The Hood Canal Bridge connects the Kitsap and Olympic peninsulas in Washington state. It is the world’s longest floating bridge that exists in a saltwater tidal basin (7,869 feet in length). A vital link between those peninsulas, daily traffic flow is over 16,000 vehicles daily. Made up primarily of pontoons, it’s anchored at both ends by fixed bridges.

But it is those center sections that may be acting as a deathtrap for Hood Canal steelhead – and potentially salmon. At low tide, the pontoons cover 95% of the canal’s width. Steelhead, which swim in the upper layers of the water column, may be held up by the 12-foot deep pontoons, making them easier prey for predators (eagles, seals). Or the complex water flows around the bridge may be confusing the fish.

Fisheries scientists don’t fully know yet what’s going on. But it’s clear this is another adverse impact on increasingly vulnerable fisheries.

Read more here.