Its hard to imagine some people catching and releasing it. Of course, they stick a spear in the fish to get it on board but could cut the line leaving the hook in. It would be hard to sell if its not a fish you are allowed to land.
Out in the market in Madeira they have these fish and unusual red looks like beef steak. I often look into that market when on the Island but what a pong.
Many island fruits you may never see in the UK as well