Fisherola nuttalli - (Haldeman, 1841)
Shortface Lanx
Synonym(s): Fisherola nuttallii (Haldeman, 1841) ;Lanx nuttallii (Haldeoman, 1841)
Taxonomic Status: Accepted
Related ITIS Name(s): Fisherola nuttalli (Haldeman, 1841) (TSN 76567)
Unique Identifier: ELEMENT_GLOBAL.2.120919
Element Code: IMGASL6010
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Snails
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Gastropoda Basommatophora Lymnaeidae Fisherola
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Concept Reference
Concept Reference: 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.
Concept Reference Code: B98TUR01EHUS
Name Used in Concept Reference: Fisherola nuttalli
Conservation Status

NatureServe Status

Global Status: G2
Global Status Last Reviewed: 09Feb2015
Global Status Last Changed: 02Jun2000
Ranking Methodology Used: Ranked by calculator
Rounded Global Status: G2 - Imperiled
Reasons: Sporadically distributed at present in the Columbia River drainage system, with few remaining populations. Populations have been lost from most tributaries and almost all the Columbia River itself; impoundment, nutrient enhancement, and loss of rocky substrate are common threats.
Nation: United States
National Status: N2 (02Jun2000)
Nation: Canada
National Status: N1 (07May2013)

U.S. & Canada State/Province Status
United States Idaho (S2), Montana (SH), Oregon (S1S2), Utah (SNR), Washington (S2), Wyoming (SNR)
Canada Alberta (SNR), British Columbia (S1), Saskatchewan (SNR)

Other Statuses

Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Endangered (29Apr2016)
Comments on COSEWIC: Designated Endangered in April 2016.

NatureServe Global Conservation Status Factors

Range Extent: 20,000-2,500,000 square km (about 8000-1,000,000 square miles)
Range Extent Comments: This species has a restricted range in the Columbia River drainage system of the Pacific Northwest, including the lower Deschutes River in Oregon, the Snake River in Oregon and Idaho, and the Okanogan River and the Hanford Reach of the Columbia River in Washington and near Trail, British Columbia (Neitzel and Frest 1992, Gelling 2010).

This species is now presumed extirpated in Montana (Stagliano et al. 2007).

Area of Occupancy: 26-125 4-km2 grid cells
Area of Occupancy Comments: Area of occupancy calculation is based on the current range in Jordan et al. (2014).

Number of Occurrences: 6 - 20
Number of Occurrences Comments: There are few extant occurrences (subpopulations). Large populations of F. nuttalli persist in only four streams: the lower Deschutes River, Oregon; the Okanogan River and the Hanford Reach of the Columbia River, Washington; and the Snake River in Oregon and Idaho (Neitzel and Frest 1990, Richards et al. 2005).  Additional small populations are found in Oregon in the John Day and Imnaha Rivers, and the lower Columbia River near Bonneville Dam; the Methow River, Washington; and the Grande Ronde River, Washington and Oregon (see Jordan et al. 2014). Gelling (2010) notes that there is one extant occurrence in British Columbia, near Trail and historical records from River Kootanie East.

Surveys conducted before dam construction on the Columbia River (pre-1987), reported F. nuttalli from the Columbia and Spokane Rivers in Washington; the Snake and Salmon Rivers in Idaho; the Deschutes River in Oregon; and the Kootenai River in British Columbia (Jordan et al. 2014).  In Montana, it is reported from the Clark Fork basin, but these old sites may be extirpated (Stagliano et al., 2007).

Population Size Comments: Total population size is unknown. However, known collections range from one to at least 15 specimens (Neitzel and Frest 1992, Deixis MolluskDB 2013 in Jordan et al. 2014).

Overall Threat Impact: High
Overall Threat Impact Comments: The key threats to this species include habitat degradation and loss, fragmentation and isolation of the remaining populations and changes in water quality and quantity (Jordan et al. 2014).

Stream modification: many historic populations of this species were extirpated due to stream modifications. Modifications from dams, impoundments, agriculture, grazing, development, and industry (pulp mills and mining) increased sedimentation, siltation, pollution and nutrient loading, and loss of rocky substrate (Frest and Johannes 1995, Neitzel and Frest 1992, Frest 1999). Many of these factors are ongoing (Stagliano et al. 2007).

