Guppy....although it's a lot different than sitting out in the bay at night, but I've caught mackerel during the strangest hours....1, 2, 3 o'clock in the morning. Like the freak mentioned, it's all about the bait being there. The macks I was catching were feeding on silversides under some lit up docks. They'd come in waves,...
Perhaps if the lights were shining on your tackle, you'd stand a chance?
I didn't even think you could catch them at that hour, never mind at night, a Vietnam Vet turned me on to it....God rest his soul. Learned a lot of strange ways from him.
...R.I.P. Johnny boy