A team of divers, some of whom were involved in searching the Costa Concordia cruise ship, which sank off the Tuscan island of Giglio last year, have inspected the wreck of the boat, which set out from the Libyan port of Misurata.
"There were bodies everywhere, trapped inside the wreck, but also on top of it and around the boat," said Simone D'Ippolito, who owns a diving business on Lampedusa.
One of the 150 migrants to survive the sinking recounted how he left his native Eritrea a year ago. The 18-year-old, who gave his name as David, travelled overland from the east African country into neighbouring Sudan and then to Libya, a dangerous journey for which he had to pay traffickers US$3000 ($3600).
"It took us two months to cross the desert. We first travelled by foot, then in a truck. Many times I thought I would never make it. We travelled at night. During the day, when we weren't travelling, they tied us up."
Once he reached Libya he had to work for months to scrape together the equivalent of 1000 ($1600) that people smugglers demand for the boat crossing.
"I worked for nearly a year to earn enough money for the crossing. I worked as a house painter and lived in a wooden shanty. The Libyans beat us all the time. They were like mafia - they treated me like a slave."
His companion, who gave his name as Kijwa, said the Libyans were "bad people - we got many beatings".
The survivors were accommodated in Lampedusa's overcrowded refugee reception centre. It has 300 beds but is packed with more than 1000 people.
The lack of space was so acute that some survivors bedded down in an old van. Others slept on bits of mattress outdoors.
Among the survivors were 40 unaccompanied minors, aged between 11 and 17.