science π Robot fish reveals silent killer in salmon dams π
Engineers deployed a robotic "Sensor Fish" through Columbia River dam turbines to study salmon mortality. The device recorded data from dam intakes like Ice Harbor, John Day, and Bonneville over various dates. Researchers then subjected 5,767 juvenile Chinook salmon to these exact pressure profiles in hyperbaric chambers. This study proved that rapid decompression, not blades, caused most injuries to the fish. Turbine designs are now being engineered to mitigate this dangerous pressure effect.