Researchers have confirmed the presence of fishhook waterflea (Cercopagis pengoi) in Lake Champlain, bringing the known number of nonnative and aquatic invasive species in Lake Champlain to 51.
The discovery increases the likelihood of the invasive’s spread by recreationists into the Adirondack Park, which currently has at least 12 known aquatic invasive species in interior lakes where spiny waterflea has been spreading.
The fishhook waterflea is similar to the spiny waterflea, which was confirmed in Lake Champlain in 2014; they are both small crustaceans that are aggressive predators of zooplankton and are known to foul fishing lines. The Finger Lakes and Lake Ontario were the closest lakes known to host fishhook waterflea. Like the spiny waterflea, the fishhook waterflea likely arrived in Lake Champlain by hitchhiking over land on recreational boats, trailers, or equipment.
The presence of fishhook waterflea in Lake Champlain, presages its spread into the Adirondack interior, as spiny waterflea did after its discovery in Great Sacandaga Lake in 2008. By 2014, spiny waterflea had also spread to Stewarts Bridge Reservoir, Peck Lake, Sacandaga Lake, Lake George, and the Glens Falls Feeder Canal. Since then, it has spread to Lake Champlain by way of the Feeder Canal. It has also continued to spread in Hamilton County – to Lake Pleasant, which adjoins Sacandaga Lake, and nearby Piseco Lake. When spiny waterflea was discovered in Indian Lake in 2016, it had been the largest interior lake free of invasive species.
The newly confirmed fishhook waterflea specimens were collected just a week ago in the Main Lake segment of Lake Champlain, near Valcour Island and at an established Lake Champlain Long-term Biological Monitoring Program (LTMP) site supported by the Lake Champlain Basin Program. Sample analysis by the Lake Champlain Research Institute (LCRI) at SUNY Plattsburgh confirms high densities with over 100 individuals present in each sample.
Dr. Tim Mihuc and staff at LCRI analyzed Lake Champlain 2018 LTMP samples through June and did not detect fishhook waterflea. This is not a surprise as both species typically appear later in the season. The fishhook and spiny waterflea lay resting eggs that overwinter in the sediment, and once the Lake becomes warm enough they hatch in late July and their densities are highest through early fall. Females also reproduce parthenogenically during the summer season, meaning they grow clones of themselves in a brood sack. Brood sacs were present on the fishhook waterflea that were collected last week.
LCRI noted that no fishhook waterflea were identified in the 2017 Lake samples from the LTMP, and only a handful of spiny waterflea were detected in 2017. Once all 2018 samples are analyzed, scientists will have a better understanding of how widespread fishhook waterflea is in Lake Champlain. If their distribution pattern follows that of the spiny waterflea infestation the fishhook waterflea will be widespread throughout the Lake by the end of the 2018 season.
The Lake Champlain Basin Aquatic Invasive Species Rapid Response Task Force, which includes representatives from New York State Department of Environmental Conservation, Vermont Agency of Natural Resources, US Fish and Wildlife Service, Adirondack Park Agency, Québec Ministries of Environment and Wildlife, and the Lake Champlain Basin Program, is currently “assessing the potential impacts from this detection and evaluating management options” according to a statement sent to the press. There are no known control technologies to eliminate fishhook waterflea once established in a water body. “Efforts will focus on preventing the spread of this species to other bodies of water in the region,” the press announcement said.
Fishhook waterflea and many other aquatic invasive species have life stages that are invisible to the naked eye so it is important to be diligent about boat washing and moving between lakes. Lake users are asked to take spread prevention measures to help prevent the spread of fishhook waterflea to other inland waterbodies.
Native to Eurasia, the fishhook waterflea arrived in the Great Lakes in ballast water in the 1980s, and has since spread to other waterbodies. They feed on tiny crustaceans and other zooplankton that provide food for native species. Fishhook waterflea causes no known risk to human health, though the tail spines of the fishhook waterflea can foul fishing gear. While the impact from this species to the Lake’s food web is unknown, spiny waterflea has altered zooplankton communities in Lake Champlain and other lakes where the species has become established. The eggs are resistant to drying, which has implications for the types of actions that will prevent their spread.
Anglers may have a greater likelihood of seeing fishhook waterflea on their equipment. Some useful tips for anglers include changing fishing line and tackle when moving from one water body to another and carefully inspecting and removing any debris from fishing gear (including rods, spools of fishing line, nets, and downrigger cables). All boaters should focus on draining bilge water and checking anchor lines as they are likely vectors that spread fishhook waterflea.
Hot water, high pressure disinfection of boats and equipment that are in contact with water bodies known to contain fishhook and spiny waterflea is recommended. Other ways to help prevent the spread of fishhook and spiny waterfleas:
Clean- Inspect and remove plants, animals, and mud from boat, trailer, anchor lines, and angling equipment.
Drain – Drain water from all compartments including the bilge, live wells, bait buckets, storage compartments, etc.
Dry – Allow your boat, trailer, and all equipment including fishing gear, bumpers, ropes, and anchors to completely dry.
Drying times vary based on temperature, humidity, and material. Visit the 100th Meridian Initiative for guidance on drying times.
More information on fishhook waterflea can be found here.
Illustrations, from above: photo of fishhook waterflea (courtesy SUNY Plattsburgh); Adirondack lakes surveyed since 2002 and number of aquatic invasive species documented in each (courtesy Nature Conservancy); aquatic invasive species sources for the Adirondack Park (courtesy FUND for Lake George).