It's lockout time for invasive carp — and a few humans.
The Upper St. Anthony Falls Lock on the Mississippi River in downtown Minneapolis will be shut down in a year in an effort to keep the havoc-wreaking fish from spreading northward to Lake Mille Lacs and other northern waterways.
U.S. Sen. Amy Klobuchar, U.S. Rep. Keith Ellison and others congregated Tuesday in front of the lock to highlight bipartisan efforts to pass a $12 billion water transportation infrastructure bill that includes the lock-closing provision. The bill is awaiting President Obama's signature.
The lock is not heavily used by recreational boaters, which helped in gathering support for closing it. Still, opponents of the closure — mostly river industry groups — have argued that it could hurt the region's economy, particularly in the realm of tourism, and might not really stop the invasive fish from moving north.
The aquatic invaders, bighead and silver carp, can weigh more than 100 pounds. They are capable of eating from 20 percent to 120 percent of their body weight each day, handily outcompeting native fish and disrupting ecosystems. Native to Asia, they were introduced into the United States about 30 years ago and spread rapidly.
When a barge or recreational boat enters the Upper St. Anthony Falls Lock to go upriver, the U.S. Army Corps of Engineers closes the lock's lower doors and water is pumped in, rising like the water in a filling bathtub.
Once the lock is filled, its upper doors are opened and the barge or recreational boater can continue up the river.
Klobuchar said closing the lock is just a first step in stopping that fishes' northward drive. More research is required to find ways to fight invasive species without affecting other fish, she said.