In theory it always sounds a good idea, however, there are significant ecological, social, economic and management reasons why such a ban would be both unworkable and unacceptable.
From a perspective of the North Sea as a whole and playing devils advocate on some issues;
• fish do not recognise boundaries,
• many species spend a limited time inside the 12nm limited before migrating out again
• most of the major spawning grounds are offshore (well outside the 12nm limit),
• fishing effort may well cease, but you can’t guarantee successful spawning,
• environmental factors, of which we have no control over, play a significant role in the success or otherwise of recruitment,
• the ecological implications would need to be established first, such as interactions with other species, which would take time therefore an immediate ban would not be viable,
• would any ban include species considered to be within safe biological limits
• if so, then its possible that they would out-compete those species which any recovery plan (ban) would try to re-establish,
• if not, then a significant proportion of effort would be shifted to target those species, with a further decline in stocks which are presently sustainable,
• the great majority of large trawlers fish outside the 12nm limit,
• to be effective any ban would need to be multi-lateral (include all EU member states),
• the cost as a consequence of a multi-lateral closure would be prohibitive,
• enforcement would be a significant issue with different member states administering varying degree’s of enforcement,
• illegal fishing effort inshore would increase significantly,
• there would be significant objection from the public, not just in the UK but throughout all members states, to pay huge amounts of money to fishermen, who have after all contributed to a greater or lesser degree, to the current state of fish stocks and the marine habitat,
• social unrest and possibly crime would increase (fishermen + lots of spare cash + lots of spare time =?????),
• who would support the service industries,
• who would support the processing sector,
• any such ban would increase effort massively outside EU waters, impacting third world nations and their own fishing rights and grounds,
• aquaculture would spread, impacting local habitats (salmon fish farms etc. and impacts as a result of),
These are just a few of the problems or issues that the proposed implementation of any such ban would raise. There would be benefits to the angler; however, these may be on a local or regional basis, and very short scale, a pain in the a**e if your area is not one to benefit significantly.