From time to time, you pick up a newspaper or glance at the TV and read about a displaced species that is thriving in a new environment, often to the dismay of local residents.
Tropical snakes in Florida, killer bees invading the South, Dutch elm disease, spreading fire ant populations, Japanese beetles and exotic vines that wrap telephone wires along our highways are a few case studies.
It is a phenomena created by man's expansion around the globe and those hitchhikers who become a real environmental problem in their new home.
Civilized man has learned to produce new compounds that improve the quality of life in diverse ways. Nevertheless, there is a downside to the science. The use of chemicals has impacted the waters of Lake Pinehurst right here at home, and it has created a jeopardy not planned for.
The condition that caused the use of herbicide spraying was the rapid expansion of aquatic weeds believed to be hydrilla. The treatment was ordered by the Pinehurst Resort, owner of the more than 200-acre manmade lake and by the homeowners association whose members have upscale homes on the shoreline.
A byproduct of the program was damage to the small-fish breeding grounds. These small fish, mainly bluegills, are the food stock for larger game fish, such as largemouth bass, that delighted anglers, young and old, for many years.
Power boats are not permitted on the lake, and so the buzz-buzz of wave runners, the crisscrossing wakes of water skiers and motorboat chicken games have to be played out somewhere else. That peaceful quality of life is suitable for retirement living.
The lake is ideal to host cocktail cruises on low-speed pontoon boats, sailboating, swimming, tubing and, until recently, fishing. Residents and their guests trolled for largemouth bass and other game fish that were plentiful in the lake. Pinehurst Resort advertised a well-stocked lake and provided fishing guide services for guests who wanted a day off from golf and a day on the water.
Fighting the Invader
But the ecology of Lake Pinehurst changed dramatically when hydrilla -was alleged to have found a home in the lake bed. Hydrilla is native to central Africa or possibly Australia, according to the North Carolina Agricultural Extension Service. It apparently entered the United States as an aquarium plant that was sold to retail dealers across the country for decorative fish tanks to display in homes and business offices. In 1960, hydrilla was discovered growing wild in Florida and the invasion began in ponds, lakes and rivers. The plant can survive freezing temperatures, and an expansion to the north and west was under way.
The Extension Service's publication states that "large hydrilla mats prevent access to many of the prime locations used for waterfowl hunting and most warm-water sport fishing. Low oxygen levels in these mats make them unsuitable for the growth and survival of sport fishes and most other aquatic animals.
"Heavy hydrilla infestations (those that cover more than 25 to 30 percent of the surface in large lakes and impoundments) eliminate fish habitat, cause stunting, and reduce the number of harvestable fish."
Aquatic vegetation had always been a nuisance in the shallower parts of the lake, but for years a program of limited spraying kept the vegetation under control without causing a problem for the ecology of the lake.
The arrival and rapid growth of hydrilla changed the game. Ugly mats of the weed clogged the bays of the lake. Previously, the shallow areas had been a friendly environment for the smaller fish to feed and grow before becoming dinner for the larger game fish in the lake.
As a result of the expansion of aquatic vegetation, Pinehurst Resort, in partnership with the Lake Pinehurst Association, three years ago began an intensive annual program of spraying herbicides on the lake to kill the vegetation. This program costs more than $20,000 per year and is jointly funded by the resort and the homeowners association.
No Longer Premier
Jack Wood, one of the more avid anglers who fishes Lake Pinehurst regularly, said, "Until just a few years ago, Lake Pinehurst was the premier fishing lake in Moore County. And the fishing was superb with catches of several dozen nice bass not uncommon. That is not the case anymore.
"After three years of spraying herbicides on the lake, all the grasses and other aquatic vegetation are pretty much gone.
"Without the structure provided by the vegetation, there is no habitat for small forage fish like bluegills to hide, feed and grow. So now they are basically gone from the lake, and the bass have nothing to eat."
At the urging of fishermen in 2011, the Pinehurst Resort awarded a contract to Foster Lake & Pond Management of Garner to measure the health of Lake Pinehurst. The scope of the project included an analysis of the health of the current fish population in the lake, analysis of the food chain, survey of the lake's bottom, study of aquatic plants, water quality and the negative effects of the lake's population of trash fish.
Funds for buying grass carp, a sterile fish that feeds on aquatic vegetation, were diverted to engage Foster Lake, which conducted the study using electrofishing techniques. The company uses special equipment that can sample, weigh and measure large numbers of fish without harming them. Water quality testing indicated measurements consistent with what is typical for this area.
Aquatic vegetation proved to be bladderwort, and the report stated that no hydrilla was found actively growing, but Foster Lake noted that tubers from the weed could be present in the hydro soil. The grass carp were found to be healthy and actively feeding on what little aquatic vegetation remained after the spraying program.
The Foster Lake report stated in part, "I know that there is a delicate balance in Lake Pinehurst between what is considered 'good' vegetation and 'bad' vegetation. The submersed weeds that are located in Lake Pinehurst can provide some habitat but can also reach nuisance levels very quickly. Dense mats of these plants can do more harm than good. However, some plant life is very beneficial to a fishery by providing habitat and a source of food for small, newly hatched fish."
Fixing the Problem
The Foster report verified that the main problem in the lake was the shortage of forage fish, those upon which the game fish feed. As a result, the game fish were found to be stunted and unhealthy. The report went on to recommend a variety of noninvasive plants that would add to the fish habitat as well as biofiltration to the lake.
Recommendations were made including harvest of certain fish, forage fish stocking, a feeding program and habitat enhancement. In an attempt to add habitat to the lake, the village of Pinehurst supplied a large quantity of discarded Christmas trees that were submerged in the lake's bottom last February and anchored there with supplies provided by the resort. It is not an ideal solution, since Christmas trees compact and decay within a few years, observed one interested fisherman.
Assistant Village Manager Jeff Batten indicated that Christmas trees can be supplied on an annual basis. Foster Lake recommended various types of artificial habitat that does not decay and are said to be effective in providing habitat for small fish.
The Foster Lake report concluded, "The electrofishing survey of Pinehurst Lake indicates an unproductive fishery in poor shape. We recommend supplemental stocking, harvest of largemouth bass, habitat enhancement, and supplemental feeding with a high protein feed. You can expect a rapid improvement in the fishery if these recommendations are implemented."
Funding for such projects is not -currently available from either the Lake Pinehurst Association or the Pinehurst Resort, although comprehensive -spraying of herbicides continues each year.
A small group of sportsmen and homeowners who are concerned about the state of the fishery in Lake Pinehurst are hoping to find a way to permit aquatic vegetation control in -conjunction with actions that will be a compromise between homeowners who find any vegetation offensive and more natural conditions where game fish can grow once more.
Walter B. Bull Jr. lives in Pinehurst. Contact him at firstname.lastname@example.org.