BC Conservation Data Centre: Conservation Status Report
Thymallus arcticus - Nahanni lineage
Arctic Grayling - Nahanni Lineage
| Scientific Name: | Thymallus arcticus - Nahanni lineage |
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| Scientific Name Synonyms: |
Thymallus arcticus pop. 3
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| English Name: | Arctic Grayling - Nahanni Lineage |
| Provincial Status Summary | |
| Status: | S3? |
| Date Status Assigned: | January 02, 2012 |
| Date Last Reviewed: | January 02, 2012 |
| Reasons: | Arctic Grayling, Nahanni lineage, are found only within the Nahanni and Lower Liard rivers in northwestern BC. Threats to this population include impacts from forestry and agricultural, oil and gas and exploration and mining. |
| Range | |
| Range Extent: | F = 20,000-200,000 square km |
| Range Extent Comments: | The Nahanni lineage of Arctic grayling were found in the Muskwa, Beaver, LaBiche, Petitot, and Minnaker rivers in the Lower Liard River drainage, and the Nahanni River in the Mackenzie River drainage (Stamford and Taylor 2004). There is some overlap with the Southern Beringean lineage lineage within the Beaver, LaBiche, and Minnaker rivers in the Lower Liard River drainage; these will be included in the Nahanni lineage. |
| Area of Occupancy (km2): | U = Unknown |
| Linear Distance of Occupancy: | U = Unknown |
| Area of Occupancy Comments: | The area of occupancy for the Nahanni lineage of Arctic grayling is unknown. |
| Occurrences & Population | |
| Number of Occurrences: | BC = 6 - 80 |
| Comments: | The Nahanni lineage has only been confirmed genetically in 8 different rivers in BC (Stamford and Taylor 2004). It has only been identified in the Nahanni and Lower Liard rivers, and is closely associated with the Nahanni River Valley located in the upper Mackenzie River watershed (Miller et al. 2008); therefore, it is unlikely to occur in any other watersheds. Specifically, Arctic Grayling presence in the Lower Liard includes: Muskwa, Prophet, Toad, Beaver, Fort Nelson, Petitot, Fontas, Sikanni Chief (Miller et al. 2008). |
| Number of Occurrences with Good Viability / Ecological Integrity: | U = Unknown |
| Comments: | The number of sites with good viability or ecological integrity is unknown. |
| Number of Occurrences Appropriately Protected & Managed: | Rank Factor not assessed |
| Comments: | A portion of the Liard River is protected by the Liard River Corridor Provincial Park and Protected Area. |
| Population Size: | EF = 2,500 - 100,000 individuals |
| Comments: | The exact population size for the Nahanni lineage of Arctic grayling is unknown. Two Arctic grayling were captured by electrofishing and one by seine net in the Muskwa River in 2007 (data from Fish Collection Permit FJ07-25405). Assuming 100 individuals per km of river (Miller et al. 2008) and approximately 600km of river inhabited (estimate from Figure 3 in Stamford and Taylor 2004), there could be up to 60,000 fish (juveniles and adults) present. |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | B = High |
| Comments: | Threats to the Nahanni lineage include ongoing forestry and agricultural impacts, continuing and new developments in oil and gas projects and exploration, and mining (Miller et al. 2008). Placer mining increases the turbidity of the water, and leads to a decrease in the number of juvenile grayling that are able to use the habitat (Birtwell et al. 1984). Mining and oil and gas development can result in habitat losses, stream crossings, fish passage issues, and increased metals, total suspended solids and water withdrawal (Miller et al. 2008). Overfishing and climate warming are also potential threats (Miller et al. 2008). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | U = Unknown |
| Comments: | The short-term trend for the Nahanni lineage of Arctic grayling is unknown. McPhail (2007) reports that Arctic grayling populations in the Mackenzie River are in better shape than in the Upper Peace watershed. |
| Long-Term Trend: | G = Relatively Stable (<=10% change) |
| Comments: | The long-term trend for the Nahanni lineage of Arctic grayling is unknown. However, due to the increased development of industrial activities in the North (i.e., Alaskan pipeline, Northeast Coal Development Project, oil and gas development and mining), there may have been some impacts to habitats. Stable to slight decline? |
| Other Factors | |
| Intrinsic Vulnerability: | C=Not intrinsically vulnerable |
| Comments: | Arctic grayling mature at approximately age 4-5; the females can produce from 1000-17000 eggs dependent on size (McPhail 2007; Miller et al. 2008). |
| Environmental Specificity: | B=Narrow. Specialist or community with key requirements common. |
| Comments: | Arctic grayling are a cold water adapted species; however, they require warmer water for spawning and rearing (Mike Stamford, pers. comm.). |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | Patricia Woodruff (reviewed by Sue Pollard) |
| Date: | March 18, 2011 |
| References | |
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McPhail, J.D. 2007. The freshwater fishes of British Columbia. The University of Alberta Press, Edmonton, Alberta.
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Miller, E.F., S. Williamson, L. Blouw and A. Clarke. 2008. British Columbia Arctic grayling information synopsis. Ministry of Environment, Environmental Stewardship Division, Fish and Wildlife Section, Prince George, BC.
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Stamford, M.D., and E.B. Taylor. 2004. Phylogeographical lineages of Arctic grayling (Thymallus arcticus) in North America: divergence, origins and affinities with Eurasian Thymallus. Molecular Ecology 13:1533-1549.
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Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
Suggested Citation:
B.C. Conservation Data Centre. 2011. Conservation Status Report: Thymallus arcticus - Nahanni lineage. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Mar 13, 2025).