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200735800 - Estimating the detection efficiency of snorkeling for detecting anadromous salmonid parr

Sponsor: US Forest Service (USFS) - Rocky Mt Research Station

Budgets: FY07: $342,912 | FY08: $294,702 | FY09: $309,731

Short description: Although snorkeling is widely used to monitor anadromous salmonids, the bias and precision of snorkeling has rarely been assessed. The project sponsors propose to develop sampling efficiency models to allow correction of extant and future data with systemwide application.

view full proposal

Final Council recommendation (Nov 2006)

Funding category: Expense

Recommended budgets: FY07: $0 | FY08: $0 | FY09: $0


ISRP final recommendation: Fundable


The scientific requirement for accurate and precise estimates of juvenile salmon abundance is well explained. Snorkeling is widely used as a juvenile salmonid census technique, especially in areas with listed species, because it does not involve handling individuals. However, in many cases there is no basis for estimating the degree to which snorkeling underestimates the actual number of fish present (it will likely always be an underestimate). This proposal outlines a study that will facilitate statistical models that allow snorkeling estimates to be corrected to provide more precise and accurate population censuses. The approach to resolving the uncertainty of the estimates appears sound. The ability to more accurately census juvenile salmonid populations is critical to status and trend monitoring, as well as estimating restoration effectiveness. This project has the potential to significantly improve monitoring accuracy by providing tools to correct snorkel estimates. Table 1 provides a very nice summary of the uses of juvenile abundance data in management. The proposal describes its general relevance to other projects that involve snorkel estimates (there are apparently 17) and also the major monitoring efforts such as CSMEP, the NOAA Fisheries Pilot projects, and INPMEP. Methods were thoroughly explained, especially the techniques used to construct the statistical models. This project will use ten-fold cross validation to evaluate model accuracy. It was nice to read a proposal that provided an adequate description of product quality. The sampling plan and analysis was excellent. The sequence of decision-making on the statistical analysis is the appropriate way to proceed in these circumstances. The presentation of the sampling, analysis, and decision-making is the best among other comparable systemwide proposals. With regard to the effects of water clarity on snorkel enumeration, why not just use a turbidimeter instead of the secchi-disk method? It might be a bit less subjective. Many of the habitat measurements described on pages 10-11 were not related explicitly to the goals of the proposal. How will this information factor into model development?

State/province recommendation: MS: Recommended Action

Review group: MSRT

Recommended budgets: FY07: (n/a) | FY08: (n/a) | FY09: (n/a)

Comment: The need for this type of work will be determined in the PNAMP and CSMEP projects developing standardized sampling protocols. Several MSRT members felt that their agencies/tribes had addressed this need (accuracy and precision of snorkel estimates). The project sponsor remained skeptical that this was the case and that there remained a regional need for this work. The ISRP should comment on the utility and purported uniqueness of the proposed methodology. The final CSMEP report may speak to the need for this type of study.

State/province recommendation: Fundable when money available

Review group: Snake

Recommended budgets: FY07: (n/a) | FY08: (n/a) | FY09: (n/a)

Comment: State Tier 2