Annual stocking of larger adult, say at least 7"-8" YP, will allow the YP to maintain their numbers. Bill Cody will probably have an opinion on this, but I am betting it will be the same or similar. In smaller ponds, LMB tend to over time remove YP from all but the most heavily vegetated ponds. Heavy culling of the BG will never remove them all, so you'll still see some forage value out of them. However, YP aren't a good replacement for BG in my opinion.