Biocomplexity and Spawning Escapement Goals
Photo by Ken Morrish, Fly Water Travel
State of the Salmon collaborates with scientists, salmon managers, conservationists, fishers and others to help facilitate a synthesis and dialogue about conserving biocomplexity. We explore opportunities to promote application of new concepts in various management and policy contexts around the Pacific Rim.
The loss of Pacific salmon biodiversity is a challenge heightened by the complex nature of interactions between populations and their unique habitats at various life stages and widely ranging spatial scales. This diversity of interactions leads to the formation of unique life histories and strategies that determine productivity, resilience and, as a result, the species' ability to sustain themselves in the face of human and environmental impacts. A growing number of scientists are now referring to this dynamic interaction between genes, organisms and their environment as biocomplexity. The way resource managers should best conserve this biocomplexity when establishing spawning escapement goals is a key policy issue that must be addressed.
The topic of establishing and managing for escapement goals has been the subject of much study and debate over the past several decades. The current range of salmon depletions and the dramatic changes of climate and environment create an increasing urgency to evaluate current management approaches.
Much of the debate has centered on the level of spawning escapement required for a given river system to sustain populations at healthy levels and how finely these escapement goals should be defined (e.g., at what level of aggregation) and managed in mixed-stock fisheries in order to adequately sustain the productivity and diversity of wild salmon populations. Compounding these central issues, managers have the further process challenges of forecasting and monitoring salmon population sizes and regulating fisheries and enforcing compliance — all of which are subject to management errors and uncertainty, and all of which can impact the long-term status of stocks.
State of the Salmon has adopted this family of issues and focuses on the following questions in our work:
- What approaches are used throughout the North Pacific for setting escapement goals and managing to achieve them?
- Which ones are likely to be most effective in conserving biocomplexity within dramatically changing landscapes, where resilience and the capacity to adapt to new habitats and ecosystems may determine the future of salmon populations?
- Where has the management of uncertainty and risk been most successful?
- What lessons can we learn that will give managers a better toolkit to ensure the abundance, productivity diversity and spatial distribution of salmon into the future?
- What empirical evidence do we have for linking nutrients to salmon production capacity and how should these ecosystem concepts be built into escapement goal setting?
- How does the context of humans living in and investing in ecosystems need to change in order for a sustainable salmon culture to emerge, beyond the challenges of harvest?
- What linked protection strategies are essential for habitat quantity and quality in order to comprehensively conserve biocomplexity and salmon ecosystem health?
Current Science
Scientists at the University of Washington have focused their work on defining the importance of biocomplexity in stabilizing total productivity – over a range of spatial scales, in both fish and human systems. They document how salmon populations and systems that have been productive in one timeframe can be much less productive in others. This leads to the important conclusion that maintaining stock structure is essential to long-term sustainability.
More information
Hilborn, R., Quinn, T. P., Schindler, D. E. & Rogers, D. E. 2003. Biocomplexity and fisheries sustainability. (234kb pdf) Proc. Natl Acad. Sci. 100, 6564–6568.
Hilborn, R., Quinn, T. P., & Schindler, D. E. "Biocomplexity and fisheries sustainability." (1.97mb pdf) Presentation.