Rethinking Strategies for Increasing Salmon Survival

New research by Dr David Welch and his team from Kintama Research Services shows that survival of Chinook salmon measured by a wide range of government agencies has fallen to ca. 1% for many regions along the North American West Coast. Within the Columbia River, the Snake River populations which are often singled out as exemplars of poor survival, are similar to most other regions. The size of the decline is too large to be compensated by freshwater habitat remediation or cessation of harvest, and too widespread to be driven by localized sources of mortality such as dams in the Columbia River or salmon farming in British Columbia. The team also calls for a systematic review to address the consistency and comparability of survival to adult return data. In particular, they identified major biases introduced into studies based on PIT tags in the Columbia River that omit the effects of harvest. These results have significant implications for informing conservation strategies to protect and restore this important species.

The paper is freely available from Wiley Online Library .

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