The prime example is the TYEE. 25 years ago they were classified as Chinook weighing 50 lbs or more. The decline, is definitely a result of over fishing.
That's kind of hard to prove.
For salmon, I would think that the decline in total population size could be caused by overfishing (along with habitat destruction - let's not forget about that). But the percentage of springs that reach a given size should remain the same, unless something is applying very strong selection pressure and affecting the genetics. Sounds like a good thesis topic.
I should go back to school so I could go fishing for a few years.
Long lived fish that spawn multiple times, on the other hand, are a different story. Species such as lingcod, rockfish and herring are being harvested when they've barely reached sexual maturity. So it's true that they never get a chance to grow big.
Gooey, maybe when you say greenling you are now talking about juvenile lingcod (ophiodon elongatus) which sometimes have green flesh?