Your best bet for seafood in Tampa will probably be at Rocky Point. There are several seafood places there and the location is fairly convenient (unless you're hitting it at rush-hour).
Rocky Point is along the bay just west of the airport along highway 60, which is the Courtney Campbell Causeway. Past Rocky Point, the causeway heads across Tampa Bay to Clearwater and the beaches.
There you will find:
Rusty Pelican Restaurant, 2425 N Rocky Point Dr
Landry's Seafood House, 7616 W Courtney Campbell Cswy
Crabby Bill's Beach Club, 7700 W Courtney Campbell Cswy
Oystercatchers, 2900 Bayport Dr
Crawdaddy's, 2500 Rocky Point Drive
Castaways, 7720 W Courtney Campbell Cswy
Bahama Breeze, 3045 N Rocky Point Dr E
and if all else fails, there's a Red Lobster at 6455 W Courtney Campbell Cswy.