A fence is a strange thing to call a conservation triumph. Yet on Heirisson Prong, a thin spit of red earth jutting north into Shark Bay, a single wire-and-mesh line strung across the narrowest neck of the peninsula in 1990 became one of the boldest experiments in Australian wildlife history. The idea was simple and audacious at once: seal off the tip of this finger of land, drive out the foxes and feral cats that had hollowed out the continent's small mammals, and bring back the animals that European settlement had erased. For a while, against the odds, it worked.
Australia has lost more mammal species than any other continent, and for a long time nobody agreed on why. When the Heirisson Prong project began in 1989, many scientists still doubted that introduced predators were the cause. Surely habitat loss or disease explained the vanishing bettongs and bandicoots? But the evidence kept pointing the same direction. Where foxes were poisoned, rock-wallabies rebounded. Where cats roamed, reintroductions failed. The small, ground-dwelling marsupials that once burrowed across these plains had evolved with no defense against a stalking cat. Heirisson Prong offered a rare chance to test the theory under controlled conditions, and to act on it before more species slipped away.
The project was not born in a university lab but in Useless Loop, the tiny salt-mining settlement at the base of the peninsula. The Useless Loop Community Biosphere Project Group organized it, modeling the reserve on UNESCO's biosphere concept: a protected core for nature, ringed by a working zone where solar salt was farmed in a way that shielded rather than harmed the wildlife within. The national science agency CSIRO ran the research from 1990 to 2005, with funding from the salt company, government grants, and the volunteer organization Earthwatch. The peninsula's geography did half the work. Long, narrow, and close to islands where remnant mammal populations had survived, it could be fenced and stocked like an ark.
In 1992 the first burrowing bettongs, small kangaroo cousins that dig warren-like burrows, were carried over from Dorre Island and released into the predator-free zone. Twelve animals became twenty-three within a year. Western barred bandicoots followed from Dorre Island in 1995, and greater stick-nest rats, gentle builders of grass-mound homes, arrived from Salutation Island in 1999. For the first time in generations, these creatures bred freely on the mainland. Heirisson Prong became a source rather than a refuge, sending bettongs and bandicoots out to found new colonies on Faure Island and at the Arid Recovery reserve in South Australia. Some bettongs were still thriving here in 2013, more than two decades after their return.
No fence is perfect, and this one had a weakness it could never overcome. On the eastern side, a tidal flat more than a kilometer wide made the barrier nearly impossible to seal. Foxes and cats found their way through. When foxes were poisoned in the buffer zone, the cats multiplied in their place, and cats proved maddeningly hard to trap; the abundance of bettongs and rabbits meant a feral cat never needed to risk a baited lure. By 2008 the western barred bandicoots were gone again, locally extinct. As conservation authorities shifted focus to more defensible islands like Faure and Dirk Hartog, support for the community group ended in 2013, and the fence began its slow decline.
Heirisson Prong did not end in permanent victory, but its legacy outlasted its wire. The project helped settle the scientific argument once and for all: introduced predators, not just lost habitat, had driven Australia's mammal collapse. That lesson now underpins predator-proof sanctuaries across the country, from the Wadderin Sanctuary in the wheatbelt to the Venus Bay peninsula in South Australia. The bettongs that left this peninsula seeded populations that endure elsewhere. A handful of volunteers from a salt town had shown that the tide of extinction could be turned, at least within a fence, at least for a time, and that proof is its own kind of permanence.
Heirisson Prong reaches north into Shark Bay at roughly 26.25 degrees south, 113.42 degrees east, the narrow western arm enclosing Useless Loop's salt ponds. From 3,000 to 5,000 feet the geometry is unmistakable: the geometric pink and white salt evaporation pans on the peninsula's flank, the thin neck of land, and the deep blue of Denham Sound to the east. The nearest airfield is Shark Bay (Monkey Mia) Airport (ICAO YSHK), about 50 km northeast across the sound near Denham; the larger regional hub is Carnarvon Airport (ICAO YCAR) some 130 km north. Light winds and the dry Gascoyne climate give excellent year-round visibility; morning light best reveals the contrast between red dunes and turquoise water.