Nile crocodile Conservation and Research in South Africa
The importance of crocodiles in maintaining biodiversity in wetlands and waterways, their cultural significance, and their historic exploitation led many countries to develop national laws to protect them. It was only in 1967 and 1968 that Nile crocodiles in South Africa were given some protection under provincial ordinances. Up to then crocodiles were classified as vermin.
Crocodiles have been described as one of nature’s greatest masterpieces. They are critical in sustaining biodiversity of wetlands and encouraging the health of waterways. As an example, they prey on the most abundant species, such as the Sharptooth catfish (Clarius gariepinus), thereby increasing resources for less abundant smaller species, such as tilapia (Oreochromis aureus) and yellow fish (Labeobarbus aeneus). These species prey on mosquito larvae thus potentially reducing the risk of associated mosquito-borne diseases.
Across Africa, the Nile crocodile has long been associated with spiritual power and exists within a great diversity of human cultures, in a variety of social and economic contexts.
Of the five species of crocodiles found in Africa, only the Nile crocodile (Crocodylus niloticus) occurs naturally in South Africa. Historically they occurred in all rivers, lakes and estuaries on the northern and eastern side of South Africa, wherever the climate was suitable. The Nile crocodile population in South Africa is relatively small and it has never supported populations comparable in size with those of equatorial Africa. Nile crocodiles were heavily exploited for their skins in an uncontrolled manner throughout Africa, during the early 19th century and were exterminated in some parts of South Africa. The wild Nile crocodile population in South Africa was estimated to be 9500 based on surveys carried out in the early 1990s.
Conservation Status of Nile Crocodile
South Africa has a long and illustrious history of crocodile conservation and research with many individuals making both national and international contributions. The need and importance to conserve wild Nile crocodile populations in South Africa and crocodile farming were the key drivers for their interest.
Crocodile research in southern Africa is synonymous with Tony Pooley (affectionately known to the isiZulu people as Mashesha). Tony founded the Ndumo Crocodile Centre which later moved to its current location at St Lucia, KwaZulu-Natal where he conducted pioneering research on Nile crocodile behavior, embryology and husbandry. His rearing and restocking efforts from 1967 – 1977 played a significant role in re-establishing crocodile populations in Zululand (North-eastern KwaZulu-Natal province) following decades of killings and persecution. In 1971 Tony was invited to attend the inaugural meeting of the IUCN-SCC Crocodile Specialist Group (CSG) and in so became a founding member. On the veterinary side Prof Fritz Huchzermeyer stands undeniably as another founding South African personality of CSG and crocodile research. His seminal work “Crocodiles: Biology, Husbandry and Diseases” was the first comprehensive book on crocodile diseases.
These pioneering individuals (and others not mentioned) played a leading role in crocodile conservation, biology and husbandry and undoubtedly served as motivation for several South African academic institutions to become involved in crocodile research and crocodile health and welfare. These institutions included the University of KwaZulu-Natal, University of Pretoria, University of Stellenbosch, Tshwane University of Technology, UNISA and University of Witwatersrand. A non-exhaustive list of Nile crocodile research includes four postdoctoral studies, 15 PhD, 31 Master, one Honours and BTech degree. A number of scientific publications have also emanated from a broad multidisciplinary research programme that focused on pansteatitis mortalities in crocodiles. Since 2000, the majority of Nile crocodile research came from two regional programmes: The University of Stellenbosch’s Okavango Delta and Middle Zambesi Valley and the University of KwaZulu-Natal’s Zululand Crocodile Research Programme (from 2009). More recently (2015) the Exotic Research Centre (ELRC) at the University of Pretoria was established that focusses on research, training and diagnostic interventions required by the crocodile and ostrich farming industries, including health and welfare and the exotic leather market.
Whereas in the past crocodile populations were under threat due to exploitation and poaching for their skins, more recently the threats to wild populations are of anthropogenic nature, particularly with regard to competition for aquatic habitat in a country with relatively low rainfall and fast developing population supported by formal and informal agricultural sectors. Research conducted following the death of 216 adult wild crocodiles (caused by an outbreak of pansteatitis) in the Kruger National Park during the period 2008 – 2012 highlight the need for ongoing monitoring and scientific research to negate the adverse impact of environmental factors on crocodile populations.
Crocodile farming in South Africa creates extensive opportunities for crocodile research and diagnostics that are of great value to conservation, particularly with regard to crocodile health and welfare. This is epitomized by the research contributions of Prof Huchzermeyer to crocodile conservation, who as a veterinarian and veterinary pathologist became involved in disease management on crocodilian farms and is similarly utilised by the ELRC.