I was recently in Galveston with a marine biology camp, and everyone went fishing in a boat basin in the evenings. The usual catch was pinfish, with the occasional croaker or piggy perch, maybe a seatrout if someone was really lucky. Thanks to that, nobody had heavy line, and quite a few people regretted it.
It was about an hour until sunset when all the kids on one side started yelling about a huge fish. When everyone went to look, there was an alligator gar cruising right up along the dock. It was probably about four feet long, with very dark coloration, multiple scars (possibly from propellers) on its head, a lure (no visible line) hanging from its jaw, and half a dozen inch-long pilotfish following it. It looked very calm, and probably would have hung around for pictures, but one of the kids threw a castnet at it. I'm not sure what he meant to accomplish, the gar was longer than the net, but a weight slapped the gar and it darted off into the murk. Everyone got a very good look at it, though, it had been right up under the surface. There was no way that was anything other than an alligator gar.
About ten minutes after that, one kid put an entire frozen shrimp on his hook and chucked it in. Almost immediately, his pole bent over like he'd caught it on a reef, but the line was moving- and then it snapped. Evidently the gar was hanging around, and he stole several more baits before it got dark. Nobody managed to catch him, of course, and he didn't surface again.
My question is this: what was an alligator gar doing in a boat basin? There weren't any large rivers anywhere near there, he was in full-strength saltwater, but he seemed perfectly fine.
Also, I talked to some fishermen on a different dock who claimed they'd caught gator gar before, in saltwater. Is this something that happens on a regular basis, or has our recent absurd level of rain washed them down out of rivers?