UDTR Global Rights of Nature Radar

Drift feeding by brown trout fry under downramping flow conditions: effects of substrate structure

Identification

Public canonical key

radar:r-320d37402e2dd68607d98a67f0f49e97

Authors

Mladen Avramović · Fahimeh Rashidabadi · Dennis Leandersson · Mahboobeh Hajiesmaeili · Joschka Wiegleb · John Piccolo · Johan Watz

Reported year

2026

Reported language

en

Source type

article

First detected

2026-11-14T01:59:17.575220+00:00

Last metadata observation

2026-11-14T01:59:17.575220+00:00

Last HTTP verification

Not checked

Documentary abstract — original language

In regulated rivers, hydropeaking may create abrupt sub-daily changes in discharge that can rapidly alter fish habitat. Although hydropeaking impacts on juvenile salmonids have been widely studied, short-term effects on foraging by early life stages remain poorly documented. We used a laboratory flume experiment to test how a downramping flow regime and substrate heterogeneity affect the foraging performance of brown trout ( Salmo trutta ) fry. We exposed fry to four treatments, combining two flow conditions (stable vs. downramping) and two substrates (gravel vs. gravel with cobbles). We quantified individual total prey intake, assessed from stomach contents, and drift-feeding activity from video analyses. Our results showed that the flow treatment had no detectable effect on total prey intake, indicating that both stable and rapid flow reductions did not disrupt short-term feeding under an adequate food supply. The number of drift-feeding attempts was similar across all treatments. In contrast, the presence of cobbles increased total prey intake, suggesting that structural complexity enhanced intake by providing hydraulic refuges and additional feeding opportunities. Prey intake showed a general size-dependent pattern, with larger fry consuming more prey. Our findings indicate that adding or maintaining fine-scale substrate complexity is a potent enhancer of fry feeding and should be considered as a restoration measure for habitat mitigation in hydropeaking rivers.

Identifiers

OPENALEX

https://openalex.org/W7148493198

DOI

10.1016/j.ecohyd.2026.100755

Documentary context

Documentary family

article

Source-reported types

article

Publishers

Elsevier BV

Entity mentions are not evidence of legal recognition. Jurisdiction studied is separate from author affiliation country.

Sources

OpenAlex · Record 1

• Document · https://doi.org/10.1016/j.ecohyd.2026.100755

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