Linking the Swimming Ability of Small Freshwater Fish To Body Form and Ecological Habit

Abstract

Swimming ability tests can inform physiological, biological and ecological studies, but there are few such data available for Australian freshwater fish. Here, an incremental velocity test was used to assess the swimming ability of three common species, namely Australian smelt, common galaxias and flat-headed gudgeon. Body form is one indicator of swimming ability (the more streamlined a fish, the stronger the swimmer), and ecological habit (behaviour) is another. Although the common galaxias and Australian smelt swam more strongly than the flat-headed gudgeon, the latter’s ability to exploit patches of slower velocity partially explains why these species may co-habit in river reaches. Swimming ability data can be used to inform ecological knowledge and management decisions, but the limitations of the data should be considered for purposes such as habitat modelling.