BIG BEEF CREEK, Kitsap County — Megan Moore slowly sliced open a half-inch of a young steelhead’s silvery belly. She pressed in a battery-like tube and stitched the fish up with two tiny sutures.
These acoustic tags, small sound-transmitting devices, allow researchers to track the movement of fish as they work their way down this creek and into Hood Canal.
Some of the 40 to 50 young steelhead tagged each week by Moore, a biologist with the National Oceanic and Atmospheric Administration, and her team will grow big and return to the stream to spawn after a few years.
But past tagging data showed half of the fish from monitored streams die at a human-made barrier: Hood Canal Bridge.
Salmon and steelhead like to stay in the top 3 feet of water and the fish struggle to figure out they can go under the floating bridge. Instead they hit it like a wall and swim back and forth until they discover how to go around the pontoons. There, seals can find a swim-through buffet of baby fish, often corralled in the corners, where longer pontoons jut out.
That might soon become harder for seals after crews install a massive fish-guidance structure made of plastic pipes and sheets at the bridge this week. The aim is to direct steelhead around the bridge to safety.
Lawmakers two years ago secured up to $3.6 million for Long Live the Kings, a Seattle nonprofit dedicated to salmon recovery, to develop and test the structure. The group has been working with tribes, state and local agencies to find ways to reduce fish deaths at the bridge.
The project is a drop in the bucket in terms of salmon recovery dollars, in a state where hundreds of millions have been invested in restoring floodplains from farms and industry, and ripping out old culverts and other fish barriers. But this new structure at the bridge, a “fillet” in civil engineering parlance, is just a Band-Aid.
If it works, it could make the case for permanent fish-friendly fixes at the bridge and possibly serve as an alternative to culling predators.
Here, at the cold and dim abandoned fish hatchery at Big Beef Creek near Seabeck, and in a new industrial fish hatchery on the Skokomish River north of Shelton, Moore’s team will eventually tag 300 young steelhead.
Some 40 receivers along the canal will pick up each tagged fish’s whereabouts and travel time all the way to the Strait of Juan de Fuca. Researchers will be studying travel time and survival rates with and without the fillet installed. The study will last six weeks.
Crews slowly lowered the fillet, a 22-foot-tall yellow and black triangular contraption into the Duwamish River this month.
Here, the grumble of boat engines, screech of forklifts backing up and crunch of excavators moving scrap metal echo along the channeled waterway. More than a dozen pieces of plastic were delivered here to be assembled into this 70,000-pound fish-guidance structure.
When attached, the structure will create a flat surface that — in theory — fish can follow around to swim past the bridge.
Data on juvenile steelhead passage and survival collected from the fillet study will be sent to the telemetry company to process by the end of this year, and researchers will begin their own analysis when they receive the final dataset.
The pristine Big Beef estuary — where the freshwater creek meets Hood Canal’s salty tide — looks like something out of Alaska. Cattails and grasses flank the marshy banks, snags stand in the muck and Douglas fir and cedar cast shadows across the creek’s meandering bends. Streams that spill into Hood Canal have some of the best intact salmon habitat in the state.
The canal is a fjord — not a human-made canal — that forms one of the four main basins of Puget Sound, part of the broader transboundary waters that constitute the Salish Sea. It separates the Olympic and Kitsap peninsulas.
But even the salmon and steelhead from streams like these are struggling. Winter steelhead runs have fluctuated, trending in decline across most Hood Canal streams, according to estimates provided by the state Department of Fish and Wildlife.
Long Live the Kings’ Salish Sea Marine Survival Project found that the biggest factors affecting marine survival of Chinook, coho and steelhead were food supply and predation.
Climate change and an increase in nutrients from agriculture, sewage and stormwater are likely affecting the food web, causing phytoplankton to bloom sooner and limiting the amount of available zooplankton that coho and Chinook rely on early in their lives.
Meanwhile, young salmon and steelhead are threatened by predators at every moment as they migrate through the Salish Sea. Studies have shown that from 5% to 39% of juvenile Chinook are consumed by seals in Puget Sound, and an estimated 37% to 43% are eaten in the Strait of Georgia.
Even in places with fewer barriers to fish passage, such as the Nisqually estuary that has been restored mostly back to its natural state, pinniped predation rates are high, Moore said.
About 20% of the baby steelhead migrating through the Nisqually estuary die. According to a 2022 study, about 90% of those deaths are from harbor seals.
A report commissioned by the state Legislature and completed by the Washington Academy of the Sciences last fall reports that seals and sea lions are likely impeding salmon recovery, and the full effects of predation on salmon might not be fully understood without lethal intervention.
Other methods to deter seals have largely been unsuccessful over the years. A recent study using a new “targeted acoustic startle technology” device to scare seals from eating juvenile steelhead at the Nisqually estuary was largely unsuccessful.
The noise did change harbor seals’ behavior slightly, but not enough to affect steelhead survival rates.
Moore has been studying steelhead behavior in Hood Canal for nearly two decades, leading the telemetry study in 2017 and 2018 that found steelhead were getting holed up at four corners of the Hood Canal bridge.
When a fish was eaten by a seal, the acoustic receivers picked up erratic seal-like movements from the transmitter. When the seal’s digestive system passed the tag, it became stationary on the seafloor and was marked as a death in Moore’s study.
Alongside Moore’s previous research, scientists from Port Gamble S’Klallam conducted visual surveys and collected acoustic data on how Chinook salmon interact with the bridge. The tribe will continue collecting video and visual surface surveys while the fillet is in the water.
Hans Daubenberger, senior research scientist for the Port Gamble S’Klallam tribe, played a yellowish sonar recording this month. The video looks like an ultrasound.
Little silvery dots on the screen were a school of young Chinook, he explained. In the recording, the fish corral in one corner of the bridge, and a big oval blob swoops through the school.
“This is a seal,” he said, pointing to the blob. “So you’ll see, it’ll come up and swim right through the school of fish, and they’re really good at just sucking fish. It’s like a vacuum cleaner. They just suck fish down.”
For years, Port Gamble S’Klallam didn’t have the money to hire specialists to study what was affecting salmonid species, said Jeromy Sullivan, chair of the tribe.
The fillet project is the culmination of decades of work.
“Salmon has always been a part of our culture, since time immemorial it’s always been a part of us, part of a part of our identity,” Sullivan said. “This is a big deal, we went through such a long process over years. And this is where we’re at, we’re not close to a solution yet. But this is a Band-Aid that I hope really works.”
