A few local lakes I fish have been going downhill in quality regardless of species. My fish & game club has tournaments on the private lake we own property on and bass number and weight in particular are much less than 15 years ago when 3-5 bass were caught more often. I wonder if tournament weigh-ins do damage regardless catch & release. Dry nets can't but do damage to slime coats and especially if fish are dropped accidentally.
Crappie size-range of 12" or better is a thing of the past on this lake and I know the lake like that back of my hand. I fish it off and on from late March to Nov. Daily numbers, that include all species, is still fine at anywhere from 40 to over 100 fish per outing - many of which were spawned in the lake. (I've posted many photos of those fish on C.com to illustrate lure and tackle theories.)
Other lakes that are public also have suffered dut to overfishing plus and no fish regulation enforcement is present from my experience or from the doz. or more anglers I know I compare notes with. I see illegal crappie (numbers, size and out-of-season fish) taken out of variuos lakes I fish at least 5x a year. Saying something, as I've learned, only gets me a middle finger - definitely not worth a tire being punctured.
Oh well, I'm after numbers anyway and catching any fish that bite my creations. Got no problem catching large suckers, white perch or large catfish any day! No one keeps them for any reason.