Asian clams versus native B.C. clams comparison. Photo: Columbia Shuswap Invasive Species Society

Asian clams versus native B.C. clams comparison. Photo: Columbia Shuswap Invasive Species Society

Invasive Asian Clams found in Pend D’Oreille River

Watercraft users and anglers are urged to clean, drain and dry gear

The Ministry of Environment has confirmed that invasive Asian clams (Corbicula fluminea) were found in the Pend D’Oreille River this spring.

This is the first confirmed presence of live invasive freshwater clams in the Central Kootenay region. However, this is not the first confirmation of these clams in B.C.: they exist in the Lower Mainland, and in 2020 they were found in Shuswap Lake. The ministry is assessing distribution and have conducted preliminary surveys near the Salmo River confluence.

The non-native clams are a concern to the Central Kootenay Invasive Species Society (CKISS), a local non-profit that works to prevent the spread of invasive species in the region. The clams can clog water treatment systems, contaminate drinking water, and negatively alter aquatic ecosystems by competing with native species for food and habitat.

In response to the recent discovery, CKISS is urging watercraft users and anglers to Clean, Drain, and Dry all gear and watercraft every time they leave a lake or river. The larvae of this species are microscopic and could hitchhike in the smallest amount of water in your watercraft, surviving to populate another lake. A single clam can create a new population due to self-fertilization, producing up to 70,000 eggs per year.

Asian clams are found in the pet trade as an aquarium species, which is another potential pathway for this invasive species to spread. CKISS wants to remind aquarium owners to never dump the contents of their aquarium (animals and plants) into natural places including waterways. CKISS has a program called Don’t Let It Loose, which promotes responsible pet and aquarium ownership. Tips on what to do with an unwanted aquarium pet can be found here:

“Unfortunately, once established, eradication of these invasive clams from a waterbody is highly unlikely due to limited management options. This is why prevention is the best tool we have,” states Laurie Frankcom, CKISS education program co-ordinator.

In addition, the CKISS wants members to be on the look out for, and report any sightings of, Asian clams. The shells are triangular shaped, usually less than 2.5 cm but up to 6.5 cm in length. They can be yellow-green to light-brown in colour with elevated growth rings. They are found in freshwater at the sediment surface or slightly buried in silt, sand, or gravel substrates. Reports can be made through the Report Invasive Species app, provincial website or by calling the B.C. Conservation Officer Services Hotline: 1-877-952-7277.

The CKISS is also monitoring the region’s major waterbodies for invasive zebra and quagga mussels, a different invasive aquatic mollusc, and to-date, they have not been detected anywhere in B.C. waters.