No two ponds are exactly alike. Even ponds in the same watershed and built very close to each other can be very different in appearance, and differences in watershed and soil characteristics are particular to each pond. Differences affecting management are those associated with water quality, plankton and fish populations. Another factor that demands attention in Smith County is weed control.
Aquatic weeds are a common problem in farm ponds, although some aquatic vegetation might be good for the pond. Rooted aquatic vegetation does provide small fish with places to hide from larger predators. The problem with weeds is uncontrolled growth. If too many weeds become established in the pond, too many small fish survive (overpopulate) and predators become thin because they are not able to prey on the forage species. Large growths of weeds also remove nutrients, which reduces algae production (food).
Aquatic weeds can be controlled by manual, chemical and biological means. Manual removal of species such as cattails is practical when they first start to colonize a pond. Woody vegetation along the dam also can be controlled manually.
Chemical control with herbicides is possible, but few herbicides are approved for aquatic vegetation. Vegetation much be accurately identified before it is treated. Herbicides can kill planktonic algae, which leads to oxygen depletion. Oxygen depletion after herbicide treatment is particularly common in hot weather. Check with a fisheries biologist or call the Smith County Extension Office for plant identification information and current herbicide recommendations. When using chemical pesticides, protect yourself and others by strictly following all label directions.
The simplest and most economical long-term aquatic weed control method for aquatic weeds such as duckweed, hydrilla pondweed and milfoil is to stock sterile triploid grass carp. The grass carp was brought to this country for aquatic weed control. Grass carp consume vegetation almost exclusively after they reach 10 inches in length. They will not reproduce in the pond, will not muddy the pond like common carp, will not disturb the nests of other fish and they consume 30 to 40 percent of their body weight in weeds every day during warm weather. The use of grass carp is regulated by the Texas Parks & Wildlife Department. Contact the department or the Smith County Extension Office for information on required permits, stocking rates and lists of available sources.
If you have any questions regarding pond management, contact the Smith County Extension Office, 1517 W. Front St. Tyler; or call 903-590-2980.