This text was initially featured on Hakai Journal, an internet publication about science and society in coastal ecosystems. Learn extra tales like this at hakaimagazine.com.
Every summer time on the Ballard Locks close to Seattle, Washington, hundreds of vacationers collect to look at steelhead trout and coho, sockeye, and chinook salmon valiantly leap up the fish ladder as they head from Puget Sound to Lake Washington and the spawning grounds past. So, too, do a handful of hungry seals and sea lions.
“Pinnipeds—seals and sea lions—are means smarter than I believe we give them credit score for,” says Laura Bogaard, an ecologist with Oceans Initiative, a Seattle-based nonprofit analysis group. “They found out it’s an all-you-can-eat buffet.”
For many years, pinnipeds have been congregating on the Ballard Locks to gorge themselves on fish populations already harassed by air pollution, habitat loss, and overfishing. To guard the fish, conservation managers have been attempting quite a lot of strategies to shoo them away. They put in a fiberglass killer whale that bellows predatory calls and used a tool referred to as a pinger to attempt to scare the pinnipeds away. (The pinger, it turned out, had extra of a dinner-bell impact.) They’ve even fed the pinnipeds fish laced with lithium chloride, a noxious however not lethal chemical, and proceed to make use of firecracker-like seal bombs.
Nothing they’ve tried appears to work. The difficulty has been so longstanding that some conservation managers argue for measures as excessive as culling problematic pinnipeds.
“The massive problem,” says Andrew Trites, a pinniped researcher on the College of British Columbia, “is you’re attempting to cease [pinnipeds] from doing one thing that [has] such a optimistic reward, which is attending to eat. Meals is the last word payoff, and that’s why it’s been a close to inconceivable factor to cease.”
However Bogaard says {that a} new gadget, known as the Focused Acoustic Startle Know-how (TAST), appears to have labored the place different approaches failed.
Between 2020 and 2022, Bogaard examined the TAST on the Ballard Locks. She discovered that whereas the variety of seals within the space remained the identical, they stayed farther from the fish ladder. The challenge, nevertheless, was shut down in the summertime of 2022 as a result of the experimental protocols weren’t appropriate with different administration measures getting used on the Ballard Locks. Bogaard plans to proceed testing the gadget at Tumwater Falls Park in Washington, one other salmon choke level.
The TAST represents an thrilling new development in pinniped deterrents as a result of it takes benefit of one thing known as the acoustic startle reflex, says Thomas Götz, a marine mammal researcher on the College of St Andrews in Scotland who co-created the know-how. “If a sound has sure properties, then it triggers a muscle contraction—a flinch,” he says. For pinnipeds, he explains, the noise is like fingernails on a chalkboard.
After years learning the consequences of sound on marine mammals, Götz, together with the TAST’s most important co-developer, Vincent Janik, additionally on the College of St Andrews, discovered {that a} sound with a frequency between 500 and a couple of,000 hertz will startle a seal however is basically exterior the delicate listening to ranges of different wildlife equivalent to salmon and whales. In addition they discovered that in contrast to present acoustic deterrent gadgets equivalent to pingers, which pinnipeds finally get used to, the TAST’s significantly grating noise creates a flight response that appears to get stronger with repetition.
In experiments performed by Götz at fish farms in Scotland, utilizing the TAST led to a 97 p.c drop in fish predation by pinnipeds. The know-how is at the moment being utilized by fish farms in Scotland and Norway, and Götz is researching its potential for deterring pinnipeds and whales from fishing nets and oil spills.
Trites, who was not concerned within the analysis, says the TAST has thrilling potential. “It’s an exquisite idea, however I believe it nonetheless wants additional testing and validating to make sure that it does work.” He says that the context and particular location through which the gadget is used might be an vital nuance in its effectiveness.
Bogaard is cautiously optimistic concerning the know-how, too, however she is cautious to notice that it’s not a silver bullet for saving imperiled fish.
“I believe along side different administration practices it undoubtedly exhibits quite a lot of promise when it comes to its skill to maintain seals away from a selected space of concern,” she says. But when the tip aim is saving salmon, she provides, extra must be carried out to guard the watersheds the place salmon spawn.
This text first appeared in Hakai Journal, and is republished right here with permission.