Garry Lindner knows a thing or two about crocodiles. When he was growing up, his father was a ranger at Kakadu National Park in Australia's Northern Territory. "He was always bringing home crocs that he'd shot," says Lindner. "We had a big chest freezer, and sometimes you'd get up in the morning and find a 6ft salty in there."
"Salties" are the man-eating saltwater crocodiles that roam the Territory's beaches and waterways, and Lindner, a heavy, thick-set man with forearms like Popeye, is at the sharp end of a debate about controlling the population. He is Kakadu's chief crocodile-hunter, the man responsible for visitor safety in a park with 5,000 resident salties.
Across the Territory, there are 70,000 crocodiles, and casual encounters have become almost commonplace. Diners at a smart harbourside restaurant in Darwin watched open-mouthed recently as a croc swam past their table. A man on a jet-ski was chased near a nudist beach, and a barmaid was savaged while fishing by a boat ramp. Crocs have snatched dogs off leads and barramundi off fishing-lines. Sleeping campers have been attacked in their tents.
But while locals are keenly aware of the perils of living in close proximity with these formidable creatures, a proposal to allow a limited quota to be hunted by wealthy tourists has touched a raw nerve. Salties were hunted almost to extinction last century, and their recovery since 1971 - when they became a protected species - is a source of pride. The idea of shooting them for sport is anathema to many Territorians, as well as to animal-welfare groups.
Despite their name, salties - which grow to more than 5m - are also found in fresh water areas hundreds of miles inland. In Kakadu, one of the country's principal tourist destinations, they are visible everywhere: sunning themselves on river banks, gliding silently through the water, lying semi-submerged in the shallows.
Every croc more than 2m long is a hazard to humans, and there are warning signs all over Kakadu. Lindner's aim is to leave the salties to thrive in their natural environment, as far as possible, while protecting the park's 170,000 annual visitors. A fatal attack on a German woman, who went for a moonlight swim in 2002, was a grim reminder of the threat from these prehistoric predators, virtually unchanged over 200 million years.
This is a critical time for Lindner and his staff. The dry season - the peak tourism period - is about to begin. Today, he is on the tracks of an errant crocodile that has been hanging around a popular swimming-hole in Jim Jim district. As he leaves his office at ranger headquarters in the township of Jabiru, he picks up a large black nylon bag. "Just some firearms for personal protection," he says. "It'll probably be a safe day, but you never know."
The rifles are out even before Lindner's mud-spattered Land Cruiser reaches the area where the croc was first spotted a week ago. As we bump along a narrow track, he and two fellow rangers, Buck Salau and Pat Shaughnessy, notice a wild buffalo standing in a clearing. It's a danger to hikers; Lindner takes aim and fires an ear-splitting shot. The wounded animal flees into the forest. The three men pursue it and finish it off.
Soon afterwards we reach a creek just downstream from the swimming-hole. A small aluminium rowing-boat awaits us. It seems flimsy - too flimsy for a croc-hunting expedition. Only a thin, low barrier separates us from creatures that might be lurking in the water. What if a croc leaps into the boat? "It could happen," agrees Lindner.
We push off through the swampy shallows, fringed with paperbark and pandanus trees. It's a tranquil spot. I almost trail my fingers in the beautiful clear water, then quickly think better of it. Lindner points to some bubbles, which turn out to be caused by fish. Then he tenses. "What's that over there?" he says, indicating a bow wave ahead. It's our croc. We see a dark silhouette but, with a flick of the tail, it is already off.
Lindner's team carries out regular night-time surveys, using spotlights that pick up the shine of crocodiles' eyes. Floating traps - cylindrical cages that snap shut when the bait is taken - are set throughout the visitor season. Occasionally problem crocs are harpooned from a boat, then hauled ashore, their jaws secured.
In an effort to detect salties, polystyrene floats are tied to rocks, sometimes smeared with tuna oil to make them more tempting. The float in our creek has acquired fresh bite marks, and pieces of meat stuffed inside it have been removed. But the trap is empty, and the bait - a pig's haunch - is untouched. The men sigh. "We'll get it eventually," says Lindner. "We might put a road-kill wallaby in the trap."
