After being devastated by whirling disease in the 1990s, Colorado\u2019s rainbow trout populations are recovering in most major rivers, Colorado Parks and Wildlife officials said.<\/p>\n
\u201cIt\u2019s been a long road, but bringing back populations of fish that were essentially extirpated from Colorado can only be called a huge success,\u201d said George Schisler, a Fort Collins-based Parks and Wildlife scientist. The agency released a statement last week trumpeting the rainbow trout\u2019s recovery.<\/p>\n
Yet in the Animas River, trout are having a \u201ctough time,\u201d because of reduced runoff in recent years and water quality issues, said Joe Lewandowski, a Parks and Wildlife spokesman in Durango.<\/p>\n
\u201cThe Animas, it still is challenging for fish,\u201d Lewandowski said.<\/p>\n
Reduced runoff has added to other concerns, such as water being drawn out of the Animas for Lake Nighthorse, harmful metals in the water and runoff from housing developments and agriculture. Lewandowski said. Scientists are seeing little natural reproduction in the Animas\u2019 fish population.<\/p>\n
\u201cThat\u2019s kind of a signal the water quality is not as good as it could be, obviously,\u201d Lewandowski said.<\/p>\n
The agency is stocking the river with Hofer rainbow trout, which trace their lineage to a German hatchery and have proved resistant to the whirling disease parasite. It\u2019s far too early to tell if the stocking effort will be successful, Lewandowski said. The stocking effort has boosted rainbow trout populations in other waterways.<\/p>\n
\u201cIt\u2019ll probably be several years until we can say how they\u2019re doing,\u201d he said.<\/p>\n
Statewide, the picture is somewhat better. Since last summer, Fish and Wildlife said, anglers have reported they are catching good-sized rainbow trout in the upper Colorado, Rio Grande, upper Gunnison, Poudre, East, Taylor, Arkansas and Yampa rivers, among others.<\/p>\n
Whirling disease devastated Colorado trout fisheries beginning in 1986. By the mid-90s, rivers in Colorado were thoroughly infected, Parks and Wildlife said.<\/p>\n
Whirling disease is caused by a spore that infects the spine of very young fish. The infection deforms the spine causing the fish to swim in a whirling pattern. Trout die shortly after becoming infected.<\/p>\n