LAUSR

The influence of urea and thiourea on the dynamics of the migration activity of climbing perch Anabas testudineus was studied. The exposure of climbing perch to 0.05% solutions of these substances leads to a modification of migration activity: the dynamics of movements in the water flow changes, and the frequency of jumping decreases. Urea and thiourea have a similar effect on the rheoreaction of the climbing perch: the proportion of fish which moving downstream were reduced. However, the effects of these compounds differ in the time of the beginning of the effect on migration activity: on the 2nd and 5th days of exposure, respectively. Both substances modify group behavior in climbing perch, reducing the number of fish movements in groups by 10%.