The elusive croc is thought to be a 3m male, probably an "outcast". The social dynamics of saltwater crocodiles are intriguing. Each billabong (creek) is dominated by a "boss croc", the biggest male, which sits surrounded by a harem of females. The other males occupy places in the hierarchy relative to their size - and since salties prey on each other, the small ones are perennially nervous. When a male reaches a size that could threaten the boss, it is pushed out of the billabong by its peers.
Lindner, 39, frankly admits he is fascinated by crocs. His chaotic office at Jabiru is plastered with photographs of salties, and a large croc skull is prominently displayed. "They're just a very impressive large predator, and there's also the element of danger," he says. "They're unpredictable and ever present in this environment." Is he scared of them? "Yup. Because I know what they're capable of. The power of their jaws, their sheer strength."
Four women are on his team, including Kathy Wilson, 37, who oversees the croc operation in Jim Jim. Wilson's two brothers also work with crocs. Lincoln removes them from Darwin Harbour, where 150 are fished out every year. Rydal lost his right hand while harvesting eggs from nests. Wilson says: "They're fantastic animals, perfectly designed for what they do. I'm in awe of them, but I'm not afraid. It's just what you're used to. I'm scared of staying in town on my own overnight."
The rangers are particularly attached to the biggest crocs, some of which have distinctive personalities. These "identity crocs" are show-offs and, when they swim along, others give them right of way. One billabong, Goose Camp, has been ruled since 1975 by a 5m salty christened Tough Nut by locals. Tough Nut has a lumpy head and a ferocious reputation.
Since the Seventies, when the population in the Territory dwindled to 3,000, salties have staged a phenomenal recovery. That means, though, that increasing numbers of them are straying into far-flung territory. And that means more work, and more worry, for Kakadu's rangers. Last year they were vilified by tour operators for closing a swimming-hole after two crocs moved in. While they spare no effort to make the park safe during the dry season, they can never feel 100 per cent relaxed. "You feel sick to the pit of your stomach every year for a couple of months," says Shaughnessy.
It was Lindner and Salau, with two other rangers, who captured the crocodile that killed Isabel von Jordan, the German tourist. The spectacle of the woman in the crocodile's jaws still haunts them. "It was sitting in the water like a dog with a bone," says Lindner. "Time stood still for me. I watched it swim along with the girl in its mouth. It wouldn't let go." It distressed him, too, that the crocodile had to be killed. "It was an identity croc that was well known to us."
There have been numerous other incidents, in and outside Kakadu. Croc-odiles are getting bolder. An 11-year- old Aboriginal girl was recently attacked. A 22-year-old man was killed last year in the Finniss river, south of Darwin. Salau was mauled while conducting a night-time survey on a beach north of Kakadu. "He came up from behind, grabbed my foot and dragged me off," he says. "He got me by the stomach and we were rolling around in the sand. I managed to get my arm round his head and he let go. It was horrific."
Six hundred salties are legally culled by landowners in the Territory every year. The government's proposal is for 25 of the largest to be shot by "trophy hunters" who would pay at least $6,000 (£2,300). The Parks and Wildlife Commission says safari hunting would inject funds into Aboriginal communities, which own much of the land.
The plan, which has yet to be approved, has angered animal-welfare groups, which say crocs are unlikely to be killed humanely. But many crocodile experts have endorsed the idea. Max Davidson, a respected Aboriginal tour operator, says: "It will give the crocodile a value, which means people will respect it more and probably protect it more. The safaris would be strictly regulated. People won't be going off and shooting crocs willy-nilly."
Charlie Manolis, the chief scientist at Crocodylus Park, a research institute in Darwin, agrees. "In Sydney, the most you have to put up with is a possum making a noise on your roof," he says. "Here people have to deal with Australia's largest predator. They're big animals, they kill people and threaten livestock. If this programme went ahead, they'd be seen as an asset rather than a pest or liability."
Back in Kakadu, Lindner declines to discuss the subject. But he notes that the big crocs are an integral part of the population. Squashing a fly against the windscreen with his huge thumb, he says the management techniques used in Kakadu replicate the way that Aborigines used to control crocodiles through hunting. "The population is at its peak now, and the crocs are just doing their stuff. We're allowing that to happen. We're living in very privileged times, especially if you've got an affinity with crocodiles."