Endangered fish threatened by Asian fish tapeworm

The Asian fish tapeworm, an exotic parasite, has invaded the endangered humpback chub (Gila cypha) population from the Colorado and Little Colorado Rivers in Grand Canyon, Arizona. This parasite causes disease and death in carp in aquaculture settings and may retard growth in hatchery-reared roundtail chub (Gila robusta). Other consequences include destruction and dysfunction of the intestinal lining and adverse changes to certain blood parameters. Introduced into the U.S. in the 1970s with imported grass carp (Ctenopharyngodon idella), the Asian fish tapeworm (Bothriocephalus acheilognathi) was discovered in the Little Colorado River (LCR) by 1990. The LCR is the main tributary to the Colorado River in Grand Canyon and is an important spawning area for humpback chub.