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A lot can happen in 12 seconds—a car can be stolen, a mammal can poop, a person can free-fall 700 meters, and, as it turns out, a longfin squid can get used to the sound of a pile driver.
When first subjected to the loud hammering of a pile driver—a ram that drives supports into the seabed for construction projects—squid predictably freak out: squirting jets of ink, changing color, swimming away. But give them 12 seconds and they’ll settle down. This adaptability, described in a new study, could be a bad thing. “It may decrease their vigilance to actual threats,” says Ian Jones, a doctoral candidate in marine biology at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution. To find this out, Jones played recorded pile-driving sounds to 16 different squid in a tank, then repeated the experiment 24 hours later to see if the squid were used to the noise. (They weren’t: they flipped out again, then acclimated just as quickly.)
Playing pile-driving sounds to a squid may seem silly, but it’s serious science. For marine life, underwater noise from ships, cities, and sonar can range from distracting to deadly. To date, most research on noise pollution has been on mammals or fish, but Jones wanted to look closer at cephalopods because big changes are afoot on the east coast of the United States. The US Bureau of Ocean Energy Management has proposed 28 offshore wind farms for development along the coast and many of the sites overlap the range of longfin squid, a US $26-million-per-year fishery.
Unlike whales, it’s not clear how important sound is to squid and other cephalopods such as octopuses. “We know that squid and cephalopods detect sound,” Jones says, “but exactly why is still a mystery.”
Michel André, a bioacoustician at the Polytechnic University of Catalonia in Spain, says it’s only in the past decade that scientists have learned that noise pollution can really mess with cephalopods. They don’t make sounds or have ears, but they have an organ called a statocyst that helps them balance, the same function as a human’s inner ear. The statocyst also detects vibrations from noise.
André says statocysts can be damaged and scarred by loud noises underwater. So even if a cephalopod isn’t hearing, “they must feel that they’re not okay,” André says. “It’s physiological.”
Jones’s squid seemed okay with pile driving after their initial panic, but that’s a problem if it makes them lax around predators. That’s what Jones wants to test next. After all, imagine your neighbor starts blasting AC/DC loud enough to shake the floors. Twelve seconds later, you might go back to what you were doing but be too distracted to notice someone creeping in through the window.