Wonka, to tell you the truth, we haven't sampled any considerable size LMB so far, and by that, I mean any specimen over 25 inches. Remember, we do not weigh them.
But each lake has its designated sampling zones, and they are adhered by every year. It wouldn't be fair to sample zones at random. The data is collected each year, from specific areas ONLY. This is to ensure accuracy and biomass of each area, among other things.

Here's an example of an average size LMB, sampled at Saugatuck Reservoir this past spring, just so you have an idea.



I don't remember exactly how much it measured, but it was in the low 20's. And this is average.
I'm not saying that larger ones don't exist, but are quite rare, certainly, we have yet to sample anything over 8 pounds.
However, electrofishing isn't an exact science. Hit and miss, just like fishing. Besides, the boat is driven along the shore, in 3-6 feet of water, sometimes deeper, but it becomes inefective under that. One reason being that we cannot see fish 10 feet down even if shocked, for example.