Bull Trout Spawner Escapement in the Salmo River Watershed
This project will conduct bull trout redd counts in known areas of the Salmo River in 2024. This is part of a long-term monitoring program for this at-risk species in the Salmo River Watershed that will provide important information about population trends.
Since surveys began in 1998, the bull trout spawning population has been below 100 individuals in half of the 11 surveys conducted. Conservation requires 50–100 individuals per population to minimize inbreeding effects.
Executive Summary
This project aligns with the Columbia Riparian and Rivers Action Plan priority action COLRRA.SOI.SB.21.01: ‘Focal and Inventory species projects for species at risk-P2’.
Bull Trout Escapement surveys in the Salmo River Watershed represents a monitoring action,while the long-term trend analysis provided in this report represents a population assessment action. Bull Trout redd surveys had been conducted annually in spawning tributaries of the Salmo River watershed over a 23-year period (1998-2024), with the exception of four years when surveys were not conducted (2016, 2020, 2021, and 2023).
In 2024 surveys took place during October 15-19, under favourable conditions, with redds being clearly identifiable in all survey areas. Two live adult Bull Trout were observed, one in the Upper Salmo River and one in the South Salmo River.
The section of the South Salmo River (SSR) from the United States/Canada border to the upstream migration barrier within the U.S. was once again not surveyed in 2024. The inability to survey this area is due to a combination of difficult access and sensitivities around crossing an international border in a remote area (the Bull Trout migration barrier is in the US, several kilometers upstream of Canada/US border). In 2024, surveys were completed in Clearwater Creek (including lower Qua and Apex Creeks), Sheep, (including Curtis Creek below a migration barrier), the upper Salmo River mainstem, the South Salmo River (from the US border to Lost Creek) and in Hidden Creek. In total, 77 redds were observed in the surveyed reaches in 2024. Sheep Creek had the highest number of observed redds with a count of 44; the upper Salmo River held 16 redds, there were 11 redds in the surveyed portion of the South Salmo River, and 6 redds below the barrier in Clearwater Creek. When the observed number of redds identified within the watershed are expanded by assuming two adults were associated with each redd, the aggregate escapement in 2024 (including the expanded estimate for the entire spawning section of the South Salmo River) was 181 adults, which is 142% of the long-term (1998-2023) mean (127 redds).
In addition to detailed results for 2024, this report includes an analysis of spawner abundance trends for the period of record, an analysis of population level effects of nutrient addition in Sheep Creek, and a review of conservation status and threats to Salmo River Bull Trout
In response to an observed decline in Salmo River Bull Trout escapement in 2006 and 2007, the SWSS hosted a series of multi-stakeholder workshops in 2008 and 2009 in order to discuss and prioritize threats to the survival of Bull Trout in the Salmo River system. A series of recommendations were developed as a result of these meetings and are presented in Appendix C.Since their initial development, the SWSS has periodically updated and expanded this list to reflect evolving scientific understanding and emerging conservation needs.