Asian carp were first introduced to southern states of the US from China in the 1970s to help clean tanks in fish farms. They escaped and for more than 30 years have steadily worked their way up the Mississippi river system, devouring food and devastating native fish populations along the way. Last December, DNA of the carp was found just a few miles from the Great Lakes outside Chicago, a discovery that Ullrich described as “a major shock to everyone”.

‘Terminator’ carp threatens Great Lakes

Will the US government invoice the fish factory farmers for the environmental cost? “Earlier this month the Obama administration put forward a $78.5m plan for blocking the fish,” states the article published in The Guardian. Then, there’s the cruelty issue.

Its focus lies in an electronic barrier that has been built by the US army corps of engineers across a canal through which the fish would have to swim to reach the lakes. The barrier, opened last year, has been designed to allow ships to pass while deterring fish. It works by shooting a high-voltage current through the water strong enough to stun, but not kill, the carp