Size matters, but species do not: no evidence for species-specific swimming performance in co-occurring Great Basin stream fishes

For fishes, swimming performance is an important predictor of habitat use
and a critical measure for the design of effective fish passage systems.
Few studies have examined burst and prolonged types of swimming
performance among several co-occurring species, and swimming performance
in many fish communities is undocumented. In this study, we characterize
both burst (c-start velocity) and prolonged speed (critical swim speed)
across a poorly documented, co-occurring group of stream fishes within the
Great Basin of the western USA. We documented the variation in swim speed
associated with species, habitat, and body size. Body size had an
overwhelming effect on both burst speed and prolonged speed, whereas
habitat use, and species identity were not significant predictors. Among
species, there is no evidence of a trade-off between burst swim speed and
prolonged swim speed. Lack of a trade-off in performance between burst
swim speed and prolonged swim speed among species may be due to
unexpectedly high prolonged swim speeds exhibited by species that used
substrate bracing behaviors. Incorporating body size and variation in
behavior, such as substrate bracing behaviors, into fish passage models
will likely be sufficient to ensure passage of all species without the
need to account for species-specific swimming abilities. However, these
results characterize the swimming performance for threatened and common
fish species such that other comparisons can be made and species-specific
studies can access accurate data.