Fish morphology and passage through velocity barriers. Experience with northern straight-mouth nase (Pseudochondrostoma duriense Coelho, 1985) in an open channel flume

Abstract

Knowing the relationship between size, morphological traits and swimming performance of fish is essential to understand the swimming capacity to successfully surpass these obstacles and the selective pressure that barriers in rivers and streams could exert on fish. Northern straight-mouth nase, an endemic potamodromous cyprinid fish species from the Northwest of the Iberian Peninsula, was selected to carry out volitionally swimming performance experiments in an open channel against three different flow velocities, using telemetry and video cameras. The use of thin-plate spline, on 10 landmarks, evidenced unknown patterns linked to velocity barriers. At lower flow velocity, size is the main factor explaining the swimming performance; thus, large individuals swim up more efficiently. In contrast, at high flow velocities, shape becomes the essential explanatory variable; thereby, streamlined body shapes with a higher relative position of the tail and a narrower caudal peduncle are more efficient. The obtained results show the existence of a relationship between fish morphology and swimming performance, with potential consequences due to selection pressures associated with velocity barriers and their implications on behavioural and dispersal processes. To sum up, velocity barriers could exert a selection pressure on nase populations, so the fishway design and removal should be (re)considered.

Effect of thermo‐velocity barriers on fish: influence of water temperature, flow velocity and body size on the volitional swimming capacity of northern straight‐mouth nase (Pseudochondrostoma duriense)

“…Swimming performance is affected by behavioural processes, and fish are expected to be much more motivated to pass velocity barriers during the reproductive season, when, in the case of cyprinids, the temperature increases (García-Vega et al, 2022), or falls in the case of salmonids (Goerig et al, 2017). Moreover, differences in the swimming ability of fish are expected in other reaches and habitats, directly related to their morphology or their genetic origin (Alexandre et al, 2014;Sánchez et al, 2022), which must be considered. Therefore, despite the fact that thermal response of swim speed could be somehow predictable, the ecological, physiological and phylogenetic factors that underlie the relationship remain unclear.…”

“…More specifically, Wardle (1978) found that after an 8 h rest, the 50%-80% of the muscle glycogen is restored. In particular, swimming experiments in fishways with confined and reused fish showed no variations in the swimming performance after 12 h resting (Bravo-C ordoba et al, 2018;Sanz-Ronda et al, 2019). Therefore, the 12 h recovery period among consecutive tests should be sufficient for the fish to restore the muscle glycogen and metabolize most part of lactate.…”

Fish Upstream Passage through Gauging Stations: Experiences with Iberian Barbel in Flat-V Weirs

“…Simulations showed that a high initial velocity or a low downstream water level (e.g., due to scouring or other river geomorphological features) will provoke greater magnitudes of velocities in the downstream face and immediately after it, surpassing fish swimming capability even for the observed passable discharge ranges. Moreover, differences in the swimming ability of fish are expected in other reaches and habitats, directly related to their sizes [16], their morphology [17], or their genetic origin [52], which must be considered.…”

“…This enlarges the area with high velocities and low depths (hydraulic barrier) below the weir [11], further reducing, the fish passage probability. Furthermore, weirs can act as selective barriers since the swimming and leaping ability of fish is directly related to fish size and morphology, which may have further implications on the behavioral and dispersal processes of fish populations [16,17]. Habitat fragmentation caused by river barriers is among the main causes of the global decline in freshwater biodiversity [18].…”

Preface: Insights and advances in Iberian ichthyology

“…Some notable results of the VIII Iberian Congress of Ichthyology are presented in this Themed Section with two guest editors, Javier Sánchez-Hernández and Rufino Vieira-Lanero, who managed the peer review process. This Themed Section covers various aspects of marine and freshwater fish biology that were presented at this congress such as fish migration (García-Vega et al, 2021), conservation status (Miqueleiz et al, 2021), swimming performance (Sánchez-González et al, 2021) and population structure (Schroeder et al, 2021). It should be noted that this Themed section presents papers of the meeting, and that although most papers covered the Iberian Peninsula (García-Vega et al, 2021;Miqueleiz et al, 2021;Sánchez-González et al, 2021), there is one focused on Brazilian fishery grounds (Schroeder et al, 2021).…”