West Coast Vancouver Island Chinook rebuilding: Risk assessments

Across Nuu-chah-nulth territory, most West Coast Vancouver Island (WCVI) Wild Chinook populations have collapsed and remain in a depressed state with little evidence of recovery.

Just ask any Nuu-chah-nulth elder and they will tell you stories of abundant wild salmon runs sustaining our communities that they no longer witness. In response, the Department of Fisheries and Oceans (DFO) Canada introduced Bill C-68 that was passed into law in 2019.

This bill included revisions to the Fisheries Act with fish stock provisions that mandates DFO to develop rebuilding plans for “Stock Management Units” such as WCVI Chinook. However, no rebuilding process has been developed leading to WCVI Chinook being the first “pilot” stock to undergo this process. The question then became, “where do we start?”

 It was decided by DFO that the best place to start is to identify all the risks and limiting factors to Chinook production across all the different life-history stages. From the eggs in the gravel to the adults returning to spawn, what are the causes and mechanisms leading to the low survival observed by our Chinook?

Starting in 2014, and continued in 2022, work had already begun identifying risks to survival that WCVI salmon encounter during their time spent in freshwater. Sixty-eight limiting factors were identified for Nuu-chah-nulth Nations, salmon stakeholders and DFO to review and determine the severity of their risk to salmon survival.

“These risk assessments facilitated discussion between Nations and experts to collaboratively develop a list of priority risks on a river-by-river basis that can then be used to apply for funding for restoration or mitigation activities by river that are a top priority” – Candace Picco, Ha’oom Fisheries Society. 

Through multiple workshops there were several preliminary top risks that were identified. The first stemmed from the loss of wild adult spawners and the genetic diversity among the populations. This was largely attributed to overfishing, pinniped predation and hatchery fish mixing and spawning with low numbers of wild salmon.

Another top risk was from high in-river egg to smolt mortality due largely to historic poor logging practices degrading the spawning habitat. Upon completion, the next step was to undertake the daunting task of following the Chinook offspring through their long journey in the marine environment and to identify and rank the risks to their survival.

DFO led the WCVI Chinook Marine Risk Assessment in collaboration with Nuu-chah-nulth and Pacheedaht Nations. The primary objective was to identify and rank the principal factors affecting the marine survival of Nuu-chah-nulth Chinook through a series of multi-day workshops.

Their approach relied on knowledge from the Nations, area-based experts, DFO and leading researchers. Preliminary work by a smaller working group identified six themes that each would be covered by their own two-day workshop, as follows:

  • Oceanographic influence and water quality
  • Parasites, pathogens and contaminants
  • Nutrition and changes in prey quality, availability, timing and competition
  • Predation affecting WCVI Chinook
  • Hatcheries and genetics
  • Harvest

Each workshop consisted of participants first presenting and sharing research and information to create a common understanding of the status and knowledge that exists. Through this process knowledge gaps and research or monitoring requirements were identified.

 Like the freshwater risk assessment, a list of limiting factors were produced for each theme at each life-history stage which were then ranked by participants by how high of a risk they were to WCVI Chinook survival. Risk was determined by how much Chinook were exposed to the risk and how impactful the risk was.

The overarching goal of these risk assessments was to identify the limiting factors that had the most impact or highest risk to Chinook salmon survival. Results are currently being summarized, and  next steps include the discussion and evaluation of how DFO can mitigate these risks.

With only a limited amount of resources and capacity, Nuu-chah-nulth Nations and DFO must design a rebuilding plan that focuses combined efforts on tangible activities and actions that will have the most impact on the restoration of Wild Chinook salmon in the Ha-ha-houlthee of Nuu-chah-nulth Ha’wiih. 

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