Every year, aquatic invasive species cost Pennsylvania millions of dollars, underscoring the importance of being vigilant while recreating and informing officials of any potential spread.
Aquatic invasive species (AIS) are non-native plants, animals, or pathogens that harm the environment, reduce biodiversity, and cost communities time, money, resources, and lost revenue. AIS differ from native species, which play an ecologically important role in the aquatic community, or naturalized species that aren’t native but don’t cause harm to humans or the ecosystem.
“Oftentimes, [AIS] are introduced by humans, sometimes on purpose but mostly by accident,” said Amber Stilwell, a Coastal Outreach Specialist for the Pennsylvania Sea Grant working in the Lake Erie Region.
Regardless of how they arrive, once established, AIS are very difficult to get rid of.
“They grow really fast, they eat a lot of food, they take up a lot of space, and they can be really dangerous to water quality and the species around them,” Stilwell said.
For that reason, it’s better to prevent AIS from getting there in the first place.
To avoid further spread, officials post signage at water recreation sites across the state that help people to identify AIS and provide methods for killing them before they take their water craft out again. The general advice is: clean, drain, dry. Drying boats and equipment for at five days is advised, as some species can live outside water for longer periods.
Humans contribute to the spread of AIS in numerous ways. Species like the New Zealannd mud snail can stick onto boats, motorized or unmotorized, and hitch a ride to another body of water. Many crayfish species are accidentally moved form one water body to another, mostly as bait. Other times, invasive species are introduced after people release their pets into the wild. (The goldfish was one of the first AIS in North America, brought in the 1600s for aquariums and water gardens.)
Hydrilla’s ability to grow an inch per day has earned it the nickname “nature’s perfect week. Once it gets large enough, it blocks enough sunlight to alter the chemistry of the water. The plant restricts boating, fishing, swimming, and other recreational uses. Hydrilla mats can get so dense that even a motorized boat can’t get through.
Ways to Report AIS
- Use Pennsylvania Sea Grant's mobile app: PA AIS
- Call 1-822-INVASIV
- Fill out Pennsylvania Fish and Boat Commission's online form
Climate change has altered ecosystems, disrupting native species and making it easier for invasives to proliferate. Kudzu vine, for example, reacts strongly to the amount of carbon dioxide in the atmosphere. A rise in carbon levels has allowed kudzu to grow bigger, faster, and stronger.
New Zealand mud snails and hydrilla are appearing in new locations as warming waters expand their range.
“These highly adaptable, highly successful species that aren’t native are able to withstand changes in climate in our region better than our native species,” Stilwell said.
To prevent their spread, Pennsylvania Sea Grant has a team of experts who focus on rapid response, addressing incidents before they get out of hand. The Pennsylvania Department of Conservation and Natural Resources, along with various partners, has also been working for several years now to manage hydrilla in places like Pymatuning Reservoir, the largest lake in the Commonwealth.
Part of the effort to stop AIS spread includes training local organizations to deal with infestations on their own. Mercer County Conservation District, with PA Sea Grant’s support, devised a system for tackling a water chestnut infestation. Since then, the species has nearly been eliminated.
“They were able to respond to an overwhelming amount of water chestnut,” Stiwell said. “Now they are seeing only a couple plants pop up once in a while to the point where they can manage it with volunteers just removing a few plants.”
The Pennsylvania Fish and Boat Commission, the U.S. Fish and Wildlife Service, the Susquehanna River Basin Commission, and other partners have been working to monitor and control Northern Snakehead in the lower Susquehanna River, a predatory species that poses a threat to native fish.
Pennsylvania Sea Grant also focuses on public outreach. The organization works closely with the Governor’s Aquatic Invasive Species Council, which educates the public on invasive species issues and advocates for funding and policies to better combat them.
If people encounter, AIS, Stilwell recommends they take photos and report it. If it’s an invasive animal and it’s safe to do so, take up-close photos from multiple angles. If it’s a plant, get photos of the leaves, stems, and roots if available. Then take a wider shot of the whole infested area.
When it comes to plants, Stilwell says not to try to pull out any invasives. Some reproduce by fragmentation, and if a segment floats away it could start a new infestation elsewhere.
People can report the discovery of AIS to Pennsylvania Sea Grant with a mobile app: PA AIS, or call 1-833-INVASIV. Fish and Boat Commission also has an online form people can fill out to report AIS.
At home, one of the best things people can do to address invasive species is to replace them with native varieties. Pennsylvania Sea Grant is planning several workshops in 2024 for landscapers and water gardeners to teach them the importance of planting native species.
To learn more about aquatic invasive species and help in their removal, consider attending some of these upcoming events, organized by Sea Grant and partner organizations.
Oct 13: Native Plant Walk in North Park, hosted at North Park Cabin (intersection of Wildwood Road and Babcock Road in Allison Park) Pittsburgh, PA 5:30-7:30 p.m.
Oct 14: Park Till Dark, PA Sea Grant will have a booth at the spillway kayak launch from 10 a.m.-4 p.m.
Oct 25: Invasive Species Happy Hour Hike, Asbury Woods, Erie, PA 4-6 p.m.