Used to able to walk on St. Andrews Marina on a late afternoon and see king mackerel stacked like cord-wood where the charter boats dock. Most of them would end up in the garbage cans...tails sticking out. They were just slaughtering them and throwing them away.
They also use to have some huge nets with spotter planes and they used to catch pompano by the acre. Sometimes the net boats would enter a small local bayou, spread the net and remove every single fish from the lagoon except those small enough (bait fish) to go through the mesh of the net.
Between the net ban, catch and release and conservation measures like size and bag limits, the stock of fish has never been better. There are more fish than ever and they're bigger fish.
I retired from running an 85 foot fishing boat, the Florida Queen (WL-4586) on bottom fishing trips in the Gulf for 30-some odd years. We were air conditioned, nice galley, crew of 12 not counting the cooks and the bunk rooms slept 40 fishermen. We worked bottom structure for snapper and grouper anywhere from 30 miles (day trip) to about 80 or so on overnight trips and two-day trips.
By 1980 the grouper and snapper were starting to seriously thin out and we had some very disappointing catches. Now the grouper and snapper stocks are back and better than they were in the "old days".