The death of six marine mammals found May 4 in two closed floating traps below the Columbia’s Bonneville Dam was likely caused by overheating, according to the findings of a necropsy performed on each of the animals.
The death of six marine mammals found May 4 in two closed floating traps below the Columbia’s Bonneville Dam was likely caused by overheating, according to the findings of a necropsy performed on each of the animals.