Why fertilize the pond?

County Agent’s Corner

Filamentous algae can be a headache.

Filamentous algae can be a headache.

Most of us know someone that has a farm pond and that is a good thing if you like to fish. Local farm ponds provide us with some of our best opportunities and memories when it comes to fishing, frog-gigging, and snake shooting!

Growing up, we had a couple of local ponds that we frequented, with permission. One of them was only about a half-acre or so, but we always caught a few fairly good-sized bass out of it. The other pond was much larger and was stocked with catfish, but since we commercial fished all the time, catfish didn’t interest me much.

Looking back, I now realize that by fishing the little pond several times during the year, and keeping a few of the bass, we were helping the pond maintain a proper balance. In a bass/bream pond it is important to keep a good ratio of bass to bream so there is always a good food supply for the bass allowing them to increase in size. If we had continually pitched the bass back into the pond, pretty soon the pond would have become bass crowded. This means there are too many bass for the food chain to support; the bass don’t die, they just stunt. A stunted bass will have a big head and a skinny body. Its head will look like the fish should weigh five pounds, but it will weigh only about two pounds.

Today, as I visit farm ponds I see this situation. I encourage pond owners to invite local kids or family to fish the pond and keep the small bass. By keeping the smaller fish you allow the ones that are left to move up in size. If the pond is managed properly, you may remove 10 pounds of bass per acre, per year, in an unfertilized pond. If the pond is properly fertilized, you may remove 20 pounds of bass per acre, per year.

Ponds may also be managed by selectively removing fish. If you want to move your bass up in size, remove the smaller ones. If you want to have greater numbers of bass in the pond to catch, remove the larger ones. The catch and release protocol that is in place in professional fishing is based on river systems, not ponds. By releasing the fish back into a pond, you are guaranteeing that your fish are going to stunt and the number of large bass will be limited.

If you are fishing and removing bass and bream from the pond for table fare, you may want to consider fertilizing the pond. Again, you can remove twice the pounds of fish from a fertilized pond versus a non-fertilized pond.

Another reason to consider fertilizing recreational ponds is to control weeds. If sunlight penetrates the water to the bottom of the pond, you will get a nice, thick growth of filamentous algae. It will form a thick mat on the pond surface making it impossible to fish. If it covers enough of the pond surface, it can eventually lead to a fish kill.

While algae is a plant and produces oxygen in the daytime, it also uses oxygen. When the sun goes down, algae stops producing oxygen, but continues to use oxygen reserves in the water. Sometimes it uses more than it makes, especially on a warm cloudy day, which may lead to a fish kill, which usually occurs at night. That is why it is rare to see this event actually underway.

As much water as we have had lately, any attempts to fertilize the pond would have minimalized due to the amount of water going out the spillway. As ponds return to normal pool, you may begin to fertilize. Fertilization to control weeds needs to take place prior to weed growth. Once weeds or filamentous algae appears, your efforts go toward making weeds grow and the situation worse. Do not fertilize any pond that has weeds already growing. If you are using your pond to irrigate out of, I wouldn’t fertilize because phytoplankton may clog your filters and drip lines.

To learn more about managing ponds, join us for a pond management workshop on Thursday, March 7. Topics include liming and fertilizing, harvest, dam maintenance, fish kills, stocking, aquatic weed management, and much more. The program will be conducted at The Village at Blount Springs Chapel, 200 Murphy Creek Road, Hayden, AL 35079. There is a $25 dollar fee that covers refreshments, handouts, and lunch. Registration forms may be picked up at the Extension office or e-mail me at porchdw@auburn.edu and I will send you one. Ponds are a great asset when managed properly, but may also be a headache for some people. Join us for this opportunity. Seating is limited.

Dan Porch is County Extension Coordinator with the Blount County Extension Office. Dan lives in and loves Blount County and is available to answer your questions about conservation, agriculture, natural resources, and gardening. He can be reached at (205) 274-2129 or porchdw@aces.edu.