So, the UK was basically entitled to fish almost up to the French, Dutch, Belgian, and Danish coasts, and you don't think there was anything wrong with that?
Or that there's something wrong with the notion that it was reasonable to more equitably divide up the exclusive fishing areas,
and put in place regulations and quotas to prevent overfishing?
Really?
FWIW, the Common Fisheries Policy was set up in 1970, even before we'd joined the (as was) EEC. There's quite a lot of information on the following link:
Common Fisheries Policy
But it is fact-based, so you may not like it much.