Author(s): Susana D. Amaral; Paulo Branco; Christos Katopodis; Maria T. Ferreira; Antonio N. Pinheiro; Jose M. Santos
Linked Author(s): José Maria Santos, Christos Katopodis
Keywords: No Keywords
Abstract: Numerous studies have been reporting serious changes in fish communities that are strongly related to the influence of physical stressors, such as the presence of hydraulic infrastructures (e. g. dams, weirs) along the river systems. Even small weirs, that are a priori considered as permeable to fish movements, may cause successive losses of connectivity by partially or totally blocking migratory movements, with negative consequences for fish populations. Potamodromous cyprinid species are particularly impacted due to their need of undergo seasonal upstream migrations. Recent studies have addressed the effect of hydraulic parameters on upstream movements past small weirs. However, about passage behaviour, little is known on how these parameters interact to induce a swimming or a jumping behaviour in negotiating such obstacles. This study aims to evaluate the passage behaviour (swimming vs. jumping) of Iberian barbel (Luciobarbus bocagei), a mediumsize potamodromous cyprinid species, over an experimental small broad-crested weir, considering the effect of key hydraulic parameters: plunge pool depth (D), waterfall height (H), and flow discharge (Q). A total of 16 configurations were tested contemplating different combinations of D (10,20,30,50 cm) and H (5,10,15,25 cm) with a constant Q (50 L. s-1). The configuration with the highest passage success was tested for different discharges (Q=25,75,100 L. s-1). Results showed that passage behaviour was highly dependent on the configurations DxH tested (Freeman–Halton test, p 0.05). These outcomes are useful to identify potential migration obstacles, for this and other medium-sized potamodromous cyprinids, and to design more permeable barriers and efficient fishways.
Year: 2018