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Shortface Lanx - Fisherola nuttalli

Potential Species of Concern

Global Rank: G2
State Rank: SH

Agency Status
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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 opaque chestnut-brown. Dimensions: 8 mm long, 6.25 mm wide, 3 mm high."

Diagnostic Characteristics
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 opaque chestnut-brown. Dimensions: 8 mm long, 6.25 mm wide, 3 mm high."

Range Comments
Limited to tributaries of lower Columbia River (Frest and Johannes 1995). Rangewide, Fisherola nuttalli is found in scattered localities in the Columbia River drainage system of the Pacific Northwest, including Idaho, Washington, Oregon, and possibly Montana. Its presence in the Columbia River drainage in British Columbia is assumed from the discovery of a shell (Clarke 1981). Occurrences are still reported in the Okanagan River drainage in British Columbia and confirmed in the Deschutes River of Oregon (Neitzel and Frest 1990), Snake River (*Middle Snake River-downstream of Hells Canyon Dam-ID/OR).

In Idaho they are reported from Elmore, Gooding, Idaho, Nez Perce and Twin Falls Counties. Populations within Idaho persist in parts of the Salmon and Snake rivers (Frest 1999). Although F. nuttalli is a species of concern, it appears to be doing well in the Snake River in Hells Canyon (Richards et al. 2005). In Montana they were reported from the Clark Fork basin, but these old sites may be extirpated.


Habitat
Found in cold, unpolluted, well-oxygenated, permanent, medium-sized streams to large rivers, at least 30 meters and up to 100 meters wide. Habitats are cobble-boulder diatom covered substrate in the main channels, or close to fast-flowing water (rapids), often co-occurring with Fluminicola columbiana (Neitzel and Frest 1989, 1990). This species is not found in areas with a high abundance of macrophytes or epiphytic algae, in areas with a bedrock substrate, or in areas that are dredged or mined (Frest 1999). Fisherola nuttalli occurred primarily in the fastest waters in a Snake River study and the probability of capturing F. nuttalli increased with increasing conductivity from 300-400 (EC) (Richards et al. 2005). This species feeds by scraping algae and diatoms from rock surfaces in the streams. May occasionally feed on other plant surfaces. Dispersal and movement is by a slow snail-like crawl or can be transported by stream current. Present all year, but not active in winter.

Reproductive Characteristics
Freshwater pulmonates generally reproduce by copulation and cross-fertilization. Eggs are laid from spring-fall 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).

Management
Fisherola nuttalli is sporadically distributed at present in the Columbia (formerly widespread) and a few major tributaries in four states and possibly one province. Populations have been lost from most tributaries and almost all the Columbia River itself. It may be extirpated in British Columbia and Montana. It has no USFWS status at the present time, but was a candidate for the USFWS Threatened Species status in 1995, recommended by Frest and Johannes. It is currently a US Forest Service Species of Concern (SOC) (G2) and listed imperiled (S1) in ID and recently changed from imperiled (S1S2) to presumed extirpated Montana.

Threats or Limiting Factors
Threatened by impoundment and damming (Frest and Johannes 1995). Specific threats to populations of Fisherola nuttalli have been identified as loss of habitat through impoundments, degraded water quality and siltation of cobbles, as well as nutrient enrichment. Effluence from agriculture, industry, and urban and residential developments has reduced water quality in much of the known range (Frest 1999).

References
  • Literature Cited AboveLegend:   View Online Publication
    • Clarke, A.H. 1981. The freshwater molluscs of Canada. National Museum of Natural Sciences, National Museums of Canada, Ottawa. 446 pp.
    • Frest, T.J. 1999. A review of the land and freshwater mollusks of Idaho. Final report to the Idaho Conservation Data Center, Idaho Department of Fish and Game, Boise, Idaho. 281 pp. plus appendices.
    • Frest, T.J. and E.J. Johannes. 1995. Interior Columbia Basin mollusk species of special concern. Final report to the Interior Columbia Basin Ecosystem Management Project, Walla Walla, WA. Contract #43-0E00-4-9112. 274 pp. plus appendices.
    • Hannibal, H. 1912. A synopsis of the recent and tertiary freshwater mollusca of the Californian Province, based upon an ontogenetic classification. Proceedings of the Melacological Society of London X(II):112-165.
    • Hyman, L.H. 1967. The invertebrates Mollusca I. Volume VI. McGraw-Hill, New York, NY. 288 pp.
    • Neitzel, D.A. and T.J. Frest. 1989. Survey of Columbia River Basin streams for Giant Columbia River Spire Snail Flumincola columbiana and Great Columbia River Limpet Fisherola nuttalli. Technical Report #PNL7103, Battelle Pacific Northwest Labs. 59 pp.
    • Neitzel, D.A. and T.J. Frest. 1990. Survey of Columbia River Basin Streams for Columbia Pebblesnail and Shortface Lanx. Fisheries 15(2):2-3.
    • Richards, D.C., M. Falter, G.T. Lester 2005. Additional information request Ar-2-listed mollusks. Report to the Idaho Power Company. Hells Canyon Project FERC No. P-1971-079.
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Shortface Lanx — Fisherola nuttalli.  Montana Field Guide.  .  Retrieved on , from