I think the fishing position is that:
our fishermen/women used to have quota. That’s like an entitlement to catch x amount of a certain type of fish. Different types of fish have different quota and you get allocated it. I think it’s to make sure there are enough fish not caught so supply is plentiful and they don’t go extinct kind of thing.
So you might be allocated lots of quota for a fish you don’t catch and hardly any quota for the fish which are plentiful that you need to land to make profit.
So the answer is to swap your quota for that fish you don’t want for someone else’s unwanted quota for the one you catch lots of.
So you swap and then you can legally can catch lots of what you need and the other person can catch lots of what they need. Job done. Both happy. (Or you can lease your quota out, and get money for it, that you then use to lease in someone else’s unwanted quota, ie either way you achieve the same thing, more quota to get more fish).
But the new rules say no swapping or leasing with the eu countries.
So it means you are stuck with less entitlement to the fish you want. So you have to catch less and make less profit. So you have to hope someone here wants to do a swap/lease with you.