Loss of riparian vegetation: changes in riparian vegetation have been noted basin-wide, including a significant decline in riparian-associated species such as cottonwood and willow due to forest conversion, streamside disturbance, roads, and dams (USDA 1996 in Jordan et al. 2014). Decreased riparian vegetation alters the cobble substrate used by this species by destabilizing stream banks and increasing sedimentation and siltation.

Habitat fragmentation: many of the remaining sites are separated by large areas of unsuitable habitat, which limits gene flow. In addition, small isolated populations are extremely vulnerable to stochastic events, and are generally at greater risk of extirpation from normal population fluctuations due to predation, disease, and changing food supply, as well as from natural disasters such as floods or droughts (Jordan et al. 2014).

Water quality and quantity: populations are also threatened by changes in water quality and quantity due to irrigation withdrawals. A survey of the interior Columbia River basin conducted by the US Forest Service (1996) found that most streams in the region are fully or over-appropriated for water diversion, with irrigation as the primary usage.

Long-term Trend: Decline of 30-70%
Long-term Trend Comments: Fisherola nuttalli was historically widespread, with populations scattered throughout the lower Columbia and Snake Rivers as well as some of their major tributaries. It is now apparently reduced to four large subpopulations, the largest in the 51 mile long Hanford Reach (Mazzacano 2008), These sites are separated by large areas of unsuitable habitat from those in the river's major tributaries (Neitzel and Frest 1992, Jordan et al. 2014).

Other NatureServe Conservation Status Information

Inventory Needs: Targeted surveys of known subpopulations and new sites are needed. Surveys by Neitzel and Frest (1992) documented the species in 9 out of 30 streams and many of these have not revisited.

Protection Needs: Hanford Reach, which hosts one of the largest populations of F. nuttalli, is the only remaining undammed, non-tidal stretch of the Columbia River in the United States. Habitat alteration or stream modification in that area could be severely detrimental to the survival of this species in Washington (Mazzacano 2008).

Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) This species has a restricted range in the Columbia River drainage system of the Pacific Northwest, including the lower Deschutes River in Oregon, the Snake River in Oregon and Idaho, and the Okanogan River and the Hanford Reach of the Columbia River in Washington and near Trail, British Columbia (Neitzel and Frest 1992, Gelling 2010).

This species is now presumed extirpated in Montana (Stagliano et al. 2007).

U.S. States and Canadian Provinces
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States ID, MT, OR, UT, WA, WY
Canada AB, BC, SK

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
ID Cassia (16031), Elmore (16039), Gooding (16047), Idaho (16049), Jerome (16053), Minidoka (16067)*, Nez Perce (16069), Owyhee (16073), Twin Falls (16083)
OR Gilliam (41021)*, Jefferson (41031)*, Malheur (41045), Multnomah (41051), Sherman (41055)*, Wallowa (41063)*, Wasco (41065)*
WA Asotin (53003)+, Okanogan (53047)+, Spokane (53063)+
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
17 Upper Spokane (17010305), Lower Spokane (17010307), Okanogan (17020006), Methow (17020008), Lake Walcott (17040209)+, Upper Snake-Rock (17040212)+, C. J. Idaho (17050101)+, Lower Owyhee (17050110)+, Hells Canyon (17060101)+, Lower Snake-Asotin (17060103)+, Lower Grande Ronde (17060106), Lower Salmon (17060209)+, Middle Columbia-Hood (17070105)+*, Lower John Day (17070204)+*, Upper Deschutes (17070301)+*, Lower Crooked (17070305)+*, Lower Deschutes (17070306)+*, Lower Willamette (17090012)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
General Description: Accentric conical shell up to 0.5 inches long, 0.4 inches wide, and 0.2 inches high (Neitzel and Frest 1989). Shell small, solid, roundly ovate, slightly broader posteriorly, high-arched, apex posterior; finely concentrically striate, depressed conic (Hannibal 1912). "Shell coarse, somewhat ponderous, wide, ovate, elevated; lines of growth conspicuous; apex eroded, placed far back: anterior and lateral slopes convex, posterior slope steep and rectilinear. Color opake chesnut-brown. Dimensions: 8mm long, 6.25mm wide, 3 mm high."
Reproduction Comments: Freshwater pulmonates generally reproduce by copulation and cross-fetilization. Eggs are laid from spring to autumn in gelatinous capsules attached to plants, stones, or other objects. They lack a free-swimming larval stage, and hatch as young snails, anatomically complete except for the reproductive system (Hyman 1967).
Ecology Comments: "Generally, freshwater snails require access to air for respiration (although integumental oxygen transfer may occur). They are resistant to cold and freezing. Light intensity is not important except as it affects growth of their food sources" (Hyman 1967). Given F. NUTTALLI'S highly oxygenated habitat, integumental respiraton may be more important than suggested by other other freshwater snails known to Hyman. They are probably food items for fish, frogs, salamanders or birds.
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: Slow snail-like crawl, or subject to transport by stream current.
Special Habitat Factors: Benthic
Habitat Comments: Fisherola nuttalli is generally restricted to perennial streams and rivers ranging from 30-100 m wide. It requires clean, cold, well-oxygenated water with gravel, cobble, and boulder substrate (Neitzel and Frest 1990). Occurs on diatom covered rocks in the main channels, or fast-flowing water (rapids), of the streams (Neitzel and Frest 1989). In an assessment of Hells Canyon Dam (Snake River, Idaho), F. nuttalli was found on cobbles in higher velocity areas of the stream much more frequently than any other mollusk species; this was considered to reflect the species? preference to attach themselves to hard surfaces in high velocities to avoid competition with other species (Richards et al. 2005)
Food Comments: Feed by scraping algae and diatoms from rock surfaces in the streams. May occasionally feed on other plant surfaces.
Phenology Comments: Present all year, but not active in winter.
Length: 1 centimeters
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation
Group Name: Freshwater Snails

