Scientists are zeroing in on best practices to save endangered PNW salmon

It started with a simple question: Why are salmon dying in the Salish Sea? The answer, as it turns out, would pull scientists from 60 organizations in a variety of directions.

The Salish Sea Marine Survival Project (SSMSP), led by Long Live the Kings and the Pacific Salmon Foundation, connected scientists and organizations from both sides of the border – all interested in dwindling salmon populations in shared waters of Washington and British Columbia.

Their work boils down to two overarching ideas: changes to the salmon food supply and a dramatic increase in predators.

The "fix" for the problem isn’t as easy as throwing money at the problem, it requires intensive on-the-ground work:

  • Habitat restoration
  • Recover herring, and forage fish populations
  • Building resilience in existing salmon through diversity
  • Reducing seal populations
  • Identifying toxic hot-spots, and fix them
  • Optimize health of hatchery-reared salmon
  • Protect/manage river flows
  • Improve forecast of adult returns

"If you think there’s one problem that’s causing the decline of our salmon you’re wrong," said Lucas Hall, the associate director for government relations for Long Live the Kings. "There are a number of things impacting our salmon, so to understand and learn about those things we need to be listening to people and we need to be having conversations and learning about different perspectives."

The urgency Hall reflects is obvious. Chinook, Coho and steelhead in the Salish Sea have struggled to recover despite major efforts to reduce harvest, restore habitat and improve hatchery practices.

The SSMSP technically wrapped up in 2021, but the urgency was such that many projects were already being put into practice before the 8-year-long project wrapped up. The work drew a sharper focus on near-shore habitats and estuaries, marine mammals and plankton – an important food source for juvenile salmon.

Examples of the work that Long Live the Kings is targeting vary greatly – the SSMP built a sort of blueprint of the most urgent projects.

THE HOOD CANAL BRIDGE

The SSMSP can identify specific locations that need help. One area that’s been identified is the Hood Canal bridge – the 1.5-mile long floating bridge seriously hinders migrating fish.

Studies show up to 50% of young migrating fish will fail to make it to the other side of the bridge, thanks in part to the concrete that extends roughly 15-feet deep beneath the water. The slow-down allows predators to pick off salmon at an unusual rate, causing lower returns.

Engineers are now designing modifications to the bridge that could help salmon.

NEAR-SHORE HABITAT AND ESTUARIES

It’s no secret that habitat restoration has long been a key strategy for recovering salmon populations. While salmon spend a large portion of their lives in the high seas, they have pivotal stages of life in freshwater streams.

When juvenile salmon first make their way toward the ocean they need safe passage and food resources. However, as cities have grown around prime rivers, streams and estuaries the likelihood of salmon surviving has dropped off.

Paul Cereghino, a NOAA restoration ecologist, notes that 2/3 of estuaries – the place freshwater and saltwater meet – have been lost during settlement and development. His office recently helped fund work on the Skokomish River that restored old farmland built in the middle of an estuary.

The old "Nalley farm" is now slowly turning back to nature with the stewardship of the Skokomish Tribe, the Mason Conservation District and other non-profits.

"This is one of our reconstructed channels," explained Joseph Pavel, the Director of Natural Resources for the Skokomish Tribe.

Pavel has been advocating for the project since the early 90s, work began in the mid 2000s – today the major work is behind them, however there is still ongoing work to ensure invasive plants don’t take over the estuary.

"We removed close to 3 miles of dikes, filling in 10s of thousands of feet of what we call burrow ditches," explained Pavel. "They built all of this through the middle of a forested wetland – they filled it, and roads were laid down too. No culverts. No ditches. No consideration to the existing channel network that we see an example of here upstream and downstream."

FORAGE FISH

Salmon represents a way of life for tribes, they’re part of our culture – they’re even food for orca, so saving them is sort of a no-brainer in the grand scheme of things.

Saving herring? That doesn’t have the same ring to it – but scientists have realized that food availability is key for juvenile salmon. While enroute to the high seas herring eggs are a key food for salmon, and adult herring are a great alternative for seals to eat.

"The awareness of the importance of herring was always there," explained Jed Moore. "The will to look at it and research it more heavily on behalf of salmon is the newer thing."

Both the Nisqually and Port Gamble S’Klallam Tribes are currently doing research projects to determine whether they can encourage herring to spawn using indigenous techniques, techniques once used to harvest eggs for food could now be re-worked to supplement and spur additional herring to spawn.

THE WORK ISN’T DONE

The work, of course, isn’t done. There is no magic switch to bring back salmon to the runs that historically returned to the Pacific Northwest, but the work happening is an attempt to use the best possible science to target projects that can bring real change.

Hall notes that the SSMSP exposed more questions, and we still need answers to those questions if we’re going to continue to target the best strategies to return salmon runs.

"We need to simultaneously look at those questions, things like climate change, and look more closely at how climate change will affect salmon and even human populations," said Hall.

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