The body of Mike Lynch's 18-year-old daughter Hannah has been recovered from the site of a shipwreck off Sicily, sources told Reuters. 

She was the only person still unaccounted-for since the British tech magnate's family yacht sank this week, killing him and six others.

Italian emergency services resumed their search on Friday and rescue divers recovered the body hours later.

A spokesperson for Mr Lynch's family said they are devastated and in shock, in a statement on Friday.

"The Lynch family is devastated, in shock and is being comforted and supported by family and friends," their statement said.

"Their thoughts are with everyone affected by the tragedy. They would like to sincerely thank the Italian coastguard, emergency services and all those who helped in the rescue."

"Their one request now is that their privacy be respected at this time of unspeakable grief."

The British-flagged Bayesian, a 56-metre-long  superyacht carrying 22 passengers and crew, was anchored off the port of Porticello, near Palermo, when it capsized and sank on Monday within minutes of being struck by a pre-dawn storm.

A judicial investigation has been opened into the sinking, which has baffled naval marine experts, who say a boat like the Bayesian, built by Italian high-end yacht manufacturer Perini, should have withstood the storm.

The CEO of The Italian Sea Group TISGR.MI, which owns Perini, said the shipwreck was the result of a string of "indescribable, unreasonable errors" made by the crew. 

He ruled out any design or construction failings.

"The boat suffered a series of indescribable, unreasonable errors, the impossible happened on that boat … but it went down because it took on water. From where, the investigators will tell."

Pulling the wreck out of the sea, where it is now lying on its right side, apparently intact, at a depth of about 50 metres, may help investigators determine what happened to it, but the operation is likely to be complex and costly.

Nick Sloane, the South African engineer who led the operation to salvage the Costa Concordia cruise liner that sank in 2012, said in Italian media interviews on Friday that the operation would cost around 15 million euros ($25 million).

He told La Repubblica newspaper the yacht's salvage would have to be completed by mid-October, and take six to eight weeks, including preparation work. 

Bringing the yacht to the surface will have to be done "very, very slowly", and might take a couple of days, he said.

Reuters