Asian clams are small light-colored clams with shells ornamented by distinct, concentric rings. They may be confused with native fingernail clams which are very fragile and easily smashed between your forefinger and thumb. Asian clams are much more robust and difficult to break.
How It Spreads
The main vector for the spread of Asian clam is human movement and activities. It is believed that they first were brought to North America for food, and have since been introduced to new areas through bait bucket releases,ballast water transport, aquarium/water garden releases,as hitch-hikers with imported aquaculture species, and intentional introductions for food
Impacts to Rivers
Due to their voracious filter feeding, Asian clams tend to out-compete both native mussels and juvenile fishes for food. Food competition coupled with competition for space has lead to decreased abundances and diversity of native mussels and clams in waterbodies where Asian clams are introduced.
The Asian clam can have large economic impacts on industrial and power plants that intake water from rivers and lakes. Alive and dead clams clog the intake pipes and it is costly to remove them; an estimated one billion US dollars each year is spent removing clams from industrial and power plant pipes.