Speckled dace (Rhinichthys osculus) COSEWIC assessment and status report: chapter 11
Technical Summary
Rhinichthys osculus
speckled dace – naseux moucheté
Extent and Area Information
Population Information
Threats (actual or imminent threats to populations or habitats)
Decreasing summer low flows; the limited distribution, which can be impacted by a single large event; and cumulative habitat degradation including possible water quality issues related to industrial activity (forestry related), urbanization (sewage) and agricultural run-off, i.e., irrigation/water diversion in terms of changing run-off patterns and demand in relation to climate change leading to extended low-flow periods.
Rescue Effect (immigration from an outside source)
survive in Canada?
immigrants in Canada?
Quantitative Analysis
Analysis has not been done. None
Existing Status
Nature Conservancy Rank (NatureServe 2005)
Global – G5
National:
- U.S.: N5, PS under Endangered Species Act (several subspecies are threatened or endangered in the U.S). One subspecies (R. osculus reliquus) is extinct.
- Canada: N1N2
Regional:
- U.S.: AZ – S3S4, CA – S5, CO – S5, ID – S5, NN – S5, NV – S5, NM – S3, OR – S4, UT – S5, WA – S4
- Canada: B.C. S1S2 (Province lists as Red)
Wild Species 2000 (Canadian Endangered Species Council 2001)
- National: 6
- Regional: BC – 3
COSEWIC
- Vulnerable (Special Concern) 1980
- Endangered (2002)
- Endangered (2006)
Status and Reasons for Designation
Status: Endangered
Alpha-numeric code: B1+2ab(iii)
Reasons for Designation: The species is restricted to the Kettle River mainstem and two main tributaries in south-central British Columbia where it appears to be limited by the availability of suitable habitat. As this population is isolated above Cascade Falls, it cannot be rescued from downstream United States populations. The Kettle River is a flow-sensitive system that appears to be experiencing increasing frequency of drought conditions. The species is threatened by these reduced water flows and projected increasing water demands.
Applicability of Criteria
Criterion A: (Declining Total Population): Not Applicable – Decline is inferred, but the rate of decline is not known.
Criterion B: (Small Distribution, and Decline or Fluctuation): Meets Endangered under criteria B 1+2ab(iii) – The area of occupancy is 7.47 km², and exists at 3 locations with continuing decline observed or projected in the extent and quality of available habitat as a result of increases in water extraction and drought conditions.
Criterion C: (Small Total Population Size and Decline): Not Applicable – Number of mature individuals is not known.
Criterion D: (Very Small Population or Restricted Distribution): Meets Threatened D2 – Area of occupancy is 7.47 km² and is known from only 3 locations.
Criterion E: (Quantitative Analysis): Not Applicable – No data.
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