Fisherola nuttalli

Giant columbia river limpet

Family: Lymnaeidae · Class: Gastropoda · Order: Hygrophila

Fisherola nuttalli is a small pulmonate (air-breathing) freshwater snail in the family Lymnaeidae, distinguished by its distinctive limpet-like appearance. The species has an uncoiled, conical shell with a wide oval base measuring approximately 8-15 mm in length and a smooth, eccentric (off-center) apex (Xerces Society 2019). Unlike typical coiled snails, F. nuttalli's shell resembles a flattened cone, earning it the common name "shortface lanx." Historically, F. nuttalli was distributed throughout much of the Columbia River drainage system across Washington, Montana, Oregon, Idaho, and British Columbia. The species was once found scattered throughout the lower Columbia and Snake Rivers and their major tributaries. However, most populations have been extirpated due to extensive habitat modification. Currently, large viable populations persist in only four stream systems: the lower Deschutes River in Oregon; the Okanogan River and Hanford Reach of the Columbia River in Washington; and portions of the Snake River in Oregon and Idaho. Additional small populations remain in Oregon's John Day and Imnaha Rivers, the lower Columbia River near Bonneville Dam, Washington's Methow River, and the Grande Ronde River system spanning Washington and Oregon. This species requires very specific habitat conditions, inhabiting cold, unpolluted medium to large streams with fast-flowing, well-oxygenated water. F. nuttalli is typically found on cobble and boulder substrates at the edges of rapids, where swift currents provide optimal oxygen levels. According to recovery planning documents, the species occurs at depths ranging from 5 cm to 75 cm, with depths of 6-15 cm being most typical (USFWS Snake River Recovery Plan). The snails prefer smooth basalt surfaces and actively avoid areas with large aquatic macrophytes or excessive filamentous green algae growth. F. nuttalli individuals are present year-round in their stream habitats but become inactive during winter months. The species exhibits limited dispersal capabilities, moving primarily by crawling slowly across substrate or being carried passively by water currents. Like other members of the Lymnaeidae family, F. nuttalli likely feeds by grazing on periphyton and organic detritus attached to rocky surfaces, though specific dietary studies are limited. The species faces critical conservation challenges due to widespread habitat degradation throughout its historic range. Primary threats include habitat alteration from dam construction and water impoundments, reduced water quality from agricultural runoff, urban development, industrial pollution, and livestock grazing impacts. Siltation from these activities degrades the clean cobble-boulder substrate essential for the species' survival. The dramatic range reduction, with populations now restricted to a few scattered locations, places F. nuttalli at high risk of extinction. NatureServe ranks the species as G2 (Imperiled), with state rankings of S1 (Critically Imperiled) in Idaho and Oregon, S2 (Imperiled) in Washington, and SX (Presumed Extirpated) in Montana (Xerces Society 2019). Conservation efforts focus on protecting remaining habitat quality in occupied streams and monitoring population stability.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.