Clam
Freshwater Golden Clam
Corbicula fluminea · also called Asian clam
These illustrations are AI-generated, not photographs, and are not to scale. They show what to look for; they are not a substitute for an expert identification.
How to identify it
Size: Usually 1 inch or less.
- A thick shell shaped like a rounded triangle.
- Heavy, evenly spaced ridges running around the shell like growth rings.
- Yellow-green to golden-brown on the outside.
- Pale purple or bluish-white on the inside.
- Fine teeth along the hinge where the two halves meet.
Don’t confuse it with
Native fingernail and pea clams are small, thin and smooth, without heavy ridges. Native mussels are much larger.
Where it came from
Native to Asia, Africa and Australia.
First found in North America on the Pacific coast in the early 1900s. In the Great Lakes it is often found near warm-water discharges such as power plants.
Earliest dated Michigan record: 1980, Lake Erie near Monroe. This is the oldest dated record in the USGS non-native species database, not necessarily when it first arrived.
Why it matters
It can build up in very large numbers, clog water intakes and compete with native clams and mussels for food.
Michigan law
Not on Michigan's list of prohibited or restricted species. The boating and bait rules below still apply to everyone. The state’s page on this species.
If you find it
- Don’t move it. Michigan law requires boaters to remove all aquatic plants from boats, equipment and trailers before launching. Before trailering, you must pull all drain plugs, drain live wells and bilges, and make sure the boat and trailer are free of aquatic plants and animals. What the law requires
- Never release bait. Releasing baitfish into Michigan waters is illegal. Put unused bait in the trash, never in the water.
- Report it. Take a photo, note where you saw it, and report it to the Midwest Invasive Species Information Network (MISIN) or through Michigan’s invasive species program. Experts there can confirm what you found.
- Ask before removing or treating. Treating a lake with herbicides or other chemicals needs a state permit, and some removal work does too. Start with the state’s Aquatic Nuisance Control program before taking action.
Michigan lakes where it has been recorded
30 Michigan lakes on this site have a record of this species.
Allegan
Barry
Berrien
Branch
Cass
Ingham
Jackson
Kalamazoo
Kent
Lapeer
Lenawee
Livingston
Macomb
Oakland
Roscommon
Van Buren
Washtenaw
Wayne
Wexford
A lake that is not listed may still have it. Records exist only where someone found the species and reported it, so “not recorded” does not mean “not present.”
Lake records: Midwest Glacial Lakes Partnership Conservation Planner; underlying records from the USGS Nonindigenous Aquatic Species database.
Sources
- Michigan Invasive Species Program: Asian clam
- USGS Nonindigenous Aquatic Species: Asian clam fact sheet
Earliest dated record: USGS Nonindigenous Aquatic Species database.