Blocking Invasive Aquatic Species

摘要

Voracious snakehead fish from China crawl out of a Maryland pond, while 100-pound Asian carp smash into recreational boats on the Mississippi River. Armies of alien rats, numbering in the millions and weighing up to 20 pounds, raze wetland vegetation in Louisiana. Softball-sized snails called Rapa whelks silently devour any and all Chesapeake Bay shellfish in their paths. The images would be comic if they were not real. Instead, they have helped to convince Congress that the threat to the U.S. economy and environment from these and other nonnative species is enormous and that the federal government should get serious about keeping them out.