[Image: neighborhood pond]
News Release Distributed 08/06/12
Many people enjoy living near a body of water. For this reason, there has been an increase in the number of recreational ponds built in Louisiana over the past 10 years, according to Greg Lutz, an aquaculture scientist with the LSU AgCenter.
“Most of the newer ponds in the state are the result of new housing construction with homes being built around the pond,” Lutz said. “The majority of the ponds are not large, ranging from approximately one-half acre to less than 2 to 3 acres, but some are as large as 40 acres.”
The estimated number of private recreational ponds in Louisiana is around 120,000 with the owners representing a broad spectrum of socioeconomic classes. Lutz noted that studies have found that in rural areas, a well-managed pond can increase property values five to 15 percent.
But just like your lawn, ponds require maintenance and prudent planning.
“A lot of potential problems can be eliminated through proper design and construction,” Lutz said.
He recommends consulting with someone from the Natural Resources Conservation Service before beginning construction. “Poor design can lead to many problems such as water seepage, water quality issues and aquatic weed problems.”
Lutz said that nearly 60 percent of the calls he gets concerning pond issues are related to nuisance weeds. He said proper design and fertility practices can alleviate this problem.
If weeds get established, there are only a few herbicides that can be used on fish ponds, and the herbicides are usually effective on specific plants while exhibiting little or no control over others. A pond owner may be required to buy multiple herbicides and conduct multiple applications to rid the pond of weeds.
A soil sample should be taken either before or after the pond is filled. The sample is used to evaluate the fertility of the pond and determine if lime is needed to increase fertility, Lutz said.
Make sure the sample is a mixture from five or more locations around the bottom of the pond in areas that represent the average depth, Lutz said. Contact your parish LSU AgCenter extension agent for guidance on getting the soil analyzed.
Water quality can be a major issue in ponds in late summer and early fall. High water temperatures reduce the dissolved oxygen capacity of a pond. At the same time, algal production intensifies, creating more demand for oxygen at a time when capacity is lower. This situation places stress on resident fish.
Lutz said larger fish experience higher levels of stress because they require more oxygen than smaller fish. Lutz added that fish under stress are more vulnerable to diseases.
In early autumn, ponds are at risk of undergoing temperature inversion, commonly referred to as a “turnover.” This occurs is when large amounts of water in the lower half of the pond are nearly devoid of oxygen and mix into the upper half, reducing the oxygen throughout the pond.
Turnovers can be triggered by strong winds or unusually heavy rainfall. With the month of September in the peak of tropical storm activity, the likelihood of a turnover increases.
A pond owner is limited in what can be done to remedy a turnover. “Aeration of the pond is about the only option. Even then it won’t solve the problem, but it can provide a place of refuge for fish until the situation cures itself,” Lutz said.
If a fish kill occurs, Lutz said, the size of the fish may give clues to the cause. “If larger fish are dying first, it is generally a dissolved oxygen issue. If small fish are dying first, it is usually a toxicity issue. If a turnover occurs, both large and small fish will die at the same time,” he said.
For more information regarding pond management, visit www.lsuagcenter.com and type in “pond management” in the search box.