CHICAGO (CBS) — Despite efforts to rid Chicago’s Sanitary and Ship Canal of Asian carp, evidence of the invasive fish is still showing up.

As WBBM Newsradio’s Lisa Fielding reports, the Army Corps of Engineers says in all of last year, it took 2,378 water samples above the electric barrier, and only 34 samples tested positive for Asian carp DN, according to the Milwaukee Journal Sentinel.

LISTEN: WBBM Newsradio’s Lisa Fielding reports

This year, according to the Journal Sentinel, the corps landed 17 positive results from 114 water samples, after just one day of taking samples.

The samples that tested positive for Asian carp DNA jumped almost 15 percent, the newspaper reported.

Most of the positive samples were from Lake Calumet, which is linked to Lake Michigan via the Calumet River system, the Journal Sentinel reported.

The corps says a positive sample doesn’t mean evidence of live fish above the barrier. The DNA samples could be coming from barges carrying contaminated bilge water, or in the excrement of birds.

Asian carp pose a significant threat to the ecology of the Great Lakes, to the point where several states have called for an order to close the Sanitary and Ship Canal.

So far, federal courts have rejected the lawsuits, and the U.S. Supreme Court has decided not to hear the cases.

This is the third year in a row that the Army Corps of Engineers has found Asian carp DNA in Chicago.

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