Piranhas are known for their sharp teeth and carnivorous appetites, but few think about the sounds they make. These small fish “bark” by contracting their gas bladders to produce a noise. A new study reveals that these barking sounds differ based on species and offer a way for researchers to identify the fish even in dark waters.
An upcoming talk at the Acoustical Society of America will shed light on these barking sounds and how they may help researchers for identification purposes. Past research on piranhas in laboratories have noted these “barking” sounds made by these fish, but the upcoming talk will look at sounds made by fish in the wild.
The talk will be held by Rodney Rountree, according to EurekAlert, during which time he’ll talk about working with the University of Victoria’s Francis Juanes on documenting fish calls. The sounds, when coupled with passive acoustic monitoring, may prove useful for tracking piranha populations in places where cameras aren’t an option.
During his work, Rountree documented fish calls using a hydrophone, “auditioning” more than 550 fish across 70 or more species. Of those, four were piranhas, which can be distinguished from each other via sound using statistical analysis. Unlike some other surveying methods, such as capturing the fish, this method would be non-invasive.
The technology may usher in a new way of monitoring fish species and populations in waters that are too dark for cameras. Hydrophones could be, for example, attached to the bottom of boats that are parked in place, allowing researchers to gather recording of sites for later analysis.