Croc mystery still not solved
2009-06-18 08:37
Vanderbijlpark - Crocodiles have once again started dying in the Olifants River Gorge in the Kruger National Park. Since the end of May a total of 12 carcasses were removed from the gorge.
This comes exactly one year after the mass death of Nile crocodiles (Crocodylus niloticus) during the winter last year when over 160 of these crocs died in the Olifants River due to pansteatitis - an orange hardening of the reptile’s fat.
Prof Henk Bouwman, of the school for environmental sciences and development at the Potchefstroom campus of North-West University, on Wednesday said scientists are incredibly frustrated because they’ve now been working for over a year to try to determine the exact cause of the deaths.
“Unfortunately we don’t have any real answers yet,” he said on Wednesday from the Kruger Park.
Bouwman, along with a team of students, scientists from the Universities of Pretoria and the Free State, as well as researchers from Sanparks, caught fish - the crocodiles’ food - in the river on Wednesday to determine the extent to which the fish were affected.
Thus far, no dead fish have been noticed in the river.
Bouwman said it is clear that the deaths were facilitated by the drop in temperature.
Fat becomes indigestible
He is of the opinion that the crocodiles eat fish in summer, which gives them direct energy. However, as soon as winter arrives, the crocodiles don’t eat and are thus dependent on their fat for energy. But the fat becomes indigestible because it is hardened and thickened.
The crocodile deaths stopped during the summer last year. Furthermore, Bouwman said his students will be taking samples of snails to analyse and try to determine whether they were exposed to poisonous substances which attack the hormones (Endocrine disruptives).
Some scientists feel that the heightening of the Massingir Dam’s wall in Mozambique is one of the reasons for the deaths, since it pushes sediment up into the gorge. The Olifants River Gorge is the crocodiles’ breeding area.
Dr Jan Myburgh of the department of paraclinical sciences of the faculty of veterinary science at Onderstepoort, earlier said the fat reaction in the Kruger Park crocodiles is exactly the same as that which caused the deaths of hundreds over the past few years in the Loskop Dam. There are currently only five crocodiles left in the Loskop Dam.
'Answers keep evading them'
Bouwman said researchers from San Parks are working day and night to try and solve the puzzle, but the answers keep evading them.
Bouwman was on his way to Stockholm, Sweden, to speak about the crocodile deaths at a conference, when he heard of the new batch of crocodile carcasses. He immediately cancelled his trip.
His speech was delivered by someone else. In the meantime, Bouwman has learned that scientists from Norway, Sweden and Denmark are all ready to come and help with the research surrounding the mysterious crocodile deaths.
Due to acidic mine water, mining activities and pesticides and insecticides, the Olifants River is one of the most stressed rivers in the country.