The organisms can weigh up to 440lbs and grow up to 6ft in diameter.

The three men forced into the sea, near Chosi, were rescued by another trawler.

Waters around Japan have been inundated with the jellyfish this year.

Experts believe weather and water conditions in the breeding grounds off the coast of China have been ideal for the species in recent months.

"The arrival is inevitable," Hiroshima University Professor Shinichi Ue told the Yomiuri newspaper.

"A huge jellyfish typhoon will hit the country."

Nomura's jellyfish have been known to wreak havoc in Japanese waters.

Many fishermen have tried to keep jellyfish out of their nets by using sharp wires.