Aquatic Invasive Species
image source: lake-hubert.com
Aquatic Invasive Species
Invasive species are non-native species that have detrimental impact on ecosystems and native species. Both aquatic and terrestrial invasive species can be spread into the Twin Lakes through innocuous actions or activities like boating, fishing, hiking, new construction land development, or even the transport of firewood. However, there are other, more direct actions that lead to the introduction of an invasive species such as releasing bait fish or an aquarium pet like gold fish into our Twin Lakes.
No matter how they arrive, invasive aquatic and terrestrial species are making their way across Pennsylvania and beyond, and unfortunately, controlling and/or eradicating them is expensive and time-consuming which is what is being seen with Curley Leaf Pondweed in the Little Lake.
Sea-Grant Pennsyvlania Webinar Replay from Aug 27, 2024
Twin Lakes and Curley Leaf Pondweed
The Small Lake
Curly-leaf pondweed, a rooted, submersed aquatic plant with variable olive-green to reddish-brown coloration, was first observed in Small Lake several years ago. Until 2024, little action had been taken to address its presence, leading to its widespread distribution throughout the small lake. In June 2024 a company was hired to mechanically harvest the top 5 feet of the plants and Twin Lakes’ resident jointed to pull some of the weeds along the short line.
CLPW can be identified by its wavy, lasagna-like leaves, approximately half an inch wide and two to three inches long, with serrated edges and blunt tips. These leaves are arranged alternately along the stem, which branches multiple times near its apex and can display colors like white, green, brown, and red.
In June, the plant produces reddish-brown flower stalks that extend above the water's surface, reaching about one inch in height. Reproduction primarily occurs through brown turions, resembling small pinecones, though it can also reproduce via seeds. The plant's thick, pale yellow rhizomes connect numerous stems, facilitating its spread from the shoreline to depths of 15 feet, thriving in low water clarity and disturbed environments.
How it got here and the future
Curly-leaf pondweed is native to Eurasia, Africa, and Australia. It was likely introduced when common carp were intentionally introduced into Midwest waters as a game fish in the 1880s. Regarding Twin Lakes, the species was likely spread through the movement of watercraft and water-related equipment. Eradicating CLPW will be difficult if not impossible with harvesting or potentially through the use of herbicides. So far it is contained within the small lake. Unless movement of watercraft from between the small lake and large lake is limited, it will most likely also become pervasive in the large lake and become a bigger problem to deal with.
Impact of Time and Costs Addressing Invasive Aquatic Plants and Animals
image source: Pennsylvania Sea Grant
What can we do at Twin Lakes to Control Aquatic Invasive Species
Regardless of how they arrive, once established, AIS are very difficult to get rid of.
Plants like Curley Leaf Pondweed grow really fast, take up a lot of space, and they can be really dangerous to water quality and the species around them.
For that reason, it’s better to prevent AIS from getting there in the first place.
To avoid further spread, Stewards of Twin Lakes is posting signage at the launch and beach sites across Twin Lakes to suggest methods for killing AIS before they take their Row Boats, Kayaks, Sale Boats or other watercraft 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.