BEIJING — Once a rare delicacy served to honored guests, shark fin soup had become so popular among China’s fast-growing elite in recent years that it was pushing some shark species close to extinction.
Now, there is fresh hope for sharks around the world. The demand for shark fins has plunged, providing a rare victory for conservationists that could have wider implications for other endangered wildlife.
Thanks to a former NBA star, a coalition of Chinese business leaders, celebrities, and students, and some unlikely investigative journalism, eating shark fin soup is no longer fashionable here.
But what really tipped the balance was a government campaign against extravagance that has seen the soup banned from official banquets.
‘‘People said it was impossible to change China, but the evidence we are now getting says consumption of shark fin soup in China is down by 50 to 70 percent in the last two years,’’ said Peter Knights, executive director of WildAid, a San Francisco-based group that has promoted awareness about the shark trade.
The drop is also reflected in government and industry statistics.
‘‘It is a myth that people in Asia don’t care about wildlife,’’ Knights said. ‘‘Consumption is based on ignorance rather than malice.’’
The dramatic expansion in China’s middle and upper classes has transformed the country into a major driver of global wildlife trafficking.
The Obama administration is so concerned about Chinese demand for endangered wildlife that it made the subject an important part of its bilateral dialogue this year.
More than 70 million sharks were killed last year, largely to satisfy demand from China’s newly rich for shark fin soup.
Lavish spending by China’s wealthy has also sent demand for ivory skyrocketing, fueling a massive expansion in elephant poaching in Africa.
The consequences of the trafficking go beyond a crisis for wildlife. The illegal ivory trade has financed global crime networks and local insurgents, including Somalia’s Al Shabab — responsible for last month’s attack on a Nairobi shopping mall.
‘‘Conservation is more about China now than it is about Africa,’’ said Knights. ‘‘China can be the savior of wildlife or it can be the demise of it.’’
Shark fin soup is believed to have been created more than 1,000 years ago by an emperor in the Sung dynasty who was trying to show off to his guests. Consumption of the expensive soup was revived in recent years at banquets and weddings as a sign of social status.
But it became so popular that 10 of the 14 species of oceanic sharks most commonly fished for their fins are at ‘‘very high’’ or ‘‘high’’ risk of extinction — including iconic species like the Great Hammerhead — and the other four are approaching that status, according to conservation groups.
Just a few years ago, most Chinese people were oblivious to what was happening. One survey carried out in 2005-2006 showed 80 percent of respondents did not even know the soup — known in Chinese as ‘‘fish wing’’ soup — was made with shark fins.
But in 2006, WildAid enlisted Chinese professional basketball player Yao Ming, who played for the Houston Rockets, to front a public awareness campaign.
One ad showed diners refusing the soup when confronted with the gory reality of sharks whose fins have been sliced off. The finless fish are often tossed back into the sea to die.
A successful businessman, Jim Zhang, was so moved that he began working to change attitudes about sharks, eventually becoming a full-time environmentalist.
In 2010, he conducted a poll on the popular microblogging service weibo that drew 30,000 participants, 99 percent of whom supported a ban on shark imports.
‘‘That really encouraged me,’’ he said. ‘‘I realized that we have a voice here, and we have to take action.’’
Zhang persuaded about 30 members of China’s 2,987-delegate Parliament, the National People’s Congress, to sign a proposal in 2011 calling for a ban on shark fin imports.
The initial proposal was rejected by the government, but a second one had more success. It came amid a growing effort by many countries to limit the trade in endangered shark species and their fins.
In July 2012, the Chinese government pledged to ban shark fin soup from official banquets within three years.
Then, as part of its new campaign against extravagance, instructions went out to officials all around the country in February and March to ban lavish banquets.
Instead, they were told to serve ‘‘ordinary food’’ and not to offer shark fin soup or dishes made with protected wildlife.
In September, similar instructions were sent out by the government in Hong Kong — a major center for the shark fin industry — ‘‘to demonstrate its commitment to green living and sustainability.’’
There was also help from state-run media: China Central Television ran a series of reports this year that found that restaurants were serving up fake shark fin soup — using starch, gelatin, and seaweed gum.
Even more damaging was the finding that many soup samples contained dangerous levels of cadmium and methyl mercury.