Djambawa Marawili, a Yolngu clan leader and artist with one of his artworks on display at the Australian National Maritime Museum. Credit:Louise Kennerley Two bark paintings – including petitions in English and Yolngu gummed on to pieces of stringybark, surrounded by sacred designs – didn't stop the mine. But they did draw national attention to their plight and added momentum to the 1967 referendum that included Aborigines in the census. And decades later, in 2008, Yolngu clans combined to create art that helped convince the High Court of their coastal rights. The successful Blue Mud Bay Case gave traditional owners exclusive access rights to the low-tide mark of about 6000 kilometres – or 80 per cent of the Northern Territory's coastline. Exercising those rights, still largely stalled in negotiations, also offer the promise of much-needed local jobs from compliance to fishing. Two of Mr Marawili's works that featured in the court case are among about 40 artworks in the Gapu-Monuk Saltwater exhibition that opens on Thursday at the Australian National Maritime Museum.

Many of the stories, depicted mostly in bark paintings, may have remained in the shorter-lived form of body art were it not for Mr Marawili's urging of other clan elders to "lay out your visions, your dream". "Some of the old people said, 'why are you killing us, destroying our knowledge?'" he says. "I told them: 'This is not about you now. This is about the young generation.'" The original prompt to action was the discovery of a severed head of a crocodile – a sacrilegious act – beside an illegal barramundi fishing camp near the Indigenous community of Baniyala. Mr Marawili, now 64, says his father "lifted me up, he made me walk", starting a journey that has taken him around Australia and the world, exhibiting his art and gently pressing the cause of this people. Familial touches appear in his two paintings. One has an outline of the rock, Djambawa – which Mr Marawili's father renamed after him – that is home to a sacred fire lit by Baru, his clan's crocodile totem.

The second features Makassans, traders from Indonesia who visited the Yolngu for centuries before the Europeans arrived and ended the practice in 1907. There are also Yolngu men in a canoe. "My father, he was one of the great sailors ... he sailed a lot around the coast," Mr Marawili says. Joe Morrison, chief executive of the Northern Land Council, says the success of the Blue Mud Case caught many by surprise, which helps explain its limited implementation so far. "Art is a very practical manifestation of the traditional knowledge that people have got when it comes to their country," Mr Morrison said. "Whether terrestrial or the sea, in many Indigenous people's minds ... these things are not separated in a physical sense, nor spiritual sense," he says. "Art is a good way to portray that."

Loading For Mr Marawili, there has never been any question the place "where the clouds are rising" is part of Yolngu territory, adding it is time for governments to enable his people to take control as the High Court decided. "Talking is not enough, wishing is not enough," he says. "Making it reality, it's really good."