Do Channel Characteristics and Local Hydraulics Predict the Concentration of Invertebrate Prey Available to Salmon and Trout in Streams?
Additional Funding Sources
This project was made possible by the NSF Idaho EPSCoR Program and by the National Science Foundation under Award No. OIA-1757324.
Presentation Date
7-2022
Abstract
Drift refers to the suspension and downstream transport of invertebrates in streams[1]. Understanding the factors that influence drift concentrations is important because salmonids are primarily drift-feeding fishes and drift concentration affects growth potential as measured by Net Energy Income (NEI). Invertebrates enter and exit drift passively due to water velocity and turbulence or shifting substrate, or actively to avoid predators or search for food resources[2]. Currently, the relationship between channel characteristics, hydraulic conditions and drifting invertebrate concentration is poorly understood. Often, for the sake of simplicity, invertebrate concentration is assumed to be constant throughout a stream. The overall goal of this project is to determine if drift concentration differs predictably among different habitat types in a stream system or if hydraulic conditions (velocity, turbulence). Our preliminary goal was to test if drift concentration (#/m^3) differed across transects spanning different habitat types and hydraulic conditions. In order to accomplish this, a modified version of the CHAMP protocols were used to take drift samples along three transects in North Fork Asotin Creek. Each transect had a variety of habitat types within them.
Do Channel Characteristics and Local Hydraulics Predict the Concentration of Invertebrate Prey Available to Salmon and Trout in Streams?
Drift refers to the suspension and downstream transport of invertebrates in streams[1]. Understanding the factors that influence drift concentrations is important because salmonids are primarily drift-feeding fishes and drift concentration affects growth potential as measured by Net Energy Income (NEI). Invertebrates enter and exit drift passively due to water velocity and turbulence or shifting substrate, or actively to avoid predators or search for food resources[2]. Currently, the relationship between channel characteristics, hydraulic conditions and drifting invertebrate concentration is poorly understood. Often, for the sake of simplicity, invertebrate concentration is assumed to be constant throughout a stream. The overall goal of this project is to determine if drift concentration differs predictably among different habitat types in a stream system or if hydraulic conditions (velocity, turbulence). Our preliminary goal was to test if drift concentration (#/m^3) differed across transects spanning different habitat types and hydraulic conditions. In order to accomplish this, a modified version of the CHAMP protocols were used to take drift samples along three transects in North Fork Asotin Creek. Each transect had a variety of habitat types within them.