Evaluation of horizontally and vertically aligned bar racks for guiding downstream moving juvenile chub (Squalius cephalus) and barbel (Barbus barbus)
Evaluation of horizontally and vertically aligned bar racks for guiding downstream moving juvenile chub (Squalius cephalus) and barbel (Barbus barbus)
Bar racks are commonly installed to divert fish away from water intakes, such as those at hydropower stations or other abstraction points. In temperate regions their effectiveness has predominantly been assessed in relation to diadromous species, such as salmon and eel. This study compared the efficacy of horizontally and vertically oriented racks (5 mm diameter and 10 mm spacing) to guide downstream moving groups of five chub (Squalius cephalus) and barbel (Barbus barbus) to a bypass channel in a recirculating flume under two discharge regimes, and with the rack angled at either 30° or 45° to the direction of flow. Regardless of treatment, the bulk flow predominantly passed through the bars resulting in a lack of a well-established sweeping flow across the rack face, and consequently many instances of entrainment and impingement occurred. Total guidance (the number of bypass entries expressed as a percentage of the total number of approaches) was low and comparable between species with means of 21.3% and 24.8% for chub and barbel, respectively. Bar orientation had limited influence on all metrics, with the exception of the number of guidance events which was higher for the vertical treatment. Interspecific differences in the number of entrainments and guidance events and the exhibition of fine-scale avoidance behaviours were apparent, being higher for chub. In conclusion, the racks used here were not suitable for guiding juvenile cyprinids under conditions similar to those tested. Accounting for interspecific differences and reducing avoidance behaviour are important factors that should be considered in advancing guidance screens for multiple species.
Avoidance, Bar racks, Cyprinidae, Fish passage, Guidance
De Bie, Jasper
064ae5a8-77bf-4197-9496-9540e26a585a
Peirson, Graeme
d51969a8-c948-448a-9aa6-8a466c69aedd
Kemp, Paul
9e33fba6-cccf-4eb5-965b-b70e72b11cd7
1 November 2021
De Bie, Jasper
064ae5a8-77bf-4197-9496-9540e26a585a
Peirson, Graeme
d51969a8-c948-448a-9aa6-8a466c69aedd
Kemp, Paul
9e33fba6-cccf-4eb5-965b-b70e72b11cd7
De Bie, Jasper, Peirson, Graeme and Kemp, Paul
(2021)
Evaluation of horizontally and vertically aligned bar racks for guiding downstream moving juvenile chub (Squalius cephalus) and barbel (Barbus barbus).
Ecological Engineering, 170, [106327].
(doi:10.1016/j.ecoleng.2021.106327).
Abstract
Bar racks are commonly installed to divert fish away from water intakes, such as those at hydropower stations or other abstraction points. In temperate regions their effectiveness has predominantly been assessed in relation to diadromous species, such as salmon and eel. This study compared the efficacy of horizontally and vertically oriented racks (5 mm diameter and 10 mm spacing) to guide downstream moving groups of five chub (Squalius cephalus) and barbel (Barbus barbus) to a bypass channel in a recirculating flume under two discharge regimes, and with the rack angled at either 30° or 45° to the direction of flow. Regardless of treatment, the bulk flow predominantly passed through the bars resulting in a lack of a well-established sweeping flow across the rack face, and consequently many instances of entrainment and impingement occurred. Total guidance (the number of bypass entries expressed as a percentage of the total number of approaches) was low and comparable between species with means of 21.3% and 24.8% for chub and barbel, respectively. Bar orientation had limited influence on all metrics, with the exception of the number of guidance events which was higher for the vertical treatment. Interspecific differences in the number of entrainments and guidance events and the exhibition of fine-scale avoidance behaviours were apparent, being higher for chub. In conclusion, the racks used here were not suitable for guiding juvenile cyprinids under conditions similar to those tested. Accounting for interspecific differences and reducing avoidance behaviour are important factors that should be considered in advancing guidance screens for multiple species.
Text
De Bie et al. 2021 AcceptedManuscript
- Accepted Manuscript
More information
Accepted/In Press date: 5 July 2021
e-pub ahead of print date: 8 July 2021
Published date: 1 November 2021
Additional Information:
Funding Information:
This study was funded by the EPSRC on DTP Grant 11, with additional funding from the Environment Agency . The authors thank Dominika Mackiewicz for her assistance during trials and with collecting ADV measurements. Special thanks to Alan Henshaw (Calverton fish farm, UK) for kindly providing the large numbers of experimental fish required for this study. Thanks to the members of the ICER team who assisted during trials.
Funding Information:
This study was funded by the EPSRC on DTP Grant 11, with additional funding from the Environment Agency. The authors thank Dominika Mackiewicz for her assistance during trials and with collecting ADV measurements. Special thanks to Alan Henshaw (Calverton fish farm, UK) for kindly providing the large numbers of experimental fish required for this study. Thanks to the members of the ICER team who assisted during trials.
Publisher Copyright:
© 2021 Elsevier B.V.
Keywords:
Avoidance, Bar racks, Cyprinidae, Fish passage, Guidance
Identifiers
Local EPrints ID: 450068
URI: http://eprints.soton.ac.uk/id/eprint/450068
ISSN: 0925-8574
PURE UUID: 09719901-6184-4a4d-acf1-1c4efb2a436c
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Date deposited: 08 Jul 2021 16:30
Last modified: 17 Mar 2024 06:42
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Author:
Jasper De Bie
Author:
Graeme Peirson
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