CRUSTACEANS Crayfish: Northern crayfish Orconectes virilis Louisiana crayfish Procambarus clarkii Water nymph crayfish Orconectes nais Rusty crayfish Orconectes rusticus

Crayfish: Northern crayfish Orconectes virilis Louisiana crayfish Procambarus clarkii Water nymph crayfish Orconectes nais Rusty crayfish Orconectes rusticus Utah is inhabited by a single native crayfish known as the Pilose crayfish Pacifastacus (Hobbsastacus) gambelii. Its native range is in northern Utah’s Bear River, Weber River and Ogden River drainages and in the Raft River Mountain’s drainages. Isolated populations, also, persist in Salt Creek, east of the Great Salt Lake. None of the invasive species of crayfish found in Utah are known to overlap its range (Figure 1). Crayfish are not native to the Colorado Plateau (Dean 1969) or to the Bonneville basin south of Utah County (Johnson 1986), including the Sevier River Drainage. Two other species of Pacifastacus are native to states adjoining Utah: Pacifastacus leniusculus in Nevada and Pacifastacus (Hobbsastacus) connectens in Idaho (Pennak 1978). Both may be native to Utah waters, however, this possibility has yet to be confirmed (Johnson 1986). The signal crayfish Pacifastacus leniusculus is present in Utah County, and may have been introduced there (Johnson 1986).