One of Washington’s most iconic bridges may be hurting salmon

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PORT LUDLOW, Wash. -- The tourist slogan for the Olympic Peninsula is "the Wild Side of Washington."

But one of the main transportation thoroughfares connecting travelers in Seattle to the famous towns and sites of the Olympic Peninsula may be hurting one of the Northwest's most famous residents: Salmon.

A bridge too deep?

Vital elements of the Hood Canal's natural ecosystem are at risk. Mainly, Chinook, chum salmon and steelhead trout are all listed under the Endangered Species Act.

One of their biggest blocks?

The fish are dying because of the Hood Canal Bridge, which was built in 1961.

Barry Berejikian of NOAA Fisheries leads a team that tags and tracks steelhead in the Hood Canal. Fish numbers further south in the Hood Canal stay strong, he said, but plummet once they reach the bridge. Data suggests that as many as half of migrating steelhead don't make it past the concrete structure.

"It's a big number," Berejikian said.

Bridge Pontoons Diagram

A number of factors impact fish. First, lights and noise from cars on the bridge slow salmon, disorienting them. Second, biologists have discovered fish only swim in the top three feet of the water at the spot.

Both conditions make it easier for predators to pounce.

"The fish are having to funnel through certain areas and the predators are pretty smart and they figure that stuff out," Berejikian said.

More mysteries

Scientists also wonder if the bridge is impacting the flow of water in the Hood Canal, impacting the water quality.

The bridge is more than a mile in length. In recent years, Hood Canal has experienced low oxygen levels, algae blooms and warming waters. It's not certain, but this could all be caused by the bridge impacting water flow.

Too make matters worse: There's no easy engineering fix. WSDOT would be in charge of changes, but it needs to get water quality data and fish mortality rates before engineers start to consider structural solutions.

And any bridge fix could be expensive.

Fish passageway.

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