- Offtake exceeding 5% - Subsistance offtake - sport hunting

Illegal offtake

Levels of illegal hunting could affect the survival of buffalo. Tagg, Mayes and Scheepers (pers.comm. 10/10/02) state that significant illegal hunting is taking place. A population model for buffalo has been developed to explore the maximum illegal harvest which a buffalo population of 3,000 could sustain. It is assumed that mortality would affect both sexes and all ages equally.

Illegal harvest %	0	1	2	3	4	5
Rate of population growth %	5.5	4.3	3.3	2.3	1.2	0.1
Years to reach 10,000 animals	24	29	37	54	154	563

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Offtake exceeding 5%

Under the rainfall conditions in the Caprivi (which set female fecundity), the population can sustain slightly more than a 5% offtake. The higher the proportional offtake, the lower is the growth rate of the population and, at a 5% offtake, it is effectively stationary. To examine rates of population decline when the harvest exceeds 5%, it is not useful to examine percentage offtakes because these result in a lower and lower number of animals being killed as the population declines so that the population tends to stabilise at some low level.

 

A more realistic examination of rates of decline for unsustainable harvests removes a fixed number from the population each year which inevitably results in extinction. In the table below, the number of years to extinction is shown for various fixed offtakes from a starting population of 3,000 animals.

Illegal harvest (% of 3,000 buffalo)	6	7	8	9	10	15	20
Fixed annual offtake	180	210	240	270	300	450	600
Years to extinction	46	28	21	17	14	8	6

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Subsistance offtake

The maximum sustained yield from a population capable of growing at 5% per annum is about 5% and quotas should not exceed this. Far more important is that legal hunting of buffalo for 'own use' is financially and economically short-sighted. The returns possible from international sport hunting of buffalo are so much higher than subsistence uses that there is no sense in pursuing short-term lower valued options. Moreover, there are no short-cuts in the process: there is no sex or age class of the buffalo population which can be hunted for meat without prejudicing the overall potential in the international safari hunting market.

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Sport Hunting

The present trophy quota for buffalo (less than 10 in the entire Caprivi) is unlikely to have any impact on the buffalo population. If the population as a whole is about 3,000 animals it could tolerate a quota of some 90 trophy bulls. If, as assumed in the financial analysis for sport hunting in the Caprivi, there is a 'huntable population' of about 1,000 animals outside protected areas, a quota of 30 animals would be sustainable.