The Asian clam, a non-native invasive species, is a threat to become established in Conesus Lake.

What is an Asian clam?

The Asian clam has two half shells hinged together, typically is less than 1.5 inches long, and has an oval/triangular shape. They are yellow brown, and light brown to black with distinctive elevated concentric ridges on the surface. The Asian clam prefers sand, mud, or gravel bottoms in shallow water. The Asian clam is hermaphroditic (you only need one to reproduce). A single clam can release over 400 offspring per day. They have a life span of approximately seven years. They do not swim, but can be moved easily by water currents and transported by humans.

Why are Asian clams considered a threat to reach Conesus Lake?

Asian clams have spread rapidly in lakes, canals, streams, rivers, and reservoirs throughout North America…..most recently to Lake George and Owasco Lake. Invasive species specialists believe most lakes in New York State are at risk.

Why are Asian clams a problem?

When Asian clams become established they can cause algae blooms and foul water intake pipes. Since they reproduce so rapidly, they displace native species and natural predators are not able to control them. They can reach densities of 500 clams per square foot of lake bottom. Their excrement releases nutrients (nitrogen and phosphorous) into the water column. Once Asian clams are established in a lake, it is almost impossible or cost prohibitive to eradicate them. Lake Tahoe residents have spent $1.4 million in an attempt to control Asian clams in one infected area.

Where are Asian clams from?

The Asian clam originally came from both Asia and Africa. They were first discovered in North America in 1938 in Washington State. They were thought to have been brought here as a food source. Some people consider them to be a good luck charm and use them in aquariums.

How can Asian clams be introduced into Conesus Lake?

The juvenile Asian clam can be relocated easily in bait buckets, live wells, engine cooling systems, trailers, etc. They may also be released, either deliberately or accidentally, directly into the water. There are no current restrictions on the sale, purchase, or transport of Asian clams.

What can residents do to help?

Residents and lake users are encouraged to use the following Best Practices.

Before launching a boat into Conesus Lake

  • Drain all water from engines, live wells, bait buckets, and other equipment. Do not allow the discharged water to flow into a stream or water body.
  • Check and remove any visible mud, plants, fish, or organisms from boats, trailers, equipment, etc.
  • Wash the boat, trailer, and all equipment.
  • Never release any plant or animal into Conesus Lake unless it came from Conesus Lake.
  • Do not purchase or use Asian clams for any purpose.
  • Do not dispose of water, gravel or any other contents of an aquarium in a manner that can flow to a stream or body of water.
  • Spread the word to lake residents, boaters, fisherman, and other lake users.
  • Become a lake monitor and periodically observe your shoreline for washed up Asian clamshells.
  • Report any suspected sightings of Asian clams to: Conesus Lake Watershed Manager, 585-243-7550.

What is being done to address this threat?

The Conesus Lake Association is working with the Conesus Lake Watershed Council to develop a monitoring program and action plan. Early detection – before the infestation becomes widespread – provides the best chance for eradication. Impervious mats and suction harvesting are accepted eradication techniques.

More details will follow at a later date.

Additional Information

USGS Asian Clam Fact Sheet

Map of known Asian clam locations in New York State.

Lake George Asian Clam Eradication Project

Owasco Lake Asian Clam Task Force