ROME — Roughly one of every six migrants who set out in traffickers’ unseaworthy boats from Libya perished at sea last month, UN refugee agency officials said on Friday. The period corresponds to crackdowns launched by Italy and Malta against private rescue boats operating in the area.
Even taking into account that traffickers often send out more boats in the summer to take advantage of warmer weather, that mortality rate was ‘‘dramatic and exceptional,’’ said Carlotta Sami, a Rome-based spokeswoman for the UN High Commissioner for Refugees.
Last month, 629 died while 3,136 were rescued at sea, according to UNHCR data. In comparison, in June 2017, 418 died while 23,524 were rescued.
Private aid boats carried out some 40 percent of the rescue operations in January-April 2018 for migrants disembarked in Italian ports, including those first rescued by military and merchant vessels and later transferred to the aid groups’ ships.
But in recent weeks, the private boats’ ability to operate has been sharply curtailed by anti-migrant politics.
Italy’s new right-wing interior minister, Matteo Salvini, is denying the aid boats docking permission at Italian ports, while Malta is investigating whether the vessels follow international maritime rules, so they are no longer stopping in Maltese harbors for fresh supplies and refueling.
UN refugee agency officials noted that in the first six months of 2018, one of every 19 migrants setting out at sea from Libya died, compared to one of every 38 in 2017.
The officials cited the effects of Malta’s and Italy’s crackdowns combined with the poorly equipped Libyan coast guard’s struggles to conduct successful rescues as factors in making the crossings more perilous than before.
‘‘In the current situation, the search-and-rescue ability has been clearly and severely reduced,’’ Sami said. ‘‘This is having an immediate impact’’ on survival, Sami said, adding that the private rescue ships should be allowed to operate.
Although the voyages are deadlier, the number of migrants taking them is sharply down this year.
In the first half of this year, 45,700 asylum-seekers and migrants reached European shores after rescue, five times lower than the same period two years earlier, the UNHCR said.