Mackerel Ball

Mackerel perform a natural defense mechanism called a bait ball. Giant schools of mackerel rush together and swim in a giant circle. The idea behind to move is to ward off predators with the massive size of the fish ball. Unfortunately for the mackerel, tuna and dolphins don't really care. The tuna and dolphins swarm on the mackerel and pick the ball apart. The ball is so huge that even birds swim down to grab a few bites.