Aquatic invasive species are one of the top threats to Adirondack waters even though the region is in relatively good shape, for now. Adirondack waterways have fewer AIS compared to neighboring waters such as Lake Champlain, Lake Ontario and the St. Lawrence River and Hudson River. Plus, two out of three waterways surveyed by volunteers are free of aquatic invasives, which is great news. We are well positioned to fend off new arrivals with effective education and prevention programs. The time to act is now. When recreating on lakes, ponds and rivers this summer, keep watchful eyes for these potential invaders.
Round goby is an invasive fish from Europe that feeds on small native fish, competes for spawning sites and steals anglers’ bait.
(Center for Great Lakes and Aquatic Sciences Archive, University of Michigan, Bugwood.org)
The round goby is a small fish native to Europe that was likely introduced via ballast water discharge. It was first observed in 1990 in the Great Lakes Basin but is now widespread throughout the Great Lakes. In New York, they are already in the St. Lawrence River and moving eastward through the Erie Canal.
Gobies prey on small fish and feed on the eggs and fry of darters, lake trout and sculpin. Adults take over and aggressively defend near-shore spawning sites. They are prolific breeders, spawning every 20 days during the spawning season.
Round gobies also eat zebra mussels, another invasive species; however, given the contamination found in some populations, this can result in bioaccumulation of toxins in gobies, which can then be spread up the food chain to shorebirds and other species that consume the toxic fish. A link also may exist between round gobies and the outbreaks of Type E avian botulism on Lakes Erie and Ontario, which may have led to a massive die off of loons in 2012.
Round gobies grow 3 to 6 inches long but can reach 10 inches in length. Key identifying characteristics include a black spot on the rear of the upper dorsal fin, raised frog-like eyes, thick lips and a slate gray or black body, mottled with black or brown spots.
Round gobies are not known to be in the Adirondacks or Lake Champlain but will have dramatic impacts on native species and game fish if introduced. Anglers also find them to be a nuisance as they are quick to steal bait.
Bloody Red Shrimp
The bloody shrimp is native to the Black and Caspian seas and a more recent arrival, first observed in 2006. They, too, were likely introduced as stowaways in ballast water of ships. Sightings were reported first in southeastern Lake Ontario near Oswego and in Lake Michigan. Specimens also were found in stomachs of white perch caught in Lake Erie. Most recently, they were detected in Seneca Lake and Montreal Harbor.
As their name suggests, bloody red shrimp are reddish in color. They are less than a half an inch in length and have stalked eyes. The shape of the tail is the best way to distinguish it: it has a flat end with two prominent spines.
This invader favors rocky substrate, is less abundant on soft sediments, is usually scarce in areas of dense vegetation or high siltation and tends to avoid sunlight. They group together, creating locally dense swarms up to 1,000 individuals per meter squared. Look for reddish swarms in shadowed areas along the shoreline, especially near docks, edges and boats.
They are prolific, producing up to four generations a year, and eat a variety of smaller animals and algae. Its history of invading canals, streams, lakes and reservoirs throughout Europe indicate the potential for significant impacts to inland lake systems.
Hydrilla is one of the world's worst aquatic invasive plants. It invaded several ponds in Suffolk and Orange counties and most recently Cayuga Lake inlet and the Erie Canal in North Tonawanda. Its tolerance of varied water quality conditions and light levels, and its ability to grow in shallow areas and depths of 25 feet, make it a tough competitor.
Hydrilla is a popular aquarium plant. Once introduced into the wild, it spreads easily through recreational boating. Plants grow quickly, up to an inch a day, and form thick, tangled mats, degrading water quality, recreation, aesthetics and habitat for native plants and wildlife.
Hydrilla easily can be confused with elodea, a common beneficial native plant, also called waterweed. Hydrilla can be distinguished from its native look-alike by its whorl of four to eight blade-shaped leaves. Native elodea has a whorl of only three leaves. Hydrilla leaves also have serrations or "teeth" on the edges and one or more "teeth" on the middle of the underside of the leaves. The edges of elodea leaves are smooth.
These AIS are on the move in New York. Reporting new infestations early is essential for successful control. Experts are at-the-ready to assist with identification. If you spot any of these organisms during your aquatic Adirondack adventures, please take a photo, collect a sample, if possible, and report to Meghan Johnstone, APIPP's aquatic invasive species project coordinator, at 518-576-2082 or email@example.com.
Help protect Adirondack waters: Always place unwanted bait in the trash, and remember to clean, drain and dry your watercraft and gear after each use.
Eye on Invasives is a biweekly column that spotlights a top invader when it is easiest to identify. Hilary Smith directs the Adirondack Park Invasive Plant Program (APIPP), a partnership program housed at the Adirondack Chapter of The Nature Conservancy in Keene Valley. Find out more about this award-winning program online at www.adkinvasives.com.