Herring fish signal each other by what scientists call FRTs. Believe it or not, this stands for Fast Repetitive Tick Sounds. But only recently have they found out what else FRTs mean.
It’s been known for quite some time that these fish make unusual sounds, but it wasn’t until these scientists captured wild herring and observed them in captivity that they realized these fish produce the sounds by expelling air through their anuses. Herring are more likely to make these “Fast Repetitive Tick Sounds” (abbreviated FRTs… we assume the pun is intended) when other fish are present, suggesting that FRTs are used for social communication. Now if only I could use my farts for communicating anything else besides “Retreat!”
There are more details on the science of herring farts at Discover. -via Not Exactly Rocket Science