VANCOUVER, Wash. — An invasive species of clam has gained a major foothold in the Columbia River. That's the finding of a study conducted by a team from Washington State University, Vancouver, just published in the journal International Review of Hydrobiology.
The Asian clam, or corbicula fluminea, has been in the Columbia River since the 1930s, probably arriving on ship hulls or imported as a food item from Asia. While the clams aren't new to the river, they may be a red flag for other invasive species to potentially make an appearance, according to Salvador Robb-Chavez.
Robb-Chavez is a masters graduate in environmental science from WSU Vancouver, and the study's lead author. He said that there are a lot of these Asian clams in the river now, from Astoria all the way to the Tri-Cities.
“They've been here for quite a long time but most people don't know that they’re passing by them every single day on I-84," said Robb-Chavez. "There are abundant numbers in the urban areas, especially, of the Columbia River, but were found throughout the entire breadth of my study area.”
According to Robb-Chavez, his team found Asian clams in concentrations of 430 per meter by meter square in some of the most concentrated samplings along the Columbia River.
The invasive clams are known to be a detriment to native mussels, the first food cultural resource — they out-compete them for space, they out-compete for food, and ultimately diminish the mussles' condition and abundance.
Asian clams eat the same plankton that native muscles eat — and further up the food chain, so do salmon. And while Asian clams are bad enough, they are not the only invasive species in the river. They are just one in a long laundry list of invasive species that have been brought to the system by human activities.
Robb-Chavez said that this study on Asian clams in the Columbia River should serve as a warning about keeping other invasive species out of the river — because as bad as Asian clams are, quagga and zebra mussels are worse, and the Columbia River has so far avoided an invasion from these more damaging mollusks.
So what can you do to help? If you're a boater, be sure to follow state invasive aquatic species rules, to make sure your boat is cleaned up properly and doesn't spread any unwanted creatures from waterway to waterway.