A monk seal is pictured at the national park of Alonissos, in Greece's Sporades islands, in this undated handout photo released by the Hellenic Society for the Study and Protection of the Monk Seal

A man has been fined and expelled from Croatia after he punched a Mediterranean monk seal, one of the world's most endangered species, reports said on Thursday.

Dozens of tourists and locals had gathered on the beach at Gortan bay on the northern peninsula of Istria—a protected habitat for the monk seal—when a 56-year-old Macedonian man suddenly rushed forward and started hitting the seal with his fists.

The seal was not injured and managed to flee from the beach into the sea, state news agency Hina reported.

The man, whose name was not revealed, was sentenced to pay a 210-euro ($280) fine and expelled from Croatia for five-year period for "breaching the Law on Nature Protection," Hina said.

The Mediterranean monk seal is one of the rarest sea animals, with less then 600 remaining individual mammals registered in some parts of the Mediterranean Sea and the Atlantic ocean.

One of the most endangered mammals in the world, it was for decades believed to have been extinct in the Adriatic, but since 2005, several animals have appeared in the waters around northern Croatian port Pula.