Image of 'world's largest lobster' contains signs of AI

AI experts said a picture appearing to show fishermen posing with a giant lobster showed signs of manipulation, after it made the rounds in social media posts claiming it showed the "world's largest lobster" weighing 150 kilograms (330 pounds). The world's heaviest recorded lobster in fact weighed 20.14 kilograms, according to the Guinness World Records.

"Puerto Rican fishermen from Gran Canaria have caught the world's largest lobster, which weighs 150 kilograms and is two metres 60 centimetres long without the antennae," read a simplified Chinese X post shared on June 24.

The post, which was shared by an account with more than 145,000 followers, shows a picture of three men posing alongside a huge lobster on a fishing boat.

The image circulated in similar posts in English, Chinese and Thai which also falsely claimed it showed the world's largest lobster.

While some social media users said the image looked fabricated, others appeared to believe it was real.

"This looks a bit scary," one commented. 

Another wrote that the fishermen should "release it".

Visual inconsistencies

AFP spoke to three computer scientists who said the image shows telltale signs it was created with artificial intelligence.

Siwei Lyu, director of the University of Buffalo's Media Forensic Lab, pointed out that the sea level on the horizon was not straight (archived link). 

"This image is pretty clear to me to be AI-generated," he said.

The men in the picture also have "distorted facial expressions" and "abnormal hand poses", said Shan Jia, research scientist at the University of Buffalo's Department of Computer Science and Engineering (archived link).

Shu Hu, head of Purdue University's Purdue Machine Learning and Media Forensics Lab, added that the boat's deck appeared "misaligned" and that the shape and colour of the arms of the man in the middle were "not symmetrical" (archived link).

A search on the Guinness World Record's website found no specific entry for the "world's largest lobster".

However, the heaviest recorded marine crustacean weighed 20.14 kilograms (44.4 pounds) and measured 1.06 metres (3.4 feet) from the end of the tail-fan to the tip of the largest claw (archived link).

The American or North Atlantic lobster was caught in 1977 in Nova Scotia, Canada and "later sold to a New York restaurant owner", Guinness World Records said.

There is also an entry for the largest slipper lobster, although Guinness World Records pointed out that slipper lobsters "are not true lobsters" (archived link).

Fact-checkers at Snopes also debunked the fabricated lobster picture in 2023 (archived link). 

AFP has previously fact-checked AI-generated pictures of animals shared as real photos, including a giant octopus and a pink dolphin. 

July 11, 2024 This story was amended to correct a typo in the lede.