Mark Recapture

How many fish are in the river?

On February 28th, 2025 Joe Thorley, presented on “How many trout are in the river?” Rethinking the logic of riverine population abundance assessments at the Alberta Native Trout Science Workshop & Gathering II

Elk River WCT Abundance Analysis 2022

The suggested citation for this analytic appendix is:

Hill, N.E., Pearson, A.D., & Thorley, J.L. (2023) Elk River WCT Abundance Analysis 2022. A Poisson Consulting Analytic Appendix. URL: https://www.poissonconsulting.ca/f/876409566.

Background

The Elk River is one of eight upper Kootenay River tributaries (Bull, Michel, Skookumchuck, St. Mary, upper Kootenay, White and Wigwam) that are designated as Class II due to the importance of their recreational fisheries for Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi). The population abundance of Westslope Cutthroat Trout in the Elk River is uncertain. To improve population estimates a mark-recapture analysis using Passive Integrated Transponder (PIT) tags deployed by both boat electrofishing and guides was recommended (J. L. Thorley 2021).