It's a Small World After All

If you doubt that the world is getting smaller and more interconnected all the time, consider the case of the Asian clam (Corbicula fluminea). This small mollusk (less than 2 inches long) is native to Southeast Asia, Africa and Australia. It was introduced into the United States through the Pacific Northwest in the 1930s. It may have been brought here intentionally as a food item or accidentally with a shipment of Asian oysters. Asian clams rapidly spread to water bodies around this country and have been known from Missouri since the 1950s.

Several weeks ago, groundskeepers at Springfield’s Rivercut Golf Course noticed dozens of leaking sprinkler heads used to water the grasses on the course. Investigation of the problem led to the discovery of broken pieces of Asian clam shells in the malfunctioning sprinkler heads. Last year’s flooding of the James River caused floodwaters to back up onto the golf course, reaching the lake used to store water for the irrigation system. The clams probably multiplied quickly in the lake and eventually were pumped into the irrigation pipes that feed the sprinkler heads.

Can you imagine the harried invasive species biologist who goes to the golf course to forget about the incessant bad news of spreading invasive species only to encounter the Asian clam sabotaging his weekend getaway? He can run, but he cannot hide!

Asian clams have caused many more serious problems since arriving here, leading to costs of a billion dollars a year for cleaning and removal from intake pipes in the water and power industries. Several nuclear reactors have been shut down temporarily for removal of clams in their cooling systems. They have even damaged concrete when the river gravel added to the cement was infested with the small clams. Ironically, most dispersal of the clams, other than by passive movement of water, has been by people.

If you were hoping for a positive note at the end, you’ll have to wait for a blog on a different topic than invasive species, where good news is nearly nonexistent.

Photo above courtesy of Shawn Liston, Audubon of Florida, Bugwood.org

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