Monday August 24, 2026
Space Daily —
Every spring, millions of young salmon ride the Columbia and Snake rivers toward the Pacific, and on the way down many of them pass through the spinning turbines of hydroelectric dams. For decades, the assumption about the ones that didn’t survive was intuitive: giant steel blades, small soft fish, do the math.
But the carcasses told a stranger story. Most dead turbine-passed smolts came out without a scratch on them. Whatever was killing them wasn’t, for the most part, touching them. To find out what was, engineers at the Pacific Northwest National Laboratory built a fish that could take notes on the way through.
The robot that rode the turbines
The device is called the Sensor Fish, a rugged cylinder about the size of a smolt, packed with instruments that record pressure, acceleration, rotation and temperature 2,000 times a second. Researchers released them into dam intakes on the Columbia, including runs at Ice Harbor, John Day and Bonneville, and collected them downstream, each one carrying a millisecond-by-millisecond diary of what a fish actually experiences inside a working turbine.