LOS ANGELES — An emotional battle over a traditional soup has split California’s Chinese-American community as environmental and animal welfare groups push the Legislature to ban the sale and possession of shark fins.

The ban bill passed the Assembly last month, 65-8, but is running into trouble in the Senate.

The fight has pitted influential Chinese-American politicians against one another, some of whom are running for mayor of San Francisco. Chinese traders and restaurant owners have hired lobbyists to oppose a ban, and busloads of Chinatown residents have descended on the Capitol in Sacramento, saying that a ban would violate cultural customs.

Houston Rockets basketball star Yao Ming has joined other celebrities, such as Leonardo DiCaprio and Scarlett Johanssen, in public support of a ban. “Remember, when the buying stops, the killing can too,” says Ming, in a YouTube video that shows him pushing away a bowl of soup.

Shark fin soup, which can cost as much as $80 a serving in restaurants, has been a Chinese delicacy for hundreds of years and often is served at weddings and banquets. It is a status symbol, considered to have medicinal properties, and its defenders see its consumption as a fundamental cultural right.

But Assemblyman Paul Fong, D-Cupertino, a sponsor of the bill, said he “grew up on shark fin soup” but only recently realized that “Anything that is unhealthy, that the culture is practicing, we should stop doing it. We used to bind women’s feet and that was unhealthy for the woman.”

Scientists say the fin trade has contributed to the catastrophic declines of shark populations worldwide, threatening to disrupt ocean ecosystems, and encouraging the proliferation of other predators, which diminishes stocks of fish for human consumption. Fishermen cut the fins from landed sharks and dump them back in the sea, often still alive.

State Sens. Leland Yee, D-San Francisco, and Ted Lieu, D-Torrance, have proposed amendments to allow the sale of fins from sharks that are legally fished in California waters, and the import of fins which can be certified as having been sustainably harvested.

Yee, who is running for San Francisco mayor against two Chinese-Americans who support a ban, has called it “an unfair attack on Asian culture and cuisine.”

In an interview, Lieu said that the bill is “inconsistent” because it would not ban selling shark meat in California, only shark fins. And he said, “it creates a disparate impact on a subset of a particular culture: those who consume shark fin.”

Thursday, before a packed hearing room, the bill passed the Senate Natural Resources & Water Committee, but only after Fong agreed he would work with opponents to amend the bill before it goes before the Senate Appropriations Committee. It is not expected to reach the full Senate before August.

A compromise may be difficult to defend and enforce. Jennifer Fearing, state director of the Humane Society of the United States, said banning the sale of imported fins while allowing the sale of California fins would violate international trade rules. Moreover, she said, “The minute you allow some fins and not all fins, there’s no way it can be enforced” because the financial incentive is high.

Animal-rights groups, arguing that finning is an inhumane practice, have joined with the Monterey Bay Aquarium, the California Academy of Sciences and environmental groups to lobby for a ban.

Hawaii and Washington state have passed shark fin bans and President Barack Obama earlier this year signed federal legislation tightening a ban on shark finning in U.S. waters.