Key factors explaining critical swimming speed in freshwater fish: a review and statistical analysis for Iberian species

Abstract

Swimming performance is a key feature that mediates fitness and survival in aquatic animals. Dispersal, habitat selection, predator–prey interactions and reproduction are processes that depend on swimming capabilities. Testing the critical swimming speed (Ucrit) of fish is the most straightforward method to assess their prolonged swimming performance. We analysed the contribution of several predictor variables (total body length, experimental water temperature, time step interval between velocity increments, species identity, taxonomic affiliation, native status, body shape and form factor) in explaining the variation of Ucrit, using linear models and random forests. We compiled in total 204 studies testing Ucrit of 35 inland fishes of the Iberian Peninsula, including 17 alien species that are non-native to that region. We found that body length is largely the most important predictor of Ucrit out of the eight tested variables, followed by family, time step interval and species identity. By contrast, form factor, temperature, body shape and native status were less important. Results showed a generally positive relationship between Ucrit and total body length, but regression slopes varied markedly among families and species. By contrast, linear models did not show significant differences between native and alien species. In conclusion, the present study provides a first comprehensive database of Ucrit in Iberian freshwater fish, which can be thus of considerable interest for habitat management and restoration plans. The resulting data represents a sound foundation to assess fish responses to hydrological alteration (e.g. water flow tolerance and dispersal capacities), or to categorize their habitat preferences.

Individual differences in dominance-related traits drive dispersal and settlement in hatchery-reared juvenile brown trout

“…In contrast, deep-bodied shapes associated with burst swimming are more likely to play a role in prey-predator and competitive interactions 45 . Robust shapes with a bigger dorsoventral musculature are linked to explosive swimming 40 , 46 , which is essential in aggressive movements and can promote social dominance in a context of social interactions. In our study system, where dispersal occurs over a small spatial scale and mainly downstream, the continuum robust/elongated shape factor should not be determinant of dispersal distances per se (via swimming performance), and the relation between shape and dominance seems the most plausible explanation for the observed linkage between shape and distance 14 , 19 .…”

Acclimation effect on fish behavioural characteristics: determination of appropriate acclimation period for different species

“…In other words, rheophilic fish will naturally choose the optimal conditions for them, i.e ., those that best meet their body composition and physiological needs. In addition, when assessing fish responses to hydrological alterations ( e.g ., water flow tolerance and dispersal capacities), or categorizing their habitat preferences, such key factors as critical swimming speed, body length and shape factors should be considered (Cano‐Barbacil et al ., 2020). Therefore, when transferred to a new environment, especially the one with a limited swimming area and static water conditions, salmonids may experience greater stress than eurytopic P. fluviatilis and G. aculeatus , which are adapted to living in more various habitats.…”

“…In other words, rheophilic fish will naturally choose the optimal conditions for them, i.e., those that best meet their body composition and physiological needs. In addition, when assessing fish responses to hydrological alterations (e.g., water flow tolerance and dispersal capacities), or categorizing their habitat preferences, such key factors as critical swimming speed, body length and shape factors should be considered (Cano-Barbacil et al, 2020).…”

Swimming Performance of Four Carps on the Yangtze River for Fish Passage Design

“…Critical swimming speed is an important indicator of aerobic exercise; it represents the maximum sustained swimming ability of fish, while burst swimming speed is an evaluation indicator of anaerobic swimming ability of fish [9]. Thus, the relationship between the critical swimming speed and burst swimming speed is aerobic exercise and anaerobic exercise.…”

“…Juvenile carps usually migrate by utilizing their swimming ability [6]. Therefore, testing juvenile carps' swimming performance can provide data for establishing fish passage and ecological habitat, and can be used in fisheries management and ecophysiological studies [7][8][9][10].…”