Changing oceans, ecosystem effects, and Canada’s Wild Salmon Policy

Canada’s Wild Salmon Policy (WSP) has helped produce numerous accomplishments but its continued effectiveness may be challenged by rapidly changing ocean conditions. To illustrate how incipient ecosystem changes can affect salmon and how the WSP is situated to guide responses to these changes, here we review the emergence of thiamine deficiency complex (TDC) in Chinook salmon. TDC results from a combination of factors that allow it to emerge rapidly. Analyses completed in 2023 indicated that TDC was likely present in eight ecologically distinct Canadian Chinook salmon populations. Responding to developing threats like TDC requires ongoing monitoring, international collaboration, and an understanding of environmental drivers to apply response mechanisms to manage vulnerable populations, key components of the WSP. Still, conducting and integrating mechanistic studies into management remains challenging, especially if climate change alters underlying ecological interactions. In implementing the WSP, re-emphasizing ecosystem studies and supporting them with both a consistent funding source and a specific directive for responsive ecological research could allow Canada to strengthen its ability to safeguard salmon populations in the face of acute ocean changes.