A Brandt's cormorant hunts for a meal in a school of Pacific mackerel beneath an oil rig off the coast of Los Angeles, California, USA

© Alex Mustard/Minden Picture

A seabird gets ‘schooled’

This deep-diving Brandt’s cormorant appears to be on the hunt for a meal, and there’s plenty of Pacific mackerel to choose from here off the coast of Los Angeles, California in the United States. While seabirds like the cormorant are a threat to these fish, the mackerel aren't exactly defenseless. Fish have many unique means of defence, such as travelling in dense schools like this one. It's a technique that not only allows for speedy travel (because it reduces friction on most of the fish in the school)–schooling also makes it more difficult for predators to pick out an individual victim. For these fish, there's safety in numbers. But when all else fails, they can take some advice from Dory in 'Finding Nemo'—'Just keep swimming, just keep swimming.'