Hong Kong has bowed to years of pressure from environmental groups, saying it will no longer allow shark fin to be served at official functions.
The authorities were ''determined to take the lead and set a good example'', the government said.
The initiative went ''beyond the minimum expectation laid down'' in the United Nations treaty on trading in threatened species, it said, and it applied to bluefin tuna and black moss, a type of algae popular in Asian cuisine.
Scientists estimate up to 100 million sharks are killed each year, mostly for their fins, which are typically served in soup. The practice is widely considered cruel and wasteful, because the sharks are often thrown overboard, finless, to die.
About half the world's shark fin trade takes place in Hong Kong.
In March, member nations of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, a UN treaty, called for trade in five shark species - oceanic whitetips, scalloped hammerheads, two other types of hammerheads, and porbeagles - to be carefully monitored.
That has put shark fin consumers in Hong Kong, mainland China and elsewhere in an awkward spotlight. Last year, China said it would prohibit official banquets from serving shark fin soup, but the measure was expected to need as many as three years to take effect, and even then, compliance may be uneven.
Pew Charitable Trusts executive vice-president Joshua Reichert said it was ''particularly significant'' because of Hong Kong's role in the shark fin trade.
Black moss is being removed from official menus because of concerns that it is being overharvested in Mongolia and China, exacerbating desertification.
New York Times