I’m pretty sure there are places you can go and buy fish straight off the dock. I think that happens at Haulover in Miami, for example.
A buddy of mine and I once caught wahoo until we got tired of catching them. It turned out that the town we fished out of was having some sort of celebration that night and we literally fed the whole town. The women in charge of the cooking cut the fish into rectangular steaks and wrapped them in foil and threw them on an enormous grill. It was great.
Bonito is a challenge. I eventually discovered that it makes a pretty good ceviche - it responds well to the citrus juice. But what I did more than anything is cram a bunch of it in a mason jar, fill it with olive oil and maybe a little garlic, salt, and then put the jars in a big pot of water and heat the water until the fish is cooked. It makes an outSTANding jarred tuna, you can eat it any way you want, but it works especially well in a salad. And in Panama, man, that can barely give that fish away. The olive oil costs more than the fish, easily.
Everyone always talked about Airline Seafood in Houston but the times I went there I thought it was terrible. Some of the markets in Chinatown are ok, H-Mart is usually pretty reliable, but I agree, if you’re serious about it your best bet is Seabrook.
Lots of places to buy fresh off the boats, but they are usually commercial markets. I was thinking more like just some local guys out for fun. You used to be able to go up and say “Whaddya catch? I’ll give you a couple of bucks for that”. Maybe you still can. My local fish guy goes down to Seabrook every morning. I check with him for whatever he was able to get that day. You just never know.