Answer:
Aggregation is a mechanism developed by a group of fish called shoal that stay together for social functions. Schooling in shoal is an aggregation technique whereby shoaling fish swim together in a coordinated manner in the same direction. Defense against predators is one of the benefits derived from aggregation which increases the chance of survival of schooling fish. This helps in detecting predators and in reducing the chance of individual capture.
For example, schooling fish that are of the same size and silvery in appearance, through aggregation, would make it difficult for a predator that is visually oriented to pick an individual out of the group as a result of “confusion effect” created by the schooling fish.
Aggregation in schooling fish also helps the group to easily scan for predators around as there are bound to be “many eyes” on the look out for predators. This helps in reducing the chance of predatory attack on the group and increasing the chance of survival of schooling fish.
The larger the number of the schooling fish in aggregation, the higher the chance of survival against predators.
