Not sure what kind of seafood you want, but several members of my travelling party had crab legs at Captain's Grille (Yacht Club.) Apparently they were good, BFF says that she would highly recommend them and they were some of the best she's ever had. (The corn, however, was disappointing, she says.)
ETA: She adds that the shrimp in the pasta dish at Sci-Fi was good, too. I wouldn't know; although the pasta was great I had it with tofu instead, lol!