The ocean is loud place. Many sounds are a result of human activity, but marine life can be just as noisy, and researchers just discovered a new voice. A study published earlier this month is the first to document that fish larvae make sounds.
Just a few months ago, we learned that baby sea turtles make noises and communicate with each other while still inside their eggs. This communication is most likely to coordinate hatching times because travelling in large groups is always safer — the more hatchlings that cross the beach at one, the better chance they have of making it and not being picked off by predators.
The same motivation appears to be a factor for larval fish. They make “knock” and “growl” sounds that researchers from the University of Miami Rosenstiel School of Marine and Atmospheric Science (RSMAS) believe help small larvae “maintain group cohesion in the dark.”
“Although many adult fishes produce sounds, no one has previously considered that larvae, too, may be sound producers,” Claire Paris, RSMAS associate professor of ocean sciences explained in a news release. “This is a true discovery as it reveals the existence of a communication system for young fish larvae.”
RSMAS researchers completed experiments in the lab and in the field to listen to larval gray snapper (Lutjanus griseus), which settle in shallow seagrass beds after spending their first 30 days of life as pelagic larva. Experiments in the field were conducted during the day and at night, revealing that the fish larvae made sounds only at night. The team also found that they produced “knocks” and “growls” in the range of 200-800 Hz, which is within the hearing range of most adult fish.
“The study was setup to record ambient sounds around the drifting arena that might guide the fish larval orientation. It was a fantastic surprise to listen to the recording and hear that the larva itself was emitting sound,” Paris said. “Communication between larvae could allow them to maintain group cohesion, which is critically important for faster swimming, finding navigational signals and settlement cues, and better survival during the pelagic phase.”
These findings highlight the need to understand the impact that anthropogenic noise in the ocean will have on these newly-discovered communication systems.
To learn more:
- Read the full news release: New Study First to Document the Voices of Fish Larvae.
- Read the abstract: First evidence of fish larvae producing sounds.
- Check out this related article from Discovery News: Ghostly Sounds at Night Are Often Made by Fish.
Copyright © 2014 by Marine Science Today, a publication of Marine Science Today LLC.