When the expansion of the Panama Canal is completed in 2016, giant ships that now must dock at West Coast ports after crossing the Pacific will be able to deliver cargo directly to ports on the Gulf of Mexico and the East Coast. One thing they may be delivering, according to a recent study, is a much larger number of alien species.

With a third set of locks and wider and deeper channels, the expanded canal will be able to accommodate ships as long as 1,200 feet (366 meters) and as wide as 160 feet (49 meters)—235 feet (71 meters) longer and 54 feet (16 meters) wider than current limits. Ports along the Gulf and East Coast are already