SEOUL, South Korea (AP) — A city in South Korea was trying Thursday to come up with a new way to free a huge dusky shark out of a narrow canal. Workers in the port city of Busan had herded the shark, nicknamed Bukangi, out of the canal the day before, after weeks of trial and error — only for it to swim right back in hours later.

Now Busan authorities and the country’s Oceans and Fisheries Ministry are determined to guide Bukangi back to open water, saying it is critical for the shark’s safety and health.

The unconventional rescue effort on Wednesday involved dozens of workers maneuvering a floating platform through the canal to push the 3-meter-long (9.8-foot) female shark out.…