Fish are shrinking around the world. The average body weight of nearly three-quarters of marine fish populations sampled dropped between 1960 and 2020, a recent study suggests.

Nah, read about this in the 90's (I think?). The article was about a specific Atlantic fish, I forget, been a long time. Scientists were puzzled as to why the fish were shrinking.

Fisherman are only allowed to keep the big ones, throw the little 'uns back. This creates evolutionary pressure for younger/smaller fish to come to maturity and start reproducing sooner.