Language selection

Government of Canada / Gouvernement du Canada

Search

Terms of Reference

Recovery Potential Assessment for Southern British Columbia Chinook Salmon, East Coast Vancouver Island (Designatable Units 19 and 20)

Regional Peer Review - Pacific Region

March 18-20, 2025

Nanaimo, BC

Chairperson: Katherine Bannar-Martin

Context

Southern BC Chinook Salmon (Oncorhynchus tshawytscha) designatable unit (DU) 19 (East Vancouver Island, Stream, Spring population) was assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as endangered in 2018 as they have been at a “low abundance for a long period of time” (COSEWIC 2018). Declines in marine and freshwater habitat quality are threats facing this population. Chinook salmon DU 20 (East Vancouver Island, Ocean, Summer population) was also assessed as endangered (COSEWIC 2020). For DU 20, fewer than 1000 wild spawners have been estimated to remain in this population. Exploitation rates are relatively high (about 40%), and marine survival estimates have been low for many years. Additional threats include ecosystem modifications (dam construction and channelization) and drought.

Because of these at-risk assessments, Fisheries and Oceans Canada (DFO) is supporting the development of advice on whether these DUs should be listed on Schedule 1 of the Species at Risk Act (SARA). As part of this process, science advice is required, typically provided through a Recovery Potential Assessment (RPA) structured according to national guidance.

While COSEWIC assessed DUs 19 and 20 separately, subsequent DFO Science examination of analogous conservation units (CK-23 and CK-83) found little evidence to separate the two and recommended that CK-23 (East Vancouver Island-Nanaimo-SP) be deprecated and its associated data included with CK-83 (East Vancouver Island Georgia Strait SU 0.3, DFO 2023). Following this recommendation, elements presented in this RPA will not make the distinction between DUs 19 and 20 but will refer to this population collectively as East Vancouver Island Summer Chinook. Where possible and relevant, information will be presented highlighting use of the Nanaimo River and Puntledge River by portions of this population.

Objective

To provide up-to-date information, and associated uncertainties, to address the following elements:

Biology, Abundance, Distribution and Life History Parameters

Element 1: Summarize the biology of East Vancouver Island Summer Chinook.

Element 2: Evaluate the recent species trajectory for abundance, distribution and number of populations.

Element 3: Estimate the current or recent life-history parameters for East Vancouver Island Summer Chinook.

Habitat and Residence Requirements

Element 4: Describe the habitat properties that East Vancouver Island Summer Chinook need for successful completion of all life-history stages. Describe the function(s), feature(s), and attribute(s) of the habitat, and quantify by how much the biological function(s) that specific habitat feature(s) provides varies with the state or amount of habitat, including carrying capacity limits, if any.

Element 5: Provide information on the spatial extent of the areas in East Vancouver Island Summer Chinook’s distribution that are likely to have these habitat properties.

Element 6: Quantify the presence and extent of spatial configuration constraints, if any, such as connectivity, barriers to access, etc.

Element 7: Evaluate to what extent the concept of residence applies to the species, and if so, describe the species’ residence.

Threats and Limiting Factors to the Survival and Recovery of East Vancouver Island Summer Chinook

Element 8: Assess and prioritize the threats to the survival and recovery of East Vancouver Island Summer Chinook.

Element 9: Identify the activities most likely to threaten (i.e., damage or destroy) the habitat properties identified in elements 4-5 and provide information on the extent and consequences of these activities.

Element 10: Assess any natural factors that will limit the survival and recovery of East Vancouver Island Summer Chinook.

Element 11: Discuss the potential ecological impacts of the threats identified in element 8 to the target species and other co-occurring species. List the possible benefits and disadvantages to the target species and other co-occurring species that may occur if the threats are abated. Identify existing monitoring efforts for the target species and other co-occurring species associated with each of the threats, and identify any knowledge gaps.

Recovery Targets

Element 12: Propose candidate abundance and distribution target(s) for recovery.

Element 13: Project expected population trajectories over a scientifically reasonable time frame (minimum of 10 years), and trajectories over time to the potential recovery target(s), given current East Vancouver Island Summer Chinook dynamics parameters.

Element 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 the potential recovery target(s) identified in element 12.

Element 15: Assess the probability that the potential recovery target(s) can be achieved under current rates of population dynamics parameters, and how that probability would vary with different mortality (especially lower) and productivity (especially higher) parameters.

Scenarios for Mitigation of Threats and Alternatives to Activities

Element 16: Develop an inventory of feasible mitigation measures and reasonable alternatives to the activities that are threats to the species and its habitat (as identified in elements 8 and 10).

Element 17: Develop an inventory of activities that could increase the productivity or survivorship parameters (as identified in elements 3 and 15).

Element 18: If current habitat supply may be insufficient to achieve recovery targets (see element 14), provide advice on the feasibility of restoring the habitat to higher values. Advice must be provided in the context of all available options for achieving abundance and distribution targets.

Element 19: Estimate the reduction in mortality rate expected by each of the mitigation measures or alternatives in element 16 and the increase in productivity or survivorship associated with each measure in element 17.

Element 20: Project expected population trajectory (and uncertainties) over a scientifically reasonable time frame and to the time of reaching recovery targets, given mortality rates and productivities associated with the specific measures identified for exploration in element 19. Include those that provide as high a probability of survivorship and recovery as possible for biologically realistic parameter values.

Element 21: 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 in support of the listing process.

Allowable Harm Assessment

Element 22: Evaluate maximum human-induced mortality and habitat destruction that the species can sustain without jeopardizing its survival or recovery.

Expected Publications

Expected Participation

References

Notice

Participation to CSAS peer review meetings is by invitation only.

Date modified: