PPond asks " Will most all the males naturally stick with the females and be there to milt and do their thing for the female eggs that are strewn in the shallows with that much water present for them? " If you stocked a bunch of pregnant and fat, female YP along with mature males into 50 or more acres of water how many would it take to have a sustained pop?"
Yellow perch are group or school oriented fish. They usually relate nearby to each other. Usually for best egg fertilization and during a normal YP spawning event, often up to 8-10 or more eager males will trail along side of a swimming female that is extruding the egg ribbon or skein. As the ribbon moves out of the traveling female's body the males are providing milt to hopefully coat the ribbon in a cloud of white milt. Too few males results in a small and less dense cloud of milt and fewer eggs get fertilized. Thus some extruded ribbons can have varying degrees of percent fertilized eggs depending on how many attending males were present. I have seen some YP ribbons have 20% to up to 50% eggs not fertilized. Different eggs in each ribbon can have milt from different male perch, thus a ribbon can be fertilized with DNA from several males and the ribbon does not have just one set of genetic material from one male perch.

This whole perch spawning process is quite a bit different technique than the way sunfishes and bass spawn as with paired individuals creating a real high percentage of fertilization of each egg drop.

2nd Question; "If you stocked a bunch of pregnant and fat, female YP along with mature males into 50 or more acres of water how many would it take to have a sustained pop?" Well it all depends. What is the goal of stocking the YP? Bonus fish? See if any can survive in that water body? Provide more forage fish? Create a good catch rate that equaled the BG and BCP? A mixed bag of panfish as harvest? Numerous options are present.

One of the major limiting factors is - Is the habitat right for yellow perch and does the habitat promote survival of YP to harvestable sizes.

Second factor - will the competition factor for food and space be adequate for all size classes of YP to survive using the available food sources. Is there an excess for the new YP? Does the lake have enough food available to sustain a third panfish species? . Are the current panfish populations and the lake's carrying capacity of BG&BCP allowing enough food resources to be present for new individuals of YP.? I question if the niche requirement of YP will fit into the current carrying capacity of the 50 ac example lake's ecosystem. You don't just dump fish on top of a current full fish community or ecosystem and expect the new fish to THRIVE. Usually an established current ecosystem is at carrying capacity with current standing stock. Often if there was available growing space or room available,,, the existing fish would have already occupied this 'space'. There needs to be an unfilled niche for ANY new specie to really succeed.

Third factors are - Predation pressure, predator size class structure, and predator density in relation to habitat type and density. If the lake has LMB and walleye(WE). Both LMB & WE in my opinion do prefer to eat slender, relatively slow moving moving, more close to the bottom oriented fish, such as YP compared to eating can lid shaped BG & BCP who usually tend to live higher in the water column. If the lake has just LMB then predation would occur at just one "level". LMB and WE favor eating bottom and shallow oriented fish where all YP thrive or have a niche. IMO and experience,,,, LMB tend to be primarily day time active predators whereas WE are usually low light and evening / dark oriented predators - thus their big glassy eyes. YP are day active and vulnerable to LMB pressure. YP rest on bottom at night and are very vulnerable to WE predation. Thus with good populations of both LMB & WE, YP are attacked 24hrs a day - i.e. intense predator pressure. Will the current predators find it easier and more convenient to prey on offspring of the new YP compared to the other available forage items of can small lid BG&BCP? Forage density, predator sizes, their density, and amount or proper HABITAT / COVER are all important factors for YP survival with LMB and or WE. Lots of cover, often as submerged weed beds and maybe habitat diversity , IMO need to be present to allow enough YP to survive, reproduce, and grow to harvestable sizes.

Stocking Density - general rule is the more and larger ones that are stocked the better the chance some will survive. However many YP that you stock, IMO an equal number of similar sized other panfish species should be removed. Do it to make room for the new mouths to feed on a now increased amount of available uneaten natural foods.

IMO if lake conditions are conducive to YP survival stocking,,,, 10 to 20 mixed mature sizes ((5"-8"+) of YP per acre will allow you to see if survival in the lake is possible. Also in the right conditions stocking 5-10 YP as mature adults pre acre might allow a YP spawn their first spring. Another stocking option would be to add or stock YP egg ribbons or skeins into the lake's good habitat area. Proper Habitat then determines survival rate of hatchlings. YP can be prolific. The key amount to stock is to add enough for a YP spawn to occur before the stockers are eaten or die. Survival and growth of offspring will become evident in years 2 and 3 after initial stocking. IMO I don't think electroshocking is a good way to accurately sample and monitor YP populations because YP are bottom oriented, often in deeper water and electro-fishing does best when fish are up off the bottom in more littoral areas. YP IMO can be effectively sampled in large water bodies with fyke nets, gill nets and panfish angling in appropriate littoral areas and at appropriate times.