Evaluating Sampling Techniques for Low-Density Populations of Arctic Grayling (Thymallus arcticus)

Abstract

Abstract In Alberta, Canada, and throughout its North American range, Arctic Grayling (Thymallus arcticus) populations are rapidly declining. As part of monitoring and recovery planning, sampling protocols currently require direction for consistency and cost effectiveness. We assessed whether common sampling techniques, backpack electrofishing and angling, could reliably detect the presence and determine abundance estimates of the species in wadeable tributary streams of the Athabasca River. Additionally, we report on the use of a novel technique, egg-kick surveys, to detect spawning habitat and monitor abundance. Backpack electrofishing and angling with dry flies had the highest detection probabilities, although CPUEs were generally low. Egg-kick surveys rarely detected Arctic Grayling and generally failed as a monitoring tool in our study streams. We found that the size structure of catches were subject to temporal biases (early versus later summer) and dependent on gear type. As expected, angling detec...