Swimming performance of two Iberian cyprinids: the Tagus nase Pseudochondrostoma polylepis (Steindachner, 1864) and the bordallo Squalius carolitertii (Doadrio, 1988)

Abstract

The main purpose of this study was to gather swimming performance information for two endemic cyprinids of the Iberian Peninsula to contribute to the optimization of fish ways. Critical swimming speed (U crit ) was determined for the Tagus nase Pseudochondrostoma polylepis (Steindachner, 1864) and for the bordallo Squalius carolitertii (Doadrio, 1988) in a swimming tunnel. From a total of 80 P. polylepis tested, the mean (± SD) U crit observed was 0.78 ± 0.15 ms )1 (c. 3.74 ± 0.93 BL s )1 ); the 68 S. carolitertii tested presented an U crit of 0.54 ± 0.1 ms )1 (c. 4.43 ± 0.74 BL s )1 ). Significant interspecific differences were found between the U crit of the tested cyprinids. Intraspecific comparisons between the U crit and the variables of size, sex, condition factor and gonado-somatic index were also made. No sex-or gonad maturation-related differences between the U crit were identified, but the robust P. polylepis were found to be stronger swimmers. Water velocities in fish ways for P. polylepis and S. carolitertii should aim, on average, for lower than 0.7 and 0.5 ms )1 , respectively.

Passage Performance of Potamodromous Cyprinids over an Experimental Low-Head Ramped Weir: The Effect of Ramp Length and Slope

“…Since the swimming performance of the Iberian barbel is quite similar to the swimming performance of other rheophilic cyprinids and salmonids of the same length [22], these results may be more broadly applicable. Nevertheless, species swimming traits and the different strategies to negotiate obstacles should always be considered [30,48,49]. Finally, configuration L150 S20, which displayed intermediate values of water velocity when compared to the other configurations tested, was the combination that recorded the best results for N and PE%, and registered also nearly 70% of AE%, a value that may be considered as a reasonable percentage for attraction.…”

Pool-Type Fishways: Two Different Morpho-Ecological Cyprinid Species Facing Plunging and Streaming Flows

“…s −1 ) – and of chub’s sister species the bordallo ( Squalius carolitertii (Doadrio, 1988)) [51] –0.54 m.s −1 (4.4 BL. s −1 ).…”

Passability of Potamodromous Species through a Fish Lift at a Large Hydropower Plant (Touvedo, Portugal)

“…It is our conviction that nase made larger use of the fish lift when the powerhouse was off (i.e., with turbines shutdown) due to the lower water velocities (0.21-0.55 m s −1 ) that occur at the lift entrances upon this scenario [44]. Though nase is a medium-sized cyprinid [63], for which adults can cope critical swimming speeds up to 0.78 m s −1 [64] and therefore theoretically being able to negotiate such a range of velocities, individuals found in both river segment downstream and lift were mainly juveniles, small-sized fish (mean: 13.0 cm TL), for which swimming performance is typically lower than larger conspecifics [65,66]. It is thus important to ensure that water velocities that nase will face within the entrances that lead to the lift are sufficiently attractive-not too low (<0.20 m s −1 ) to hinder attraction [29], nor too high, above their critical swimming speed (>0.78 m s −1 , [64])-for appropriate entrance and passage, particularly during summer and early fall when most of the individuals (74.7%) used the fish lift.…”

“…Though nase is a medium-sized cyprinid [63], for which adults can cope critical swimming speeds up to 0.78 m s −1 [64] and therefore theoretically being able to negotiate such a range of velocities, individuals found in both river segment downstream and lift were mainly juveniles, small-sized fish (mean: 13.0 cm TL), for which swimming performance is typically lower than larger conspecifics [65,66]. It is thus important to ensure that water velocities that nase will face within the entrances that lead to the lift are sufficiently attractive-not too low (<0.20 m s −1 ) to hinder attraction [29], nor too high, above their critical swimming speed (>0.78 m s −1 , [64])-for appropriate entrance and passage, particularly during summer and early fall when most of the individuals (74.7%) used the fish lift. It is tempting to suggest that managers should try to implement management strategies, such as periodic turbine shutdown [67], that best balance the trade-off between energy production and the potential for upstream fish migration [68], at least during the critical migratory periods.…”