The shark that became famous in South Korea has returned to where it was trapped.

Tenacious and clever: the shark that became famous in South Korea, trapped since last month in a canal in Busan, reappeared there a few hours after being evacuated, authorities announced Thursday, concerned about its health.

The animal, nicknamed "Bukhangi" by the South Koreans who are closely following it, was led out of the canal on Wednesday, guided by nets attached to mobile floating pontoons.

But a few hours later, he dove under a net meant to prevent him from turning back and returned to swim in the waterway where, with winter approaching, temperatures become dangerous for his health.

The 3.5-meter-long bull shark "is now between the outer net and an inner net installed 30 to 40 meters (...) further inside the canal," an official from the Department of Oceans told AFP.

A new attempt to get him out, the fourth, therefore began on Thursday morning: the outer net was raised so that Bukhangi could leave the canal.

This shark, a species usually found in tropical climates, has generated considerable excitement in the country. More than 1.6 million people flocked to the canal in Busan, a southeastern port city, to catch a glimpse of it, sparking an unexpected local economic boost that was welcomed by the authorities.

But rather than an attraction, environmental organizations see its presence in South Korea as an alarming sign. They link its appearance to warming seas: rising temperatures push warm-water fish northward, with subtropical sharks following these prey.