Included in the team that conducted the post mortem and capture operations were crocodile capture expert Hannes Botha from Mpumalanga Parks and Tourism Agency, Dr Jan Myburgh from Onderstepoort, Prof Henk Bowman from North-West University and IUCN crocodile expert Dr Fritz Huchzermeyer.

“Although we learnt a lot during the operation, we have not yet found the exact cause of the pansteatitis that has caused the deaths of so many crocodiles in this river system,” said the KNP’s head of Scientific Services, Mr Danie Pienaar.

The three-day, three-night operation not only saw post mortem operations on a number of crocodile carcasses found on the banks of the rivers concerned, but it also included the night capture of 11 live crocodiles. This is the first time that such a large scale night capture operation has taken place in the KNP.

“A new theory that is being investigated is that because the live crocodiles are preying on the carcasses, they are getting infected from eating affected fat and tissue and thus continue spreading the disease. In order to break this potential cycle, we have taken the decision to remove the carcasses from the water and burn all the carcasses we find,” Mr Pienaar added.

So far, 10 crocodile carcasses have been burnt. KNP Veterinary Surgeons from Veterinary Wildlife Services (VWS) also took the opportunity to do post mortems on three of these carcasses, before they were burnt.

But it was the live capture of crocodiles on the nights of Sunday to Tuesday (August 3 – 5, 2008) that was of considerable interest to all concerned. The operation was a first for the game capture team of VWS and they were able to capture 11 specimens. Blood and tissue biopsy samples were taken from all these reptiles, before they were tagged with plastic markers and released back into the water.

“Although we didn’t manage to capture our goal of 30 crocodiles, the operation has given us an idea on the rate of infection at the confluence of the Olifants and Letaba Rivers specifically with seven out of the 11 captured crocodiles showing affected fat on the biopsy sample. This high infection rate unfortunately also means that we can still expect a large number of crocodile deaths in the lower Olifants and Letaba rivers ” Mr Pienaar added.

So far, the results of tests done on the water and crocodile tissue samples from laboratories both in South Africa and overseas have yet to give conclusive answers on the reasons why the crocodiles have been dying. Presently, KNP rangers and scientists have counted 130 crocodile carcasses, with more discovered during every survey flight, which are conducted weekly with a Bantam Ultralight Aircraft.

“However, we can rule out blue-green algae and we can also confirm that the water in the Olifants River is safe for drinking, which is certainly good news for tourists to the area, particularly those staying at Olifants Rest Camp and undertaking any of the activities in the area, including the Olifants Back Pack Trail and the Olifants Wilderness Trail,” concluded Mr Pienaar.

The river system of the Olifants and Letaba rivers, which includes the Olifants River Gorge, has the highest Nile Crocodile population densities in the entire KNP.