By James Regan

Jabiru, Australia - It's been years since hunting in the crocodile-infested waters of northern Australia was a rite of passage for locals and an adventure holiday for rich tourists.

The crocs, now protected, have an air of arrogance towards their former enemies.

Scores of crocodiles up to 4.6m long swim in northern Australia's South Alligator River or soak up the sun on its banks, sensing little to fear from the occasional passing motorboat.

"They are proud devils," said Garry Lindner, who tracks crocodiles inside Kakadu National Park for Environment Australia, a government agency.

As Lindner steers a small aluminium speedboat around the peering eyes of almost submerged crocodiles along the 95km river, a 22-calibre rifle close at hand, he speaks of the need for humans to keep their distance.

Attacks on humans are rare, thanks to warning signs inside the park urging tourists to stay away from river edges and waterholes.

Crocodiles are territorial and capable of leaping nearly their full length out of the water to attack. They have been known to capsize boats and canoes, Lindner warns.

Lindner mostly relocates crocodiles to the dense mangrove swamps in the park's interior that are out of bounds to all but the most intrepid tourists but he is sometimes forced to kill the animals, usually with a single shot, if they pose immediate danger.

"If we've got to kill one, we will give the croc to the traditional landowners (Aborigines) who regard the meat, especially the tail, as a delicacy, though some people find it a bit fatty," Lindner explained at his base in Jabiru, 3200km north-west of Sydney.

Word of a Lindner kill spreads quickly among the Aborigines, who are quick to stake a claim to the meat, but the huge carcass of a crocodile that killed and tried to eat a German tourist last year remains in a deep freeze.

Lindner, sitting in his office where crocodile skulls rest on chairs and are stacked on filing cabinets, says he had to shoot it.

"But nobody wants it," he says.

Glenn Bernard Robless, a tour guide, pleaded guilty in March to making a dangerous omission that caused the death of 23-year-old Isabel von Jordan and was given a three-year suspended sentence.

The 4,6m crocodile took Von Jordan while she was having a moonlight swim in a billabong.

The freshwater and saltwater crocodiles - wrongly named since both species are at home in any type water - have been protected from hunters since the 1960s so their numbers have swelled in the park.

Long gone are the likes of European royalty and car loads of local young bloods who killed thousands of crocodiles each year, sometimes chasing them across wetlands, guns blazing, often with the blessing of cattle farmers who saw the reptiles as vermin.

Now, with the croc population now more than 6 000, there are fears of more attacks on visitors.

Officials of Kakadu, a 20 700-square kilometre reserve, have been forced to declare some of the most popular places no-go zones after crocodiles were sighted on the prowl.

"Everyone wants to see a croc - but not up too close," says Tony Heenan, who runs daily treks through Kakadu's riverways and gorges.

Lindner said five large crocodiles were sighted in popular tourist swimming holes this year. Two were known to venture away from the area and one was removed, leaving two unaccounted for.

"We know they are out there, we're just not sure where," Lindner said.

One of the most popular attractions, Twin Falls, has been closed because of croc sightings since the annual "big wet" ended in May due. June typically marks the start to the winter vacation season.

Another popular vacation spot, Jim Jim Falls, only opened in mid-June but even there one of the first things day visitors encounter is a steel mesh alligator trap, baited with chicken or pig parts.

It's there to catch crocs before they reach the pitch-black waters of the popular swimming pool.

Which, however, was eerily empty of all but a few daring bathers.