Modelling Temperature, Body Size, Prey Density, and Stream Gradient Impacts on Longitudinal Patterns of Potential Production of Drift-Feeding Trout

Authored by J J Laliberte, J R Post, J S Rosenfeld, J A Mee

Date Published: 2016

DOI: 10.1002/rra.3048

Sponsors: No sponsors listed

Platforms: No platforms listed

Model Documentation: Other Narrative

Model Code URLs: Model code not found

Abstract

In this study, we modelled idealized stream reaches using empirical hydrodynamic and bioenergetic parameters to predict how rainbow trout production depends on physical and biological variations across a downstream gradient, and we compared these downstream effects in a low and high-gradient stream reach. We found that longitudinal production potential (i.e. net rate of energetic intake per 100m of stream length) generally increased with increasing stream size when stream gradient was low. This was not the case, however, for high-gradient streams, wherein maximum longitudinal production potential was associated with middle or low stream size (Q(MAD)=2.5 to 25m(3)s(-1)). Areal production potential (net rate of energetic intake per m(2) of wetted stream bed) reached a maximum at low stream size (Q(MAD)=2.5m(3)s(-1)) with both high and low gradients. We also showed that high stream temperature and low drift density could potentially cause adult rainbow trout to be excluded from stream reaches with high flow. The models presented here have a stronger mechanistic basis for predicting fish production across heterogeneous stream environments and provide more nuanced predictions in response to variation in environmental features than their physical habitat-based predecessors. Copyright (c) 2016 John Wiley \& Sons, Ltd.

Tags

Individual-based model growth Brown trout Rainbow-trout Invertebrate drift Habitat requirements Serial discontinuity concept Hydraulic geometry River-continuum Salmonid habitat