SYDNEY, Australia — As Australians flocked to the beaches at the height of a hot Southern Hemisphere summer, a commercial fisherman hired for the task hauled in a 10-foot tiger shark caught on a baited line. The fisherman shot the shark in the head four times with a .22-caliber rifle off the coast of Western Australia and then towed the carcass out to sea, where it was dumped.

The catch on Jan. 26 — Australia Day, a national holiday popular for beachgoing — was the first under a new “catch and kill” policy in Western Australia for large tiger, bull and great white sharks. Since then, at least one more large shark has died on the line; several smaller ones were caught and released.

The official cull comes after seven fatal shark attacks on swimmers in the state in the last three years, the most recent in November, when a 35-year-old surfer was killed. In one of the attacks, at one of the most popular beaches in Perth, no body was found, only the man’s damaged swim trunks. Five of the attacks were by great whites, officials say.

The state government’s decision is meant to reassure beachgoers, but it has horrified conservationists and flies in the face of global efforts to protect sharks, whose numbers have been in decline amid heavy pressure from Asian appetites for shark fin soup. Opponents of the cull policy have mounted protests and consulted lawyers about trying to halt it in the courts. International celebrities have weighed in, including the British actor and comedian Ricky Gervais and the billionaire entrepreneur Richard Branson.