The problem IMO is that fishing rights are not transferable property. The stock of fish itself therefore has much less value to the fisherman -- rather like someone who has a derivative claim on a stock's dividend, he's not interested in retaining earnings because they're not his.
I'm not much of a fisherman, but I presume that harvesting that last 5% would be prohibitive.
It seems that making fishing rights transferable increases management requirements. What about people who've been guiding or doing something else the last few years? What about people who are on their way out, but now have something worth a fortune? What about the up and comers who are saving for their own boat and don't get in the door in time? If we still have too many fishermen, will we start paying people not to fish after they bought these expensive permits with the understand that they could fish with them?
Why stop at fishing? I think the quality of lumber today is lousy. It's over competitive. It might help to limit the number of logging and milling licenses that are handed out, maybe making them transferable.
From what I can tell, fishermen don't lack for a sense of ownership in the species. They generally like the lifestyle and have too much invested to want to see it deteriorate. They're just willing to individually cheat if it will multiply their income, just like anyone else.