Empirically Estimating Carrying Capacity for Juvenile Chinook Salmon

Photo 1: Juvenile Chinook salmon, or parr, caught during a fish survey. Photo credit: Richard Carmichael Photo 2: Electrofishing a stream in Idaho (Bear Valley Creek) in order to estimate Chinook parr abundance. Electrofishing surveys were done with either a mark–recapture or depletion design. Photo credit: Biomark Photo 3: Habitat sampling crews measuring stream habitat as part of the Columbia Habitat Monitoring Program, including a topographic survey (top panel) and water quality (bottom panel). Photo credit: Columbia Habitat Monitoring Program (CHaMP). Photo 4: Example of a site with high estimated capacity. Habitat exhibits high complexity including multiple channel unit types, variation in wetted channel widths, depths, and water velocity, and increased bank roughness caused by overhanging vegetation and large woody debris. Photo credit: Columbia Habitat Monitoring Program (CHaMP). Photo 5: Example of a site with low estimated capacity. Habitat has very little complexity including lack of variation in widths and depths, little water velocity refugia, no cover for juvenile fish, and an overwidened channel likely due to cattle grazing. Photo credit: Columbia Habitat Monitoring Program (CHaMP). These photographs illustrate the article “Estimating carrying capacity for juvenile salmon using quantile random forest models” by Kevin E. See, Michael W. Ackerman, Richard A. Carmichael, Sarah L. Hoffmann, Chris Beasley published in Ecosphere. https://doi.org/10.1002/ecs2.3404.