Kevin,
In a small pond, 1/3 acre, you can reasonably support about 35 pounds of LMB. I have a couple of relatively small ponds with LMB and the problem I have to manage for is overpopulation and stunting of the LMB. My opinion is that genetics, while a factor, is not nearly as significant factor in your LMB size and health as the carrying capacity of your pond, the forage, and maintaining a proper balance. When adding adult LMB to a small pond, carefully consider the pond balance and overall numbers of LMB to avoid overpopulation problems.
