TyW � I�ve been reflecting on your comments and questions, just as Bill is currently doing. Bill has provided his usual reliable, good advice. I have a couple of points that I might add.
First on the walleyes � if you are in a gravel pit/sand pit type of pond, you might actually get a little bit of walleye natural reproduction and survival to adulthood. We manage an 8-acre gravel/sand pit north of town. The walleyes actually do produce a few offspring each year that survive. However, when we electrofish the entire shoreline of the pond in the fall, we typically see 3-4 young walleyes (6-7 inches, most often). That is NOT enough reproduction to sustain a predator base in a pond to maintain control over a panfish species (much less provide fillets for anglers). My best advice for walleyes in north country ponds is that they be used as a secondary rather than primary predator. Restocking, likely with large fingerlings (as Bill has already described), will be necessary to maintain a fishable population. I realize that you indicated that continual purchases of walleyes are not going to occur.
So, that brings the largemouth bass to the top of my mind as the top predator. They will sustain themselves naturally in gravel/sand pits, and they will effectively control bluegills.
Second, I am a little concerned about the eventual sizes of bluegills that might be produced in your pond. Everyone on this site, including me, always talks about largemouth bass thinning small bluegills, increasing bluegill growth rates, and producing big bluegills. However, �big� is relative when it comes to bluegills. Some sand/gravel pits have quite a bit of water movement through them. As a result, their productivity levels can be lower than expected. I know that you have a biological background, so the gravel pits are more likely to be mesotrophic or even oligotrophic, rather than eutrophic. More productive waters produce BIG bluegills, probably because bluegills feed on zooplankton and the larger aquatic insects.
We manage a 3-acre sand/gravel pit with largemouth bass and bluegills. The pond is relatively new, and it just looks pretty sterile. Do you know what I mean? There are some aquatic plants, but not many, despite the ultraclear water. There is very little in the way of free-floating algae in the pond. There are plenty of largemouth bass to control bluegills, and bluegill density is only moderate, certainly not high (not overabundant). There are few small bluegills because of largemouth bass predation, and most are �big.� However, �big� in this infertile water means mostly 6-7 inch bluegills. An 8-incher is rare.
I�m afraid that most Minnesotans think big bluegills are 10 inches or longer, based on a lot of those good panfish lakes around the state.
Now, I have managed another gravel pit that was older, and simply looked more productive (more plants, more algae, water not as blue). In that pond, we did produce bluegills that exceeded 10 inches when the largemouth bass was the predator in the system.
So, I don�t want to be negative about the bluegills without a solution. However, I don�t have that solution. I just wanted to provide you a little food for thought. Also, I thought Bill Cody might give this bluegill situation a little thought, and we�ll see if he has any helpful thoughts. I wonder how much experience he might have with the sand/gravel pits in Ohio.
Dave
