Oysters can detect deep notes
Researchers establish the molluscs react to sounds, with implications for food supply.
If you care about the welfare of oysters, never take one to a heavy metal concert. That’s the strong implication of research published in the journal PLOS ONE.
A team led by Jean-charles Massabuau from University of Bordeaux in France decided to investigate whether oysters have a sense of hearing.
This might seem a strange interest, but it seems molluscs have been left behind when it comes to research on the hearing abilities of sea creatures. Massabuau and his team decided to remedy that – and for good reasons. Oyster farming is a significant global industry. The molluscs also play a key role in marine ecosystems. So the question of whether they are being affected by increasing levels of humanmade underwater noise pollution is important.
To find out how sensitive oysters are to sound, the scientists set up two groups of the molluscs in tanks fitted with speakers, which broadcast a range of singlefrequency tones at various volumes for three minutes at a time.
The effect on the oysters was measured by whether, and to what extent, they closed their shells when the sounds were played. The team found the animals were particularly sensitive to low-frequency tones, especially between 10 and 200 hertz, but did not react to higher ones.
In other words, an oyster would clam up at a Black Sabbath concert, where the decay of the kick drum would push out between 20 and 100 hertz, but would be unperturbed by Franz Liszt’s Liebesträume for solo harp.
The researchers suggest deep notes might be generated by the interaction of waves and rocks, triggering opening and closing behaviours in the oysters as tides rise and fall.
Unfortunately, they also include sounds emitted by cargo ships, underwater pile driving and wind turbines – raising the possibility that man-made noises might disturb the natural lifestyle of oysters and, ultimately, our diets.