Is your pond healthy? This is a question landowners should ask themselves when maintaining water sources on their property. Jeremy Duck, fisheries biologist at the Oklahoma Department of Wildlife Conservation, says a “healthy pond”’ is a very broad term, and the definition comes down to what the pond is being used for.
“If it is a water hole for livestock and it has water in it, most of the time it’s a healthy pond,” Duck explained. “But if you’re wanting to have a pond that your cattle can use, but you can also send take your grandkids to and catch a fish, that’s a little bit different. A muddy pond may not look appealing to the eye, but fish can live in that. A super clear pond can look very appealing, and fish can live in it, but you typically can’t have a lot of livestock using it, if any, or else they’re just going to make it muddy. So, there’s kind of that balancing act.”
Algae issues
Algae growth is one of the most common problems that can occur within a pond. Duck said floating filamentous algae is a stringy, slimy type of algae that is usually at the bottom of ponds, but can float to the surface in late summer.
“A lot of people hate that stuff because it looks disgusting, and it has an odd smell to it,” he said. “You can also wake up one day and you have a bunch of dead fish in your pond because of algae.”
In situations where a pond is full of algae, there can be significant algae bloom or growth, and then the vegetation will all die off and decompose—which is often exacerbated by late summer heat. Decomposition uses oxygen in the water and there is not enough available to keep fish alive.
Duck said nutrient availability in a pond is a major contributor to algae growth and limiting the nutrients that enter the water is the best way to reduce it.
“Not all that nutrients are used up every year, and they can accumulate within that water system until it becomes a problem,” Duck said. “You can either limit exposure from those nutrients by not having as many head of cattle on the pasture or create a bigger watershed. You want to have some sort of riparian zone, like grasses and trees, that will help absorb some of those nutrients and block those that run off. Preventing nutrient runoff from adjacent field can also be a significant factor in reducing nutrients to the pond.”
Duck said the best way to eliminate algae overgrowth in a pond is to treat it with copper. However, he said proper timing is crucial.
“With the algae, you have to treat it when it’s exposed,” he said. “Putting copper in a pond before it is a problem doesn’t do anything, because that copper ends up just dissipating and nothing happens. The rule of thumb is that you don’t ever want to treat more than a quarter of your pond, because you would be creating dead algae that’s going to decompose and use up more oxygen. You can cause fish kills if you end up treating your whole pond at once, versus doing it in sections.”
Other types of algae—specifically blue green algae—can be toxic to people and animals. The only indicator of a blue-green algae bloom is the color of the water, but to be certain it needs to be tested. Duck said there are several treatment methods to eliminate blue green algae from ponds. He said most of them are safe for cattle to consume while drinking the pond water but always read labels or consult a veterinarian prior to treating a pond.
Fish habitat and species stocking
Although they can be indicative of excess nutrients in a pond, aquatic weeds or vegetation can be good in ponds if they are kept in check. Duck said vegetation such as cattails and American pond weed typically will not overtake a pond and can provide great fish and wildlife habitats.
The type of fish stocked in a pond can also impact a pond’s health and its diversity in fish population. Duck recommended three main fish species for stocking private ponds. These include bluegill, channel catfish and largemouth bass.
“The bluegill will grow up and eat a lot of insects, and some of the algae,” he explained. “They are prolific spawners and will reproduce all summer. Largemouth bass is a fish people love to catch, and they will eat some of the bluegill.”
Duck said channel catfish are considered a bonus fish, although they do not spawn very well in ponds. This means they will have to be restocked periodically. He said they are omnivorous and will eat some of the bluegill, insects and pond vegetation.
Another species that can contribute to a pond ecosystem is redear sunfish. Duck said these fish will eat worms, snails and little muscles. Some ponds can become infested with a parasite called yellow grub, which attaches to snails and muscles as primary hosts and fish as secondary hosts.
“Sunfish can help break that cycle by eating the snails and muscles so the parasite can’t reproduce and complete a full cycle,” Duck said. “So that’s another good one that you can put in there for a good, healthy pond.”
The only fish species he does not recommend stocking in a personal pond is crappie.
“Crappie are a very prolific spawners, and you can end up having a stunted population very quickly,” he explained. “The department’s stance has always been, don’t stock crappie on anything less than 77 acres. It needs to be something that has a larger body of water that can tolerate them.”
General pond maintenance
Much of the High Plains have received excessive rainfall this year, and that influx of water into low or dry ponds can cause excessive growth of aquatic vegetation in now-full ponds. Fortunately, Duck said new growth can be a positive for ponds, because when it decomposes, it can help filter the ponds.
“It’s also going to produce fantastic habitat for fish to spawn in and for fingerlings to hide in and eat insects,” he said. “A lot of times, when our ponds fill up, we end up having really good reproduction of fish that year and the next.”
However, the influx of water can also trigger additional nutrients to runoff into waterways, which can start the algae overgrowth cycle once again. As far as maintenance for cattle ponds, Duck said one of the best strategies is to keep cattle off dams and spillways.
“If you can fence that part off, that’s best, because that’s your whole structure,” he explained. “Cattle are heavy animals, and in their normal activity, they can end up impacting and developing ruts and all sorts of things.”
Duck said cattle in and around a pond can also create more sediment that will naturally wash into the pond and slowly make it shallow, mucky and less reliable as a water source for livestock.
“If the pond is down, landowners may want to reshape the pond so that it has deeper sections,” he said. “As soon as your pond is super shallow, the light can penetrate all the way to the substrate of the pond, and then vegetation can grow. If you end up having a long, huge area, half of your pond ends up getting silt and sediment in it because the cows have been walking down to it. You can end up having lots of vegetation in this shallow pond, and you won’t have as much water holding capacity in that pond. Then when you have a drought, that’s a smaller footprint of what’s left of your pond.”
Although shade trees can be an asset around a pond, they can also become problematic if they die.
“A lot of people end up letting their ponds have trees grow on the dam, or around that area itself,” he said. “Those roots will grow through that dam, and if that tree dies, or if that root goes a certain way, it can create leaks and cause lots of issues long term.”
Duck recommends removing trees in the wintertime because it’s cooler outside and easier to work on ponds during that season.
Lacey Vilhauer can be reached at 620-227-1872 or [email protected].
