Shark trapped in South Korean city won't return to sea

She has become one of the most popular attractions in South Korea, with more than 1.6 million people flocking to the port city of Busan for a glimpse.

A month ago the 3-metre dusky shark unexpectedly entered the city's canal — one of Asia's busiest ports — and now appears reluctant to leave.

The shark, named Bukangi, has become so popular she is now a mascot for the city and Busan Mayor Chun Jae-soo thanked her for generating publicity he said would otherwise have cost "trillions".

There have been three attempts to help her return to the ocean, including a mammoth operation on Wednesday, during which hours were spent guiding her with floating platforms, nets and divers.

A few hours later, the oceans ministry said the shark had swum under one of the nets and back into the canal.

It said Bukangi's condition was stable but authorities were worried the shark had not been feeding regularly and could face health risks from falling water temperatures.

South Korean National Institute of Fisheries Science senior researcher Kim Hyun-woo said it was possible the bright lights and noise from vessels had interfered with the shark’s senses and the canal now appeared to be a safe space for it.

"The shark has been staying inside the canal for an extended period, so I didn't expect it to head straight out into the open water," he said.

"It would be best to give it about a week to leave on its own."

Officials have opened the outer net and reinforced barriers to prevent the shark from retreating further back into the canal.

Environmentalists believe climate change and warming ocean temperatures may have caused the shark to enter the canal.

Dusky sharks are classified as endangered by the International Union for Conservation of Nature.

Reuters/AP