I am liking that you are only catching slab 12" crappie. That is highly unlikely in a pond teeming with crappie of all sizes.

Any chance the allowed fishermen to your pond would have bucket stocked some crappie without your permission? I know some really "nice guys" that might do me a "favor", not realizing that they are ignorant about pond management.

That might explain your crappie observations. Frequently, crappie are introduced accidentally during the initial stocking, but you have lived there long enough without crappie so that is probably not the case. If crappie were bucket stocked, then a successful spawn in Year 2 or Year 3 by a few crappie (with few or no successful subsequent spawns), might explain your observations.

Another option is crappie introduced during a flooding event. Is there an active or ephemeral creek that feeds your pond? If an upstream neighbor had some crappie escape their pond during a flood, that might have allowed them to reach your pond in a rare event. That might explain why you mostly appear to have only a single size class.

My experience fishing 5-40 acre ponds as a kid is that the ponds would sometimes hit the "sweet spot" where they had ample populations of healthy bass in all size cohorts including some large hogs. They also had large slab crappie at that time. And also had large BG. In my (non-expert) analysis, each species had lots of fecund brooder fish so they produced lots of offspring. Each of the three species could then forage on a diverse population of the other two species (plus some cannibalism as needed). I would love a 5-acre pond like that!

Unfortunately, each of these "perfect" ponds would eventually become unbalanced and the fishing would decline. I do know that none of the farmers or ranchers that let us fish ever performed any electroshock surveys - so none of these ponds were ever intensely managed.

I think the crappie may be able to keep your BG down for a season or two, but it is hard to suppress BG populations long term if they have healthy water and adequate spawning and cover habitat.

I really like your idea of performing an electroshock survey and then managing based upon the results. There are some true experts on the forum that can really crunch that data for you!

My only advice would be to create some brush piles around your pond in deeper water. Maybe in the 6-12' depths, and bring the brush up to 2-3' within the surface. In the early spring, your probably caught LMB, crappie, and BG in shallow water. However, in the late spring and early summer the crappie should move out to the deeper brush piles. You should be able to catch them there with small live or artificial baits and then get a better sampling and see if you are starting to develop a population of numerous, smaller crappie. These brush piles should also concentrate the fish for the shocking survey. It is much tougher to sample the crappie when they are just spread out and suspended in deeper open water.

I hope you and your family have great fun enjoying your pond right now with good populations of LMB and crappie! Even with reduced numbers of BG, some of the survivors should grow quite large. A fish fry with crappie and BG is truly a treasured family event in my neck of the woods!