IISG recently released a new WATCH card featuring two new invasive species—the Brazilian elodea and hydrilla. These costly noxious weeds have been invading and causing harm in parts of the U.S.

“They have the potential to crowd out native species, alter habitat, and hinder recreational activities such as boating and fishing,” said IISG aquatic invasives extension associate Kristin TePas.

Costs have quickly added up in Indiana in efforts to control these invaders. According to TePas, in 2006 an infestation of hydrilla was found in a 735-acre lake that is expected to cost the state $1.5 million to remove. This followed a previous infestation of Brazilian elodea in a 109-acre impoundment, which cost the state $135,000 to eradicate.

Both hydrilla, native to Asia, and Brazilian elodea found their way into U.S. waters through aquarium trade. Recently these plants have been spread to new waters via boats and recreational equipment and as a hitchhiker on other plant materials.

Boaters and anglers can help by regularly cleaning their boat equipment when they leave a water body and by reporting any sightings. Hobbyists can help by purchasing plants other than Brazilian elodea and disposing of unwanted aquarium and water garden plants in the trash rather than nearby water bodies.

The new WATCH card provides a brief description of the plants as well as illustrations and a photograph of the two species. It also includes a clear description of how to tell them apart from native elodeas, as they are similar in appearance. The card also provides useful information to help prevent the spread of these invaders and what to do to report a new sighting.

IISG Instagram

Do you work or live along the Great Lakes coasts? Watch our newly released video series collection, containing several short videos that overview the range of coastal protection options in the Great Lakes, including:- Natural processes in the Great Lakes- Hard coastal protection structures and how they interact with/alter natural processes- Nature-based coastal solutions in the Great Lakes, ranging from green to gray approachesFind our two new video series at the link in bio.
Located in Washington, D.C., the Sea Grant Knauss Fellowship provides a unique educational and professional experience to graduate students who have an interest in ocean, coastal and Great Lakes resources, and in the national policy decisions affecting those resources. This is a one-year fellowship open to any student, regardless of citizenship, who is enrolled toward a degree in a graduate or professional program on the day of the deadline.Students enrolled at an Illinois or Indiana university or college should submit their applications through Illinois-Indiana Sea Grant by emailing Angela Archer at amcbride@purdue.edu. Students in surrounding states without a Sea Grant program should contact the National Sea Grant College Program at oar.sg.fellows@noaa.gov for a referral. Application deadline: June 3, 2026.To learn more about the fellowship, visit the link in bio.
Science is Survival at C2E2 2026! Catch us at the Chicago Comic & Entertainment Expo (March 27–29) as we explore the underwater world of Subnautica through the lens of Great Lakes science.Stop by our booth to discover how Great Lakes food webs, invasive species, and aquaponics stack up against your favorite survival game!Learn more about the event at the link in bio.