Minnesota Attorney General Lori Swanson has filed a brief with the U.S. Supreme Court supporting Michigan's lawsuit seeking to prevent Asian carp from entering the Great Lakes.
Swanson filed the document Monday, saying Asian carp could eventually threaten the native fish population of Lake Superior, which she called "an important environmental and economic asset to the State of Minnesota."
Michigan is asking the Supreme Court to close shipping locks near Chicago to prevent the fish from invading the Great Lakes.
Officials poisoned a section of the Chicago Sanitary and Ship Canal earlier this month to prevent the carp from getting closer to Lake Michigan while an electrical barrier was taken down for maintenance.
But scientists say DNA found north of the barrier suggest at least some of the carp have gotten through and may be within 6 miles of Lake Michigan. If so, the only other obstacle between them and the lake are shipping locks, which open frequently to grant passage for cargo vessels.
The Supreme Court is expected to consider Michigan's lawsuit at a conference on Jan. 8.
(The Associated Press contributed to this report.)