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Fluminicola fuscus

(Haldeman, 1847)

Ashy Pebblesnail

G3Vulnerable Found in 1 roadless area NatureServe Explorer →

G3VulnerableGlobal Rank

Near threatenedIUCN

Very high - highThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.943075

Element CodeIMGASG3500

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryInvertebrate Animal

IUCNNear threatened

Endemicoccurs (regularly, as a native taxon) in multiple nations

KingdomAnimalia

PhylumMollusca

ClassGastropoda

OrderLittorinimorpha

FamilyLithoglyphidae

GenusFluminicola

Synonyms

Fluminicola columbianaHemphill in Pilsbry, 1899Fluminicola columbianusHemphill in Pilsbry, 1899Fluminicola hindsi(Baird, 1863)Lithoglyphus hindsii(Baird, 1863)

Concept Reference

Liu, H.P., Walsh, J. and Hershler, R. 2013. Taxonomic clarification and phylogeography of Fluminicola coloradensis Morrison, a widely ranging western North American pebblesnail. Monographs of the Western North American Naturalist 6(1):87-110.

Taxonomic Comments

The genus Fluminicola is in need of revision because genetic analyses show that the genus is paraphyletic (Hershler and Liu 2012).

The taxonomic treatment of Fluminicola fuscus has undergone several changes since the mid-1990's. Hershler and Frest (1996) determined that Fluminicola hindsi and columbianus (misspelled columbiana in Turgeon et al. 1998) are junior synonyms of F. fuscus. Liu et al. (2013) conducted mtDNA analyses on Fluminicola coloradoensis, which resulted in the unassigned Snake River basin populations being assigned to F. coloradoensis, as well as the re-assignment of the lower Salmon River (Idaho) populations of Fluminicola fuscus to F. coloradoensis.

Conservation Status

Rank Method Rank calculation - Biotics v2

Review Date2025-04-03

Change Date2025-04-03

Edition Date2025-04-03

Edition AuthorsCordeiro, J. (2009); Jurist, K.; T. Frest (2000); Ormes, M (2015); rev. T. Cornelisse (2025)

Threat ImpactVery high - high

Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)

Number of Occurrences81 - 300

Rank Reasons

This species has a large range and a moderate number of occurrences range-wide, but it is subject to many threats and there is evidence of long-term population declines, although short-term population trends are unknown.

Range Extent Comments

This species occurs in Vancouver, Canada and the in northwestern United States from Washington and Oregon, east to Colorado (InvertEbase 2025; RARECAT 2025).

Occurrences Comments

This species is known from at least approximately 103 occurrences using a 1 km separation distance and records from 1994-2025 (RARECAT 2025; InvertEBase 2025).

Threat Impact Comments

This species is threatened by impaired water quality from sedimentation, agricultural runoff, nutrient enhancements, and mining and pulp mill effluents; by habitat fragmentation due to stream modifications, including dams, impoundments, water diversions; by habitat degradation and loss leading to stabilizing riparian vegetation; and likely somewhat by climate change due to increased temperatures, altered flow regimes, and reduced dissolved oxygen (Frest and Johannes 1995, Jordan et al. 2013; Oregon Biodiversity Information Center 2024; WDFW 2025).

Ecology & Habitat

Habitat

This species is found in small to large rivers, in swift current on stable gravel to boulder substrate in cold, unpolluted, highly oxygenated water (Hershler and Frest 1996).

Other Nations (2)

CanadaN1

Province	Rank	Native
British Columbia	S1	Yes

United StatesN2

Province	Rank	Native
Washington	S2	Yes
Oregon	S2	Yes
Idaho	S3	Yes

Threat Assessments

Threat	Scope	Severity	Timing
1 - Residential & commercial development	Restricted (11-30%)	Serious - moderate	High (continuing)
1.1 - Housing & urban areas	Restricted (11-30%)	Serious - moderate	High (continuing)
7 - Natural system modifications	Restricted (11-30%)	Moderate or 11-30% pop. decline	High (continuing)
7.2 - Dams & water management/use	Restricted (11-30%)	Moderate or 11-30% pop. decline	High (continuing)
9 - Pollution	Large (31-70%)	Serious - moderate	High (continuing)
9.1 - Domestic & urban waste water	Restricted (11-30%)	Serious or 31-70% pop. decline	High (continuing)
9.1.2 - Run-off	Restricted (11-30%)	Serious or 31-70% pop. decline	High (continuing)
9.2 - Industrial & military effluents	Restricted (11-30%)	Serious or 31-70% pop. decline	High (continuing)
9.3 - Agricultural & forestry effluents	Restricted (11-30%)	Serious or 31-70% pop. decline	High (continuing)
11 - Climate change & severe weather	Large (31-70%)	Moderate - slight	High (continuing)
11.1 - Habitat shifting & alteration	Large (31-70%)	Moderate - slight	High (continuing)