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on some evidence of historical or current presence of single or multiple specimens, including live specimens or recently dead shells (i.e., soft tissue still attached without signs of external weathering or staining), at a given location with potentially recurring existence. Weathered shells constitute a historic occurrence. Evidence is derived from reliable published observation or collection data; unpublished, though documented (i.e. government or agency reports, web sites, etc.) observation or collection data; or museum specimen information.
Mapping Guidance: Unlike most freshwater mussels [possibly excepting Uniomerus tetralasmus (Say, 1831) (see Isley, 1914)], some freshwater pulmonates are able to survive in intermittent streams and ponds by settling into sediment on the bottom and aestivating in otherwise dry or frozen conditions. Some species (e.g. Stagnicola spp.) may form a sheet of mucus just within the aperture called an epiphragm that effectively seals the snail from harsh external conditions (Jokinen, 1978; Brown, 1991). For ephemeral or intermittent water species, it may be particularly difficult to define the limits of an occurrence. Movement out of the water for the purposes of aestivation is on the order of cm (Jokinen, 1978), not m or km, so this behavior should not affect separation distance between occurrences. Species that may be found in intermittent waters include: Aplexa elongata, Fossaria bulimoides, F. dalli, F. modicella, F. obrussa, F. parva, Gyraulus circumstriatus, G. crista, G. parvus, Laevapex fuscus, Physa vernalis, Physella gyrina, Planorbella campestris, Planorbula armigera, Stagnicola caperata, S. elodes, S. exilis.
Separation Barriers: Separation barriers are largely based on permanent hydrological discontinuity between water bodies, with distances of 30 meters or greater between maximum high water marks constituting a separation barrier. Additional barriers are chemical and/or physical and include any connecting water body (regardless of size) with one or more of the following on a permanent basis: no dissolved calcium content, acidity greater than pH 5, lack of dissolved oxygen, extremely high salinity such as that found in saline lakes and brine waters, or temperature greater than 45

An additional physical barrier, particularly for flowing water, is presence of upland habitat between water connections. High waterfalls and anthropogenic barriers to water flow such as dams are barriers as they limit movement in an upstream direction.

