Ecologists Use New Underwater Tool to Identify Fish Sounds

Underwater coral reefs are filled with thumps, pops, and snaps from shrimp and fish. Ecologists often use underwater microphones to monitor the health of marine environments, but have largely been unable to interpret these sounds due to the diversity of species present.

A new tool from the FishEye Collaborative combines underwater sound recordings with a camera equipped with a 360 view to pinpoint the sounds made by individual fish. This collaboration between bioacoustic researchers at the Cornell Lab of Ornithology and Aalto University has already identified 46 fish species from the coral reefs of Curacao in the Caribbean, with more than half of these species previously unknown to make sound.

The findings were published in the journal Methods in Ecology and Evolution. Lead author Marc Dantzker explains that the diversity of fish sounds on a coral reef rivals that of birds in a rainforest, with an estimated 700 fish species producing sounds in the Caribbean alone.

The new Omnidirectional Underwater Passive Acoustic Camera, known as UPAC-360, visualizes sound data and overlays it on a 360-degree image to reveal which sound came from which fish. The most extensive collection of fish sounds ever published is now available at fisheyecollaborative.org/library.

Identified sounds can be used to train machine learning systems to automatically detect fish species in underwater recordings, similar to the Cornell Lab of Ornithology's Merlin Bird ID app. The UPAC-360 can be deployed in reefs to collect data without requiring a diver or boat, allowing for continuous monitoring.

Researchers are expanding their efforts globally, with plans to study other reefs, including those in Hawaii and Indonesia. This innovative acoustic monitoring technology aims to enhance ocean conservation, allowing scientists to decode reef soundscapes and use them as indicators of reef health.