Are you saying they just made those up? Not impossible but then what are the real figures?
I'm not saying it's made up any more than you're saying these fishermen are liars. If fishing is going up, then it's not in decline, and there's no problem.So why is fishing in decline, and why do we have a problem?

Another question might be who will buy our fish with a 20% tariff?
British people. We eat a lot of fish.

If we left the EU it wouldn’t necessarily mean that the situation would improve.
I don't think anyone pretends to be certain things will improve. How can anyone know? People are just willing to take the risk. 52% of people, in fact.