A campaign must have influential supporters to be successful. Efforts to discourage Chinese from eating shark fin were given a boost three years ago when Hong Kong Disneyland took them off its wedding banquet menu and basketball star Yao Ming , formerly of the Shanghai Sharks team, signed up. The joining of the mainland's foremost internet auction website, Taobao, gives the cause financial clout; by refusing to allow trade in the delicacy, the message has gone out loud and clear to the site's 83 million registered users. These are welcome moves, but breaking the habits of centuries of culture and tradition will need considerably more backing if sharks are to be saved from extinction. A study released last month by the Australian government and wildlife-trade monitor Traffic determined that one in five shark species was threatened with extinction. Rising consumption of shark's fin soup, a Chinese banquet staple, was blamed. The trend is alarming because of the manner in which the fins are acquired - they are generally hacked off live sharks, which are then dumped back to sea to suffocate, bleed to death or be devoured by other creatures - and the importance of the predator to ocean ecosystems. Shark fin is considered a luxury and is therefore expensive; the wealthier the mainland gets, the more people want it. Shark fin is virtually tasteless to all but the connoisseur. It could easily be substituted as an ingredient in the chicken broth that is the base of shark's fin soup by noodles of a similar texture; right-thinking caterers and people with budgets in mind already do this. However, their lead is not having a noticeable impact. Shark populations remain threatened, despite bans imposed by the European Union, the United States, South Africa, Brazil and Costa Rica. With an illegal trade believed to be three times the legal one and in the absence of regulation and a lack of fishing catch data, the key to saving sharks is discouraging consumption of fins. More than half of the trade comes through Hong Kong; authorities here and on the mainland could help by spearheading anti-finning education campaigns. Just as important, though, is getting big companies and sport and entertainment stars on board.