AFAIK herring is now at very healthy levels again in the North Sea, right? I was under the impression that it's one of the few "good" fish you could still eat nowadays, or should I adjust those dietary habits again?
I’m not an expert, but I think it’s more or less sustainable, but not at the levels just before the moratorium (https://www.researchgate.net/publication/274558008_Recruitme...), and a lot lower than historical levels (can’t find a simple reference, but there’s data that on that. Found https://edepot.wur.nl/317580, which isn’t that clear and certainly not succinct)
