On June 23, 2019, a significant rock slide was discovered in a narrow section of the Fraser River at Big Bar. The rock slide created a five-meter waterfall that many stocks of Chinook, Sockeye, Coho, Pink salmon, and steelhead need to overcome to reach their spawning grounds. This blockage impedes migration to most of the watershed and so far has stopped spawning migrations for the vast majority of Fraser Sockeye stocks.
While plans are in place to continue remediation efforts into the future, the slide and the migration challenge it created will impact the number of spawners reaching the spawning grounds for years to come. At this point, it is assumed that funding would be available for further work to restore or mitigate migration passage and this proposal therefore focuses on the management implications.
For effective management of the stocks located upstream of the rock slide, it is crucial to understand the current and long-term impacts of the slide on migration success and survival rates under different river conditions such as discharge, temperature, debris, etc. In order to efficiently explore the impact of the slide on populations of Fraser salmon we will take a two pronged approach to initiate some immediate analysis and preparatory work for the 2020 field season, while developing a robust framework to identify and target key data and analysis gaps.