for those migrating in-river as juveniles.
The conservationists say sockeye that migrated in the river as juveniles in 2011 and 2012 also survived at higher levels when returning as adults in 2013 and 2014 than those that were collected and barged. The groups’ letter used data from the NOAA report and the Fish Passage Center.
This year’s high flows and spills will reduce the number of juveniles barged, the conservationists said. In addition, they said U.S. District Judge Michael Simon’s ruling for increased spill in 2018 would again reduce the number of transported juveniles.
Nonetheless, the Idaho groups told federal agencies, “Active management should be used to reduce it further, starting this year.”
NOAA Fisheries spokesman Michael Milstein told NW Fishletter that his agency had no plans to cease transport of sockeye.
He said that 2015 was only one year and an unusual one.
“Most years we see higher survival of the transported fish all the way through to Lower Granite, and the average over several recent years shows the advantage goes to transported fish,” he said, pointing to work by the Northwest Fisheries Science Center, a NOAA Fisheries affiliate.
“If you were placing bets, you’d certainly put some of your money on transported fish,” Milstein said.
The NOAA spokesman said that the agency would be watching the yearly survival data carefully and considering “whether and how to make any adjustments in the future.”
He also noted that steelhead benefit significantly from transportation; but should sockeye barging be eliminated, so too would steelhead transportation. Sockeye and steelhead juveniles are in the river at the same time and are collected together. -Laura Berg