In January 2025 the Port of Seattle started testing a new device to deter Sea Lions from the docks at Shilshole. Broox Ultrasonic Pest Repellent.

The port employees have put the devices in problem spots temporarily and moved them to new locations as needed.

The sea lines seem annoyed enough by the devices that they have spent more time on the seawall than the docks. An independent university researcher has reported that the seals were spending more time on the breakwater than the docks.

There is an internal presentation by a Port of Seattle employee documenting many of the deterrents that have been attempted in the past, as well as both the damage and dangers encountered. Hopefully it will be publicly shared as a resource available to other marinas dealing with similar issues.