Selecting the best technical fishway design for Iberian barbel, Luciobarbus bocagei (Steindachner, 1864): vertical slots versus submerged notches with bottom orifice.

When engineers and ecologists face a fishway design, many issues need to be considered, the type of fishway being the first and foremost. It is an especially complex issue in areas with species whose migratory and swimming behavior are as yet poorly known as Mediterranean barbels. The present study focuses on the fish passage of two of the most common types of technical fishways: Vertical Slot (VS), and Submerged Notch with Bottom Orifice (SNBO). Both types were studied and compared in terms of ascent ability (as the success rate and transit time) and motivation (as the proportion of attempts and attempt rate).

Motivation was greater for VS and the ascent similar in both types, but not seeming to have a relevant effect in the overall passage of this fishway types. Fish length had an effect on ascent time, being faster the biggest ones in the size range analyzed.

These results provide new data of fishways performance and may help ecologists and engineers with their decision making, mainly in Mediterranean areas with similar habitats and species

Passage performance in VS and SNBO were similar and easy: more than 90 % of fish did it successfully and spent lower than 23 min in ascend 2,25 m in high. Fish length had an effect on ascent time, being faster the biggest ones. Motivation was greater for VS, although it did not seem to have a relevant effect in the overall passage of this fishway types.

Ascent abilityin VS and SNBO were similar and easy: more than 90 % of fish did it successfully and spent lower than 23 min in ascend 2,25 m in high. Fish length had an effect on ascent time, being faster the biggest ones. Motivation was greater for VS, although it did not influence in passage performance.