Decompression, not blades, is the primary killer of salmon in Columbia River dams
Research from the Pacific Northwest National Laboratory confirms that rapid pressure drops, rather than turbine blade strikes, cause most deaths in young salmon passing through Columbia River dams. By using robotic 'Sensor Fish' to map pressure changes and testing 5,767 juvenile Chinook in controlled chambers, scientists identified swim bladder rupture and gas embolisms as the lethal mechanism. This finding has led to the development of 'fish-friendly' turbine designs that mitigate decompression, significantly improving survival rates for migrating smolts.