The Experimental Study and Computer Simulation of Fish Behavior in the Uniform Environment

We have studied experimentally the carp exploratory behavior in the circular corridor under uniform illumination and in the absence of external landmarks. The behavior was not uniform despite the uniformity of environment The alternation of two modes of behavior, search (accompanied by high turn frequency) and ranging (with few or no turns), was observed. The existence of distinct modes manifested itself in the positive correlation between turn frequencies at successive time intervals, as well as in abrupt switching between high and low turn frequencies. We developed a model based on the one-dimension map: X
n
= λ
n
X
n−1
(1X
n−1
), where X is the tendency to turn, and parameter λ is influenced by Gaussian white noise caused by spontaneous nervous activity. There was a correlation between successive values of the tendency, as well as switches from series of low values to series of high ones under influence of the noise. The behavior of the model is the case of noise-induced phase transitions and matches experimental data qualitatively. It is concluded that a noise generated by the nervous system can play a role in the shaping of animal behavior.