Algae is very common and will be present in all water that is exposed to sunlight. However, on occasion, this common aquatic inhabitant can become overwhelming in farm ponds.
There are three main types of algae in found in freshwater ponds.
Chara is a branched algae that resembles flowering plants. It has a musky odor and a “crunchy” feel, and is totally submerged.
Single-cell and colonial algae include microscopic phytoplankton species that occur in plankton blooms and are usually considered desirable as part of the food chain in fish production.
Filamentous algae is most commonly seen in North Texas pond waters. It is considered a nuisance and seen as a mass of thread-like filaments totally without leaves, often visible in mats that float to the surface. It has been described as a mass of wet wool or bright green hay.
Filamentous algae can be raked or seined from the pond’s surface. This is generally recommended as a first step to control it since it is obviously the cheapest method. Another mechanical method of control for algae is an Aquashade product. Aquashade is a nontoxic dye or colorant. It will prevent or reduce algae growth by limiting sunlight penetration. Because these products can alter the pond’s natural food chain, they should be used with caution.
Biological controls for algae would include either triploid grass carp or tilapia.
Triploid carp are regulated and will require a license from the
Texas Parks and Wildlife Department — www.tpwd.
state.tx.us. Triploid grass carp will consume filamentous algae, but it is not their preferred food. They will consume other aquatic vegetation first.
Tilapia will readily consume filamentous algae. However, they are a warm-weather species and will not survive in temperatures below 55 degrees. This may reduce their effectiveness in this area since weather fluctuations could delay stocking.
Chemical methods of controlling filamentous algae are usually successful and include copper-based compounds, alkylamine salts of endothall, and diquat.
Copper sulfate, or “blue stone,” is the most common treatment. It comes in several forms, but the smaller crystals dissolve more easily than the larger variety. This treatment will be less effective in very hard water as it will bind with calcium.
Cutrine Plus, K-Tea, Captain, Algae Pro, Clearigate and others are all chelated copper herbicides that are able to control filamentous algae. All copper compounds can be toxic to fish if used above labeled rates or if they are used in soft or acidic water.
Hydrothol 191 is an alkylamine salt of endothall and acts as a contact herbicide. It works quickly and kills all plant cells it contacts. It also can be toxic to fish.
Pond design and construction can be the most significant method to control unwanted aquatic vegetation. To learn more about these topics, visit http://aquaplant.tamu.edu.
The Denton County Beef, Crops and Forage Committee will have a pond management workshop and fish fry May 10 at Rancho De La Roca in Aubrey. Guest speaker will be Will Moseley, wildlife and fisheries consultant, Samuel Roberts Noble Foundation. The meal will be served at 6 p.m.
Cost is $15. Registration deadline is May 7.
To register or for more information, call 940-349-2880 or e-mail firstname.lastname@example.org.