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Terms of Reference

Coastwide Evaluation and Classification of Pacific Region Estuaries based on Anthropogenic Activities and Significant Fish Habitat

Regional Peer Review - Pacific Region

April 12-13, 2023
Sidney, BC

Co-Chairs: Katie Gale and Laura Sitter


Estuaries are highly productive ecosystems that support a high diversity of habitats, including eelgrass beds, saltmarshes, and mudflats. Found at the intersection of terrestrial, freshwater, and marine environments, estuaries are a geographic and life history bottleneck where anadromous fish have been shown to aggregate and are areas important for juvenile salmon (Levings 2016; Chalifour et al. 2019). As such, estuaries were identified as ecologically and biologically significant areas (EBSAs, Clarke and Jamieson 2006). More recently, estuaries were reassessed against the suite of EBSA criteria and found to score either high (aggregation, biological diversity, special importance for life history stage, and productivity) or medium (vulnerability, uniqueness, and importance for threatened species) (Rubidge et al. 2020). The final EBSA criterion, naturalness, was considered variable for estuaries because the analysis did not assess threats facing individual estuaries. Estuaries are however the site of many anthropogenic activities and the fish species and habitats within are threatened by multiple factors, including habitat degradation and modification, pollution, invasive species, overexploitation of fish, and climate change. Estuarine activities in the Pacific Region have been reviewed in other assessments (Hodgson et al. 2020; Robb 2014) which supports the need to expand/continue this research.

Canada’s Oceans Act provides the legislative framework for an integrated approach to managing Canada’s estuarine, coastal, and marine waters. The Fish and Fish Habitat Protection Program (FFHPP) at Fisheries and Oceans Canada (DFO) is responsible for estuary and coastal management planning for fish and fish habitat. As such, FFHPP has requested that Science Branch provide a coastwide evaluation of Pacific Region estuaries for activities that may impact fish and fish habitat and help to identify the importance of the estuaries to salmon, other significant fish species (e.g., herring), and the presence of sensitive fish habitat (e.g., eelgrass). This work will build on past research and analyses, including the systematic mapping of 439 estuaries in the Pacific Region (Pacific Birds Habitat Joint Venture [PBHJV] Technical Team 2020; Ryder et al. 2007), an assessment of Pacific Region estuaries (Robb 2014), and recent assessments of salmon biomass in Pacific estuariesFootnote 1. The analyses will be completed at a coastwide scale, though will identify activities and environmental impacts relevant to individual estuaries. The work will not incorporate the full ecosystem risk assessment framework (ERAF, O et al. 2015).

The assessment, and advice arising from this Canadian Science Advisory Secretariat (CSAS) Regional Peer Review (RPR), will assist managers in developing management and conservation actions appropriate to estuaries along the Pacific coast. Using the described methods, the analyses for evaluating estuaries can be updated iteratively as new spatial datasets become available. The information may also contribute to the identification of areas of high conservation value for marine spatial planning (MSP) initiatives on the coast of British Columbia, as well as the identification of at-risk areas that can help to guide emergency response programs.


The following working paper will be reviewed and provide the basis for discussion and advice on the specific objectives outlined below.

C.K. Robb, P.L. Thompson, J. Cristiani, B. Proudfoot, and Rubidge, E.M. Coastwide evaluation and classification of Pacific Region estuaries based on anthropogenic activities and significant fish habitat. 2023. CSAP Working Paper 2021FFHPP07.

The specific objectives of this working paper are to:

  1. Review the current anthropogenic activities and environmental impacts to estuaries in the Pacific Region.
  2. Map the key ecological and anthropogenic features within Pacific Region estuaries, including:
    • a. Anthropogenic activities and environmental impacts (including climate change); and
    • b. Significant fish species and sensitive fish habitat.
  3. Review and apply approach for estuary assessment based on anthropogenic activities, where data are available.
  4. Identify estuaries of importance to salmon and other significant fish species (e.g., herring spawning areas), and presence of sensitive fish habitats (e.g. eelgrass), where data are available.
  5. Examine and identify uncertainties in the data and methods.

Expected Publications

Expected Participation



Participation to CSAS peer review meetings is by invitation only.

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