While scientists have been battling to keep a ravenous, invasive fish species out of the Great Lakes, some worry that spring floods along the Mississippi River may be spreading the Asian carp downstream. Duane Chapman, a U.S. Geological Survey biologist and Asian carp expert, says the fish are likely to show up in places where Mississippi floodwaters intruded. They can weigh up to 100 pounds, grow four feet long and live for 25 years. Where they invade they can crowd out food sources of native species for decades.
In Missouri, the U.S. Army Corps of Engineers blew up a levee to send some of the river water into a floodway at Birds Point-New Madrid; it also opened the Morganza and Bonnet Carré spillways in Louisiana. “That entire area could see carp spreading to formerly virgin areas,” Chapman says.
Greg Lutz, professor of aquaculture at the LSU AgCenter, says that means big pressure on the food supply for fish. “There’s a rule of thumb for fish size and food consumption. You can say a one-pound carp has eaten at least 10 pounds of plankton to get that size. So if you have hundreds of thousands of pounds of carp, they are eating millions of pounds of plankton.”
The Atchafalaya River could be especially susceptible. Mike Kaller, an LSU biologist, says Asian carp have been found for several years in the southern end of the Atchafalaya basin, but not on its middle and northern segments. That distribution may change now because the opening of the Morganza spillway west of Baton Rouge could bring fresh carp stocks into the wetlands that make up the northern part of the basin.
