Blue ringed octopus, which can kill with one bite, picked up at Manly beach clean-up

A  BLUE-RINGED octopus, considered one of the most dangerous animals in the sea, found lurking in an old coffee cup at a clean-up.

A  BLUE-RINGED octopus, considered one of the most dangerous animals in the sea, was mistakenly picked up with some rubbish by a beach clean-up volunteer at Manly Cove at the weekend.

The small creatures, which are normally brown but produce bright blue rings or lines when provoked, can give a fatal bite.

Within minutes, the ­extremely powerful venom can cause numbness of the lips and tongue, followed by breathing difficulties and sometimes death if the victim does not receive immediate medical help.

Blue-ringed octupus can kill.

Deborah Dickson-Smith, one of the volunteers ­involved in the clean-up, said everyone was told to wear gloves to protect themselves from dangerous items such as broken glass, as well as from sea life such as the blue-ringed octopus, which is common in Sydney but rarely seen ­because it is shy and non-­aggressive.

This is a blue-ringed octopus found at Narrabeen Lagoon a few months ago.

“One of the volunteers picked it up along with some rubbish and tipped it onto a tarp on the beach for sorting,” Ms Dickson-Smith said.

Ms Dickson-Smith was volunteering at the clean-up event organised by the Dive Centre Manly and supported by the Two Hands Project.

Bottle tops found at Manly Cove during the clean-up. Picture: Supplied/ Deborah Dickson-Smith.

“I then saw the octopus in a bucket inside a cup,” she said. “It had very bright blue marks, so was obviously very angry.”

She said the group had been working at the Skiff Club end of Manly Cove, which was packed with beachgoers and kayakers.

“One of the volunteers picked it up along with some rubbish and tipped it onto a tarp on the beach for sorting,” Ms Dickson-Smith said.

The octopus had been hiding in a discarded coffee cup about 50m from the shore, when the cup was collected.

The octopus was put back into the ocean.

Manly Sealife Sanctuary’s Rob Townsend said the species was ­incredibly common around the waters of Sydney but rarely seen.