The vertical migration of <em>Daphnia sp.</em> is their characteristic behaviour.
These organisms migrate to the surface of the water body during night and remain at the bottom during the day.
Behaviorists believe that <em>Daphnia sp. </em>does this to avoid predation.
During the day, it remains at the bottom that lacks light and avoids being noticed by the fishes. But at night when the day light is absent it swims up to feed upon the algae present in the clear surface water.
Thus we can conclude <em>Daphnia</em> population is responding to the clarity of water.
