Researchers from MARE - Marine and Environmental Sciences Centre and from CE3C – Centre for Ecology, Evolution and Environmental Changes , both from the Faculty of Sciences , University of Lisbon (CIÊNCIAS ULisboa), have just published a study demonstrating that the flying gurnard (Dactylopterus volitans) emits sounds while simultaneously performing movements to communicate – a discovery that enriches our knowledge about the "symphony" of the ocean.
Since the 1970s, scientists had suspected that this species produced sounds, but only now has definitive confirmation and detailed characterization been achieved. The study shows that the flying gurnard produces two distinct types of short, repeated grunt-like sounds, that differ in duration, frequency and rhythm. These sounds were often accompanied by the opening of the species' large pectoral fins, which display blue‑spotted patterns. The researchers also found that juveniles under 10 cm in length already produce sounds — indicating that this ability is present from an early developmental stage.
Using action cams, the team was able to record individuals producing sounds while exhibiting a very characteristic visual behavior. The recordings were obtained as divers followed the fish, and the data was collected in Pasjača, in the Konavle region (Croatia; Adriatic Sea), as part of a monitoring programme of non-native species in Croatian waters.
This study, now published in the Journal of Zoology, one of the oldest and most influential scientific journals in the fields of biology and zoology, was conducted by specialists from the MARE / ARNET – Aquatic Research Network and from the CE3C, in close collaboration with researchers from the University of Zagreb, Institute of Oceanography and Fisheries of Croatia and the University of Venice.
The implications of this study go far beyond this particular species – they are essential for the understanding of how ecosystems work, explains researcher Manuel Vieira . "Many species possess their own "acoustic signature", that can reveal patterns of activity and ecological interactions. Sound can help us detect invasive species, monitor reproductive periods, map biodiversity and identify environmental changes that would otherwise go unnoticed."
The researchers highlight the importance of tools that make this type of observations possible: technologies such as action cams, and autonomous recorders, that are being used alongside artificial intelligence to study changes in diversity and the abundance of sounds over time. This approach is already enabling the monitoring of a recently detected invasive species in the Tagus estuary.
A vast underwater soundscape remains to be discovered, a true symphony, the researchers emphasize. Although cetaceans and whales are the aquatic animals with the most widely recognized sounds, in many places, it is fish and invertebrates that dominate the underwater acoustic landscape. Studying and analyzing their behavior provides a glimpse into a world still full of secrets.
"For a long time, the widespread perception was that the underwater environment was a silent space, almost devoid of sound. This idea, deeply rooted in popular culture, is far from reality.", explain Clara Amorim , researcher in the Faculty of Sciences and one of the study's co-authors. "In many places, the underwater environment is vibrant, complex and noisy – a true natural symphony. To share this diversity is to help bring people closer to the ocean, spark curiosity and foster a more conscious relationship with the marine environment."
Video: Action‑cam footage captures the colourful Flying Gurnard fish making sounds
