The vessel left on Sunday or Monday from
Sabratha, northwestern Libya, with five
children and several pregnant women among
those on board, the teenager told a member
of the UN High Commissioner for Refugees
who met him at a hospital in Lampedusa.
Most of the passengers were from Nigeria,
Mali and The Gambia, he said.
He said that the boat began taking on water
a few hours after setting off, and that he
survived by holding on to a fuel can.
"It shows that there may very well be
shipwrecks we don't know about, because
the boats sink without a trace," Flavio de
Giacomo, a spokesman for the International
Organization for Migration (IOM) said.
UNHCR said in a statement that it was
"deeply saddened" by this latest tragedy,
which "comes as a stark reminder of the
vital importance of robust research and
rescue capacities."
Since the beginning of this year, at least 590
migrants have died or gone missing along
the Libyan coast, excluding this latest
capsizing, the IOM estimates.
"Saving lives at sea must remain the key
priority for all and UNHCR commends the
action of the Italian Coast Guard in
coordination with Frontex, the European
Border and Coast Guard Agency," UNHCR's
Volker Turk said.
Last week, the Spanish group Pro-Activa
Open Arms discovered two empty and
partially capsized dinghies , raising fears that
hundreds of migrants could be dead, since
smugglers often pack 120 to 140 people on
such vessels, and sometimes many more.
But these incidents are not included in the
IOM's estimates, in particular as one of the
vessels may have been one that capsized in
Libyan waters shortly before then, in which
54 people were rescued but 66 were
missing.