Separation Distance for Unsuitable Habitat: 2 km
Separation Distance for Suitable Habitat: 2 km
Alternate Separation Procedure: Freshwater cave species (mostly prosobranchs) may occur near entrances to very deep in cave systems with specimens occurring on the undersides of small stones in riffle areas (Hershler et al., 1990). For cave species, separation distance cannot often be determined accurately due to varying degrees of accessibility to occupied cave habitat. In these instances, each cave where an observation or collection was recorded (see Minimum EO Criteria, above) constitutes an element occurrence regardless of separation distance. Multiple caves within a single hydrological cave system are each considered separately. Caves with multiple entrances and passages known to be connected, but with connecting passages too small or unsafe for human entry shall be treated as a single element occurrence when the non-negotiable portion of the cave is thought to be less than approximately 300 m linear length. Species known to occur in caves include: Amnicola cora, Antrobia spp., Antrobis spp., Antroselates spp., Dasyscias spp., Fontigens aldrichi, F. antroecetes, F. bottimeri, F. morrisoni, F. nickliniana, F. orolibas, F. prosperpina, F. tartarea, F. turritella, Holsingeria spp., Phreatodrobia spp., Stygopyrgus spp.
Separation Justification: Freshwater snails have adapted to most North American habitats including permanent standing, intermittent, and flowing waters. As a whole, pulmonates (previously Subclass Pulmonata) are better dispersers than prosobranchs (previously Subclass Prosobranchia). Pulmonates adapt better to changing temperature and oxygen concentration, resist desiccation better (use pulmonary respiration, store excreted nitrogen as urea, aestivate), and have faster crawling rates (including righting response and actual movement rate) than prosobranchs (Brown et al., 1998). Some species are more tolerant to adverse habitat conditions such as high pollution levels (e.g. Physella spp.), high altitude [e.g. Acroloxus coloradensis (Henderson, 1930)], underground cave pools and springs (e.g. Fontigens spp., Phreatodrobia spp.) and hot springs (e.g. Pyrgulopsis spp.).

Precise geographic distribution of many American freshwater snails is not known but presumably reflects past geological, geographic, and climatic change (Smith, 1989). Movements between isolated or inaccessible portions of water bodies is possible but dependent on outside, passive processes (e.g. rafting, periodic flooding, transport by vertebrates, introduction by humans). Long-distance dispersal is generally not considered when assigning separation distances as otherwise impracticably large separation distances would result.

Several factors contribute to limiting freshwater snail distribution but none apply across diverse habitats or taxa. Approximately 95% of all freshwater gastropods are restricted to waters with calcium concentrations greater than 3 mg/liter (Brown, 1991; for exceptions see Jokinen, 1983). Calcium uptake for shell construction requires energy expenditure (active transport) when calcium concentration is low, but is passive at higher concentrations (Greenaway, 1971). Typically, no known biotic or abiotic factors consistently limit the abundance or distribution of freshwater gastropods among sites (DeVries et al., 2003). At specific localities, limiting factors may include hardness, acidity, dissolved oxygen, salinity, high temperature, and food availability as associated with depth (Smith, 1989). Most species and the largest populations occur in hard, alkaline waters with normal range 20-180 ppm (Shoup, 1943; Harman, 1974). Snails are uncommon in habitats with surface acidity greater than pH 5 (see also Jokinen, 1983). Dissolved oxygen limits diversity so severely polluted waters (oxygen consumed by algae blooms) are often devoid of freshwater snails excepting pollution tolerant species. Because pulmonates can utilize atmospheric oxygen, they can exist under anaerobic conditions for longer time periods (Harman and Berg, 1971; Harman, 1974; McMahon, 1983). High salinity is limiting to freshwater gastropods and inland saline lakes generally lack an associated snail fauna. Most species (excepting hot springs species) are intolerant of temperatures greater than 45ēC (McDonald, 1969; van der Schalie and Berry, 1973), a condition rarely occurring naturally. Lower temperatures are less limiting as snails have been found foraging in ice-covered waters (Harman and Berg, 1971; Harman, 1974). Most species live in the shallows, (depths less than 3 m) where food abundance is greatest. As a result, drastic water fluctuations (draw-downs) may cause declines in snail populations (Hunt and Jones, 1972).

Any contiguous, occupied stretch of suitable flowing water habitat 2 km long or greater is considered an element occurrence. Two km was chosen based upon the limited active movement capabilities of most benthic invertebrates and observed home range of freshwater snails (J. Cordeiro, personal observation) as well as the relatively short life span of most species (five years for most stream species and two years for most pond species).

