Critical swimming speed at different temperatures for small-bodied freshwater native riverine fish species

Abstract

This study evaluated the effect of fish total length (LT) and three water temperatures (10, 15 and 20 ºC) on the critical swimming speed (Ucrit) of the species Percilia irwini (2.9 – 6.3 cm LT), Cheirodon galusdae (3.4 – 5.5 cm LT), and Trichomycterus areolatus (4.0 – 6.3 cm LT). An Ucrit estimation model was constructed for each species as a function of temperature and size. The results showed mean Ucrit for P. irwini of 44.56, 53.83 and 63.2 cm s-1 at 10, 15 and 20 ºC, respectively: 55.34, 61.74 and 70.05 cm s-1 for C. galusdae and 56.18, 63.01 and 71.09 cm s-1 for T. areolatus. Critical velocity depended on the interaction between species, body length and water. The swimming performance increased significantly with rising temperature in all three species. The velocity also increased with greater LT. After controlling for LT, velocity also increased with higher temperature in the three species. This research is relevant to small fish species that require conservation measures.