WISMAR — Rescuers in Germany launched an elaborate operation on Thursday to transport a sick humpback whale from the Baltic Sea back to the North Sea using air cushions, pontoons and a tugboat. The plan aims to have the tugboat carrying the whale, known as Timmy, leave the Baltic Sea by Friday.

Experts developed a plan to use air cushions to lift the whale onto a tarp attached to two pontoons and a tugboat. State officials approved the private initiative to transport the mammal back to the North Sea and possibly onward to the Atlantic Ocean. The distance from the Baltic Sea to the North Sea and then to the Atlantic Ocean is several hundred kilometers.

The whale, which measures between 12 and 15 meters long, has been repeatedly stranded off the Baltic Sea coast and has drawn attention across Germany for weeks. It was first spotted swimming in the region on March 3. The reason it swam into the Baltic Sea remains unclear.

Earlier attempts to refloat the mammal with the help of police boats, excavators and inflatable boats temporarily freed it, but the whale never reached the North Sea and was stranded again. It is now lying in shallow waters near Wismar, breathing slowly and heavily, and has not moved for days.

"He's not active, and he's certainly not agile, but he shows that there's still life in him." Environment Minister of Mecklenburg-Pomerania Till Backhaus said. "He's definitely suffered serious damage, that's for sure." he added.

Local media have started days-long livestreams on the whale's fate, and online newspapers have sent alerts about developments in its health, including a skin condition related to the Baltic Sea's low salt content. Activists have staged protests on the beach in Wismar calling for the whale's liberation.

Police established a 500-meter protection zone around the whale to keep bystanders away. A 67-year-old woman jumped off a boat on the weekend trying to get close to the whale before being stopped.