Bold, sustained action can revitalize wild Pacific salmon in the lower Fraser River

Nineteen major populations of wild Pacific salmon in the Fraser River are projected to decline over the next 25 years — but it’s not too late to boost their chances of recovery.

According to a new open-access study published in the Journal of Applied Ecology, active interventions to implement habitat strategies can lift populations of wild Pacific salmon, known as conservation units (CUs),  to “green status” — which means they are healthy and able to sustain fisheries under Canada’s Wild Salmon Policy.

“The Fraser is the largest salmon-bearing river in British Columbia, and 19 of 54 conservation units of wild Pacific salmon that it supports are on a declining trajectory over the next 25 years. We urgently need to take critical action to bring them back to a sustainable path,” says lead author Dr. Lia Chalifour, who completed the research as part of her PhD studies at UBC and the University of Victoria.

The authors recommend implementing an integrated habitat strategy that includes barrier removal, estuarine and freshwater restoration, in order to protect the salmon, as well as improving policies for watershed management and protecting remaining habitat.

These actions can shift 14 CUs of wild Pacific salmon to green status at a cost of $20 million per year for 25 years, or the equivalent of just $4.25 per person per year in B.C.

If the investment is doubled to around $40 million per year over 25 years and invested in all strategies assessed in the study, up to 17 of these CUs can recover.

Without intervention, the authors say none of the 19 CUs examined in the study are likely to be assessed as “green status” in 25 years.

 “The Lower Fraser has been subject to extreme habitat loss since European colonization, resulting in devastation of the watersheds that wild salmon rely on, as we saw from the catastrophic damage caused by last year’s floods. Our study found that direct investment in restoring and conserving remaining habitat can benefit the most salmon populations for the least cost,” notes senior author and principal investigator Dr. Tara Martin, a UBC professor who leads the Conservation Decisions Lab at the faculty of forestry.

The study evaluated 11 management strategies to lead the salmon to recovery. The authors also call for a co-governance framework for salmon management between Indigenous and Crown governments, which can increase the success of these management strategies.

The study comes on the heels of renewed provincial and federal commitments to funding for salmon recovery via the British Columbia Salmon Restoration and Innovation Fund. Dr. Chalifour notes that these investments must be targeted to regional challenges to achieve the best outcome for salmon.

“There is a political appetite to support the recovery of wild salmon, however without a road map to direct those recovery efforts, success is going to be limited. Applying decision-making tools such as Priority Threat Management facilitates strategic investments in management solutions that will have the greatest possible benefit to wild salmon.” 

Priority Threat Management is a conservation decision science framework developed by Dr. Tara Martin and her team that considers the predicted benefit, cost and feasibility of management strategies to rapidly identify which strategies will have the greatest impact on the largest number of populations.

Citation

Chalifour, L., C. Holt,  A.E. Camaclang,  M.J. Bradford, R. Dixon, R.J.R. Finn, V. Hemming, S.G. Hinch, C. Levings, M. MacDuffee, D.J.H. Nishimura, M. Pearson, J.D. Reynolds, D.C. Scott, U. Spremberg, S. Stark, J. Stevens, J.K. Baum & T.G. Martin. 2022. Identifying a pathway towards recovery for depleted wild Pacific salmon populations in a large watershed under multiple stressors. Journal of Applied Ecology, 00, 1– 15. https://doi.org/10.1111/1365-2664.14239

Abstract

  1. Pacific salmon (Oncorhynchus spp.) support coastal and freshwater ecosystems, economies and cultures, but many populations have declined. We used priority threat management (PTM), a decision-support framework for prioritizing conservation investments, to identify management strategies that could support thriving populations of wild salmon over 25 years. We evaluated the potential benefits of 14 strategies spanning fisheries, habitat, pollution, pathogens, hatcheries and predation management dimensions on 19 conservation units (CUs)—genetically and ecologically distinct populations—of the five Pacific salmon species in the lower Fraser River, British Columbia, Canada.
  2. The PTM assessment indicated that under the current trajectory of ‘business as usual’, zero CUs were predicted to have >50% chance of thriving in 25 years. Implementation of all management strategies at an annual investment between 45 and 110 million CAD was, however, predicted to achieve >50% chance of thriving for most CUs (n = 16), with nearly half (seven CUs) having a > 60% chance, indicating there is a pathway towards recovery for most populations if we invest now. In fact, substantial gains could be made by investing in five combined habitat strategies, costing 20M CAD annually. These habitat strategies were estimated to bring 14 of 19 salmon CUs above this 50% threshold.
  3. Co-governance between First Nation and provincial and federal Canadian governments to manage salmon populations and harvest, and improved CU-level monitoring emerged from the expert elicitation as critical ‘enabling’ strategies. By improving the feasibility of different management options, co-governance brought an additional five CUs above the 60% threshold.
  4. Synthesis and applications. Supporting wild salmon in the face of cumulative threats will require strategic investment in effective management strategies, as identified by this priority threat management (PTM) assessment. PTM uses the best available data to objectively assess the potential outcomes of management alternatives. With renewed commitments from provincial and federal Canadian governments to protect and restore salmon populations and their habitats, positive conservation outcomes following implementation of targeted management strategies may be within reach.

Infographic

Info graphic showing the research with a chart and illustrations of BC map and salmon.

Affiliations

Lia Chalifour1,2, Cassandra Holt1, Abbey E. Camaclang1, Michael J. Bradford3, Ross Dixon4, Riley J. R. Finn1, Victoria Hemming1, Scott G. Hinch5, Colin D. Levings6, Misty MacDuffee4, Derek J. H. Nishimura7, Michael Pearson8, John D. Reynolds9, David C. Scott4,5, Uwe Spremberg10, Steven Stark11, John Stevens12, Julia K. Baum13, Tara G. Martin1.

  1. The Conservation Decisions Lab, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
  2. Department of Biology, University of Victoria, Victoria, British Columbia, Canada
  3. Fisheries and Oceans Canada, Pacific Science Enterprise Centre, West Vancouver, British Columbia, Canada
  4. Raincoast Conservation Foundation, Sidney, British Columbia, Canada
  5. Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
  6. Fisheries and Oceans Canada, Science Branch, Vancouver, British Columbia, Canada
  7. Fisheries and Oceans Canada, Fish and Fish Habitat Protection Program, Integrated Planning, Vancouver, British Columbia, Canada
  8. Pearson Ecological, Agassiz, British Columbia, Canada
  9. Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
  10. Lower Fraser Fisheries Alliance, Abbotsford, British Columbia, Canada
  11. Tsawwassen Shuttles Incorporated, Tsawwassen, British Columbia, Canada
  12. United Fishermen and Allied Workers Union and T. Buck Suzuki Environmental Foundation, Prince Rupert, British Columbia, Canada
  13. Department of Biology, University of Victoria, Victoria, British Columbia, Canada

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