Toxic algae blamed for deaths of elephants
GABORONE, Botswana — The sudden deaths of 330 elephants in northwestern Botswana earlier this year may have occurred because they drank water contaminated by toxic blue-green algae, the government announced Monday.
The elephants in the Seronga area died from a neurological disorder that appears to have been caused by drinking water tainted by “a toxic bloom of cyanobacterium in seasonal pans (water sources) in the region,” said Cyril Taolo, acting director of the Department of Wildlife and National Parks.
The unexplained deaths ceased after the water pans dried up, said Taolo, in a news conference in Gaborone, the capital.
No other wildlife species were affected by the toxic water in the Seronga area, close to Botswana’s famed Okavango Delta, said Taolo. Even scavengers, like hyenas and vultures, observed feeding on the elephant carcasses showed no signs of illness, he said.
With an estimated 130,000 elephants, Botswana has the world’s largest population of the pachyderms.
After the mysterious deaths, the government conducted extensive tests to determine the cause of the fatalities. Male and female elephants of all ages died, with clinical signs limited to neurologic symptoms, said Taolo. The deaths happened mainly near seasonal water pans and did not spread beyond the initially affected region, he said.
Taolo said neurotoxins from cyanobacteria living in contaminated water could have affected the transmission of neurologic signals within an animal, causing paralysis and death, predominately related to respiratory failure.
He could not explain why these toxins did not affect any other animals drinking the affected water. He ruled out other death possibilities such as anthrax, poaching and sabotage.
“A monitoring plan of seasonal water-pans on a regular basis to track such future occurrences will be instituted immediately and will also include capacity building to monitor and test for toxins produced ... by cyanobacteria,” said Taolo.
Humpback whale finds way home
A humpback whale has found its way back to sea weeks after getting lost in a murky, crocodile-infested river in northern Australia, while an estimated 270 pilot whales became stranded in the country’s south.
There have been no previous recorded sightings of whales in remote East Alligator River in the Northern Territory’s World Heritage-listed Kakadu National Park, and no one can explain why at least three of the blue-water mammals ventured so deep inland in a river with little visibility. The last of the humpback trio managed to navigate its way through shallow channels at the broad river mouth and back into Van Diemen Gulf over the weekend, Kakadu National Park manager Feach Moyle said.
In a more-common phenomenon, about 270 pilot whales were reported stranded Monday on two sandbars off Australia’s southern island of Tasmania state. Authorities planned to launch a mission early Tuesday to rescue the whales, but about 25 of them apparently have died already.