I don't get time to fish. My kids fish as soon as water warms up and since the YP are crazy about optimal pellets, they come to the area where the kids fish like a dinner bell going off. They hit worms, corn, snails, just about anything. We usually catch the most active and usually the larger size YP as they are most aggressive.
The kids will only catch a few (4-5) and then catch a few larger shiners and then lose interest. We have not intentionally jigged on the bottom from a boat or targeted all areas of the pond with angling as a way to sample the population.
The YP are always catch and release. My plan since we have seen some very large female (12-13" and chunky) was to see what the egg drop was like this spring and then have a group fishing event and try to keep enough YP to have a fish fry. I figured if I"m going to restock anyway I might as well at least enjoy one good YP meal for everyone.
The smallest YP we catch is about 5-6" so that one is probably at least 2 seasons old. At night I usually see a lot of 2-5" perch just laying in the sand in teh shallows using a flashlight. The last two years haven't seen any of that size class so I don't think we had good recruitment or survival. I know my shiners (GSH and SFS) are probably really eating a lot of the fry or really small YOY as their population is very much going up.
The only other predator I MIGHT have (not sure) is I stocked a few WE just to see if we could dispel the myth that they don't do well in shallow ponds. I never tried to catch them and outside of a big 'V' in the water streaking through the shallows I had no idea if they were there. Last fall we had a big temp drop and a big rain where the pond took on a bunch of runoff all at once and the next day we had a few of the largest YP and 2 Walleye floaters. The Walleye were stocked at around 5" long and both of the floater walleye were about 14" long. There could easily be a few more walleye left and maybe they are cleaning up on the smaller size class YP.
