Tanzania's elephant population fell 60 percent over the last five years but the reason could well be migration, the government said, a conclusion that drew derision from conservation groups who spoke of "industrial scale" poaching.
The number of elephants in the east African country, which boasts safaris in the shadow of Mount Kilimanjaro and on the fabled Serengeti plains, fell to 43,529 in 2014 from 110,000 when the last count was taken in 2009.
Tourism Minister Lazaro Nyalandu blamed the decline in part on migration and said his department was trying to find the missing elephants in a country where tourism is the biggest source of foreign exchange.
However, wildlife trade monitoring group TRAFFIC said the results of the survey tallied with concerns that poachers were decimating the elephant population.
Demand for ivory for use in jewelry and other ornamental items from fast-growing Asian economies such as China and Vietnam has led to an escalation in poaching in Africa, threatening to wipe out large numbers of animals.
"Were they killed or did they move out of the observed area? Usually when such a large animal reduction is observed, there are a comparable number of carcasses also observed. That was not the case here," Nyalandu said in a statement.
He did not say if the missing elephants could have crossed over the border into neighboring countries such as Kenya or Zambia, which also have large numbers of elephant.
Tanzania said last year its elephant population had doubled to 110,000 in 2009 from 55,000 in 1989 as a result of a widespread anti-poaching drive.
TRAFFIC executive director Steven Broad accused the government of being in denial about ivory poaching.
"The government's figures show Tanzania lost tens of thousands of elephants over the past decade," he said. "It is incredible that poaching on such an industrial scale has not been identified and addressed before now."