Here's a long overdue update on our panfish-only pond experiment:

YP:
My brother and nephews regularly catch YP fishing, and stockers are mostly 12+" and quite fat. We have harvested about 40 of the original 130ish stockers that I estimate survived the initial transport and stocking in 2019. We stopped feeding pellets after the first year (2019), so the YP appear to be predating BG quite well overall; there's an occasional skinny 11" YP, but most all are very fat. My brother has opened a few YP that had small crayfish in their stomachs, so it appears we have a population of reproducing rusties that migrated up from the creek and the YP figured out what to do with them. They have also caught a couple 6" and 8" YP recently that are quite fat; this is about the size we stocked in spring 2019, so this leads me to believe that these are new YP recruited in the pond. Otherwise, we aren't seeing or catching hardly any smaller YP, and have never caught any in the traps, so this makes me believe that YP recruitment is very weak. I suspect this is mainly due to high numbers of small BG and now some smaller BCP. We saw YP ribbons and fry in 2020, saw ribbons in 2021 (people weren't around the pond much that year, so no one confirmed seeing fry), but this year we never saw any ribbons on the branches in the shallows. Hopefully there were a couple ribbons laid deep, out of sight. I'm considering stocking another round of YP in the coming years if necessary, and in the meantime we'll aggressively cull small BG and BCP to help with YP recruitment.

RES:
RES are doing very well. Initial 2019 stockers that were 3-4" are now around 7-8" and very thick. Our RES are pretty easy to catch and trap. We see RES of all sizes, so they're recruiting well. First sample of about 100 sunfish from 2022 early season trapping shows about 23% RES, 6% PS, 71% BG. I suspect there may be some hybridization between the redears and PS, because there is the occasional small sunfish in traps that makes me debate with myself between whether it's RES vs. PS, and I just can't ID it with certainty. We have harvested a few of the stockers.

LMB:
No sign of LMB. In the 2019 harvest there were definitely at least 2 LMB that evaded the cull. Recall that our water is typically very clear, and the pond is steep, so the LMB used to cruise the shallow ring around the outside where they were easy to see on occasion. We saw those remaining 2 LMB regularly in 2019, and had a few sightings in 2020, but they are nowhere to be seen since. Before, we always used to see LMB YoY in the shallows, but we have yet to see a single small LMB since 2019. I'm cautiously optimistic that somehow, we may have actually gotten rid of our LMB population longer term (maybe due to luck of remaining LMB being the same sex). I still suspect that at least the younger LMB from 2019 is still alive (and big) somewhere down deep, but it's very strange in our pond that we don't see any new juveniles. Some YP behaviorally seem to be filling the old niche of the LMB, where the YP will actually lone-wolf cruise the shallows between spots of cover hunting BG.

BCP:
BCP actually do spawn in our pond, apparently. They're recruiting now without the pressure from LMB. We're still determining population size, but so far numbers appear to be manageable. Several BCP in the 4.5-6" range are being seen, caught, and trapped, and their body condition is actually pretty good. We haven't seen a skinny BCP yet. Regardless, we are now removing all BCP aggressively. I think they may be helping to manage the BG YoY fairly well, but are also probably suppressing YP recruitment. In traps, I have a higher success rate trapping BCP when I soak the trap for hours at a time. I get the best yields on our sunfish with shorter soaks of the trap, because it seems they're smart enough to find their way back out given enough time. I think the BCP on the other hand are just happy chilling in the trap for hours on end.

BG:
BG are doing as BG do. Without the LMB, the BG size structure has recovered and looks almost healthy, with the caveats that we may have cropped the biggest sizes too agressively, because we don't see as many BG over 6" as we used to, and obviously with YP and BCP as our apex predators, we have overabundant small BG that probably limit BG growth rates and suppress YP recruitment. We used to have a barbell distribution of BG when the LMB were present, with a decent many 1-3" BG and 7+" BG and nothing in between, so now we have moderate-high numbers of 1-3" like before, but now we have lots of 3-5" BG as well. My brother is harvesting smaller adult BG, and going forward we will now trap and remove smaller BG aggressively this year.

PS:
PS seem to do the same in our pond regardless of what is going on around them, meaning that they always recruit in low numbers, have a reasonable-looking size structure, and a few bigger adults.