Roadless Areas (1)

Washington (1)

Area	Forest	Acres
Black Canyon	Okanogan National Forest	9,681

References (19)

Freshwater Mollusk Conservation Society (FMCS). 2021. The 2021 checklist of freshwater gastropods (Mollusca: Gastropods) of the United States and Canada. Considered and approved by the Gastropods Names Subcommittee December 2020. Online: https://molluskconservation.org/MServices_Names-Gastropods.html
Frest, T.J. and E.J. Johannes. 1995c. Interior Columbia Basin mollusk species of special concern. Final Report (contract #43-0E00-4-9112) prepared for Interior Columbia Basin Ecosystem Management Project. Deixis Consultants, Seattle, Washington. 274 pp. + tabs., figs.
Hershler R., and H.-P. Liu. 2012. Molecular phylogeny of the western North American pebblesnails, genus Fluminicola (Rissooidea: Lithoglyphidae), with description of a new species. Journal of Molluscan Studies 78(4):321-329.
Hershler, R. and T. J. Frest. 1996. A review of the North American freshwater snail genus Fluminicola (Hydrobiidae). Smithsonian Contributions to Zoology, 583: 1-41.
InvertEBase. 2025. Online. Available: https://invertebase.org/portal/index.php.
Jordan, S.F., S. Jepsen and R. Huff. 2013. Species fact sheet: Fluminicola fuscus (Columbia pebblesnail; Ashy pebblesnail; Columbia River spire snail). Interagency Special Status/Sensitive Species Program (ISSSSP) Conservation Planning Documents, U.S. Forest Service (Pacific Northwest Regional Office) and Bureau of Land Management (Oregon/Washington State Office). Online. Available: http://www.fs.fed.us/r6/sfpnw/issssp/planning-documents/species-guides.shtml (Accessed 2015).
Liu, H.P., Walsh, J. and Hershler, R. 2013. Taxonomic clarification and phylogeography of Fluminicola coloradensis Morrison, a widely ranging western North American pebblesnail. Monographs of the Western North American Naturalist 6(1):87-110.
Lysne, S.J. and R. Pierce. 2009. Mollusk survey of Crystal Creek-Spring Creek Ranches, Blaine County, Idaho, USA. Ellipsaria 11(1):20.
Lysne, S.J. and W.H. Clark. 2009. Mollusc survey of the lower Bruneau River, Owyhee County, Idaho, U.S.A. American Malacological Bulletin 27:167-172.
Montana Natural Heritage Program. 2011. Element Subnational Ranking Form in Biotics 5 database. NatureServe, Arlington, Virginia.
Neitzel, D., and T. Frest. 1992. Survey of Columbia River Basin Streams for Columbia pebblesnail Fluminicola columbiana and shortface lanx Fisherola nuttalli. PNL-8229, Pacific Northwest Laboratory, Richland, Washington.
Oregon Biodiversity Information Center. 2024. Element Subnational Ranking Form in Biotics 5 database. NatureServe, Arlington, Virginia.
NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).
Stockton, K.A., Moffitt, C.M., Blew, D.L. and Farmer, C.N. 2012. Acute toxicity of Sodium Fluorescein to Ashy Pebblesnails Fluminicola fuscus. Northwest Science 86(3):190-197.
Turgeon, D. D., A. E. Bogan, E. V. Coan, W. K. Emerson, W. G. Lyons, W. L. Pratt, C. F. E. Roper, A. Scheltema, F. G. Thompson, and J. D. Williams. 1988. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. American Fisheries Society Special Publication 16. 277 pp.
Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland. 526 pp.
U.S. Forest Service (USFS). 1996. Status of the interior Columbia basin: summary of scientific findings. General Technical Report PNW-GTR-385. Portland, Oregon: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station; U.S. Department of the Interior, Bureau of Land Management. 144 pp.
Voshell, J.R. 2002. A guide to common freshwater invertebrates of North America. McDonald and Woodward Publishing Company, Granville, Ohio, USA: 442 pp.
Washington Department of Fish and Wildlife. 2025. Species & Habitats. Online. Available: https://wdfw.wa.gov/species-habitats

Fluminicola fuscus

Habitat

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