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Plumb, J. M., W. P. Connor, K. F. Tiffan, C. M. Moffitt, R. W. Perry, and N.S. Adams. Accepted . 2012. Estimating and predicting collection probability of fish at dams using multistate modeling Transactions of the American Fisheries Society. 141:1364-1373.

Abstract

Dams can be equipped with a bypass that routes a portion of the fish that enter the turbine intakes away from the powerhouse into flumes, where they can be counted. Daily passage abundance can be estimated by dividing the number of fish counted in the bypass by the sampling rate and then dividing the resulting quotient by the collection probability (i.e., the proportion of the fish population passing the dam that is bypassed). We used multistate mark–recapture modeling to evaluate six candidate models for predicting the collection probabilities of radio-tagged subyearling fall Chinook salmon (n = 3,852) as a function of 1–2-d time periods (general model), four different combinations of outflow (i.e., the total volume of water passing the dam) and turbine allocation (i.e., the proportion of outflow directed through the turbines), and a null (intercept only) model. The best-fit model was the additive combination of turbine allocation and outflow, which explained 71% of the null deviance. Cross validation of the best-fit model accounted for the variation that may arise from different data sets and the ensuing parameter values on the collection probability estimates and yielded a standard error of 0.613 that can be used to construct approximate 95% prediction intervals in nonstudy years. Such estimates have been unavailable and will be useful anywhere estimates of daily passage abundance at dams with bypasses are needed to manage migratory fishes.

 

Current Staff

Federal Staff: 3

Masters Students: 6

Phd Students: 3

Post Docs: 0

University Staff: 4

5 Year Summary

Students graduated: 25

Scientific Publications: 80

Presentations: 237

 

Status

Published
September 2012

Unit Authors

  • John Plumb
  • William Connor
  • Christine Moffitt

Idaho Cooperative Fish and Wildlife Research Unit Cooperators

  1. Idaho Department of Fish and Game
  2. U.S. Fish and Wildlife Service
  3. U.S. Geological Survey
  4. University of Idaho
  5. Wildlife Management Institute