Coral Seafood Restaurant owner Norman Ho’s problem with shark’s fin soup is not that he’s worried about sharks. It’s that making a flavorful soup out of the tasteless fins is an elaborate, costly process.

The fins have to be soaked in cold water for half a day and then boiled with ginger and spring onions. Then soaked in tap water for four hours. And finally boiled for six to eight hours with chicken stock and Chinese ham to add flavor because there’s no taste otherwise.

“All the taste comes from the soup. You have to put the shark fin and the soup together,” he said. “To serve the shark’s fin soup is more or less status.”

The power of shark’s fin soup to convey status is enormous, and it pervades Chinese society. Serving shark’s fin soup at auspicious events has been a tradition for centuries among elites, but the Chinese bridal and restaurant industries have turned it into an essential element of any middle-class wedding or important business meal. As China’s economy expands, more people are putting the soup on the menu.

But activists in Asia and elsewhere are challenging the tradition, citing statistics that show the shark-fin trade may kill as many as 73 million sharks a year. It is possibly the single-largest threat to sharks worldwide, along with the incidental catch of sharks in global tuna and swordfish fisheries.

In the United States, which has historically focused on protecting sharks in local and federal waters, states are going after imported shark products. Washington state enacted a law last month to ban the sale and trade of shark fins. A similar bill has passed both legislative houses in Oregon and is awaiting the governor’s signature, and California is poised to adopt its own ban within weeks. Hawaii, Guam and the Marianas Islands have enacted shark-fin bans.

California and its neighboring states were a natural target for conservationists — ports in Los Angeles, San Diego and San Francisco took in more than three tons of shark products from January to March, according to the National Marine Fisheries Service.

“We protect sharks in our own water, but we contribute to the slaughter of sharks worldwide by importing thousands of pounds of shark fins,” said Michael Sutton, who directs the Monterey Bay Aquarium’s Center for the Future of the Oceans and helped craft the shark-fin ban that passed the California Assembly last month.

Meanwhile, activists in several other nations are working to enact legislation. The Chilean Senate has approved a bill that would require fishing vessels to land sharks with their fins attached, and its chamber of deputies will probably adopt it in the next few weeks. The Bahamas, hoping to head off foreign shark-fin buyers, is about to ban the commercial harvest of sharks. And the Maldives, which prohibits shark fishing in its waters, is getting ready to implement a ban on the fin trade.

“A few years ago, people didn’t even know there are sharks in Chile,” said Maximiliano Bello, a senior adviser on global shark conservation for the Pew Environment Group, who is pushing for similar reforms in Venezuela.

In many countries, these lobbying drives involve all the trappings of a political campaign: the Bahamas National Trust, a non-profit organization that manages the country’s park system, has run public service announcements on radio and TV, collected 5,000 signatures in favor of the shark fishing ban and gotten advocates, including artist Guy Harvey and “Sherman’s Lagoon” cartoonist Jim Toomey, to visit the islands to generate popular support.

Still, Matt Rand, who directs global shark conservation for the Pew Environment Group, said that only a decline in the demand for shark’s fin soup will help preserve sharks. “I hope we’re getting to a tipping point,” Rand said. “We’ve still got a way to go.”

Even in China, a shift has begun. This spring, a lawmaker in the National People’s Congress introduced legislation that would ban shark fins, and in Hong Kong, a cadre of students has begun to advocate for sharks within both academia and social circles.

Vivian Lam, who studies marine science at the University of Hong Kong, first tried to resist eating shark’s fin soup at a cousin’s wedding more than a decade ago. Sitting with her family in Hong Kong’s Convention and Exhibition Centre, surrounded by hundreds of guests, Lam whispered to her grandmother once the waiters whisked off the silver domes covering the bowls and set them down on the table: “I don’t want to eat shark’s fin soup anymore,” she confided. “Can you eat it for me?”

Her grandmother was unrelenting. “You silly girl,” she lectured Lam. “This is such a good shark’s fin soup we have. It’s already made. People will think you’re ungrateful.”

Lam gave in that day, but now that she’s in her 20s, she, along with several of her friends, no longer eats shark’s fin soup. The most environmentally conscious students at the University of Hong Kong manage to reserve one or two “green tables” at their weddings where shark’s fin soup isn’t served. The university, in fact, has adopted an anti-shark’s fin soup policy.

Tsui Lap Chee, the university’s vice chancellor, no longer lets professors or administrative officials expense shark’s fin soup on their business meals.

But while shark’s fin soup consumption is waning in Hong Kong, the restaurateur Norman Ho says, this decline is more than outpaced by the surging demand in mainland China.

“China is at the beginning of the cycle,” he says. “In China, the market for shark fin is growing as they are getting more and more rich.”

Excerpted from “Demon Fish: Travels Through the Hidden World of Sharks” by Juliet Eilperin. Copyright © 2011 by Juliet Eilperin. Reprinted with permission by Pantheon Books, a division of Random House. All rights reserved.