Effects of light on the behaviour of brown trout (Salmo trutta) encountering accelerating flow: application to downstream fish passage
Effects of light on the behaviour of brown trout (Salmo trutta) encountering accelerating flow: application to downstream fish passage
Avoidance of abrupt accelerations of flow exhibited by downstream migrating fish at screens used to divert them, or at fishway entrances, can cause delay and adversely impact efficiency. The use of alternative stimuli to attract fish and mask the unwanted deterrent effects associated with velocity gradients is of interest to those working in fish passage engineering. The influence of a continuous light source on the downstream movement of brown trout (Salmo trutta) as they encountered accelerating velocities created by a constricted channel in an experimental flume under three discharge regimes was assessed. It was predicted that: (1) in the absence of a light source, behavioural responses typical of downstream moving salmonids would be elicited on encountering velocity gradients, and that these responses would be initiated at some threshold spatial velocity gradient relative to body length and (2) light would act as an attractant and mask the deterrent effects of a velocity gradient and thus reduce delay. Typical avoidance behaviours, e.g. rheotactic switches in orientation or retreating upstream before re-approaching a velocity gradient, were common. The spatial velocity gradient threshold at which a response was initiated when dark was similar (ca. 0.4 cm s?1 cm?1) independent of discharge. Fish responded farther upstream at a lower spatial velocity gradient threshold (ca. 0.2 cm s?1 cm?1) in the presence of both mechanosensory and visual cues when light. Contrary to the second prediction, downstream movement was further delayed by the addition of a light stimulus. The findings support an alternate hypothesis, that responsiveness (avoidance) can be enhanced when multimodal stimuli are presented.
migration, behaviour, avoidance, velocity gradient, multimodal stimuli, fish passage
247-253
Vowles, Andrew
c35c3a75-2199-4665-8340-e8ee7abc25f4
Kemp, Paul S.
9e33fba6-cccf-4eb5-965b-b70e72b11cd7
October 2012
Vowles, Andrew
c35c3a75-2199-4665-8340-e8ee7abc25f4
Kemp, Paul S.
9e33fba6-cccf-4eb5-965b-b70e72b11cd7
Vowles, Andrew and Kemp, Paul S.
(2012)
Effects of light on the behaviour of brown trout (Salmo trutta) encountering accelerating flow: application to downstream fish passage.
Ecological Engineering, 47, .
(doi:10.1016/j.ecoleng.2012.06.021).
Abstract
Avoidance of abrupt accelerations of flow exhibited by downstream migrating fish at screens used to divert them, or at fishway entrances, can cause delay and adversely impact efficiency. The use of alternative stimuli to attract fish and mask the unwanted deterrent effects associated with velocity gradients is of interest to those working in fish passage engineering. The influence of a continuous light source on the downstream movement of brown trout (Salmo trutta) as they encountered accelerating velocities created by a constricted channel in an experimental flume under three discharge regimes was assessed. It was predicted that: (1) in the absence of a light source, behavioural responses typical of downstream moving salmonids would be elicited on encountering velocity gradients, and that these responses would be initiated at some threshold spatial velocity gradient relative to body length and (2) light would act as an attractant and mask the deterrent effects of a velocity gradient and thus reduce delay. Typical avoidance behaviours, e.g. rheotactic switches in orientation or retreating upstream before re-approaching a velocity gradient, were common. The spatial velocity gradient threshold at which a response was initiated when dark was similar (ca. 0.4 cm s?1 cm?1) independent of discharge. Fish responded farther upstream at a lower spatial velocity gradient threshold (ca. 0.2 cm s?1 cm?1) in the presence of both mechanosensory and visual cues when light. Contrary to the second prediction, downstream movement was further delayed by the addition of a light stimulus. The findings support an alternate hypothesis, that responsiveness (avoidance) can be enhanced when multimodal stimuli are presented.
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More information
Accepted/In Press date: 22 June 2012
e-pub ahead of print date: 26 July 2012
Published date: October 2012
Keywords:
migration, behaviour, avoidance, velocity gradient, multimodal stimuli, fish passage
Organisations:
Centre for Environmental Science, Water & Environmental Engineering Group
Identifiers
Local EPrints ID: 343257
URI: http://eprints.soton.ac.uk/id/eprint/343257
ISSN: 0925-8574
PURE UUID: c38eb2c8-668c-4a80-a29b-31a697c59377
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Date deposited: 02 Oct 2012 14:03
Last modified: 15 Mar 2024 03:34
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