Its confusing and how did they get a revised estimate, how was the first one so wrong, 87% wrong.
There is always talk about scientific methods but no one ever tells you what they are. I tried finding this out once on the ICES websites and the other EU one but couldn't find anything. Its as if they don't want to shout about it and my guess is they are not very scientific at all. All I could find was a couple of mentions of the bio mass of spawn but still nothing on how that's calculated.
The only thing I have ever had some sure feeling about for some time is that marine reserves work, plenty of information available about them and they ensure species don't become extinct and there will always be some fish to catch commercially or recreationally. This wont happen so we will be tinkering and hoping for a long time yet.