Hong Kong's being a bridge between mainland China and the rest of the world is not just about cross-border trade. The seizure at the Kwai Chung container port last week of one of the world's biggest hauls of smuggled ivory re-emphasised that our city also has a duty to uphold international rules. The mainland's rapidly growing appetite for elephant tusks puts us on the firing line. There is little more we can do than be as vigilant as is practical, though; protecting the giant mammals is largely about education.

The 3.8 tonnes of tusks in two containers from Africa was equivalent to one-sixth of the total amount of ivory seized globally last year. But how much actually passes through Hong Kong can only be guessed at. The volume of trade going through the port is simply too great to be given more than a cursory inspection. A two-month investigation by Hong Kong and Guangdong customs agents led to the latest find, and seven people have been arrested. Inspections, co-ordinated action and punishment do not get to the root of the problem, though.

Ivory has always been in demand in China and elsewhere in Asia, where it is prized as a source of wisdom, sign of nobility and symbol of wealth. Elephant populations were so threatened in the 1980s that trade in new ivory was mostly banned. The mainland's rising wealth has meant a thriving illegal industry and new crisis. A 2007 study by the International Fund for Animal Welfare shows how serious the problem is. It found 70 per cent of Chinese did not know that an elephant had to be killed to have its tusks taken.