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BC Conservation Data Centre: Conservation Status Report

Thaleichthys pacificus

Scientific Name: Thaleichthys pacificus
English Name: Eulachon
Provincial Status Summary
Status: S2S3
Date Status Assigned: March 06, 2000
Date Last Reviewed: January 12, 2004
Reasons: Eulachon are limited in range and have had significant long term declines. Short term declines have occurred but have been cyclical in some cases.
Range Extent: F = 20,000-200,000 square km
Range Extent Comments: Occupies a narrow strip of the freshwater along the mainland coast, following the coastal rainforest. Offshore they can be found in Hecate Strait, Queen Charlotte Sound, west coast Vancouver Island - generally on the shelf often at depths of 80 - 200 m.
Linear Distance of Occupancy: EG = 101-10,000
Area of Occupancy Comments: Based on a maximum of 33 runs with longer runs up to 43 km inland (Nass) or Skeena at 42 km there is about a maximum of 1300 km of occupied river.
Occurrences & Population
Number of Occurrences: BC = 6 - 80
Comments: Documented spawning in 33 rivers within BC, but may only use 14-15 on a sustained basis. Major river systems used for spawning include the Fraser, Skeena, Nass and Klinaklini (Fisheries and Oceans Canada; There are 10 in BC that are considered "major" (Hay 1999). Eulachon also occurr on the offshore shelf around Dixon Entrance, Hecate Strait, Queen Charlotte Sound and the West Coast of Vancouver Island generally at depths of 80-200 m. Rivers in BC with runs include Nass, Skeena, Kitimat, Kildala, Kemano/Wahoo, Kowesas, Kitlope, Kimsquit, Bella Coola, Kilbella/Chuckwalla/Wannock/Owikeno, Kingcome, Klinaklini, Franklin, Hemathko and Fraser Rivers (Hay 1999).
Number of Occurrences with Good Viability / Ecological Integrity: C = 4 - 12
Comments: There are thought to be 10 major runs within BC (Hay 1999).
Number of Occurrences Appropriately Protected & Managed: A = None
Comments: There is a fishery for eulachon with a daily limit of 20 kilograms.
Population Size: F = 10,000 - 100,000 individuals
Threats (to population, occurrences, or area affected)
Degree of Threat: Moderate and imminent threat
Comments: By-catch by groundfish and shrimp trawls can be high, however the incidental bycatch by the shrimp fishery has declined since 1997 (Fisheries and Oceans Canada 2003). Spawning failures have also been attributed to unnatural noise, over harvest, water quality degradation (urban land development, coastal forest practices) industrial activity (construction, blasting, changes in hydrology) and dredging. Increasing water temperatures have been found to be related to smaller sizes, lower fecundity, and lower returns. There also may be more predators as a result. The temperatures may be beyond preferred maximum for spawning (Hay 1999).
Trend (in population, range, area occupied, and/or condition of occurrences)
Short-Term Trend: FH = Decline of <30% to increase of 25%
Comments: Sharp declines in runs also observed in the Columbia (declined to 5-10%), Klinaklini and possibly other rivers in 1994. Skeena and Kemano populations have shown some recovery since 1994 (Hay 1999). Rivers which experienced virtually no returns in 2000 were: Stikine, Unuk, Skeena, Kitimat, Kemano, Kitlope, Bella Coola, Kimsquit, Owikeeno, and Kingcome Rivers and then good returns were seen in the Skeena and Kingcome Inlets in 2001 and 2002. Concurrently (2000-2002), there has been a recent increase in the abundance of eulachons in marine waters off BC and parts of Alaska. Except for 1996, Eulachon returns to the Fraser have been in sharp decline since 1993. However, the forecast for 2003 looks very good, based on the offshore biomass and age of fish with genetics indicating that they are Fraser and Columbia River stocks. Over the past 4 years there have been very poor returns on the central coast rivers, Gardner Canal, Dean Channel and the Rivers Inlet systems (Fisheries and Oceans Canada 2003).
Short-term trends appear to fluctuate greatly.

Long-Term Trend: Rank Factor not assessed
Comments: Historically very abundant (up to early 1960's), however generally considered to be in a coast wide decline since the early 1990's.
The Fraser River has been declining since the early 1960's and has declined to the point where they are no longer available for traditional harvest. They have not been seen in many traditional spawning areas for many years.
Eulachon runs have been observed to suffer drastic declines for years and come back in large numbers as recorded on the Columbia between 1835-1865. However these these cyclical declines have not been observed/recorded in Fraser River populations (Hay 1999).
Other Factors
Intrinsic Vulnerability: B=Moderately vulnerable
Comments: Eulachon are susceptible to disturbance. Runs have been observed to turn away if the fish detect a disturbance (rules based upon traditional knowledge forbid disturbance within the first few days of the run to allow spawning before the start of harvest) (Hay 1999).
Environmental Specificity: B=Narrow. Specialist or community with key requirements common.
Comments: Require cold temperatures.
Other Rank Considerations:
Information Gaps
Research Needs:
Inventory Needs: There is a lack of stock assessment information for most eulachon stocks. Development
of biologically based total allowable catches for all areas and refinements to the
stock assessment process in the Fraser River are required. Improving catch reporting methods and standards can be used to help with inventries (Fisheries and Oceans Canada 2003).
Management: All of the biological indicators, presently in use on the Fraser River, are limited by
their short time series. Therefore, it is important to continue to collect and refine
the pre-season biological indicators for the Fraser River eulachon fisheries,
specifically eulachon genetic stock identification to identify river of origin in
offshore waters, and the collection of the spawning stock biomass (SSB). These are used to then set catches. Restrict dredging in the lower Fraser River during eulachon migration, spawning,
egg and larval development (early March to June) (Fisheries and Oceans Canada 2003).

Author: Ramsay, L.
Date: November 18, 2003
COSEWIC. 2011i. COSEWIC assessment and status report on the Eulachon, Nass / Skeena Rivers population, Central Pacific Coast population and the Fraser River population Thaleichthys pacificus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xv + 88 pp.
Fisheries and Oceans Canada. 2003. Pacific Region integrated fisheries management plan. Eulachon, April 1, 2003 to March 31, 2004.
Hay, D. 1999. Eulachon Research Council meeting notes on the status of eulachon in BC. Department of Fisheries and Oceans.

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Suggested Citation:

B.C. Conservation Data Centre. 2003. Conservation Status Report: Thaleichthys pacificus. B.C. Minist. of Environment. Available: (accessed Dec 11, 2018).