Fish like the Atlantic cod above produce a surprising variety of noises that scientists are only just beginning to explore. With the dawn of a new online database, now you can too. Featured image source: Joachim S. Müller, license: CC BY-NC-SA 4.0, source: iNaturalist
Reference: Looby, A., Cox, K., Bravo, S. et al. A quantitative inventory of global soniferous fish diversity. Rev Fish Biol Fisheries 32, 581–595 (2022). https://doi.org/10.1007/s11160-022-09702-1
FishSounds database: Looby A, Riera A, Vela S, Cox K, Bravo S, Rountree R, Juanes F, Reynolds LK, Martin CW (2022) FishSounds. http://www.fishsounds.net, version 1.1. Accessed on June 7, 2022.
What sound does a fish make? The question sounds like a Zen koan, and like a koan, the answers come with many questions of their own. Nearly a thousand fish species are “soniferous,” or sound-producing, and they are found all over the globe. Soniferous fish exist in 133 taxonomic families worldwide, from the haddock of the polar seas to the barbel found in freshwater African lakes.
These fish produce sounds for many known reasons, such as territorial defense, finding a mate, and feeding, but the science of soniferous fish has many knowledge gaps. Little is known about why fish make noise, how they do it, and which species are capable of making– and comprehending– sound. However, a recent review paper and database on fish sounds aim to shed light on an under-explored field.
Come, lend an ear.
Diving into FishSounds
While it is unclear when humans first discovered that fish could be soniferous, the first scientific description of such fish was published in 1874. Between then and now there have been many studies describing the sounds specific species make, but few efforts have been made to synthesize this knowledge. The idea of creating a catalog of fish sounds has been around since at least 1970, when the prophetically-named Marie Fish and her colleague William Mowbray created a reference file for fish noises of the western North Atlantic.
However, there are numerous difficulties involved in creating a useful and centralized hub of fish sounds. For one, sound recordings are very difficult to get. Microphones have challenges picking up noises made by smaller fish, and even a clear soundbite can be difficult to pinpoint to a specific fish in the area. Past descriptions have relied heavily on qualitative descriptions of the sounds, which can be subjective. How confident are you, for example, that you could differentiate an alewife’s “mouthbubble,” “cough,” and “snitch” sounds?
Furthermore, it is often hard to tell how a given fish makes an observed sound. Noises are grouped by “active” and “passive” sounds, with the difference being whether the noise was actively generated by an internal organ or if it is the result of some other action, like the swat of a tail or the crunching of a shell. It can be impossible to detect how certain fish make the noises they do even after hours of careful study.
Despite these difficulties, scientists recently established FishSounds, the most comprehensive synthesis of fish sounds to date. Researchers parsed almost 3,000 publications for descriptions of soniferous fish, then built a database including the fish distribution, sound recordings, qualitative descriptions of the sounds, and more. As a result, it is now possible to get data on the distribution, habitats, and taxonomy of soniferous fish from a central location for the first time.
We now know, for example, that sound-producing fish are found in every region of the world and live in everything from saltwater reefs to inland lakes to brackish estuaries. The only location no soniferous fish have been found in is Antarctica, but that is almost certainly due to the simple fact that few humans go there and even fewer to listen to the fish.
A tree falls in the woods, a fish makes a grunt-thump
While FishSounds represents a monumental effort in synthesizing current scientific knowledge on scientific fish, its creators stress that there is much more work to be done. 96% of fish species have not been studied to see if they produce sounds, and some species that have been explored have conflicting entries. Apart from advancing our collective understanding of our oceans, rivers, and lakes, scientific explorations of soniferous fish can yield practical applications. Acoustic monitoring can be used to locate and quantify spawning events, detect invasive species, and even evaluate the reproductive states of fisheries.
There is a whole world of sound yet to uncover, and the increasing impact of humanity on aquatic systems may mean time is running out for some species. Habitat degradation, anthropogenic activity, and climate change all affect the ability of fish to produce and detect sound, which can make it harder to survive and reproduce. Just as the Lorax took on the job of speaking for the trees, we may also consider another task: listening to the fish.