Modelling the factors influencing ontogenetic dietary shifts in stream-dwelling brown trout (Salmo trutta)
Authored by Javier Sanchez-Hernandez, Fernando Cobo
Date Published: 2018
DOI: 10.1139/cjfas-2017-0021
Sponsors:
Galician Plan for Research Innovation and Growth
Platforms:
No platforms listed
Model Documentation:
Other Narrative
Model Code URLs:
Model code not found
Abstract
Biotic and abiotic variables shape ontogenetic trajectories of animals.
This study modelled (i) the body length related timing of the
ontogenetic switch from aquatic to surface prey and (ii) the impacts of
habitat characteristics, prey availability, and fish densities on the
relative contribution of surface prey to the overall diet of native
brown trout (Salmo trutta). We used individual-based models of dietary
data for 170 fish (length range 48-343 mm). There was a high degree of
individual variation in the use of surface prey, but logistic regression
suggested that the shift from aquatic to surface prey was established at
a body length of 81 mm (range 36-127 mm). Results of linear
mixed-effects models highlighted the importance of fish length, benthic
invertebrates, brown trout density, and water current velocity to the
switch to surface prey by riverine brown trout, with fish length being
the most influential variable. Our study provides evidence of the
importance of ontogeny (intrinsic features of individuals linked to fish
length) and individual differences in feeding behaviour to understand
water-column use for feeding by stream-dwelling salmonids.
Tags
Habitat use
Atlantic salmon
Foraging behavior
Food webs
Prey selection
Brook trout
Terrestrial invertebrates
Juvenile coho salmon
Oncorhynchus-kisutch
Swimming performance
Charr salvelinus-alpinus
Terrestrial
invertebrates