Each summer at the Ballard Locks near Seattle, Washington, a large number of tourists gather to view steelhead trout and coho, sockeye, and chinook salmon valiantly leap up the fish ladder because they head from Puget Sound to Lake Washington and the spawning grounds beyond. So, too, execute a couple of hungry seals and sea lions.
Pinnipedsseals and sea lionsare way smarter than I believe we provide them with credit for, says Laura Bogaard, an ecologist with Oceans Initiative, a Seattle-based nonprofit research organization. They determined its an all-you-can-eat buffet.
For many years, pinnipeds have already been congregating at the Ballard Locks to gorge themselves on fish populations already stressed by pollution, habitat loss, and overfishing. To safeguard the fish, conservation managers have already been trying a number of solutions to shoo them away. They installed 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 proved, had more of a dinner-bell effect.) They will have even fed the pinnipeds fish laced with lithium chloride, a noxious however, not deadly chemical, and continue steadily to usefirecracker-like seal bombs.
Nothing theyve tried appears to work. The problem has been so longstanding that some conservation managers argue for measures as extreme as culling problematic pinnipeds.
The big challenge, says Andrew Trites, a pinniped researcher at the University of British Columbia, is youre attempting to stop [pinnipeds] from doing a thing that [has] this type of positive reward, that is addressing eat. Food may be the ultimate payoff, and thats why its been a near impossible thing to avoid.
But Bogaard says a new device, called the Targeted Acoustic Startle Technology (TAST), appears to have worked where other approaches failed.
Between 2020 and 2022, Bogaard tested the TAST at the Ballard Locks. She discovered that while the amount of seals in your community remained exactly the same, they stayed farther from the fish ladder. The project, however, was turn off in the summertime of 2022 as the experimental protocols weren’t appropriate for other management measures used at the Ballard Locks. Bogaard plans to keep testing these devices at Tumwater Falls Park in Washington, another salmon choke point.
The TAST represents a thrilling new advancement in pinniped deterrents since it takes benefit of something called the acoustic startle reflex, says Thomas Gtz, a marine mammal researcher at the University of St Andrews in Scotland who co-created the technology. In case a sound has certain properties, then it triggers a muscle contractiona flinch, he says. For pinnipeds, he explains, the noise is similar to fingernails on a chalkboard.
After years studying the consequences of sound on marine mammals, Gtz, together with the TASTs main co-developer, Vincent Janik, also at the University of St Andrews, discovered that an audio with a frequency between 500 and 2,000 hertz will startle a seal but is basically beyond your sensitive hearing ranges of other wildlife such as for example salmon and whales. In addition they discovered that unlike existing acoustic deterrent devices such as for example pingers, which pinnipeds eventually get accustomed to, the TASTs particularly grating noise creates a flight response that appears to get stronger with practice.
Inexperiments conducted by Gtzat fish farms in Scotland, utilizing the TAST resulted in a 97 percent drop in fish predation by pinnipeds. The technology happens to be used by fish farms in Scotland and Norway, and Gtz is researching its prospect of deterring pinnipeds and whales from fishing nets and oil spills.
Trites, who was simply not mixed up in research, says the TAST has exciting potential. Its a lovely concept, but I believe it still needs further testing and validating to be certain that it can work. He says that the context and specific location where the device can be used could be a significant nuance in its effectiveness.
Bogaard is cautiously optimistic concerning the technology, too, but she actually is careful to notice that it’s not just a silver bullet for saving imperiled fish.
I believe together with other management practices it will be shows lots of promise when it comes to its capability to keep seals from a particular section of concern, she says. If the objective is saving salmon, she adds, more must be done to safeguard the watersheds where salmon spawn.
This short article first appeared inHakai Magazine,and is republished here with permission.