The Chicago Tribune reports a study of closing ship traffic on the Chicago River to halt the spread of Asian carp to the Great Lakes:

As state and federal officials hunt down the elusive Asian carp, the U.S. Army Corps of Engineers is looking at the financial and environmental costs of closing navigational locks in Chicago waterways and shutting down the Chicago River to boat traffic as many as four days a week. Working under intense scrutiny from Washington, D.C., and around the Midwest, the Army Corps intends to issue its recommendations this month and hopes to have them in place by April 1.

It isn't only in pro athletics that yesterday's hero becomes today's zero. Fish also fall from grace. The Asian carp's German cousin was once the darling of progressive scientists and sportspeople. Spencer Fullerton Baird, secretary of the Smithsonian Institution, proudly raised this imported miracle fish in ponds on very grounds of the Washington Monument in the 1880s. State officials joined the movement, for example in Minnesota.

Anders Halvorsen's new book on another former darling, the rainbow trout, tells a similar story. Ken Ringle, writing in the Washington Post, suggests that scientists and bureaucrats have learned humility from their predecessors' mistakes:

[I]n their campaign to increase biological diversity by stocking the nation's streams with rainbows over the past century, state and federal fish commissions unwittingly reduced diversity. Hatchery-bred fish have proved rapacious predators that gobble up frogs and native fish, some species of which have been pushed to endangerment. Even songbird and bat populations have suffered near mountain lakes where non-native rainbows consumed mayflies and other insects on which avian populations feed.

Unfortunately, none of this is a clear guide to policy on genetically modified organisms. It supports the view of GM crop advocates that conventional animal and plant breeding, and monoculture, can be very risky. But by showing that biological, cultural, and political influences can interact in surprising ways, the Frankenfish also raise the possibility that we're overlooking other risks. I recently read a story in the Times about an aquaculturist who is introducing, "pacu, a thin, silvery import from South America that she called 'vegetarian piranha.'"