Swim Speed Equations


Various authors studying a variety of fish have developed swim speed equations that relate swimming speed to fish length, or swimming speed to fish length and time to exhaustion. More recent investigations have included additional variables in their equations such as temperature or interaction terms between temperature and length and length and velocity (Peake et al. 2000). The most frequently used swim speed equations in FishXing were developed by Hunter and Mayor (1986).  These authors compiled results from previously preformed swim speed test to produce a set of regression equations relating swim speed to fish length and time to exhaustion.

Hunter and Mayor (1998) Swim Speed Equation

The general form of the this swim speed equation is,


V = swim speed of fish relative to the water

L = length of the fish

t = time to exhaustion

a,b,c = regression constants


These equations can be selected from the Literature Swim Speed Table within FishXing.  When a swim speed equation is selected, the time to exhaustion is either the time reported in the research study from which the data were derived; or if no time was reported in the study, then the default time to exhaustion is arbitrarily set at 10 seconds for burst speeds and 30 minutes for prolonged speeds.

The swim speed equations utilize the length entered into the Fish Length field on the Literature Swim Speeds tab of the FishXing input window.  Avoid extrapolating by making sure the entered fish length falls within the range of reported lengths used to develop the equation.  If the length you entered is outside the appropriate range, a warning will appear “Out of length range” on the Literature Swim Speeds tab.