Claims that a giant species of crab measuring up to five metres across is stalking Bahrain's coastline have been debunked by a marine wildlife expert.

International advertising and marketing agency Ogilvy and Mather issued a communique yesterday (August 14) claiming that a giant species of crab known as 'Portunus Giganticus' had been spotted off the coast of Sitra, said a report in the Gulf Daily News (GDN), our sister publication.

According to the public relations firm, 'renowned Madagascan expert' professor Cigam Dnalsi from the Marine Sealife Observation Centre was being sent to investigate the claims , however, no records exist online of such an expert or his supposed place of employment.

Former president of the Bahrain Fishermen Society, which is based in Sitra, Waheed Al Dossary told the GDN that he had never heard of any such sightings in all his years working in and around Bahrain's waters.

“This is the first time I have heard about a giant crab - I have no clue about it and didn't hear anything about its discovery,” he said.

“We do have crabs in Bahrain, but they are very small in size.”

The mythical crabs that the advertising agency claims have been spotted are said to weigh up to 50kg - about the same as the average 14-year-old boy - and measure up to 5m across.

Even the Japanese spider crab, which is the largest known member of the crustacean family in existence according to the UK's Birmingham National Sea Life Centre curator Graham Burrows, only measures a maximum of 3.8m across and weighs up to 19kg.

Meanwhile, the largest land-living crab, the coconut crab, weighs up to 4.1kg, can grow up to 1m in length and is at the very upper size limit for terrestrial animals with exoskeletons.

Ogilvy claims that 'Portunus Giganticus' is related to the Tasmanian giant crab, which lives in the waters of southern Australia and can weigh up to 13kg.

Apparently 'Giganticus' used to be abundant in the Gulf, but was last seen in 1974 near Al Marfa in the UAE.

No records of a 'Portunus Giganticus' exist online.

When contacted by the GDN, a spokeswoman for Ogilvy refused to comment on whether the unsubstantiated claims about a giant crab were a hoax, or reveal any further details.

A Twitter account supposedly set up to track 'Portunus Giganticus sightings in Bahrain' '“ @GiantCrabBH '“ remains inactive. - TradeArabia News Service