Farm and Ranch
Pond maintenance boosts performance, prevents catastrophes
By Adam Russell, Texas A&M
Jun 13, 2019
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College Station, Texas -- Pond health and maintenance should be a top priority for landowners who want to get the most out of their favorite fishing hole, said a Texas A&M AgriLife Extension Service expert.

Dr. Todd Sink, AgriLife Extension aquaculture specialist, College Station, said maintaining ponds is critical to increasing fish productivity and avoiding fish kills.

Environmental factors like declining dissolved oxygen during peak summer months or inhospitable pH and alkalinity levels can lead to major problems in stock ponds, Sink said.

“Summer is coming,” he said. “Right now is a good time to be planning or taking action to prevent potential issues for stock ponds. July and August can be deadly if dissolved oxygen levels are not where they should be. We want to help pond owners avoid catastrophe and take steps to set their pond on a good path for long-term production and enjoyment.”

Setting up and maintaining a pond’s ecosystem properly can produce a thriving food chain that will produce higher levels of sport and food, he said.

“Stock ponds are something that many Texans enjoy recreationally and to put food on their tables,” he said. “But pond maintenance is often overlooked in varying degrees. Some things can reduce pond production and ecosystem health while others can cause major fish die-offs. Right now is a good time to go over science-based recommendations and steps every pond owner can take to create a high-performing stock pond.”

AERATORS

Providing supplemental aeration isn’t necessary, but it is a preventative tool to ensure fish have enough dissolved oxygen, Sink said.

Choosing the right type of aerator is important, he said. He recommends the bottom-style aerator because it mixes the entire water column so fish can utilize the entire pond.

They cost a little more, but are more reliable than surface aerators, he said, which can be problematic because they mix dissolved oxygen only in the top two to four feet of the pond.

“Surface aerators don’t mix as much dissolved oxygen, and they don’t prevent stratification and possible turnover,” he said. “When the sun heats pond water, typically about six to eight feet deep in Texas, the top layer becomes less dense. So, you have warm, less dense water sitting  there, and the cool bottom layer becomes devoid of oxygen. A turnover event occurs when the water cools down and the water with no oxygen mixes with the top layer. That mix can cause fish kills.”

Sink said aerators should be on a timer and only run from dusk until dawn,  when oxygen is most needed in ponds.

AQUATIC VEGETATION

Aquatic vegetation is the cause of 80 percent of low dissolved oxygen fish kills in Texas, Sink said. So, it’s important to ensure that no more than 10-15 percent of the pond’s overall area is covered in vegetation.

Fish kills in farm ponds and lakes can be caused by many factors, but the most common problem is the lack of dissolved oxygen due to aquatic vegetation. (Texas A&M AgriLife Extension Service photo by Dr. Todd Sink)
“During the day, vegetation produces oxygen, but it also consumes oxygen all night long when there is no light for photosynthesis,” he said. “So at some point, especially in summer, the dissolved oxygen deficit can cause fish to die.”

Sink recommends using herbicides or biological controls for aquatic vegetation. Manual removal of vegetation can cause more problems like causing the plant to spread.

Pond owners need to correctly identify the plants to determine which herbicide will be effective, Sink said. The AgriLife Extension website https://aquaplant.tamu.edu/ can help pond owners identify and choose treatment options for aquatic vegetation.

FERTILIZATION

Pond owners who want maximum fish production often need to fertilize, Sink said.

“A fertilized pond can produce four to six times more fish because it creates more food throughout the food chain,” he said. “Fertilizers feed phytoplankton, which is eaten by zooplankton. Zooplankton feed baitfish, and baitfish feed sportfish like bass and catfish. Fertilizer is the starting block for a healthy pond ecosystem.”