Breaking new ground in marine biology, a team of scientists at Scotland's Association for Marine Science (SAMS) has uncovered an extraordinary method of communication used by herring. By night, these fish emit distinctive 'rasping noises' accompanied by tiny air bubbles released from their bodies – colloquially known as 'farting'. This phenomenon was observed in real-time using infrared cameras and underwater microphones.
Dr Bob Batty, a key researcher based at the Dunstaffnage marine centre near Oban, led this project alongside Canadian collaborators Ben Wilson and Larry Dill. Initially aiming to investigate whether herring can detect predator sounds, they stumbled upon this unusual behaviour while monitoring the fish round-the-clock. The team's findings suggest that individual fish release more bubbles when in larger groups, indicating a possible social aspect to 'farting'.
Gas chromatography analysis confirmed that these air bubbles are not actual flatulence, but rather air gulped down by the herring at the surface. Dr Batty believes this behaviour serves as an essential means of communication for herring and related species like anchovies and sprats when visual cues are unavailable – typically at night.
While herrings are known to release large quantities of air bubbles during attacks, the low-level 'farting' observed by Dr Batty's team appears distinct. This research, published in the peer-reviewed journal Proceedings of the Royal Society of London, has been recognised with an Ig Nobel award for improbable biology – celebrated for sparking both laughter and thought.
Marine biologists are taking note of this breakthrough discovery. The air in a herring's swim bladder is crucial for sonar surveys used to assess fish numbers and sizes. As Dr Batty highlights, understanding when and how much air is released will significantly improve the accuracy of population assessments – an essential tool for effective marine conservation.