By Sarah Shenker
In children's storybooks, they are daring rogues or fearless adventurers.
Figures suggest that pirate attacks are increasingly violent
In real life, pirates are dangerous criminals that many fear have become increasingly brazen and violent.
In 2004, 30 mariners were murdered - half of them in the sea off Nigeria - making it one of the bloodiest years in more than a decade.
Recent attacks in the Malacca Strait in South East Asia has prompted calls for regional governments to take action.
The busy narrow shipping lane between Indonesia and Malaysia carries more than a quarter of the world's trade - and accounts for a quarter of reported attacks worldwide.
Other hotspots are the west coast of Africa and the South China Sea, but piracy has been reported in waters off India, South America, east Africa and the Middle East.
PIRATE ATTACKS WORLDWIDE
Overall, the International Maritime Bureau (IMB) says 325 attacks were reported for 2004, down from the 445 in 2003, possibly due to increased patrols in Indonesia and Malaysia.
But observers say they are concerned at the increasing violence of attacks.
Most incidents are "maritime muggings", IMB director Capt Pottengal Mukundan told the BBC News website.
The pirates use small boats with fast outboard motors for opportunistic attacks on prosperous-looking vessels. Bamboo poles are hooked on to a boat and used to climb on board, or ropes are stretched between two boats to trap a vessel.
At the other end of the scale are attacks on large commercial vessels, which are the most profitable targets.
"These are quite sophisticated operations, which involve three or four boats from which the attack is launched," Capt Mukundan says.
"The people appear very well trained, and very ruthless in getting what they want."
Indonesian rebels have been blamed for attacks in the past, but they are no longer seen as the main operators.
The Malacca Strait is notorious for attacks
"The sophisticated attacks are financed by organised crime groups that have lots of resources - they have the networks through which to sell stolen cargo, and places to keep abducted crew members who are held to ransom," Capt Mukundan says.
In a number of cases, an entire crew of a dozen has been killed, with the pirates assuming their place.
In 1998, pirates assumed control of the oil tanker Petro Ranger in the South China Sea and forced the crew to teach them how to operate the vessel.
They then made one of their hostages paint over the name of the ship with a new name, and replaced the Singapore flag with one from Honduras.
The tanker sailed to somewhere off the coast of China, where it was drained of its oil.
As Chinese officials were about to issue the ship with a new registration - allowing the pirates to sell her for an estimated $16m - the crew were able to alert the authorities.
Smaller vessels are also vulnerable to violence. Greenpeace campaigner and yachtsman Sir Peter Blake, 53, was killed in a pirate raid on his yacht in Brazil in December 2001.
Critics say measures in place to help increase security suffer from lax enforcement.
In poor countries, seafarer credentials can be bought cheaply. In small ports, officials often do not bother to verify registration papers.
Stolen ships with new identities effectively vanish - becoming known as "ghost ships".
Regional sensibilities and tensions also interfere with policing. Indonesian and Malaysian coastguards will not cross into each other's national territory, even if in hot pursuit, says Capt Mukundan.
"This plays into the hands of the criminals," he says.
The IMB wants governments be more effective in prosecuting pirates.
"Because there has not been an effective deterrent, pirates are encouraged to extend what they are doing - they feel more and more confident," says Capt Mukundan.
"It is vital that action be taken by law enforcement agencies to identify the perpetrators of these attacks and have them punished under law."