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UncertaintyFish survival is currently estimated using capture-recapture methods. How can advances in genetic stock identification, reductions in sizes of tags, new tag technologies, and other emerging methods be used to improve estimates of survival (better precision and less bias) and/or reduce costs?
ThemeMonitoring and evaluation methods
SubthemeFish survival tagging
Criticality Level Priority
Rationale Fish survival is one of the primary metrics of performance. Better estimates will allow more reliable detection of finer differences in survival rates among stocks, under different hydrosystem operations, or for different life stages thereby providing opportunities to develop management actions to help stocks with low productivity. Monitoring and evaluation of fish population status is a critical task that should occur every year as a means to inform decisions involving harvests, hatchery production, and efforts to restore fish populations (See Programmatic Comment 7). Some fish monitoring, including tagging, is funded by the Program, but much of it is conducted outside the Program by government agencies. A common strategy by the Program and outside agencies, along with cooperation and integration of efforts, is needed to effectively and efficiently achieve the goals for monitoring and evaluation in the Basin. A limitation of tagging methods is the requirement to physically handle fish and apply tags. If handling fish or the physical tag affects subsequent behavior (including survival), estimates of performance may be biased. Tagging methods also require substantial numbers of fish to be tagged to compensate for subsequent mortality and imperfect detection—this may be costly and logistically difficult to do and may not be feasible for species with low abundance. Parent-based genetic tagging appears promising based on the pace of development to date. Smaller and injectable acoustic tags would make it possible to tag smaller juvenile salmon and also juvenile lamprey to assess survival over dams. The increased use and establishment of PIT tag arrays in subbasins would provide information on straying and spawning.

last updated: Jan 27, 2016