it seems to be perfectly on the shoreline. Random noise would be everywhere. Must be strong but pointed lights flashing randomly (car lights on the shore, buoys on the water, traffic lights, etc.).
In a long exposure they just become more apparent because normally, you wouldn't see them all the time. In a "blink of an eye" you might see only one or two lights but your camera's sensor collects them all during the 8 minute (or whatever) exposure.