Gear Comparison for Sampling Age-0 Mountain Whitefish in the Madison River, Montana

Abstract

The efficacy of various sampling gears for age-0 Mountain Whitefish Prosopium williamsoni is largely unknown, which makes it difficult to investigate recruitment and early life history dynamics for the species. We compared four gears: seine, backpack electrofisher, minnow trap, and lighted minnow trap. Gears were tested in backwaters, large channels, and small channels in the Madison River, Montana. No age-0 Mountain Whitefish were captured in minnow traps or lighted minnow traps. Mean CPUE of age-0 Mountain Whitefish was higher for seining (0.18 fish/m²; SD, 0.39) than for electrofishing (0.01 fish/m²; SD, 0.03), and the CV was lower for seining. A broader length distribution was sampled by seining (17–41 mm) than with electrofishing (21–36 mm). Age-0 Mountain Whitefish CPUE in seines was highest in backwaters. In channel sites, Mountain Whitefish presence was associated with areas of still or slow water ≥2 m². Relative to the other sampling gears we evaluated, seining was the most efficient gear for sampling age-0 Mountain Whitefish in a lotic ecosystem.

Received June 19, 2016; accepted October 20, 2016 Published online January 12, 2017

ACKNOWLEDGMENTS

We thank Patrick Luckenbill for assistance with field work. Pat Clancey, Travis Lohrenz, and Kevin Hughes of Montana Fish, Wildlife and Parks provided advice on study design and assisted with field logistics. Richard Lessner and Dave Bricker at the Madison River Foundation helped to secure funding. The Channels Ranch provided river access. Funding was provided by the Madison River Foundation, Cross Charitable Foundation, PPL Montana (now NorthWestern Energy), and Montana Fish, Wildlife and Parks. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. This study was performed under the auspices of Montana State University institutional animal care and use protocol 2012-00.