The US city of Chicago is considering drastic measures to prevent giant fish infesting North America’s Great Lakes.
Authorities are thinking of blocking the city’s canal system to stop Asian carp entering Lake Michigan.
Such a move could cost up to $18bn (£11bn) and cause huge economic disruption to the city.
Cheaper options are also being examined, including making burgers out of the fish and eating them to extinction.
This species of carp, as the name suggests, is native to the Far East.
They were originally introduced to southern US states more than three decades ago to control algal build-up in sewage treatment plants. But they escaped into the Mississippi River and proliferated, making their way north towards the Great Lakes.
More than a metre in length, they have displaced indigenous fish species along the way.