This level of protection is supervisory only. Long Life Battery Powered Photo Electric Beams will definitely detect individual walking on your dock. They are immune to most false alarms generated by small animals and weather. The beams create a wireless link of up to 3,000 feet to a receiver/control panel in the home. Due to the risk of false alarms, the authorities are not notified. You would be notified, the Siren/Strobe on the dock would be activated, and external lighting (if installed) would turn on, and system video cameras (if installed) would record the events.