A Tale of Two Mollusks

From September 10, 1991 (update #10)

Those contemplating "biological control" by way of introducing other exotic organisms to help control zebra mussels should read the tale of a series of disastrous mollusc introductions in the South Pacific related by noted Harvard paleontologist Stephen J. Gould in the August issue of "Natural History" magazine. The key characters in this story are Achatina, a genus of African tree snail purposely introduced in many places to provide a delicacy food source, and Euglandina, a predatory land snail introduced to control Achatina in the many instances where its population has overrun its new home. Gould writes, "Euglandina has therefore developed a worldwide reputation as a potential agent of biological control for other snails. Yet, despite a few equivocal successes, most attempts have failed, often with disastrous and unintended side effects, as Euglandina leaves the intended enemy alone and turns its attention to a harmless victim... "Euglandina ignored Achatina and began a blitzkrieg against Partula (a genus of native land snails) -- more thorough, rapid and efficient than anything that Hitler's armies ever accomplished." Gould goes on to make a memorable case for the value of several species of Partula, now extinct. Despite the common interest in "natural" predators that can be used to control zebra mussels, Gould's tale portrays one aspect of the less than successful history for such measures.

ID: 19910910-6.

The Zebra Mussel Update was a 4- to 8-page quarterly national newsletter published by the University of Wisconsin Sea Grant Institute from May 1990 through May 1997. The ZMU documented the spread of the zebra mussel -- an exotic nuisance mussel -- through North America's freshwater environments, especially the Great Lakes, and on efforts to control it.