Eight rare rhinos were moved to help their species. It went horribly wrong.

The endangered black rhinoceros. Photo / Getty Images

Eight critically endangered black rhinoceroses died after being moved from parks near Kenya's capital to a sanctuary in a national park in the country's southeast, the government said Friday.

Preliminary investigations suggest the rhinos suffered from salt poisoning as they adapted to water with higher saline levels than they were accustomed to, according to tourism and wildlife minister Najib Balala. In a statement, he called the death toll "unprecedented" in more than a dozen years of translocations in Kenya.

The eight dead rhinos were among 11 that were moved last month to Tsavo East National Park, where wildlife officials hoped they would start a new population. An additional three animals were to join them soon, but Balala said he had immediately suspended the transfer operations.

As African wildlife numbers have plummeted because of poaching and habitat loss, conservationists and governments have increasingly turned to translocations in hopes of restoring populations in remote spots where they might be better shielded from the threats driving them to the brink elsewhere. One nonprofit, African Parks, has shipped several endangered species across the continent, including black rhinos, which it has flown from South Africa to Rwanda and Chad. Kenya moved 149 rhinos between 2005 and 2017, Balala's statement said. Eight of those died, not including the black rhinos at Tsavo East.

Translocation is a bold, quixotic, expensive and logistically complicated approach to saving wildlife. And as the situation in Kenya underscored, it is dangerous.

"Moving rhinos is complicated and risky, akin to moving gold bullion, it requires extremely careful planning and security due to the value of these rare animals," Paula Kahumbu, chief executive of the conservation group Wildlife Direct, said in a statement on Facebook that also faulted the government for waiting a week to release information on the deaths.

"I dread to think of the suffering that these poor animals endured before they died," she wrote. "We need to know what went wrong so that it never happens again."

Balala said the high salt levels in water at the rhinos' new home could have led to dehydration that caused them to drink more, "resulting in excess water intake of the saline water that further exacerbates the problem." But he said he had ordered internal and external investigations to determine the exact cause of death, adding that "disciplinary action" would be taken if the probes point to negligence or wrongdoing by Kenyan Wildlife Service officers.

The three remaining rhinos are being monitored and given fresh water in pans, the ministry said.

Black rhinos are targeted by poachers for their horns, which are highly coveted in Asia, particularly in Vietnam. Widespread poaching led the black rhino population to drop from around 70,000 in 1970 to fewer than 2,500 in 1995, according to Save The Rhino. About 5,000 remain in the wild today, the World Wildlife Fund says.

Kenya's black rhino population dropped during the 1970s and 1980s from 20,000 to about 250; today, it is around 650, according to WWF.