Underwater diver alongside the stomolophus nomurai jellyfish off the coast of Japan, October 4, 2002 Source:AP

The Nomura's jellyfish can weigh up to 200kg each and have recently begun to swarm in the waters off the coast of China.

Unfortunately for the three-man crew of the Diasan Shinsho-maru, their net dragged through such a swarm, capturing dozens of the jellyfish, which can grow up to two metres in diameter.

The three men were thrown into the sea when the vessel capsized and sank under the weight of the jellyfish, according to UK newspaper The Telegraph.

The swarm has come as a surprise to local fisherman, who reported none in 2008.

Self-described "jellyologist" Monty Graham, from the Dauphin Island Sea Lab in Alabama, said the Nomura's jellyfish swarm in order to breed.
The last spikes in Nomura's jellyfish populations occurred in 1958 and 1995, according toLiveScience

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