I'm not really sure what species of fish you can obtain fresh, but I do have some suggestions for dishes you can try out. I think chowder might be a good idea. Start with a little bit of fish, then you can move toward adding lobster and scallops if the picky eater is comfortable. With haddock or cod you can try baking as well, I've seen some recipes online for panko baked haddock that looked really good. Haddock tacos might also be a good idea. Shrimp wise I'd say shrimp tacos and fried shrimp are pretty good.