On Monday, the U.S. Army Corps of Engineers released an outline of options to stop Asian carp from migrating into the Great Lakes and threatening the region’s $7 billion sport fishing industry.

However, according to the Chicago Tribune, the Corps two-year study might be too little too late, after a string of recent DNA findings along various shorelines hint Asian carp may have already infiltrated operational barriers and made their way into the Great Lakes.

“Any kind of engineering structure has a point of weakness,” said Dave Wethington, the study’s chief author. “If there were a series of storms that totally swamp the system, you could still get transfer of species, even with a physical barrier.”

Of the eight options presented, the most expensive was an $18 billion plan to permanently separate Lake Michigan from the Chicago River and its connected waterways–a task that would take up to 25 years with no guarantee the fish wouldn’t work their way into the Great Lakes during that time. A less expensive, $68 million a year option is to net and poison carp while maintaining the electronic barrier in the Sanitary and Ship Canal north of Lockport, but it also isn’t receiving much fanfare from legislators.

“I’ve seen too many of these long-term Corps projects languish for years and fall victim to congressional inaction,” said U.S. Sen. Dick Durbin, the Illinois Democrat and assistant Senate majority leader. “We can’t gamble with the threat of Asian carp … or risk severe flood damage to the Chicago metropolitan area by pursuing a risky plan at the expense of our current efforts.”