Comparison of point and transect-based electrofishing to sample American eel (Anguilla rostrata) in wadeable riverine habitats

Abstract

Dramatic declines in American eel (Anguilla rostrata) recruitment have resulted in strong conservation measures being implemented. Recovery actions in Ontario have included stocking of glass eels. Given the financial costs and imperative to undertake effective recovery actions, post-stocking monitoring is essential. In this study, point- and transect electrofishing sampling were compared in terms of eel detection, catch rates, size-selectivity, and power to detect changes in abundance. Transect sampling was more likely to detect eels and captured over twice the number of eels than point-sampling. Differences in catch rates and statistical power were dependent on the catch-per-unit-effort measure (i.e. sampling unit vs. time). Results support a transect-based sampling program for stocked eels in Lake Ontario tributaries. © EDP Sciences, IFREMER, IRD 2011.