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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Hydro-environment : The influence of bottom rugosity on the performance of upstream fish movements
The influence of bottom rugosity on the performance of upstream fish movements
Author : PAULO BRANCO(1,2), JOSÉ MARIA SANTOS(1), CHRISTOS KATOPODIS(3), TERESA VISEU(4), MARIA TERESA FERREIRA(1) &
ABSTRACT
The placement of artificial substrates at the bottom of conventional fishways has been of increasing interest, as a means
to improve passage for several fish species. The aim of this work is to study the behaviour and performance of the Iberian
barbel (Luciobarbus bocagei), a benthic potamodromous fish, in a full-scale experimental pool-type fishway featuring
different bottom substrates to test the effect of both macro-rugosity and roughness. For this purpose, two boulder
arrangements (macro-rugosity) set at distinct densities (8 boulders/pool and 12 boulders/pool) and an artificial grass layout
(roughness) were tested with two fishway discharges (Qlow = 38.5 l.s-1 and Qhigh = 62.7 l.s-1). Fish were collected in the field
by electrofishing and transported to the laboratory, where they were held under adequate housing, nutrition and care
conditions. When using macro-rugosities, fish responded with greater success (45% of successful passes) at the higher
discharge, independent of boulder density. This was possibly due to the fact that upstream attraction was always
guaranteed, something that did not happen for the lower discharge with a higher boulder density configuration (25% of
successful passes). On the other hand, when facing a roughness grass layout (increased friction), fish responded with
greater success at the lower fishway discharge (50% of successful passes) than at the higher discharge (30% of
successful passes), where the presence of higher bottom velocities prevented further passage success. These findings
show that placing macro-rugosity or roughness (case-specific) at the bottom of conventional fishways may facilitate
passage, if an adequate fishway discharge is provided.
File Size : 270,967 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Hydro-environment
Date Published : 18/08/2015
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