Montana girl's rare freshwater jellyfish find raises ecological questions

A 10-year-old girl, Vivi Veitch, and her father discovered dozens of penny-sized freshwater jellyfish in a pond connected to Montana’s Canyon Ferry Reservoir. Montana Fish, Wildlife & Parks confirmed the species as Craspedacusta sowerbii, which is harmless to humans and native to eastern Asia but now found across much of the world. The discovery marks Montana’s second reported sighting after an initial detection near Great Falls in 2009. The jellyfish appear during warm months in a free-floating phase, while spending most of their lives as microscopic polyps attached to underwater surfaces. Officials and ecologists say the species’ potential effects on the reservoir’s ecosystem are unclear and urged residents not to release nonnative animals and to clean, drain and dry watercraft and equipment.