Courtesy of Marc Rapport, S.C. DNR
In what could be a bad dream or a bad movie, an alien life form descends on the Sampit River, making itself at home and threatening to consume its new neighbors with piranha-like jaws.
This invader isn’t from a distant galaxy - it’s a South American fish called a red-bellied pacu, and its meals consist of plants, insects and other fish.
At 33-inches long, it probably outgrew its owner’s fish tank, and the budding aquarist simply dumped it in a local stream. The pacu adapted its diet and spent its lonely days trolling the river without a mate, sparing the local ecosystem the nightmare of unchecked reproduction that can accompany aquatic invasive species, until it was caught recently by a Georgetown County fisherman.
Aquatic invasive species are defined as non-indigenous organisms that live most or all of their lives in water and have the potential to adversely affect ecological health or economic activity, according to the S.C. Aquatic Invasive Species (AIS) Task Force. The 35-member AIS Task Force was created in 2006 to develop a statewide AIS management plan and enhance interagency communication and coordination regarding aquatic invasive species issues.
While the pacu in the Sampit got local headlines, more pervasive in South Carolina is the problem of aquatic invasive plants, especially hydrilla.
“Aquatic invasive species typically develop very large populations that compete with or displace desirable native species,” says Steve de Kozlowski, assistant deputy director for the DNR’s Land, Water and Conservation Division and chairman of the S.C. Aquatic Plant Management Council.
In South Carolina, the economic and ecological repercussions include blocked water flow for municipal, industrial, agricultural and power-generation purposes; degraded water quality; boat damage; flooding because of restricted water flow; fish population declines; reduced waterfront property values; expanded mosquito breeding grounds; and impaired recreational outlets for swimming, hunting, fishing and boating.
South Carolina spends about $450,000 per year managing invasive aquatic vegetation threats alone, and Florida spends more than $20 million, according to de Kozlowski. In 1991, an invasion of the aquatic weed hydrilla shut down the St. Stephen hydroelectric plant on Lake Moultrie for weeks, costing $4 million in lost productivity and $526,000 worth of gamefish deaths.
