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A glimpse of the science
To bring traditional and local knowledge, emerging science and commitment together to develop an innovative recovery strategy for lower Fraser coho salmon, Musqueam Fisheries Commission and Pacific Salmon Foundation co-hosted a February 22 workshop “Pulling Together, Making a Difference.” Discussions at the workshop included information about the sacred connections between First Nations and coho, the Wild Salmon Policy, needs for mapping habitat, habitat restoration, marine survival of coho, community and partnerships active in the issues. The afternoon was devoted to identifying options and opportunities for committed action to address the many issues around habitat and water.
 Workshop participants discuss the links between Musqueam First Nation and salmon. Integrating the complex scientific and social issues for coho in the lower Fraser into a plausible plan of action is a profound challenge. To appreciate the science, consider just one issue: coho marine survival, discussed at the workshop by Richard Beamish, a Senior Scientist with Fisheries and Oceans Canada. We know that the number of coho that survive their 18 months in the ocean to return to the Fraser varies recently from 7.6 million in 2000 to .5 million in 2005, and that these returning coho are considerably smaller than they were in the 1970s. Beamish is exploring the possible link between these changes in the coho marine survival and changes in the Georgia Strait. Specifically, the Strait is about 1 degree warmer over the past 35 years, and the annual Spring water flow from the Fraser into the Strait, which brings nutrients into the Strait, occurs about 9 or 10 days earlier than in 1920. Just as the coho have gotten smaller, pink and chum salmon have gotten larger.
Research presented at the workshop suggests that decreased marine survival of the coho may be linked to an earlier Spring. How do the changes in habitat link to the changes in the coho returns? Emerging research results indicate the challenges for coho in marine habitats are complex, have persisted since the mid-1990s and may continue for another 30-50 years. Beamish suggest that the early Spring causes early plankton, which benefits whatever fish enter the ocean first. This may favour chum and pink salmon, who enter the marine waters earlier, and inhibit coho, who arrive after the primary plankton production has passed. It is suspected that the smaller coho are less likely to survive their time in the ocean. In short, a plausible story is that warmer temperatures lead to earlier Fraser River freshets, which lead to earlier deep water-upwelling in the Strait, which in turn leads to earlier plankton bloom, which leads to less food when the coho arrive, which leads to smaller coho, which leads to decreased marine survival. If the research continues to support this theory, Fisheries and Oceans Canada will be adjusting their major production facility enhancement management practices as well as their conservation hatchery strategies. An array of other issues and questions require scientific inquiry to inform action. We face a future of many changes due to impacts of human development and climate change. The initiative seeks to bring together the information and the people needed to act for lower Fraser coho recovery. The full workshop report for this exciting and ambitious initiative will be posted on Think Salmon when it is available.
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