Aquatic vegetation growth is the No. 1 problem that plagues Texas pond owners during the growing season. Excessive vegetation can hamper recreational activities, such as fishing and swimming, and in some cases negatively impact livestock watering and irrigation uses of the pond.
“Just because some aquatic vegetation is present, it doesn’t necessarily mean control is required,” said Billy Higginbotham, Wildlife and Fisheries specialist. “In fact, ponds managed primarily for largemouth bass may benefit from some aquatic vegetation as it provides both habitat and harbors a variety of food sources. But, once weed coverage exceeds about one-third of a pond’s surface, the benefits provided begin to decline as too much vegetation may limit the ability of bass to access forage fish present.”
AgriLife Extension’s aquatic weed website, http://aquaplant.tamu.edu, is another excellent resource for aquatic weed identification. The Aquaplant website also provides species-specific control recommendations, including chemical, biological and mechanical options.
Pond owners should also be aware that the warmer water temperatures during summer decrease the ability of water to hold oxygen.
“During the summer months, many deep ponds develop water stratification, where a warmer, lighter layer of water is found above a cooler, denser layer of water,” he said. “A cold thunderstorm or wind can cool the oxygen-rich upper layer of water to the same temperature of the oxygen-deficient deeper water and the result is a mixing of the two layers. Organic matter on the pond bottom is stirred into the water column and undergoes further decomposition while the overall oxygen content of the water declines to the point that fish die within a day or two of this weather event.”
“Oxygen will be at its daily low at daylight, so pond owners should also check their ponds early in the morning if low oxygen is suspected,” he said. “Numerous fish swimming lethargically at the surface at or near daylight is another sign of low oxygen content.
Should oxygen depletion occur, and fish are an important resource to the landowner, quick action can mean the difference between a pond full of dead fish.
Running a boat with an outboard motor in a fixed position, either against the bank or on a trailer backed into the water can help circulate the water and increase its oxygen content. If a boat and motor are not available, a pump set where the intake pulls water from near the surface and sprays it back over the pond can also increase oxygen by establishing a temporary circulation pattern and bringing more water in contact with the air interface at the surface.
“The summer months provide great recreational opportunities involving Texas farm and ranch ponds,” Higginbotham said. “Diligent weed control and a keen eye on the water can guarantee sustainable fishing and healthy fish populations throughout our long hot Texas summers, and beyond.”
Lonnie Jenschke is an Erath County extension agent.