Invasive species are introduced to local waterways from other parts of the world. In the new environment and without natural predators, many adapt to the local aquatic environment, proliferate, and out-compete native aquatic species. Their often prolific reproduction causes ecological disruptions as well as problems with human use and enjoyment of waterways, including clogging water intake pipes and suffocating ponds.
The best way to help manage aquatic invasive species is to stop their spread by cleaning boating and other water equipment and by never releasing aquarium pets or plants into the wild.
Hydrilla is an aquatic plant that invades freshwater ponds, lakes, canals, and slow moving rivers. It can tolerate conditions that most native plants find intolerable, such as low light conditions, high sedimentation, low water levels, and warm temperatures. This species out-competes native aquatic plants, can become so dense that it interferes with recreational boating and swimming, providing excessive habitat for noxious insects such as mosquitoes, clogging water intakes, and causing low oxygen conditions that can stress and potentially kill aquatic animals.
Purple Loosestrife is a plant found near a variety of aquatic habitats including wet meadows, marshes, river banks, and the banks of ponds and lakes. It spreads quickly, crowding out native vegetation and completely altering the native ecosystem; eliminating food and habitat that native species need.
The Northern Snakehead is a fish from China introduced to native waters through the aquarium trade. Snakeheads grow very large and can become expensive to feed. Because of this, it is thought that most introduced snakeheads are former pets that were released when their owners could no longer house them. It is now illegal to own snakeheads as a pet without a permit.
The Northern Snakehead’s voracious appetite disrupts and endangers native freshwater ecosystems through predation on and competition with native species. Their populations are already established in the Potomac River Basin, but the Virginia Department of Game and Inland Fisheries warns that they could spread to other Virginia waters such as the James River and the Rappahannock River drainage basin.
Zebra Mussels are freshwater mussels introduced to Virginia waterways from Eastern Europe, most likely carried on shipping equipment. They are prolific breeders and can attach themselves to any hard surface, resulting in them clogging pipes used for water treatment plants and power plants. They displace and suffocate native endangered mussels, competing with other filter-feeding aquatic animals for food and habitat, and damaging boat hulls and engines.