You try to do the right thing - clean up a polluted river - but that just creates an opportunity for an invasion by giant alien carp - only the Army, with an underwater electric fence, stands a chance of stopping them: An Underwater Fence to Stop Invasive Species (Kari Lydersen, Washington Post, July 16):
A century ago, engineers blasted the Chicago Sanitary and Ship Canal out of limestone to reverse the Chicago River, an unprecedented engineering feat that linked Lake Michigan with the Mississippi River.
The project served its purpose, sucking water from the lake to flush out the growing city's waste, but there was an unintended consequence: It created a pathway between two previously distinct ecosystems and a route for invasive species traveling in both directions. Until recent years, though, heavy pollution in the canal prevented fish from swimming through it.
Today, the canal is cleaner, and the infamous Asian carp and the round goby are both threatening to take advantage. But the government is stepping up its efforts to stop them.
The carp, prolific filter feeders that wipe out food supplies for other fish, have been slowly making their way up the Mississippi since escaping into the wild after they were imported in the 1960s and '70s to control algae in Southern fish farms.
The voracious carp, which can grow to 50 pounds, are within 50 miles of the lake, and the only thing stopping them from completing the journey is an underwater "electric fence," which the U.S. Army Corps of Engineers constructed under the canal....
Laine Welch picked up on this story today in her daily Alaska fisheries news broadcast. We're concerned about invasive species up here too: Invasive marine species annual summer worry as visitors flock to Alaska (Alaska Fish Radio, July 18):
...And tiny mud snails the size of a pin head are already here, often arriving on the bottom of visitors’ boots or other gear. Bob Piorkowski - '
If anyone is coming in from out of state - make sure your wading gear, especially with felt liners - have been in the freezer for five or six hours. It will kill the New Zealand mud snails.'
The invasive species that tops the list for Alaska worries? Atlantic salmon. In the past decade nearly 500 Atlantic salmon have been found in Alaska waters. That’s prompted the state to give them their own fish ticket number. – 666, the sign of Satan.
The Department of Fish & Game's wit ("666") highlights how important the five indigenous species of salmon (which definitely do not include invasive "Atlantic" salmon) are to Alaskans.
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