These data come from a total of 122 trials of juvenile green sturgeon rheotaxis (directionality in the face of perceived current). The trials were the basis for two experiments:
Comparing velocity present, optimotor belt absent (48 trials) with optimotor belt present, velocity not present (48 trials). Half the velocity trials took place under dark conditions (Treatment Dark, 24 trials), and half under light conditions (Treatment Light, 24 trials). For the optimotor belt trials, half took place with the optimotor belt placed above the tank (24 trials), and half took place with the optimotor belt positioned below the tank (24 trials).
For the second experiment, barbels were removed and velocity trials (Treatments Dark and Light) were repeated (26 trials).