The Economic Times

In 2012, PacifiCorp launched a trap-and-haul program to move adult salmon upstream past Merwin Dam. 14 years later, researchers found 2 stages in the system but 1 decisive bottleneck: young salmon failing to find the artificial current downstream

A trap-and-haul program on Washingtons Lewis River helps adult Chinook salmon bypass Merwin Dam by transporting them in trucks to upstream spawning habitat. But researchers tracking the salmon life cycle have identified a major weakness on the return journey. Juvenile salmon, or smolts, must travel downstream toward the Pacific Ocean, yet many struggle to locate the artificial current leading to a floating collection system near Swift Dam. Once captured, they can be transported safely downstream, but low capture rates remain the programs primary bottleneck.