Cutthroat Trout Population Response to Instream Habitat Improvement Efforts
Faculty Mentor Information
Tyson B. Hallbert and Ernest R. Keeley
Presentation Date
7-2017
Abstract
Salmonid fish populations in headwater streams are often limited by the amount and availability of suitable habitat. This limitation can be exacerbated by stressors that contribute to habitat degradation in and around streams. Intense livestock grazing in riparian areas adjacent to streams often reduces or removes streamside vegetation. This loss causes streams to become simplified and the abundance of pool habitat is reduced. In this study, we examined if the addition of instream habitat improvement structures improved the capacity for salmonid survival and recruitment in simplified streams. Four streams in Southeast Idaho, containing only native cutthroat trout, were treated with instream structures last August. Untreated control sections were established to compare the effectiveness of the structures at increasing fish abundance. Fish populations were sampled by two-pass electrofishing in July and October 2016 and will be resampled July 2017. During sampling, fish length and mass were recorded and fish greater than 80 mm in length were tagged to track growth. Using these data we will compare fish population structure in treatment and control sections. The aim of this study is to test the efficiency of woody additions at increasing fish densities in degraded streams.
Cutthroat Trout Population Response to Instream Habitat Improvement Efforts
Salmonid fish populations in headwater streams are often limited by the amount and availability of suitable habitat. This limitation can be exacerbated by stressors that contribute to habitat degradation in and around streams. Intense livestock grazing in riparian areas adjacent to streams often reduces or removes streamside vegetation. This loss causes streams to become simplified and the abundance of pool habitat is reduced. In this study, we examined if the addition of instream habitat improvement structures improved the capacity for salmonid survival and recruitment in simplified streams. Four streams in Southeast Idaho, containing only native cutthroat trout, were treated with instream structures last August. Untreated control sections were established to compare the effectiveness of the structures at increasing fish abundance. Fish populations were sampled by two-pass electrofishing in July and October 2016 and will be resampled July 2017. During sampling, fish length and mass were recorded and fish greater than 80 mm in length were tagged to track growth. Using these data we will compare fish population structure in treatment and control sections. The aim of this study is to test the efficiency of woody additions at increasing fish densities in degraded streams.