Language selection


Terms of Reference

Recovery Potential Assessment of Pacific Eulachon (Thaleichthys pacificus)

Pacific Regional Advisory Process

March 23 -24, 2011
Nanaimo, B.C.

Chairperson: Sean MacConnachie


When the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) designates aquatic species as threatened or endangered, Fisheries and Oceans Canada (DFO), as the responsible jurisdiction under the Species at Risk Act (SARA), is required to undertake a number of actions. Many of these actions require scientific information on the current status of the species, population or designable unit (DU), threats to its survival and recovery, and the feasibility of its recovery. Formulation of this scientific advice has typically been developed through a Recovery Potential Assessment (RPA) that is normally conducted shortly after the COSEWIC assessment. This timing allows for the consideration of peer-reviewed scientific analyses into SARA processes including recovery planning and listing recommendations.

Eulachon will be assessed by COSEWIC in April 2011. DFO Science has been asked to undertake an RPA, based on the National Frameworks (DFO 2007a and b) developed for this purpose. The information and advice in the RPA may be used:

Although the status and reasons for assessment have not been completed by COSEWIC, given the recent declines of eulachon in spawning rivers coast-wide it is reasonable to assume that eulachon will be assessed to be at risk of extinction.  This working paper will form the foundation for subsequent specific analysis once COSEWIC has assessed risk level and DU structure.


Taking into consideration available information, and accounting for uncertainties, provide information and advice respecting the potential for Eulachon recovery. The following working paper will be reviewed in support of this objective.

Levesque. C. and Therriault, T. Information in support of a recovery potential assessment for Eulachon (Thaleichtys pacificus) CSAP (Centre for Science Advice Pacific) Working Paper 2011/P27.

The provision of recovery potential information and advice is guided by the DFO National Framework (DFO 2007a and b) developed for this purpose. The frameworks outline the following specific elements for the provision of RPA information and advice, and will be used to guide this review.

A. Population status, trends and trajectories

  1. Evaluate present Eulachon status for abundance and range and number of populations.
  2. Evaluate recent species trajectory for abundance (i.e., numbers and biomass focusing on matures) and range and number of populations.
  3. Estimate, to the extent that information allows, the current or recent life-history parameters for Eulachon (total mortality, natural mortality, fecundity, maturity, recruitment, etc.) or reasonable surrogates; and associated uncertainties for all parameters.
  4. Estimate expected population and distribution targets for recovery, according to DFO guidelines (DFO 2005).
  5. Project expected Eulachon population trajectories over three generations (or other biologically reasonable time), and trajectories over time to the recovery target (if possible to achieve), given current population dynamics parameters and associated uncertainties using DFO guidelines on long-term projections (Shelton et al. 2007).

B. Species Residence

  1. Evaluate residence requirements for the species, if any.

C. Habitat Use of Eulachon

  1. Provide functional descriptions (as defined in DFO 2007b) of the properties of the aquatic habitat that Eulachon needs for successful completion of all life-history stages.
  2. Provide information on the spatial extent of the areas in Eulachon range that are likely to have these habitat properties.
  3. Identify the activities most likely to threaten the habitat properties that give the sites their value, and provide information on the extent and consequences of these activities.
  4. Quantify how the biological function(s) that specific habitat feature(s) provide to the species varies with the state or amount of the habitat, including carrying capacity limits, if any.
  5. Quantify the presence and extent of spatial configuration constraints, if any, such as connectivity, barriers to access, etc.
  6. Provide advice on how much habitat of various qualities / properties exists at present.
  7. Provide advice on the degree to which supply of suitable habitat meets the demands of the species both at present, and when the species reaches biologically based recovery targets for abundance and range and number of populations.
  8. Provide advice on feasibility of restoring habitat to higher values, if supply may not meet demand by the time recovery targets would be reached, in the context of all available options for achieving recovery targets for population size and range.
  9. Provide advice on risks associated with habitat “allocation” decisions, if any options would be available at the time when specific areas are designated as Critical Habitat.
  10. Provide advice on the extent to which various threats can alter the quality and/or quantity of habitat that is available.

D. Assess the Scope for Recovery of Eulachon

  1. Assess the probability that the recovery targets can be achieved under current rates of Eulachon population dynamics parameters, and how that probability would vary with different mortality (especially lower) and productivity (especially higher) parameters.
  2. Quantify to the extent possible the magnitude of each major potential source of mortality identified in the pre-COSEWIC assessment, the COSEWIC Status Report, information from DFO sectors, and other sources.
  3. Quantify to the extent possible the likelihood that the current quantity and quality of habitat is sufficient to allow population increase, and would be sufficient to support a population that has reached its recovery targets.
  4. Assess to the extent possible the magnitude by which current threats to habitats have reduced habitat quantity and quality.

E. Scenarios for Threats Mitigation and and/or Recovery

  1. Using input from all DFO sectors and other sources as appropriate, develop an inventory of all feasible measures to minimize/mitigate the impacts of activities that are threats to the species and its habitat (Steps 18 and 20).
  2. Using input from all DFO sectors and other sources as appropriate, develop an inventory of all reasonable alternatives to the activities that are threats to the species and its habitat (Steps 18 and 20).
  3. Using input from all DFO sectors and other sources as appropriate, develop an inventory of activities that could increase the productivity or survivorship parameters (Steps 3 and 17).
  4. Estimate, to the extent possible, the reduction in mortality rate expected by each of the mitigation measures in step 21 or alternatives in step 22 and the increase in productivity or survivorship associated with each measure in step 23.
  5. Project expected population trajectory (and uncertainties) over three generations (or other biologically reasonable time), and to the time of reaching recovery targets when recovery is feasible; given mortality rates and productivities associated with specific scenarios identified for exploration (as above). Include scenarios which provide as high a probability of survivorship and recovery as possible for biologically realistic parameter values.
  6. Recommend parameter values for population productivity and starting mortality rates, and where necessary, specialized features of population models that would be required to allow exploration of additional scenarios as part of the assessment of economic, social, and cultural impacts of listing the species.

F. Allowable Harm

  1. Evaluate maximum human-induced mortality which the species can sustain and not jeopardize survival or recovery of the species.

Expected Publications


DFO Science, Oceans, Habitat and Species at Risk, Policy and Economics, Aboriginal Communities, Province of BC, External Reviewers, Industry, Non-governmental organizations and Other Stakeholders will be invited to participate in this meeting.

References Cited

DFO. 2005. A framework for developing science advice on recovery targets for aquatic species in the context of the Species at Risk Act. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2005/054.

DFO. 2007a. Revised Protocol for Conducting Recovery Potential Assessments. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2007/039.

DFO. 2007b. Documenting habitat use of species at risk and quantifying habitat quality. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2007/038.

Shelton, P.A., B. Best, A. Cass, C. Cyr, D. Duplisea, J. Gibson, M. Hammill, S. Khwaja, M. Koops, K. Martin, B. O’Boyle, J. Rice, A. Sinclair, K. Smedbol, D. Swain, L. Velez-Espino, and C. Wood. 2007. Assessing recovery potential: long-term projections and their implications for socio-economic analysis. DFO Can. Sci. Advis. Sec. Res. Doc. 2007/045.


Participation to CSAS peer review meetings is by invitation only.

Date modified: