| Abstract: | The presence of cattle at Browning Spring and Ash Springs in Pahranagat Valley, Nevada, impacted fish populations by causing an increase in ammonia (NH 3 ) and nitrite (NO 2 ) levels, an increase in Pseudomonas aeruginosa and Aeromonas hydrophila , and increased, mortality and morbidity. One of the affected fishes, the White River springfish, is listed as endangered by the Department of the Interior. After removal of the cattle from Ash Springs, NH 3 and NO 2 levels decreased and fish populations increased. At Brownie Spring the NH 3 and NO 2 levels are chronically elevated, cattle are still present, and the speckled dace population has not recovered. |
