The discovery late last week of another Asian carp at the mouth of the St. Croix River underscores the need to move ahead with efforts to stop their spread, according to officials with the Minnesota Department of Natural Resources.
On Thursday, April 19, commercial fishermen working near Prescott, Wis., netted a 30-pound bighead carp from the St. Croix River where it flows into the Mississippi. One of several nonnative species of Asian carp that can cause serious ecological problems, bighead carp have been working their way north in the Mississippi River.
Thursday's catch was the second time this year Asian carp have been found by commercial fishermen in Minnesota waters. In March, a bighead and a silver carp were netted on the Mississippi River near Winona. Last April, another bighead was taken from the St. Croix near Prescott. While no established populations of bighead or silver carp are known to exist in Minnesota, environmental DNA (eDNA) testing last year suggests the fish may be more common in Twin Cities segments of the Mississippi and St. Croix rivers than either agency or commercial netting have been able to confirm.
"This latest discovery – the third in the last year – underscores the urgency surrounding Asian carp," said Steve Hirsch, director of DNR's Division of Ecological and Water Resources. "These invaders have huge potential to wreak havoc on Minnesota's fisheries and aquatic ecosystems, so we need to do everything we can to stop them from spreading, and we need to do it now."
Hirsch said the highest priority action now is for Congress to authorize closure of the lock at Upper St. Anthony Falls. Bills to that effect have been introduced by Sen. Amy Klobuchar and Rep. Keith Ellison, with other members of Minnesota's congressional delegation as co-sponsors. Those bills also would increase federal support for Asian carp control efforts in the Mississippi River and its tributaries, which has until now been limited to the Great Lakes.
As part of an Asian carp control plan, the DNR also is working on several other measures to halt or slow their spread:
- Obtain funds for a carp barrier at Lock and Dam #1 in Minneapolis.
- Continue eDNA monitoring and increase contract netting by commercial fishing operators.
- Do a vulnerability assessment to evaluate the risk Asian carp pose to Minnesota waters statewide.
- Support research to develop control techniques.
- Restore habitat for native fish species to increase ecosystem resiliency in the face of invading carp.
Populations of bighead and silver carp are established in the Mississippi River and its tributaries downstream of Dubuque, Iowa. Bighead carp can weigh up to 110 pounds and silver carp, which leap from the water when disturbed, can grow up to 60 pounds. They are voracious eaters, capable of consuming 5 to 20 percent of their body weight each day. They feed on algae and other microscopic organisms, often outcompeting native fish for food. Scientists believe Asian carp could severely disrupt the aquatic ecosystems of Minnesota waters.
More information about Asian carp is available on the DNR's website at www.dnr.state.mn.us/asian-carp/index.html.