In-Fisherman

"Pits created by mining operations often fill with rainwater, springwater or groundwater from the water table. Where water chemistry is suitable, bass and many other species thrive. Pits are typically deep and clear, with manmade structure such as shelves, roadbeds, mine shafts, and spoil piles.

Biomass is usually low due to infertile conditions, but trophy fish are possible. Some Florida phosphate pits are fertile and produce extraordinary bass fishing where the harvest is controlled. And the world-record 4-pound, 2-ounce bluegill was caught in Ketona Lake, a flooded limestone mine in Alabama."

The Fla lakes waters flow through natural limestone formations into the old phosphate pits so the two in common happens.

In much of the south the limiting factor in water fertility is acidity ( the lack of limestone). Once lime is added nothing else is required. Some locations require P but others do not. That is why it is necessary to know your watershed/water and not just blindly add fertilizer.

Here is another report on Ketona:

"Biologists, eager to learn the quarry’s secrets, sampled its bream and found no genetic reason for the massive fish. They did, however, find an environment suitable for producing big bream. There was nothing magical: The habitat had just the right combination of minerals, population control and fishing pressure.



According to biologists, the presence of limestone promotes high growth rates and higher productivity, because it enhances nutrients."


The point is all pits , like all ponds are different. Those that are old hard mineral pits (rock ,aggregate , granite etc) are usually infertile. As noted by IN-Fisherman.That was the point Dave and I were making.