Spate of crocodile deaths in Kruger puzzles ecologists

June 2008. Veterinary surgeons, scientists, researchers, rangers and managers met in the Kruger National Park to discuss the discovery of at least 30 of crocodile carcasses recently discovered in the Olifants River.

"We are in unknown territory and we certainly don't have the answers as to why these crocodiles seem to be dying, so we need to look at the problem closely and find a solution," said the KNP's Mr Danie Pienaar after the meeting.
Carcasses were first spotted by trails rangers from the Olifants Wilderness Trails on at the end of May. A veterinary surgeon from Phalaborwa went to the Olifants River and found one decomposed crocodile with a distinctive yellow-orange hardened fat in its tail.

Aerial survey
A helicopter with researchers and vets flew over the entire length of the Olifants River and the Letaba River within the boundaries of the park. During this aerial survey, 30-odd crocodile carcasses were discovered in various stages of decomposition and sample tissue of the yellow-orange hardened fat was taken, as well as a fresh crocodile carcass, which were sent to the University of Pretoria for further analysis.

It is believed at this stage that the yellow-orange fat is a condition known as Pansteatitis which is usually associated with the consumption of rotten or rancid fish.

"The carcass and the samples have been sent for a thorough post mortem and further tests as we are not sure, at this stage, what caused this condition in the Olifants Gorge as there were no recent fish kills reported from this river in the KNP. We have decided that further samples of crocodiles, fish, water and sediments are needed for detailed analysis before we can identify the cause," added Mr Pienaar.

KNP rangers, trails rangers and scientists will continue monitoring the situation along the Olifants River with regular flights of the Bantam Ultralight Aircraft and reports from the rangers, trails rangers and guides based in the area while the situation is extensively researched.

"We will be looking at this problem from all angles and have not ruled out any possibility. Although a clear cause/effect relationship cannot be found at this stage, it is clear that the Olifants River system is strained beyond it capacity to deal with this level of stress," added Mr Pienaar.

Olifants pollution
Mr Pienaar concluded that the Olifants River is the most polluted of all the rivers in the KNP and the system now has further strain from the Massingir Dam that has pushed back into the Olifants Gorge, causing sediments to be deposited. Visitors to the KNP need not worry about their own health as water utilized from the Olifants River is exhaustively monitored before declared fit for human consumption.