Hierarchical model detects decadal changes in calibration relationships of single pass electrofishing indices of abundance of Atlantic Salmon in two large Canadian catchments
Electrofishing is a commonly used technique to assess freshwater fish population abundance and in many programs, there has been a shift in the sampling methodologies towards less laborious techniques. These new techniques usually only provide an index of abundance and require calibration with other...
| Main Authors: | , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
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NRC Research Press (a division of Canadian Science Publishing)
2018
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| Subjects: | |
| Online Access: | http://hdl.handle.net/1807/92210 http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2017-0456 |
| Summary: | Electrofishing is a commonly used technique to assess freshwater fish population abundance and in many programs, there has been a shift in the sampling methodologies towards less laborious techniques. These new techniques usually only provide an index of abundance and require calibration with other sampling methods such as successive removal to be used for absolute abundance estimation. Using data for juvenile Atlantic Salmon collected in 400 sites sampled over 21 years in two large Canadian river catchments with a single sampling protocol, we developed a hierarchical Bayesian model to account for effort, day of sampling, area of the site, and catchment effects on the relationship between the single-pass index of abundance and the fish densities thereby illustrating the importance of carrying out a calibration exercise on a regular basis. Our work indicates that calibration relationships can change over time even with standardized sampling protocols and that these directional changes in important components of the sampling procedure can bias the estimate of population abundance and misinform the understanding of population dynamics. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author. |
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