Evaluation of estimation of abundance of SFAN juvenile coho salmon populations
Starcevich L. 2008. Evaluation of estimation of abundance of SFAN juvenile coho salmon populations. University of Idaho. Moscow, ID
Estimates of juvenile coho salmon abundance are computed annually from stream surveys conducted by SFAN personnel. These surveys consist of a snorkel survey followed by multi-pass electrofishing in a subset of selected pools. Historically, the subset of pools has consisted of index reaches that are monitored annually as a legacy data set. This subset was subjectively-chosen and is not a true random sample as would be preferred for a true two-phase sample. The electrofishing counts are analyzed with Microfish Software to get estimates of the abundance of the juvenile population size present after the snorkel survey. Then the Hankin-Reeves (1988) estimator, a ratio estimator of the population estimate (the snorkel counts plus the Microfish estimate), is used to obtain an estimate of juvenile coho abundance across all sampled reaches. The purpose of this report is to evaluate the existing literature and SFAN survey data to determine if the methods described above represent an unbiased approach to estimating juvenile coho abundance.
- Type
- Unpublished Report
- Authors
- Starcevich, Leigh Anne
- Date of Issue
- 2008-08
- Publisher
- University of Idaho
- Units
- GOGA , PORE , SFAN
- Keywords
- coho, monitoring, population estimation, power analysis, Salmonid