Authorities in South Korea's port city of Busan are exploring new ways to guide a large female dusky shark back to open water after it returned to a canal just hours after being led out.
The 3-metre-long shark, nicknamed Bukangi, was moved out of the canal on Wednesday following weeks of rescue efforts. However, it swam back into the waterway later that night, prompting officials to plan another operation.
Busan authorities and the country's Oceans and Fisheries Ministry say returning the shark to open water is essential for its health and safety.
During Wednesday's operation, dozens of workers used a floating platform to guide the shark out of the canal. After remaining in nearby waters for several hours, it passed beneath a protective net attached to the platform and re-entered the waterway.
Officials said Bukangi is now trapped between that net and another barrier about 50 metres inside the canal entrance. Rescuers and inspectors are discussing how to guide it out as it continues swimming around the confined area.
Lee Gwang-seok, an official with the Oceans and Fisheries Ministry, said the shark was unlikely to move farther into the canal because of the dense nets and the narrow passage.
Officials are also concerned about its health, saying there have been no clear signs that the shark has been feeding regularly during its month-long stay. Falling water temperatures could pose further risks. Authorities have yet to announce when the next rescue attempt will take place.
Named after Busan's North Port, where it was first spotted in mid-September, Bukangi has become a popular attraction as it swims slowly through the canal with its fins visible above the water.
Busan authorities have even adopted the shark as a city mascot, saying it has drawn more than 1.7 million visitors to the area. Hundreds of people gathered along the canal on Wednesday to watch the rescue operation.
Wednesday's effort was the third attempt to free the shark. Previous operations on September 29 and October 2 failed after the shark avoided boats spraying water and swam over nets placed across the narrow waterway.