How “Detect and Deter” Is Changing Salmon Protection
A new ICES Journal of Marine Science study shows that the targeted acoustic startle technology (TAST) can substantially reduce seal incursions into a salmon river when it is triggered only by real-time detection. The system used multibeam imaging sonar to identify seals and activate deterrents only when needed, and over a four-month deployment on a Scottish river, it detected and triggered on 71 upstream seal passages. Compared with historical and pre-deployment control periods, the system was associated with an approximate 90% reduction in upstream seal movements during operation.
As the authors conclude, “These results indicate that automated, event-triggered, acoustic deterrence can substantially reduce seal incursions while minimizing acoustic exposure to other sensitive wildlife”. In the detailed analysis, average seal transits per tide fell from 3.6 in nighttime control periods to 0.3 during nighttime treatment periods, a ~92% reduction, and from 0.9 to 0.1 during daytime periods, an 89% reduction. The system was also efficient in its acoustic footprint: on most days, the deterrent was active for an average of only 65 seconds, or less than 0.1% of the day.
For riverine environments around the globe, this research reinforces the value of precision-targeted acoustic tools in conservation settings. It suggests a practical path forward for reducing predation pressure on vulnerable salmon while avoiding unnecessary sound exposure in the wider river ecosystem.
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