The military is using underwater microphones and software to decipher alert sounds from sea life, like shrimp and grouper fish. By doing so, they hope to detect threats like enemy submarines. In effect, it’s like “an ecosystem of permanently floating dispersed living sensors,” says one UK specialist in naval warfare. Unlike artificial devices like sonar buoys, detection would rely on constantly present reef-dwelling species to serve as passive “sentinels.”
Since at least 2002, it’s been known that US military sonar can kill whales. Sadly, the whales died after beachings and experienced “bleeding ears.”
As an alternative, the military researchers suggest tuning in to natural sounds, reports the BBC. Although the primary purpose is detecting threats, the potential benefit to sea life could be significant. Besides tracking underwater vehicles, tracking animal communication could help scientists try to track the damage people cause to the oceans.
“Tuning in to the sounds made by normal marine life would give researchers a low-cost, environmentally friendly way of tracking the impact of human activities underwater,” says Darpa’s Lori Adornato.
“These low-impact, observational systems can be deployed to many different environments without disrupting the ecosystem nature has established,” she continued.
Eavesdropping on Sea Life ‘Pals’
Importantly, one result of this tech could be a “low-cost, environmentally friendly” way to help marine mammals. Maybe we’ll also learn to live more in harmony with the natural world and each other? Well, one can hope.
Adornato leads the “Persistent Aquatic Living Sensors (Pals) project.”
As the BBC describes it, the project has teams that “eavesdrop” on sea life.
One team at Florida Atlantic University is called the Grouper Guard Team. On this team, they focus on goliath groupers topping out at 660lb (300kg). When intruders swim nearby, the groupers emit low-frequency booming sounds. Then, underwater hydrophones can detect the grouper’s alert sounds from 2,640 ft (800 m) away.
Team Pistol Shrimp
Inside the hydrophone, onboard software runs smart machine-learning algorithms, differentiating the grouper’s alert calls from other sounds.
Meanwhile, other teams focus on the sounds of pistol shrimp. Collectively, they sound like crackling “bacon frying.” Although tiny, they are among the loudest creatures on Earth. Plus, their pincers are incredibly fast, creating a bubble and burst of light when they snap with lightning speed. Essentially, the shrimp use a sonic weapon on prey, and their sounds can even interfere with submarine communication.
“We are trying to detect the echoes that are created when shrimp snaps reflect off of the vehicles,” says Raytheon scientist Alison Laferriere. “In much the same way that a traditional sonar system detects echoes from the sound that its source generates.”
After controlled tests, this summer, the Pals project could advance to field testing in 2023 if successful.
Pistol shrimp facts by Animal Fact Files:
Talking Sea Life
Recently, scientists have been learning more about how animals communicate in the oceans. Since the 40s, biologist Marie Fish led Navy research into how hundreds of species in the ocean communicate with sound. Today, we know that corals may use sounds to navigate ocean reefs. When the corals bleach and die, scientists can play the sounds of a healthy reef through speakers. By doing so, they can encourage the reef system to repopulate.
Dolphins Use Signature Sounds as Names
In 2013, studies confirmed what had been suggested for 50 years, that dolphins call each other by a signature whistle, their version of calling each other by name. When dolphin calves are born, they learn their “name” from their mothers.
Adults can copy the sound of another dolphin’s name within one second of hearing it. Over a lifetime, each dolphin’s signature sound is the most common sound they make. In this regard, they are unlike people, who don’t tend to say their own name. Additionally, researchers found evidence suggesting the possibility of more “complicated exchanges of information.”
In 2018, a study determined that male and female dolphins retain their names into adulthood.
“Dolphins can remember other dolphins after 20 or more years without contact by remembering their whistles, said Jason Bruck, an assistant professor at Stephen F. Austin State University,” wrote Sarah Sloat.
In May 2022, researchers revealed more about studies into dolphin communication. As scientists looked closer, they found signature sounds reflect the animal’s local habitat and demographics, which implies a local culture.
“…The scientists found dolphins who live in regions with more seagrass have signature whistles that are higher in pitch and shorter in length when compared to those who live in areas where the seafloor is muddier. Meanwhile, dolphins in smaller groups had whistles that changed pitch more often than dolphins in larger groups,” NBC reported.
The more we listen and observe, the more we realize we share more in common with animals than we knew.