The other two whales were thought to have left the area, but one whale appeared to have got stuck in the river, home to a large number of saltwater crocodiles.
“The whale made its way at high tide this weekend and we are delighted that it appeared in good condition and suffered no ill effects,”
Dr. Carol Palmer, senior state government scientist, called the whale escape “great news.”
“It has been great to work with Kakadu staff and experienced scientists to identify ways to assist the whale, but I am very happy it has found its way,” Palmer said in the park statement. “This is the best result we could have hoped for.”
The whale had apparently run aground after being confused during the migration, the national park said. “As far as we know, this is the first time this has happened,” he said in a statement last week.
The park said it was concerned about a number of dangers: in addition to the crocodiles, there was also the possibility that a boat collided with the whale or inadvertently pushed it further upstream.
Saltwater crocodiles are ambush predators known to attack and kill humans. Despite their name, they can also be found more than 100 miles (161 kilometers) along the river from the coast in freshwater habitats.
According to the park’s guidelines for visitors, crocodiles can remain hidden underwater for long periods and can move around with great stealth and camouflage. They act quickly and are known to move at speeds of up to 40 feet (12.1 meters) per second when they catch prey over short distances.
CNN’s Lianne Kolirin contributed to this report.