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Recovery Potential Assessment for American Plaice (Newfoundland and Labrador Designatable Units)

Regional Advisory Process - Newfoundland and Labrador

January 24-26, 2011
St. John's, NL

Chairperson: Geoff Veinott


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 designatable 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 conducted shortly after the COSEWIC assessment. This timing allows for the consideration of peer-reviewed scientific analyses into SARA processes including recovery planning.

The Committee on the Status of Endangered Wildlife in Canada has designated the American Plaice DU, Newfoundland and Labrador (April 2009) as Threatened. This species is not currently listed under the Species at Risk Act (SARA).

In support of listing recommendations for American Plaice by the Minister, DFO Science has been asked to undertake an RPA, based on the National Frameworks (DFO 2007a and b).  The advice in the RPA may be used to inform both scientific and socio-economic elements of the listing decision, as well as development of a recovery strategy and action plan,  and to support decision-making with regards to the issuance of permits, agreements and related conditions, as per section 73, 74, 75, 77 and 78 of SARA. The advice generated via this process will also update and/or consolidate any existing advice regarding the  American Plaice DU that has been assessed as Threatened by COSEWIC: Newfoundland and Labrador.


    Assess current/recent species/American Plaice status
  1. Evaluate present American Plaice status for abundance (i.e., numbers and biomass focusing on matures) and range and number of populations for the DU.
  2. Evaluate recent species trajectory for abundance (i.e., numbers and biomass focusing on matures) and range and number of populations for the DU.
  3. Estimate, to the extent that information allows, the current or recent life-history parameters for American Plaice (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) and based on the limit reference points, where available,  developed under the Precautionary Approach Framework.
  5. Project expected American Plaice population trajectories over 48 years, which represents at least three generations for all populations, and trajectories over time to the recovery target (if possible to achieve), given current American Plaice population dynamics parameters and associated uncertainties using DFO guidelines on long-term projections (Shelton et al. 2007). See Annex 1 for details.
  6. Evaluate residence requirements for the species, if any.
  7. Assess the Habitat Use of American Plaice
  8. Provide functional descriptions (as defined in DFO 2007b) of the properties of the aquatic habitat that American Plaice needs for successful completion of all life-history stages.
  9. Provide information on the spatial extent of the areas in American Plaice’s range that are likely to have these habitat properties.
  10. 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.
  11. 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
  12. Quantify the presence and extent of spatial configuration constraints, if any, such as connectivity, barriers to access, etc.
  13. Provide advice on how much habitat of various qualities / properties exists at present.
  14. 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.
  15. 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.
  16. 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.
  17. Provide advice on the extent to which various threats can alter the quality and/or quantity of habitat that is available.
  18. Scope for Management to Facilitate Recovery of American Plaice
  19. Assess the probability that the recovery targets (see Annex 1) can be achieved under current rates of American Plaice population dynamics parameters, and how that probability would vary with different mortality (especially lower) parameters.
  20. 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.
  21. 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.
  22. Assess to the extent possible the magnitude by which current threats to habitats have reduced habitat quantity and quality.
  23. Scenarios for Mitigation and Alternative to Activities
  24. 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).
  25. 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).
  26. Using input from all DFO sectors and other sources as appropriate, develop an inventory of activities that could increase the survivorship parameters (Steps 3 and 17).
  27. 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  survivorship associated with each measure in step 23.
  28. Project expected population trajectory (and uncertainties) over 48 years, which represents at least three generations for all stocks, and to the time of reaching recovery targets when recovery is feasible; given mortality rates associated with specific scenarios identified for exploration (see Annex 1). Include scenarios which provide as high a probability of survivorship and recovery as possible for biologically realistic parameter values.
  29. Recommend parameter values for 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.
  30. Allowable Harm Assessment
  31. Evaluate maximum human-induced mortality which the species can sustain and not jeopardize survival or recovery of the species.

Expected Publications


DFO Science, Ecosystems and Fisheries Management, Oceans, Habitat and Species at Risk, Policy and Economics, Aboriginal Communities, Provinces, Industry, Non-governmental organizations and Other Stakeholders will be invited to participate in this meeting.


COSEWIC. 2009. COSEWIC assessment and status report on the American Plaice Hippoglossoides platessoides, Maritime population, Newfoundland and Labrador population and Arctic population, in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. x + 74 pp.

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. 2011. A Complement to the 2005 Framework for Developing Science Advice on Recovery Targets in the Context of the Species At Risk Act. DFO. Can. Sci. Advis. Sec. Sci. Advis. Rep. 2010/061.

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. Sci. Advis. Rep. 2007/045.

Annex 1. Elements of Discussion for Projection Scenarios

The following elements will be considered to draft recovery target scenarios in order that enough details are provided so that it removes uncertainty on what has to be done.

  1. Projection horizon
  2. Possible population targets to measure progress against it and likelihood of success using projections according to the scenarios regarding fishing mortality (see #4 below)
  3. SARA Targets:

    To satisfy COSEWIC’s assessment criteria to declare that a species is not threatened (or of it becomes special concern), i.e. that it does not require a SARA recovery strategy. This can be done using Criterion “A” rate of decline in total number of mature individuals thresholds (see Table 1 below).  By default, this is normally what should be done at a minimum.

    Management Targets:

    Use the limit reference point from the PA framework as a target for rebuilding, where available.  This corresponds to Blim.

  4. Possible Scenarios for Fishing Mortality (natural and human induced):

    The fishing mortality scenarios will be different depending on the DUs. It should also be noted that Economics will need to provide input as they will need to determine specific activities on specific fleets for each DU.  Economics would determine the most cost-effective way to find reductions in mortality.  Therefore, there needs to be a back and forth between biologists and economics.  It was determined that Science could start modelling scenarios for option a, b, and c below, but will also model “d”, a pre-specified reduction from current level of fishing mortality from all sources, that will be determined at the DU level by managers in each region:

    1. Natural mortality only (100% reduction in human induced mortality)
    2. Natural mortality and recent level of human induced mortality (0% reduction in human induced mortality) through fishing operations (bycatch from other directed fishing, discards, directed).  Need to define “recent”: e.g. last 3 years (depends on stock and availability of data)
    3. Natural mortality and only fishing mortality from by-catch and discards.  This implies no directed fishing and would be useful to model for stocks under moratorium or for stocks where there is a possibility of a closure on directed fishing (depends on stock and data availability)
    4. Pre-specified reduction from current level of fishing mortality from all sources (e.g. 50% reduction in human induced mortality).  Science will, by default, model projection scenarios based on 100% reduction rate in human induced mortality (no fishing).  This will be covered under “a.” above, but for each DUs, Management will also need to determine other reduction rate(s)that are in line what they think is achievable from a management perspective.  This(ese) reduction rate(s) will need to be identified in advance of the RPA meeting so that Science is able to run this through the projection trajectory model for each DU.

  5. Displaying results
    1. Projections, if possible, should be made based on number of mature individuals as well as biomass of spawners, over appropriate time periods as specified above; and
    2. Results should be displayed in terms of probability of achieving the set targets and describing uncertainties.
Table 1: COSEWIC Quantitative Criterion A

*The A1 and A2 subcriteria apply to decline within last 3 generations. It may be that for a given stock/DU, the population has been stable for 2 generations already, and stability for another generation would be sufficient for the stock/DU to surpass the threatened category threshold as it pertains to decline in number of mature individuals. Nevertheless, it is suggested that projections for all stocks and DU cover at least the next 3 generations.


Participation to CSAS peer review meetings is by invitation only.

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