Pond Oxygen Depletion

Asked June 29, 2015, 3:03 PM EDT


In the past few days I have seen three dead Largemouth Bass floating in my 20 acre pond. The pond has Catfish, Sunfish (Brim) and Largemouth Bass in it. The water is way too clear with visibility from 4-6 feet from the surface. Could the recent heavy rains have something to do with that? We have had serious runoff through our spillway in the last month or so. I recently watched a hour long webcast from one of your professors about pond health and I am really worried. I need an algae bloom but the pond is already heavily populated by Coontail and Hydrilla. A few years ago we had a huge problem with Yellow Water Lily that covered about 8 acres of the pond, and from what I have been told, the Lily are dormant and just waiting to come back at some point . I would like to fertilize the pond with a heavy Phosphorous based fertilizer but I am afraid it will only enhance the unwanted weeds and/or possibly awake the sleeping giant in the second coming of the Lily. I would like to treat the weeds with "blue stone" but I don't want to deplete the pond of any more oxygen!!! What do I do? Thanks, Gavin

Limestone County Texas recreational pond management

1 Response

You must treat all aquatic vegetation BEFORE you can start a fertilization program or else you just end up with more of the undesired vegetation. "Blue stone" is copper sulfate and alone it is rated as poor for the treatment of both coontail and hydrilla. I would recommend a treatment with the low cost herbicide diquat, or preferably diquat tank mixed with a chelated copper herbicide such as Nautique.

Only treat 1/4 of the pond at a time, wait 7-10 days, treat the next quarter, and so on until you have treated the entire vegetated area of the pond. No need to apply herbicide in areas that are too deep for vegetation or there is no existing vegetation.

Then you can fertilize with 5-8 lbs of phosphorous per acre using a liquid fertilizer such as ammoniated phosphate or triple super phosphate.