An infrequent but troublesome problem in East Texas ponds is blue-green algae, or cyanobacteria. These microscopic aquatic organisms thrive in warm, nutrient-rich waters.
Under certain conditions, cyanobacteria form harmful algal blooms. These blooms produce toxins, called cyanotoxins, which can harm livestock, pets, aquatic life, and humans. Ingesting water contaminated with cyanotoxins can cause illness or even death in animals. Additionally, cyanobacteria create taste-and-odor compounds that foul the water, disrupt ecosystems, and interfere with recreational use.
Many ponds in our area contain algae, but not all are harmful. Common types include filamentous or planktonic algae. The filamentous algae grows on the bottom then floats to the top. I always think of it as the “green, slime” hung up on my lures when I go fishing. The planktonic algae can simply turn a pond pea-green and gather up in clumps but, because it is a single celled plant, doesn’t get hung on lures.
Most folks who have called me, have easily noticed a very different colored algae (pond scum or slime) than what they have always had. Pond owners can identify the potentially harmful blue-green algae by its surface coloration, also called the “bloom”. The bloom can appear as a single cell or, filamentous (thin and stringy or hair-like), or colony-type algae. It is buoyant and will form “scum” layer or floating mats on water surface. It can cause blue, green, brown, or reddish-purple coloration of water. A paint-like sheen or mats on the water. True to its name, a distinct ‘blue’ coloration is evident on the surface.
If livestock or pets drink contaminated water, look for symptoms such as weakness, vomiting, diarrhea, or sudden death. Fish kills or reduced aquatic activity may also indicate the presence of cyanotoxins. To confirm, send water samples to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL). You can contact them at 979-845-3414 or visit their website at tvmdl.tamu.edu.
To prevent harmful blooms, monitor your pond water quality regularly, especially during the hot, dry summer. Reduce nutrient runoff from fertilizers and livestock waste to reduce algae food sources. If you are already near a source of electricity, aerate your pond water to disrupt algae growth and encourage oxygen flow.
If found, be sure to restrict access to the contaminated pond by livestock and pets. Next, remove algae mats if possible. Though difficult, try raking the blue=green algae onto the shoreline.
Finally, use an approved algaecides and follow the label closely. Approved algaecides can be found at most every feed store. Again, follow the label closely as misuse, and certainly overuse, can kill fish.
For a long-term solution, allow plant buffer zones around ponds to filter runoff that may contain excess nutrients from animals and fertilizers.
While I have seen countless ponds with algae, it has been uncommon (in my experience) to see this problematic alga. Left unchecked, Blue-green algae contains cyanobacteria which can pose a direct threat to livestock health, wildlife and pets.
Proper protection of our water sources ensures long-term sustainability for East Texas landowners. For much more information about this and other pond weeds, look up the Texas A&M AgriLife’s AquaPlant website here: https://aquaplant.tamu.edu/ .
