Carbon Dioxide Makes Tropical Fish Sociophobic

07.07.2014

According to a new research, made by australian biologists from James Cook University, fish may no longer recognize each other. The reason is the increase of carbon dioxide level in the atmosphere, caused by human impact. Fish are indeed socially dependent creatures. They are able to recognise other fish and even maintain some kind of relationship inside the group. These skills are needed, for example, for finding a partner or for a collective defence from predators.

Carbon Dioxide Makes Tropical Fish SociophobicTo understand the influence of CO2 on fish, a team of biologists made a curious experiment. One group of grown fry was put into the aquarium with normal ocean water, and water for another group was specially oversaturated with carbon dioxide. Period of social relationship for fish is about 3 weeks long. After this time fish from the first reservoir indeed began to show group behaviour, as they got accustomed to the aquarium neighbours and recognized each other. But such behaviour was not showed by the inhabitants of another reservoir, where the fish not only rested strangers to each other, but didn't show any interest in their neighbours.

Thus, the scientists concluded that amount of carbon dioxide affects the brain receptors, reducing the sight and smell needed for recognizing each other. Why is it so terrible – the fish themselves don't have an outstanding intellect and memory? However, if the fish have no ability to recongize their fellows, it will become more vulnerable for predators. And this can conciquently influence not only the population who live near Australian shores, but as well another fish species, including commercial ones.