An invasive species of Asian clam has been found in Shuswap Lake — the first ever confirmed presence of the clam.
Live populations of invasive Asian clams, also known as Corbicula fluminea, were found in two locations of the Salmon Arm of Shuswap Lake — at Sunnybrae and Canoe Beach — during a recent survey, according to the Columbia Shuswap Invasive Species Society.
The survey was prompted by a discovery of dead Asian clam shells found on the beaches of the Shuswap Lake last year, but conducted now as water levels are low enough to access the potential habitat for this species.
“At Sunnybrae, we were finding around 20 clams per square metre of lake bed,” said Sue Davies, aquatic co-ordinator for the society.
More surveys are underway and the society is warning the public to clean, drain and dry all gear and watercraft every time they leave a lake or river — even if relaunching somewhere else in Shuswap Lake.
“The larvae of this species are microscopic,” Davies said. “They could hitchhike in the smallest amount of water in your watercraft and survive to populate another lake.”
According to the society, this is the first confirmed presence of live Asian clams in the Shuswap, but it has also been known to exist in lakes in the Fraser Valley and on Vancouver Island, as well as in 38 U.S. States and three of the Great Lakes — Erie, Michigan and Superior.
Asian clams are small bivalve shellfish, originating in Asia, that can produce up to 70,000 eggs per year under optimal conditions and reach densities of up to 20,000 individuals per square metre of lake bed. They are filter feeders that can reduce biodiversity and food available for fish. Dense populations may have the potential to clog filters on hydro systems and water pipes, leading to costly maintenance. They are also known to harbour parasites that are harmful to humans if the clams are consumed raw.
The Asian clam shell is triangular shaped and usually less than 2.5 centimetres, but up to 6.5 centimetres, in length, and yellow-green to light brown in colour, with elevated growth rings.
Once established, eradicating Asian clams from a waterbody is unlikely and the best thing to do is prevent further spread to other lakes or rivers.
The recent survey in Shuswap Lake was conducted by the society, with funding from the Shuswap Watershed Council, direction from the Ministry of Environment and Climate Change Strategy and assistance from the Invasive Species Council of BC Job Creation Program.
The Asian clam is not to be confused with invasive zebra and quagga mussels, which are not known to be in B.C.
Members of the public are asked to report any suspected invasive species via the provincial Report Invasives BC smartphone app or by calling the Report All Poachers and Polluters hotline 1-877-952-7277.