The EU's EEZ's encompass the shallower seas (North Sea, Irish Sea), continentals shelves and consequently the most prolific fishing grounds. Iceland, Faroe and Norway enclose rich grounds in their waters and international (fishing) waters in the NE Atlantic are of great depth with scattered sea mounts and few banks.
The potential for commercial fisheries outside the EEZ's is being examined but the national fleets of the EU are under severe constraints as any catch that they may make there is counted against the established TAC.
The wisdom of such an approach is questionable and does little to encourage alternative or exploratory fisheries.