The invasive Asian clam is more common in the lower Columbia River than its native habitat of southeast Asia, according to a study of the clam’s abundance in the river.
The findings don’t bode well for potential future invasions by the even more destructive quagga and zebra mussels. So far, the Columbia is one of the only major U.S. rivers to remain free of these notorious ecology-destroying, equipment-clogging bivalves.
To understand how new invaders might spread, a Washington State University-led team studied the existing invasive Asian clams hoping to see what might limit them. Unfortunately, the answer was — not much.
“What struck me was just the sheer variety of habitats that Asian clams were able to settle down in and survive,” said Salvador Robb-Chavez, a recent WSU master’s degree graduate in the School of the Environment and the study’s lead author. “We found evidence of their presence just about everywhere in the lower Columbia River.”
For this study, published in journal International Review of Hydrobiology, the researchers sampled 27 sites along 481 kilometers (about 299 miles) of the river, stretching from the ocean to Richland, Washington. They found Asian clams were able to live at a variety of temperatures, water quality and substrates, such as silt, sand or rock.