Walt said: "I do realize that some pits are infertile and thus not very productive; I would never dispute that. I just was differing with the statement that a pit could not produce monster bluegill, which obviously is not true. I agree a hundred percent that not all pits are created equal.
But I do think it's important to note that the biologists who studied the lakes concluded that one of the two main factors in the unusual size of the bluegill was limited spawning areas. That's their conclusion, not mine, though I've observed the same thing, i.e. ponds with lots of shallow water are much more likely to be overpopulated with bluegill."
Walt, you certainly make valid points. Any time we generalize, we can always find exceptions. That’s one of the darn hardest things about being an educator, actually. I hope you realize that I just fired off a quick note, trying to “gig” Dr. Condello a little about his future challenges.
Yes, some pit-type waters are more fertile than others (the phosphate and limestone pits come to mind). Also, even the infertile ones tend to get more fertile with time. Yes, record fish could come from any water body (even the ones I discuss below). A unique individual can always show up nearly anywhere. I certainly did not mean to generalize to the point to discount Walt’s point on this. By monstrous, I was thinking of those huge, PLUMP Condello bluegills that I had held in my hands!
Again, just typing quickly and not trying to write a scientific paper.
Having said that Walt is right, I will also stand behind part of what I said. In our part of the Midwest, which I will call SD to CO to KS and back up to MN (those are the places where I have experience with the pits), sand or gravel pits that are dug into the water table are relatively infertile compared to hill ponds in those same areas that are indeed on fertile soils. I think part of this infertility comes from the ground water movement through the ponds. In addition, these tend to be very attractive waters – blue, clear, you can see fish, etc. My wife would love for us to own a pit and build a house at such a location. The typical steep sides for the pits lead to effective predation by fish such as largemouth bass on panfish such as bluegill, just as Walt said.
OK, do I have any evidence? Well, when I posted the original note, I was thinking that productivity = standing crop. You could argue that, too, and say it is too general.
However, SD hill ponds and small impoundments averaged about 70 pounds per acre for largemouth bass in a study we did; maximum was about 100 pounds per acre. In contrast, we did a population estimate on largemouth bass, in a crowded population, on a very pretty 13-acre sand/gravel pit that was long established, and the biomass estimate was only 33 pounds per acre. George Bennett, the old IL Natural History Survey biologist reported similar results, although I won’t dig up his old papers.
When great pondmeisters like Dr. Bruce manage for big bluegills, they really like to produce those with high Wr values. The Condello bluegills have those Wr values of 130 or 140 or 150! Those are the truly cool fish that he produces. It is very difficult to do that in less fertile waters. Exceptions again occur, of course, such as when people use a feeding or fertilization program. So, that really was my point. I was just trying to josh around with Bruce, but there was some validity to my story.
Edit: What do we always say? 'It all depends....'
