A comparison of swimming capacity and energy use in seven European freshwater fish species

Abstract

Abstract – Migrating fish species with different swimming capacities and energy use show different capacities for passing obstacles between habitats, such as culverts and fish ladders. Here, we present an integrated study on swimming capacity and energetic use in seven European freshwater fish species with different ranges of migration (brown trout Salmo trutta L., European perch Perca fluviatilis L., roach Rutilus rutilus L., common carp Cyprinus carpio L., gudgeon Gobio gobio L., bullhead Cottus gobio L. and stone loach Barbatula barbatula L.). Critical ( U crit ), optimal ( U opt ) and maximum ( U max ) swimming speed and oxygen consumption ( M O 2 ) were analysed and showed values correlated to migration capacity with highest swimming capacities in trout and roach and lowest in stone loach and bullhead. The resulting data can be used to make estimates of maximum passable water speeds in culverts. In conclusion, long‐distance migrators show higher swimming capacities and can potentially clear obstacles easier than short distance migrators with lower swimming capacities. Even small obstacles (<25 cm) could be a barrier for genetic exchange between populations in short‐distance migrators.