Niggly This has been explained over and over.
1) Scotland would not have to use the Euro but would be required to state an intention to join once they had met the requirements. Then delay and keep failing to meet the requirements (as other EU Countries have done) and continue to use the new Scottish Currency ad infinitum.
2. Our fishermen have already been bankrupted, not by the EU but by the Westminster Government selling the Quotas to foreigners.
3. Scotland's oil and gas have already been commandeered for the benefit of the whole UK as all oil revenues go direct to the Treasury in London. With Independence Scotland can spend these revenues IN Scotland and with new finds announced, there will be plenty left over to set up a Norwegian style oil fund. The sea border would be returned to the pre Tony Blair grab lines, putting almost all the UK's oil and gas production within Scottish waters.
4. In the UNION, Scotland has no seat at the top table, save an ineffective Secretary of State - Mundell - who was only elevated to this position because he was, at that time, the only Tory MP elected to a Scottish seat. Whereas as an independent sovereign state, which choose to remain in or join the EU, Scotland would have a seat at the top table, a power of veto, etc. etc. It would also be a magnet for inward investment for companies and finance houses, anxious to retain or set up a foothold in Europe.