Locomotor Activity of the Intact and Visually Deprived Senegal Bichir Polypterus senegalus (Cladistia) at Different Water Temperatures

Abstract

For the first time, the locomotor activity of the intact and visually deprived Senegal bichir Polypterus senegalus was assessed at different water temperatures (20, 25, 30 and 34°C). Using the open field test, it was shown that in intact fish, with increasing temperature, locomotor activity increases (most rapidly in the range of 20–25°C) and reaches a maximum at a temperature of 30°C, which can be close to the temperature optimum (or correspond to it) for the Senegal bichir. In visually deprived fish, locomotor activity is maximum at 20°C and decreases monotonically with increasing temperature; all indicators of locomotor activity (frequency of crossing test lines; time spent crossing the test line; distance covered by the fish; swimming speed) vary in visually deprived fish weaker than in intact ones. The differences in the behavior of intact and visually deprived fish indicate the presence of a functional relationship between vision and locomotor activity in evolutionarily ancient Cladistia.