Fast Repetitive Tick (FRT) is the name scientists have given to the high-pitched buzzing sound coming out of a herring's anus. Herring, an oily fish found in the waters of the Atlantic and Pacific Oceans, travel in large schools. Scientists think that herring make the sound to communicate at night. Because most fish can't pick up the high frequency, herring can communicate their location to one another without alerting many of their predators. The exceptions are whales and dolphins. These keen-hearing mammals pick up the herring's FRTs and use the signals to hunt the fish.
Breaking Wind Underwater
Scientists believe that herring are the only fish who communicate this way. Some fish make sounds through their swim bladder; a sac located in the abdomen of certain fish. The sac keeps them from sinking. At first, scientists thought that herring used their sac to make sounds. Then researchers noticed that a stream bubbles from the anal duct appeared at the same time as the noise.
How Noise Pollution Harm Marine Animals?
With so many noisy ships' engines in the oceans, noise pollution is a serious problem for many marine mammals. Killer whales that feed almost entirely on herring might not be able to hear herring's FRTs and won't be able to hunt them as well. And noise pollution might harm the herring's ability to hear and communicate with each other.