With the kids back in school after an extra long holiday break, I go to thinking about fish and their schooling.
No, I don’t mean that kind of schooling. I’m talking about the kind of school that involves travelling in numbers. Here in the north Atlantic, many fish that are found on Turner’s menu travel in schools, including yellow fin tuna and north Atlantic cod:
Fish form schools for many reasons. The first and most obvious reason is for protection. For any animal- especially small ones- traveling in a pack dissuades potential predators. Furthermore, when attacked, travelling in a school makes it easier to fluster or evade predators and makes it more difficult for the hunter to target a specific individual. Aside from protection purposes, travelling in a school also provides several other benefits. Increased success with foraging and finding food, increased probability of finding a mate, and increased hydrodynamic efficiency are also added benefits to travelling in a school.
Whether at an aquarium , in the open ocean, or on TV, if you’ve ever had the pleasure of observing the grace and fluidity of a moving school of fish you may have wondered- like I did- how do they all know which way to turn??? Like a complicated dance, it seems as if each fish is pre-programmed with a track or somehow communicating telepathically with all its travelling partners in the school. For a better idea of this pattern, check out this blog post from the New England Aquarium’s schooling exhibit.
As it turns out, fish that travel in schools are equipped with special modified epithelial (surface) cells that are found in small canals on the skin. These cells run in a lateral line down the sides of the fish’s body and are called “neuromasts.” They allow each individual fish in a school to sense even the slightest changes in water and wave pressure. In this way, fish are able to sense the movements of their peers and move with incredible speed and accuracy.
So, next time you are able to observe a school of fish in action, be sure to reflect on this incredible biological trait and appreciate how these specialized cells allow for one of the most majestic and incredible dances in nature.