These methods may be our best long-term hope to prevent new invasions. These Illinois waterways were built in the late 1800s and early 1900s to carry away the city's sewage and industrial waste. More harmful exotics are poised to visit. Rendall's biggest concern is the round goby, a fish that can spawn every three weeks and is already headed down the Illinois waterways. And other Great Lakes states fret that Asian carp could enter their waters from the Mississippi River.
Harmful species can move in either direction.
Back in Minnesota, Rendall says the DNR is receiving a growing number of requests from aquaculture and other interests to import exotic species. Rendall says several state laws now prevent importing certain dangerous species such as black carp and purple loosestrife and prohibit the release of troublesome species such as common carp and rusty crayfish. Laws preventing the transport of aquatic plants on public roads are designed in part to keep exotic plants from arriving by trailered boats from other states. The only other way to deter exotics invasions is by the endless task of informing the public about the problems that foreign species can cause. All rights reserved.