Alternatively, steady flows can perturb a fish without substantially changing its kinematic by displacing the location of the body relative to the environment. In this example, the body of a swimming fish will drift downstream relative to the earth frame of reference if its forward velocity is less than the current it is swimming against. Finally, unsteady flows can change both the kinematic and the absolute position of the fish, as when lateral body amplitude and body wavelength increase when vortice buffet fish in turbulent conditions. Thus, it is important to recognize that a fish can be described as perturbed if displaced in three-dimensional space either with or without a change in kinematic.