Yellowstone fish deaths point to huge toll of human activity on rivers

A recent outbreak of a fish parasite on Yellowstone may have seemed unremarkable, but new research shows it could be linked to years of human activities that are slowly chocking river systems to death, reports Environment 360

The Yellowstone river has its headwaters in the mountain streams and snowy peaks of the famous US national park with the same name, and makes an unfettered downhill run all the way to the Missouri river, nearly 700 miles away. It is the longest undammed river in the Lower 48 states.

Last August, the Yellowstone made national headlines when a parasite killed thousands of fish, mostly whitefish. Fear of spreading the parasite to other waterways forced Montana officials to close the river to fishermen, rafters, and boaters. At the height of summer, the stunningly scenic, trout-rich river was eerily deserted. Fishing re-opened in the fall, but the parasite has been found in other Montana waterways.