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Seal-spooking tech may assist defend endangered salmon


This article was initially featured on Hakai Magazine, a web based publication about science and society in coastal ecosystems. Read extra tales like this at hakaimagazine.com.

Each summer season on the Ballard Locks close to Seattle, Washington, 1000’s of vacationers collect to observe 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 approach 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 discovered it’s an all-you-can-eat buffet.”

For a long time, pinnipeds have been congregating on the Ballard Locks to gorge themselves on fish populations already confused by air pollution, habitat loss, and overfishing. To defend the fish, conservation managers have been attempting a wide range of strategies to shoo them away. They put in a fiberglass killer whale that bellows predatory calls and used a tool generally known as a pinger to attempt to scare the pinnipeds away. (The pinger, it turned out, had extra of a dinner-bell impact.) They have 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 challenge 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 University of British Columbia, “is you’re attempting to cease [pinnipeds] from doing one thing that [has] such a constructive reward, which is attending to eat. Food is the final word payoff, and that’s why it’s been a close to inconceivable factor to cease.”

But Bogaard says {that a} new gadget, known as the Targeted Acoustic Startle Technology (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 undertaking, nonetheless, 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 University 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 finding out the consequences of sound on marine mammals, Götz, together with the TAST’s fundamental co-developer, Vincent Janik, additionally on the University of St Andrews, discovered {that a} sound with a frequency between 500 and a couple of,000 hertz will startle a seal however is essentially outdoors the delicate listening to ranges of different wildlife comparable to salmon and whales. They additionally discovered that not like present acoustic deterrent gadgets comparable to pingers, which pinnipeds ultimately get used to, the TAST’s significantly grating noise creates a flight response that appears to get stronger with repetition.

In experiments conducted by Götz at fish farms in Scotland, utilizing the TAST led to a 97 % 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 a wonderful 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 wherein the gadget is used may very well be an vital nuance in its effectiveness.

Bogaard is cautiously optimistic concerning the know-how, too, however she is cautious to notice that it isn’t a silver bullet for saving imperiled fish.

“I believe together with different administration practices it undoubtedly exhibits plenty of promise by way of its capacity to maintain seals away from a selected space of concern,” she says. But if the top purpose is saving salmon, she provides, extra must be performed to guard the watersheds the place salmon spawn.

This article first appeared in Hakai Magazine, and is republished right here with permission.



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