Date: 18Oct2004
Author: Cordeiro, J.
Notes: Prosobranchs: Neritidae: Neritina; Viviparidae: Campeloma, Cipangopaludina, Lioplax, Tulotoma, Viviparus; Ampullariidae: Marisa, Pomacea; Pleuroceridae: Elimia, Goniobasis, Gyrotoma, Io, Juga, Leptoxis, Lithasia, Pleurocera; Thiaridae: Melanoides, Tarebia; Bithyniidae: Bithynia; Hydrobiidae: Amnicola, Antrobia, Antrorbis, Antroselates, Aphaostracon, Balconorbis, Birgella, Cincinnatia, Clappia, Cochliopa, Cochliopina, Colligyrus, Dasyscias, Eremopyrgus, Floridiscrobs, Fluminicola, Fontelicella, Fontigens, Gillia, Heleobops, Holsingeria, Hoyia, Hydrobia, Lepyrium, Littoridina, Littoridinops, Lyogyrus, Notogillia, Onobops, Paludina, Phreatoceras, Phreatodrobia, Potamopyrgus, Pristinicola, Probythinella, Pyrgophorus, Pyrgulopsis, Rhapinema, Somatogyrus, Spilochlamys, Spurwinkia, Stiobia, Stygopyrgus, Taylorconcha, Texadina, Texapyrgu, Tryonia; Assimineidae: Assiminea; Pomatiopsidae: Pomatiopsis, Heterostropha; Valvatidae: Valvata

Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 09Feb2015
NatureServe Conservation Status Factors Author: Cordeiro, J. (2008); Frest, T. (2000), Ormes, M. (2015).
Element Ecology & Life History Edition Date: 30Mar1992
Element Ecology & Life History Author(s): Wernz, J.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

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  • 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.

  • Gelling, L. 2010. Conservation Status Report: Fisherola nuttalli. B.C. Conservation Data Centre, B.C. Minist. of Environment. Available: (accessed Dec 5, 2014).

  • Hannibal, H. 1912. A synopsis of the recent and tertiary freshwater mollusca of the Californian Province, based upon an ontogenetic classification. Proc. Malac. Soc. Lond. X(II):112-165.

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  • Jordan, S.F., C. Mazzacano and R. Huff. 2014. Species fact sheet: Shortface lanx (Fisherola nuttalli). Version 2. 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: (Accessed 2015).

  • Lee, J.S. 2000. Freshwater molluscs of British Columbia: assessment for all recorded or potential taxa. Report prepared for British Columbia Conservation Data Centre, Ministry of Environment, Lands and Parks: Victoria, British Columbia. January 2000, revised March 2001. 107 pp.

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  • Neitzel, D.A. and T.J. Frest. 1989. Survey of Columbia River Basin streams for Giant Columbia River Spire Snail Fluminicola columbiana and Great Columbia River Limpet Fisherola nuttallii. Pacific Northwest Laboratory, operated for the US Dept. of Energy by Battelle Memorial Institute. Prepared for the US Dept. of Energy under contract DE-AC06-76RLO 1830.

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  • Richards, D.C., Falter, C.M., Lester, G.T. and Myers, R. 2005. Additional Information Request Ar-2: Listed Mollusks. Final report to the Idaho Power Company. Hells Canyon Project FERC #P-1971-079. 180 pp.

  • Scudder, G.G.E. 1996. Terrestrial and freshwater invertebrates of British Columbia: priorities for inventory and descriptive research. Research Branch British Columbia Ministry of Forests Research Program, and Wildlife Branch, British Columbia Ministry of Environment, Lands and Parks. Victoria, British Columbia, Working Paper 09/1996.206 pp.

  • Stagliano, D.M., G.M. Stephens, and W.R. Bosworth. 2007. Aquatic invertebrate species of concern on USFS Northern Region lands. Report prepared for USDA Forest Service, Northern Region, Missoula, Montana. Montana Natural Heritage Program, Helena, Montana and Idaho Conservation Data Center, Boise, Idaho. Agreement number 05-CS-11015600-036. 95 pp. + app.

  • Stagliano, D.M., and B.A. Maxell. 2010. Aquatic Invertebrate Species of Concern: Updated Distributions, Vital Watersheds and Predicted Sites within USFS Northern Region Lands. Report to USDA Forest Service, Northern Region. Montana Natural Heritage Program, Helena, Montana. 30 pp. plus appendices.

  • 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.

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