Vertical migration in zooplankton helps them avoid predators. Field data and lab experiments show that prey move up and down in the water to avoid being eaten by visually dependent predators. This behavior is seen in lakes like Gatun Lake in Panama and Fuller Pond in Connecticut. The prey populations change their vertical position to reduce the risk of being eaten by the dominant planktivores in the lake. This shows that zooplankton adapt their movement patterns to survive in environments where they are under pressure from predators.