Invasive clam
Identification & Biology
Photo By: Dave Wick, Lake George Park Commission
Invasive clams in hand
Invasive clams in hand
Photo By: Dave Wick, Lake George Park Commission
Invasive clams
Invasive clams
Photo By: Amy Benson, U.S. Geological Survey, Bugwood.org
Invasive clam shells
Invasive clam shells
Photo By: U.S. Geological Survey, Bugwood.org
Invasive clam
Invasive clam
Photo By: Dave Wick, Lake George Park Commission
Invasive clams in hand
Invasive clams in hand
Alias' :
Asian clam, asiatic clam, golden clam, good luck clam
Latin Name :
Corbicula fluminea
Category :
Other
Description :
- Small, freshwater bivalve
- Shell is triangular shaped and can be 2.5 cm to 6.5 cm long
- Yellow-green to light-brown in color with elevated growth rings
Invasive clams are filter feeders and have a life span of about 1-7 years. They can self-fertilize and reproduce rapidly; a single clam can produce up to 70,000 eggs/year! They are spread by human transport and water currents. They have also been sold commercially for bait, human consumption, and in the aquarium trade.
In British Columbia, invasive clams are under “Provincial Containment”, which means that the species is high risk with limited extent in the province but significant potential to spread. The management objective is to prevent further expansion into new areas, with the ultimate goal of reducing the overall extent.
Juvenile invasive clams may be confused with native fingernail clams (Sphaerium sp.). The shells of fingernail clams can be quite fragile compared to introduced invasive clams. Additionally, fingernail clams tend to have a more pinkish coloration, less pronounced ridges on the shell, and a slightly off-centre umbo, in comparison.
Habitat
Invasive clams are native to Southeast Asia and parts of central and eastern Australia, Africa, Indonesia, and Turkey. They are found in the substrates of brackish to freshwater rivers, lakes, streams, canals, and reservoirs. They prefer flowing water and have a low tolerance for pollution or near-freezing water temperatures. Invasive clams are not presently known to the Okanagan region, however they are found in some rivers in the Lower Mainland and were recently discovered in two locations of Shuswap Lake in B.C.
Impact & Risks
- Invasive clams can rapidly reproduce with densities reaching 10,000 per square meter
- They can outcompete native species for habitat and food
- Under suitable conditions invasive clams can reach high densities and have the ability to cause clogging of pipes and other structures affecting power plants, irrigation and water supply facilities, and water treatment systems
- They can alter water chemistry and drinking water by favoring algal blooms
- They alter food chains and reduce biodiversity
- They can be transported between bodies of water by bilge and livewell water in boats, on vegetation attached to anchors and trailers, or in sediments left on anchors
Prevention & Mitigation
- Properly clean, drain, dry your boat and equipment before entering a new water body.
- CLEAN off all plant parts, animals, and mud from boat and equipment (e.g. boots, waders, fishing gear). Use a power wash station if available.
- DRAIN onto land all items that can hold water (e.g. buckets, livewells, bilge, and ballast)
- DRY all items completely before launching into another body of water
- Raise awareness to avoid the spread of this species in B.C.
- Any suspected transport, possession, sale or release of invasive clams should be reported immediately to the B.C. Conservation Officer Services Report All Poachers and Polluters line: 1-877-952-7277 (RAPP). Any invasive species sightings in B.C. should be reported using the Report Invasives phone app, that is available from the provincial website: gov.bc.ca/invasive-species
Primary source for information: Invasive Clam Invasive Species Alert – Government of British Columbia
Treatment & Disposal
Okanagan Distribution
Priority Level Definitions
Watch For - Poses a significant threat (very high risk) and does NOT presently occur in the region OR is relatively new to the region and is very limited in extent.
High - High risk/impact; limited population with significant potential to spread in the region.
Medium - Medium risk/impact; limited distribution – broader population distribution with potential to spread further in a region.
Low - Low risk/impact; may be widespread or not, may be of concern in specific situations with certain high values – e.g. specific agriculture crops. Some species may be treated primarily with biological control agents.
