ESPN Outdoors is reporting that almost 1 million rainbow trout (Oncorhynchus mykiss) in a hatchery in Utah will have to be destroyed after several of the fish were found to be infected with whirling disease (Myxobolus cerebralis). Caused by a parasite, whirling disease is thought to have been introduced through European salmonid fish during the 1950s. Some native trout species, salmon, and possibly even whitefish are susceptible to the parasite, making it even more perilous to release infected hatchery fish into local water bodies. Of course, the rainbow trout is also considered an invasive species in several parts of the U.S.
Tip of the virtual hat to the Stop Aquatic Hitchhikers website for posting about the article.