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|Title: ||Cyprinid swimming behaviour in response to turbulent flow|
|Authors: ||Silva, Ana T.|
Santos, José M.
Ferreira, Maria Teresa
Pinheiro, António N.
|Keywords: ||Iberian barbel|
acoustic doppler velocimeter
|Issue Date: ||2012|
|Citation: ||"Ecological Engineering". ISSN 0925-8574. 44 (2012). 314-328|
|Abstract: ||Turbulence is a complex phenomenon which commonly occurs in river and fishway flows. It is a difficult
subject to study, especially biologically, yet turbulence may affect fish movements and fish passage
efficiency. Studies on quantifying fish responses to turbulence, particularly within fishways, are lacking.
This study investigated the swimming behaviour of 140 adult Iberian barbel (Luciobarbus bocagei) of two
size-classes (small fish: 15
TL < 25 cm, large fish: 25 < TL
35 cm) under turbulent flow conditions created
by three submerged orifice arrangements in an experimental pool-type fishway: (i) offset orifices, (ii)
straight orifices and (iii) straight orifices with a deflector bar of 0.5bo located at 0.2L from the inlet orifices,
where bo is the width of the square orifices ranging from 0.18 to 0.23 m and L is the pool length (1.90 m).
Water velocity and turbulence (turbulent kinetic energy, Reynolds shear stress, turbulence intensity and
eddy size) were characterized using a 3D Acoustic Doppler Velocimeter (ADV) and were related with fish
swimming behaviour. The influence of turbulent flow on the swimming behaviour of barbel was assessed
through the number of successful fish passage attempts and associated passage times. The amount of time
fish spent in a certain cell of the pool (transit time) was measured and related to hydraulic conditions.
The highest rates of passage and the corresponding lowest times were found in experiments conducted
with offset orifices. Although size-related behavioural responses to turbulence were observed, Reynolds
shear stress appeared as one of the most important turbulence descriptors explaining fish transit time
for both size-classes in experiments conducted with offset and straight orifices; furthermore, swimming
behaviour of larger fish was found to be strongly affected by the eddies created, in particular by those of
similar size to fish total length, which were mainly found in straight orifices with a deflector bar arrangement.
The results provide valuable insights on barbel swimming behavioural responses to turbulence,
which may help engineers and biologists to develop effective systems for the passage of this species and
others with similar biomechanical capacities|
|Description: ||Available at SciVerse ScienceDirect|
|Peer Reviewed: ||yes|
|Publisher version: ||www.elsevier.com/locate/ecoleng|
|Appears in Collections:||DRAT - Artigos de Revistas|
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