“There’s no such thing as a trouble-free fishing pond,” says John Hogue of Bryant, Ark., a retired fisheries biologist for the Arkansas Game and Fish Commission. “No matter how well you manage your pond, sooner or later you’ll experience problems of one sort or another. Many problems can be solved easily and inexpensively. Others are impossible to resolve without extensive repairs and expert advice.”
During 25 years as a fisheries biologist, Hogue dealt with every type of pond problem imaginable. Five of the most common are outlined below, with Hogue’s advice for correcting them.
Some water loss is expected in ponds. If the rate of loss is excessive, however, and a pond’s water level becomes extremely low, the cause should be investigated.
“The main cause of leaks is trees growing on the pond’s levee,” says Hogue. “I’ve never seen a pond levee with big trees on it that didn’t have seepage. If a tree dies or is cut, the roots die and leave holes in the levee, causing leaks.
“Don’t let trees grow on new pond levees,” he continues. “If trees are present already, cut those three inches or less in diameter before they cause problems.”
Leaks also occur in ponds built without a clay core in the earthen dam.
“Clay bonds the above-ground portion of the dam to the subsoil,” Hogue says. “This prevents excessive seepage. Dams constructed improperly usually leak.”
Stopping large leaks may require extensive reconstruction. When seepage is the culprit, Hogue recommends a bentonite treatment.
“Bentonite, sometimes called bentonite clay, is drilling clay that swells to twice its normal size when wet,” he says. “You can obtain it at farm co-ops and drilling equipment companies. The pond is drained, then bentonite is spread on the bottom and disked in. When the pond refills, seepage is usually eliminated.”
Pond Scum & Excessive Vegetation
A green or brown surface film on your pond can be disconcerting, but it’s seldom cause for alarm.
“Scum is usually nothing more than algae, plankton or duckweed,” Hogue notes. “These plants thrive in ponds with abundant nutrients and are often seen when people overfertilize their pond or fail to fertilize at the proper time. Avoid problems by asking a fisheries professional to explain how and when to fertilize.”
Aquatic plants are desirable in ponds, providing cover, food and oxygen for fish. Excessive growth, however, hampers fishing.
“Vegetation can be controlled chemically, mechanically or biologically,” Hogue says. “Before using chemicals, positively identify the problem plant. Then seek professional advice on safely using the proper chemicals. Decaying vegetation removes oxygen from the water, so treat only one-fourth of your pond at one time to avoid suffocating fish.
“If the problem is excessive vegetation around the pond’s edge,” he continues, “you can use rakes to remove it mechanically. This is very effective. You also can eliminate shoreline vegetation by deepening the edge of the pond, making it at least 2 feet deep. A deeper shoreline prevents growth of many plants and allows easier fishing.”
Plant-eating fish provide a biological solution.
“In Arkansas, we recommend stocking white amur (grass carp) for plant control,” says Hogue. “These fish eat soft-stemmed vegetation and algae, and if stocked in proper numbers, they provide the best means of controlling excessive plant growth. Check with your state fisheries department to see if they can be stocked legally where you live.”
Trying to raise fish in muddy water is like trying to grow vegetables under your porch. Without sunlight, microscopic plants cease growing, and water animals dependent on them fail to produce the necessary natural food for fish. The result is few fish that are hard to catch.
“To eliminate muddiness, we must determine what’s causing it,” Hogue says. “If there’s runoff over bare ground, plant cover is needed to stop the runoff. Bottom-feeding fish like carp and bullheads also can muddy the water. If these fish are present, you may have to kill out the pond with rotenone and start over.”
Turbidity is also caused by water chemistry and soil type.
“Some ponds have red clay or other bottom substrate where clay particles suspend in the water because of an electrical charge on them,” Hogue says. “In these ponds, a temporary solution is provided by adding 10 bales of fine-grass hay per acre. These are broken and scattered, and as the hay decays, it forms an amino acid that breaks the electrical charge on clay particles, causing them to settle. Besides clearing the water, the decaying hay helps produce microscopic plants and animals important in the food chain.
“Agricultural gypsum and hydrated lime also help reduce muddiness, but the water must be tested to determine application rates.”
Unbalanced Fish Populations
Maintaining a catchable fish population requires good pond construction, correct stocking and careful fishery management. Unfortunately, unregulated fishing can throw fish populations out of balance. And because individual ponds vary considerably in the amount of fish they can support and in the rate the fish grow, it’s impossible to give hard-and-fast recommendations for the numbers or weight of fish to remove.
“In new ponds, we recommend stocking largemouth bass and bluegills,” Hogue says. “Bass control the bluegills, and bluegills feed the bass. Catfish can also be added. Stocking rates are based on the condition of the pond and its watershed.
“The bass/bluegill ratio is what usually causes problems,” he continues. “With too few bluegills, bass don’t have enough food to reach a larger size. Overabundant bluegills may eat bass eggs, preventing successful spawning. It’s difficult to maintain an ideal balance, and if the fish population gets out of kilter, the pond owner may start noticing stunted or diseased fish.
“In this case, it’s usually best to get a fisheries professional to check the pond and make a recommendation. You can contact your county extension office, state wildlife agency or private fisheries consultants for help. There are also many good books and pamphlets available, and informative websites, which offer advice on solving various problems.”
These are just five of the many problems pond owners may encounter.
“If you have a problem you can’t solve,” says Hogue, “seek the advice of a fisheries biologist. Our training can help you get the most out of your pond.”