An international team of scientists have set out a detailed proposal to archive what they call the “underwater orchestra” of sea creatures’ sounds, with recordings provided both by research scientists and helpful volunteers. Such an audio library could help save endangered species, advance scientific knowledge, and possibly even reveal creatures whose existence is currently unknown.

“We’re not the first to propose this idea,” Dr Miles Parsons of the Australian Institute of Marine Science told IFLScience. However, thinking on the topic has been developing and Parsons is first author on a paper in Frontiers in Ecology and Evolution providing a much more detailed vision of how such an archive would work, and what it could be used for.

Sound can be a great way to communicate underwater, either over long distances, as whales famously do, or where visibility is limited. It is thought all of the 126 known marine mammal species use sound like this, even if some of them are outside our range of hearing. Reef fish produce an array of distinctive clicks. Penguins make quick, high-pitched sounds underwater while hunting. Marine biologists are also aware of at least a hundred sound-making invertebrates, such as snapping shrimps, but these are almost certainly the tip of a vast iceberg.

_{Minke whales are a whole different sound from humpbacks. Credit: Erbe et al/Acoustics Australia}

It is often much easier to identify an animal’s presence acoustically than visually. Parsons told IFLScience he has spent a lot of time playing “what’s that sound”, passing around underwater recordings with other fish experts in the hope of working out the species present at a particular location.

This would work much better, their paper argues, if instead of hundreds of sound libraries based at individual research institutions there was a global platform everyone could tap into. Sound-recognitions software could search abundant files to find a match for currently mysterious recordings.

Parsons points out we must start soon to get a picture of marine ecosystems in something close to a pristine state. “With biodiversity in decline worldwide and humans relentlessly altering underwater soundscapes, there is a need to document, quantify, and understand the sources of underwater animal sounds before they potentially disappear,” Parsons’s said in a statement. Creating an acoustic baseline could also help document changes to habitat as species move to cooler waters.

_{Pretty funky-sounding paddle crab. Credit: Erbe et al/Acoustics Australia}

The proposers believe the archive can be:

• A reference library of known and unknown biological sound sources
• A data repository portal for annotated and unannotated audio recordings of single sources and of soundscapes
• A training platform for artificial intelligence algorithms for signal detection and classification
• An interface for developing species distribution maps, based on sound
• A citizen science-based application so people who love the ocean can participate in this project

The authors hope the very existence of such a resource would encourage the taking of more recordings.

The archive could help scientists to identify particularly biologically rich areas that should be priorities for protection. It could also be useful for comparisons individual researchers might miss. The authors give the example of the skunk anemonefish, which makes fight sounds to scare off rivals. However, these are very different in Madagascar and Indonesia. 

Whales are also known to use local dialects and new populations have even been discovered due to their unique songs. Familiarity with this diversity could assist recognition in new locations.

_{We might not expect sea urchins, most familiar to us as lifeless shells, to make sounds at all, but they do. Credit: Erbe et al/Acoustics Australia}

Identification of sounds scientists do not recognize could inspire global searches, perhaps uncovering species that have not been scientifically described.

Parsons told IFLScience one of the goals is to increase public awareness of the richness of the oceans, and the dangers they face. “When CDs of humpback whales first came out in the 1970s they had a big impact,” he said, helping encourage the ending of commercial whaling. He hopes access to underwater soundscapes will “Increase wonder” and inspire action.

Parsons acknowledged to IFLScience questions remain about how the archive would operate and who would curate it. With technology facilitating more recordings and ease of sharing, and funding agencies increasingly aware of the value of such a project, Parsons thinks now is the time to work out the details.