Winter Habitat Selection by Large Brown Trout in Streams with and without Habitat Rehabilitation

Abstract

AbstractTo determine whether habitat rehabilitation provides functionally similar winter habitat to streams with natural features, we radio‐tagged and tracked 83 large, stream‐resident, Brown Trout Salmo trutta (>330 mm TL) and compared habitat use at pool and microhabitat scales. Brown Trout used pools similarly in streams with and without habitat rehabilitation. In all streams, trout avoided pools lacking depths >60 cm and with <10 m2 of cover. Streams with habitat rehabilitation provided similar microhabitat features to natural streams; trout selected sites with depths from 60 to 119 cm near woody debris and with water column velocity <10 cm/s in both. Trout avoided microhabitats with depths <60 cm when the habitats either lacked cover or were under ice shelves or had a water column velocity > 20 cm/s. Brown Trout selected artificially placed overhead bank structures and instream rocks in rehabilitated streams but used these natural features in proportion to their availability in streams without rehabilitation. We conclude that habitat rehabilitation created suitable winter habitat for Brown Trout in upper U.S. Midwestern streams.