African Wildlife and Environment Issue 65

There is a special place in the Okavango not often spoken about, photographed or visited by tourists. This place holds critical fish, bird and crocodile nesting habitat and is also home to a number of the different Ngamiland tribes including the Bayeii, Hambukushu, //Anikhwe and Bugakhwe people. This special place is known as the Okavango Panhandle and is made up predominantly of the Okavango river channel running from the village of Mohembo in the north to Seronga in the south.

Vincent Shacks

For crocodiles, this place is especially important as it holds 99% of all the Nile crocodile ( Crocodylus niloticus ) nesting sites for the entire Okavango Delta. With no formal protection, the Panhandle is currently demarcated as pastoral, arable and residential land, which means that humans and wildlife often come into conflict in these parts. In terms of conservation need, the Panhandle was an obvious place from which to start research work on the Nile crocodile population and the Okavango Crocodile Research project began work there in 2003. For the past 14 years our crocodile conservation programme has assisted the Department of Wildlife and National Parks (DWNP) in Botswana with the management and monitoring of this crocodile population. Our team has captured, measured and marked in excess of 2 500 crocodiles and with this data developed a management plan and numerous scientific publications on the population. The Panhandle region of the Okavango Delta has been a site of significant historical population declines of the Nile crocodile. These declines were as a result of the commercial utilisation of crocodiles by hide hunters, which saw as many as 48 000 crocodiles shot between the periods of 1957 – 1968. Commercial ranching was introduced in 1983 as a way of sustainably meeting the international demand for hides. This lead to the removal of 1 050 live adults and the collection of 14 000 eggs from the Okavango between 1983 and 1988. These numbers clearly indicate the massive impact that the cropping years had on this one population and the main aim of our research group is to carefully assess the rate of recovery that has taken place, if any. Our research on the density of this population has allowed us to come up with strategic means of assessing the population using short and intensive nocturnal surveys. Our previous population estimates carried out as part of a PhD study, allowed us to calculate a ‘correction factor’ for fast assessment of this population. The correction factor is a statistically

Recovering the Nile crocodile population OF THE OKAVANGO

Photograph: Mark Flatt Photography

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47 | African Wildlife & Environment | 65 (2017)