Idaho’s already struggling populations of wild spring and summer chinook salmon face grim consequences from climate change and could blink out in the second half of this century, according to a paper published by federal fisheries scientists.

Without unspecified intervention that leads to dramatic increases in survival, climate effects like warming oceans and reduced river flows will spell near certain doom for the chrome-colored fish, concluded the article published in Communications Biology on Thursday.

“The urgency is greater than ever to identify successful solutions at a large scale and implement known methods for improving survival,” they wrote.

Led by Lisa Crozier, a research ecologist with the National Marine Fisheries Service at Seattle, the scientists modeled the expected impacts of climate change in both fresh and saltwater. They found already low ocean survival for the fish protected as threatened under the Endangered Species Act may plummet by 90 percent.

“It’s horrendous,” Crozier said. “I wish I had a magic answer. This is not the news I want to share and certainly not the message I want to be giving but it’s the reality of where we are at right now with the amount of CO2 we have pumped into the atmosphere and our impact on the entire world really.”

The paper comes at a time when many in the Pacific Northwest are digesting U.S. Rep. Mike Simpson’s bold plan to save Idaho’s salmon and steelhead by breaching the four lower Snake River dams. The congressman has proposed $33 billion in mitigation to replace lost hydropower, help farmers get their crops to market and allow communities to make adjustments to their waterfronts and economies, if the dams are breached.

Simpson has said he doesn’t know if dam removal will save the fish but he’s convinced they will go extinct if the dams stay in place.

Crozier said a holistic solution is needed that addresses all stages of the fish, which begin their lives in mountain streams before migrating to and eventually returning from the ocean. But she is not convinced breaching the dams in eastern Washington will help. Crozier said survival through the hydro-system is already high and more is to be gained by improving ocean survival.

“It might help a little bit but there is no evidence it will solve the problem,” she said.

Other scientists argue the cumulative stress and injuries juvenile fish suffer as they pass each of the dams on the Columbia and Snake rivers, reduces their survival in the ocean.

Crozier puts more faith in actions like improving coastal habitat, reducing species that both prey on chinook and those that compete with them for resources, including more abundant hatchery salmon and steelhead, and slowing climate change.

According to a report in the Seattle Times, Richard Zabel, a co-author of the study, said anything that boosts survival should be considered.

“Dam breaching and all alternatives have to be on the table,” he told the newspaper.

But removing the dams will be a heavy lift. Several political leaders have announced their opposition and few have enthusiastically endorsed Simpson’s concept.

Idaho Gov. Brad Little reiterated his opposition to dam breaching Thursday. Following the release of Simpson’s breaching concept last week, Little avoided criticizing his former colleague in the Idaho Legislature and merely said he looked forward to working with Simpson and others to help recover the state’s threatened and endangered salmon and steelhead. On Thursday, he was more emphatic that the dams should stay.

“I remain unconvinced that breaching the dams is a silver bullet for salmon recovery. Breaching the dams would have devastating impacts on Idahoans and vital segments of Idaho’s economy,” he said.

Crozier said the paper, as grim as its conclusions are, can be a catalyst for action.

“The goal is for people to come together and look at holistic solutions, so I’m glad we are talking about and acknowledging that it needs to be taken very seriously and will require a very large scale response.”

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.

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