The Gulf of Carpentaria hosts some of Australia’s most remote coastline, but Indigenous rangers say it is being inundated with some of the highest densities of rubbish in the world.

In 2018 the Dhimurru rangers, based in Nhulunbuy, in eastern Arnhem Land, collected two-and-a-half tonnes of rubbish, 500kg more than in 2017 and roughly five times that collected in 2016.

The rangers sifted through almost 20kg of cigarette lighters, 32kg of plastic bags, 190kg of plastic bottles and another 108kg of bottle tops, more than 350kg of rope and nets, 423kg of thongs and a whopping 774kg in fragmented plastic pieces.

Many of the bottles and plastic fragments bore distinctive triangular marks where fish had taken a nibble, mistaking them for another fish, squid or jellyfish.

Facebook Twitter Pinterest Rangers shake a ghost net out of the pristine sand in Arnhem Land. Photograph: Grace Heathcote/Supplied

The area provides important foraging, breeding and nesting grounds for a number of globally threatened species, including four sawfish and six of the world’s seven sea turtle species.

The Dhimurru rangers began cleaning and monitoring a 3.5km stretch of coastline at Wanuwuy (Cape Arnhem) in 2000. They have repeated the survey every August since, taking between three and five days each time.

Zig-zagging between dune and surf, they trek along the beach collecting every piece of human-made rubbish they can see.

Facebook Twitter Pinterest Dhimurru rangers sort through broken sandals, cigarette lighters, plastic bottles, bags, piles of netting, and fragments of plastic worn ragged by the sea. Photograph: Grace Heathcote

Large items such as ghost nets, usually half buried in sand and stinking of rotting marine life, are shaken out and hoisted fold by fold on to the back of the nearest ute.

The debris is transported back to Nhulunbuy and dumped in a monstrous pile at the ranger depot. The rangers then sit and sort the rubbish into categories before painstakingly counting, weighing and recording it all.

In the two decades since the Dhimurru rangers began surveys at Wanuwuy, they have seen the volume of rubbish increase steadily. Now, they struggle to collect it all.

Facebook Twitter Pinterest A flatback turtle trapped in a ghost net, Groote Eyelandt, Arnhem Land. Photograph: Anindilyakwa Rangers

Microplastics’ rise

On Groote Eylandt, the Anindilyakwa Rangers manage some of the highest densities of ghost nets in the region, alongside some of the largest turtle populations. This includes the Northern Territory’s largest nesting colonies of the critically endangered hawksbill (Eretmochelys imbricata).

Marine debris surveys around Groote invariably turn up bleached bones and stinking, rotting turtle shells caught up inside netting. Occasionally a freshly tangled turtle can be cut free and returned to the water. Those that are badly injured pose a logistical and ethical dilemma in such a remote region where veterinary services are scarce.

Facebook Twitter Pinterest Debris washed up on a remote beach in eastern Arnhem Land. Photograph: Dhimurru Rangers

At Napranum, on the other side of the Gulf of Carpentaria, the Nanum Wungthim rangers find so many injured turtles in netting that they set up a triage centre on the beach during peak nesting season. A few are sent to the Cairns Turtle Rehabilitation Centre until they have recovered and can be returned and released. Many turtles in the region, including the green (Chelonia mydas) and flatback (Natator depressus), routinely weigh as much as 100kg, making these medical evacuations a difficult exercise.

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Worldwide, it is estimated that up to 12.7m tonnes of plastic debris enter the oceans from land-based sources each year and that number is expected only to increase.

Animals can be directly affected through entanglement, ingestion, secondary chemical leaching and smothering of habitats, while fibres and chemical traces have been found in the deepest depths of the ocean. At least 77 species in Australian waters and more than 800 species worldwide have been reported as affected by marine debris. The rising use of microplastics and the invention of “biodegradable” plastics allow tiny particles to infiltrate the food chain more effectively.

If these trends are to be halted, data like that collected by Indigenous rangers is essential. Rangers across northern Australia have found that more than 95% of the plastic bottles washing ashore are not Australian. A more likely source is the heavy fishing and shipping traffic operating in the Arafura Sea, including a large but unknown number of illegal, unreported and unregulated vessels. Almost 9,000 ghost nets removed from beaches around the Gulf of Carpentaria showed that those most likely to catch turtles appear to be trawl or drift nets from overseas fisheries.

Facebook Twitter Pinterest A ranger takes a break from the clean up on Wanuwuy beach. Photograph: Grace Heathcote/Supplied

But federal funding allocated to Indigenous rangers and the Indigenous Protected Areas they monitor is only 6% of that channelled towards government protected areas, despite being of comparable size.

Last year, the IPA program celebrated its 20th anniversary. The ranger groups associated with the IPAs employ 650 people and, in remote regions of Australia, are often the only groups able to carry out essential “caring for country” duties such as biosecurity monitoring, fire management, protection of threatened species and control of feral animals.

Labor and the Greens have announced policies to increase funding for Indigenous rangers and a move to longer-term contracts. This would create long-term employment in Australia’s most disadvantaged regions as well as support attempts to address multiple global conservation challenges. But for now the people and animals bound to northern Australia by complex and continuous ties to land and sea are dealing with the cruel irony that they cannot easily escape problems not of their own making.

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• Grace Heathcote worked for GhostNets Australia between 2010 and 2013, offering on-ground support for Indigenous rangers conducting marine debris surveys and removal across northern Australia.