Restoration efforts breathe new life into reservoirs
Anyone who enjoys outdoor recreation offered by reservoirs across the South are benefitting from ongoing aquatic ecosystem restoration projects being conducted by fisheries biologists. Created 50 to 60 years ago, the reservoirs were built for flood control, power generation, or as water collection and holding facilities for municipal water supplies. Through the years the ecosystems in these reservoirs changed and evolved, but many struggled to reach an ideal equilibrium...
• Fishing and recreation improve with aquatic plant and wildlife management program
KING OF PRUSSIA, PA, March 31, 2008 -- Anglers, boaters and anyone else who enjoys outdoor recreation offered by reservoirs across the South are benefitting from ongoing aquatic ecosystem restoration projects being conducted by fisheries biologists.
A primary goal is to provide habitat in the summer for recently hatched fish such as bass, bluegill and minnows. Native vegetation is a prime nursery habitat available for young fish. More and bigger fish are a major benefit of the efforts.
"It's important to have a diverse community of native aquatic plants in a body of water," says Rick Ott, fisheries biologist and district supervisor with the Texas Parks and Wildlife Department (TPWD) in Tyler, Texas. "These plants provide valuable fish and wildlife habitat, are a food source for waterfowl and other aquatic wildlife and improve water clarity and quality by helping reduce shoreline erosion and sediment re-suspension. They also help prevent nuisance plants from encroaching on the native community."
Created 50 to 60 years ago, the reservoirs were built for flood control, power generation, or as water collection and holding facilities for municipal water supplies. Through the years the ecosystems in these reservoirs changed and evolved, but many struggled to reach an ideal equilibrium that would support favorable aquatic plant, fish and wildlife communities. The reservoirs also were susceptible to invasion by weedy non-native plants.
To enhance the aquatic ecosystems, systematic restoration work began in the 1990s and is helping improve the region's reservoirs for all uses. Fisheries biologists from Texas to the East Coast have assumed the role of landscapers, guiding this process, supported by municipal water authorities, angler groups, lake and homeowner associations, the Army Corps of Engineers, the Southern Division of the American Fisheries Society Reservoir Committee and others.
In Texas, Ott, along with Mark Webb, fisheries biologist and district supervisor with the TPWD in Bryan, Texas, have been closely involved with that state's aquatic restoration efforts.
Reclaiming Lake Bellwood
Lake Bellwood, a reservoir serving the municipal water needs of Tyler, Texas, was nearly abandoned for recreational use in the late 1980s when 70 percent of the lake became overgrown by hydrilla (Hydrilla verticillata), an invasive non-native plant which forms a thick mat near the water's surface. Those who have swum or skied in waters heavily populated with aquatic weeds or repeatedly stripped heavy weeds from fishing lures know what a frustration an overgrown reservoir can be.
Today, thanks to an integrated pest management and restoration program started in 1997, Lake Bellwood is once again a destination for anglers and water lovers. "Lake Bellwood is in absolutely fantastic shape," says Ott. "It is filled with a wonderful, diverse native plant community that is expanding all the time. We've also seen improvements in the largemouth bass population since we've controlled the hydrilla."
"We removed the hydrilla by using a low-rate application of Aquathol® herbicide and copper early in the spring," says Ott. "Early application and minimal water flow in Lake Bellwood helped us keep the herbicides in contact with the hydrilla long enough for them to be very effective in treating it. By applying early in the season, we avoided damaging the desirable plants that were dormant or didn't yet have a lot of leaf surface."
"The Aquathol® and copper treatment worked very well yet didn't impact water quality. After excluding the hydrilla, our next step was to fill that niche in the plant community with desirable native species to resist hydrilla coming back."
After planting wild celery (vallisneria), water star-grass, American pondweed and Illinois pondweed at Lake Bellwood, biologists installed protective six-foot cages to keep fish and other herbivores away while the young plants were being established. It takes about five years for newly introduced species to establish and expand outside the protected areas.
"Our 10 years of work at Lake Bellwood are paying off and have shown anglers and water authorities alike that through careful management we can remove undesirable plant species, prevent re-infestation and improve the fish community while doing so," says Ott.
Integrated program controls weeds in Lake Conroe
In the late 1970's Lake Conroe, a 21,000-acre reservoir in southern Texas became infested with hydrilla. By 1981, nearly 7,500 acres were thick with the invasive weed. An infusion of 270,000 grass carp eliminated the hydrilla and eventually all plant life, denuding the reservoir. However, over the next 20 years these grass carp began to die of old age and hydrilla once again became a problem. To remedy the situation, biologists have implemented a program which includes restocking the lake with non-reproducing (triploid) grass carp, chemical control of hydrilla with Aquathol® for annual spot treatments and re-establishing the native plant community.
"Lake management is definitely a balancing act," says Webb. "In Conroe, the combination of grass carp and chemical treatment has helped us keep the hydrilla to between 500 and 2,000 acres which isn't bad in a 21,000-acre reservoir. As the native plant community continues to expand, we'll hopefully see more success in keeping the invasive plants out and can use chemical control primarily to clear boat lanes, around boat docks and along developed shorelines."
Aquathol® (endothall) is a product of United Phosphorus Inc. (UPI), which is one of North America's leading suppliers of post-patent crop protection technologies.