Invasive Hydrilla Found In Harriman State Park

ROCKLAND COUNTY, NY — The invasive aquatic plant called Hydrilla has been found in Lake Sebago, the largest lake in Harriman State Park, state environmental and parks officials said.

Hydrilla is native to Australia, Asia and Africa and is believed to have made its way to the U.S. as an aquarium plant. It grows and spreads rapidly and is one of the most difficult aquatic invasive plants to control and eradicate in the United States. Hydrilla is often spread by boaters, as hydrilla fragments can cling to boats and trailers. Very small fragments of hydrilla can start new populations.

Its dense mats of vegetation can interfere with boating, swimming, and fishing, and squeezes out fish and native plants.

"Nobody wants to swim in a lake like this," says the narrator of the state's video (see above).

Communities that rely on tourist dollars from recreational use of lakes and ponds can suffer serious losses in income. Waterfront property values can be greatly reduced, and property owners may incur some of the costs of management, which is expensive and long-term.

Hydrilla first appeared in New York State in 2008, and is now known to be in 12 counties. Hydrilla has been a problem in the Croton River for years.

State environmental and parks officials are working to map the extent of the infestation at Lake Sebago to determine proper management actions.

Meanwhile, the boating season isn't over. Boaters should always follow the Clean, Drain, Dry best practices before launching or retrieving any watercraft to ensure they are not bringing aquatic invasives species into a lake or carrying AIS out of a lake into another waterbody.

This is especially important in all the lakes in Harriman State Park in light of the recent identification of hydrilla.

“Aquatic invasive species like hydrilla can pose a significant threat to the health of our lakes and rivers and to the habitat they provide for fisheries," said DEC Deputy Commissioner for Natural Resources Katie Petronis. "With our extensive boat steward program and rapid response plans, DEC has been bolstering current invasive species surveillance, outreach and education and taking actions to address these invaders as quickly as possible to protect our fisheries, wildlife, and local recreational economies into the future.”

Research shows that recreational watercraft are a top vector for the transport and introduction of AIS throughout the country. At many State Park locations, watercraft inspection stewards provide education and outreach to many boaters and offer voluntary inspections. State Parks also provides environmental education on aquatic and terrestrial invasives to visitors.

The 310-acre Lake Sebago is the largest lake in Harriman State Park. The name is Algonquian for "big water."

It's not the only lake in Harriman with problems. SEE: Toxic Algae Bloom Closes Lake Welch Beach