Juggling rhino numbers

With only a month before the world decides whether to legalise trading in rhino horn, an Oxford mathematician has warned that not enough is known to establish the effect of such legalisation.

Professor Colin Please of the university's applied mathematics department said there were many "holes" and "uncertainties" in the data, making an assessment of the effect of the proposed legislation on the animals' future suspect.

"We simply don't have all the info to say what might happen."

Please is a member of the Mathematics in Industry Study Group, which met at Wits University, Johannesburg, last week. The group spent a week trying to create a mathematical framework with which to study the effects of poaching and the legalisation of the trade in horn taken from South Africa's white rhino.

The Department of Environmental Affairs announced yesterday that 32 rhino have been poached this year: 18 in the Kruger National Park, six in North West and five in KwaZulu-Natal. Limpopo lost two rhino and one was killed in Mpumalanga.

Last year 668 were killed.

"The rhino trade is very similar to the drugs trade. But in the drugs trade it is not obvious how much is produced, whereas in the rhino trade you know almost exactly how much is produced because you know how much is poached," said Please.

"In certain areas you know more, but in other areas it's a black market, so you really have no idea about [factors such as] market prices and you can't understand the financial and power structures, and the flow from here to the Far East."

The Convention on International Trade in Endangered Species is expected to debate the proposed legalisation on trading in rhino horn in Thailand in March.

Trading in white rhino horn is prohibited by Cites, to which South Africa is a signatory. There is much debate about legalising the trade, with many private rhino owners in favour and most wildlife organisations against.

The participants in the meeting at Wits will try to establish how much rhino horn is used in China and Vietnam, and when the rhino can be expected to become extinct.