A back-and-forth discussion broke out at the end of the Pacific Northwest Fish Symposium at the Walla Walla Community College branch in Clarkston on Thursday.
The all-day event featured speakers arguing against the need to breach the four lower Snake River dams to save and recover threatened and endangered salmon and steelhead.
On one side of the friendly debate were presenters from the day-long event plus a few audience members. On the other were breaching advocates, also in the audience.
The speakers that included John McKern, a retired fisheries biologist for the Army Corps of Engineers, fishing outfitter Rusty Bentz and Jerry McGehee, a retired hatchery manager for the Idaho Department of Fish and Game, argued barging juvenile fish is the best way to get them past dams on the Snake and Columbia Rivers and spilling water at the dams harms the fish because of the high levels of total dissolved gas it creates.
Current plans minimize barging and call for water to be spilled to the point that it creates total dissolved gas levels of 125 percent. That is too much, according to the dam defenders.
“If (juvenile fish) are going to travel in the river for two weeks, 125 percent is very, very unhealthy,” said McGehee.
Throughout the day, the speakers said barging protects the fish from injuries incurred while passing the dams, keeps them away from predators, prevents migration delays and protects them from high levels of saturated gas. In addition, they said the span of 2001 to 2015, a period of higher than average returns of largely hatchery salmon and steelhead, coincides with a time when juvenile fish were barged at higher rates and a recent downturn in returns matches up with a time in which barging was reduced and spill was increased.
The breachers challenged the presenters on their main points. Richard Scully and Steve Pettit, retired fisheries biologists for the Idaho Department of Fish and Game, pointed to the long-running competitive survival study that looks at survival rates for juvenile salmon and steelhead in the Snake and Columbia rivers. Among its findings is that juvenile fish survival decreases by about 12 percent each time the fish go through turbines or fish bypass systems at the dams, and that fish that complete the entire eight-dam journey by passing over spillways instead of being diverted into barges or going through turbines and fish bypass systems have higher survival levels.
McKern said he was unfamiliar with that work and has a different view.
“It’s just the opposite,” he said. “Spill is resulting in declining returns, not increasing returns.”
Martin Ahman, a retired hydraulics engineer that worked on fish passage for the corps’ Walla Walla District, said over the years his agency fine-tuned barging and the survival and smolt-to-adult return rates of barged fish climbed. In addition, he said fish and river managers fine-tuned the way spill was implemented. When fish returns climbed, fisheries managers made the assumption that more spill is better. Barging was reduced and more water was spilled.
“We started to spill more and more and more, and that is when we started to see productivity decline,” he said.
Pettit, who spent his career working on fish passage issues, said the extinction of wild salmon and steelhead was predicted before the dams and is coming to pass.
“Every single fisheries biologist from all the universities in the Columbia Basin said if you put those four Snake River dams in, wild fish will be extinct in 50 years,” he said. “That’s in the Congressional Record. If you want to read it, I’ll tell you how to get it. Anyways, here it is 50 years later and what are we looking at?”
He reiterated that the river is the best place for fish.
“Fish survive the best if they never see a barge and they never see a bypass system,” he said. “So that’s why the current levels of management are leaning greater toward in-river passage.”
Martin Dugger, one of the organizers of the symposium, said he was pleased with how it played out and the turnout of about 70 people who showed up to listen.
“Our people got up there and they talked and they made sense,” he said. “They are experts in the field and we need to start listening to them.”
Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.
