I wonder how much of a role the shutdowns due to Covid have impacted fishing. Lots more people in the outdoors than there used to be. More people fishing means increased impact on fish. Pherhaps it is the natural ebb and flow of fish population.
I witnessed an estimated 40 anglers catch limits of crappie one spring. Limit was 30 fish over 9 inches. If everyone only kept 20 fish, that's 800 less fish that made it through the spawn. I would say the average that day was 12 inches. This was from a small area of a large lake. If this happened in 10 different bedding areas. The numbers really start to add up.
3 years ago on the lake I currently fish. We had spring flooding during when the crappie spawned. Enough that cities along the lake were flooded. If fewer numbers of fry survived or hatched do to the flooding . Less mature fish to catch now. This lake has. 10 inch minimum lenght. Most of the fish I have caught have been just under that benchmark. Most everyone is reporting the same sized fish. If people get to where they can't catch fish they will move on to something else. Then possibly the fish will rebound
The love for fishing is one of the best gifts you can pass along