California's governor announced Friday that he signed a bill banning the sale, trade and possession of shark fins to protect the world's dwindling shark population.

Gov. Jerry Brown signed the bill over objections that the fins are used in a soup considered a delicacy in some Asian cultures.

Environmental and animal rights activists hailed the ban for closing off Pacific ports in the U.S. to the shark fin trade. California joins Hawaii, Washington, Oregon and Guam in the ban.

"The practice of cutting the fins off of living sharks and dumping them back in the ocean is not only cruel, but it harms the health of our oceans," Brown wrote in a statement.

The bill had split the Asian delegation in the California Legislature.

Assemblyman Paul Fong, who authored the bill, said it was needed to protect endangered shark species, but others called the measure racist because the fins are used in a soup considered a delicacy in some Asian cultures. The fins can sell for $600 a pound, and the soup can cost $80 a bowl.

The California market for shark-fin soup is the largest outside Asia. During a legislative debate, state Sen. Ted Lieu said the bill would ban only part of the shark while permitting the continued consumption of shark skin or steaks.

Critics of shark finning, which already is restricted in U.S. waters, estimate that fishermen kill 73 million sharks each year for their fins. They said it is particularly cruel because the wounded sharks often are returned to the ocean to die after their fins are removed.

Brown said researchers have estimated that some shark populations have declined by more than 90 percent.

"In the interest of future generations, I have signed this bill," he wrote.

The ban was supported by celebrities, including actress Bo Derek and retired professional basketball player Yao Ming of China. It also was backed by the Humane Society of the United States and Humane Society International.

Brown signed another bill by Fong that allows existing stocks of on-hand shark fins to be sold until July 1, 2013. It also makes it clear that sport fishermen who catch a shark can still eat the fin or have the shark stuffed and mounted as a trophy.

It also clarifies that the ban would not affect stuffing and mounting of sharks, nor the donation of fins to research or medical institutions.

"Sharks need their fins, and we don't," said Jennifer Fearing, the Humane Society's California director. "The momentum to protect sharks globally has taken a huge step forward."

The ban will take effect Jan. 1, 2012.