IN YOLNGU CULTURE – the Aboriginal language group of north-eastern Arnhem Land – there is a song sequence for the small, anchovy-like fish that lives, uniquely, around the estuarial brackish where ocean water marries fresh in a long, deep kiss. The fish is called gunmarra, and its song describes the fine-boned animal and its foamy habitat. Although sacred, this knowledge is no secret: Yothu Yindi sing the sequence on their 1989 debut album, Homeland Movement (Mushroom Records International).The cover of Homeland Movement is illustrated with a fine white lattice, each diamond interior coloured yellow or reddish-brown or black. This is the gunmarra’s home – that churning body of water where the fresh, embracing the salt, is pulled out to sea called ganma.

The gunmarra sequence is one part of a broader narrative; like two numbers logically fitted into the eternally expansive pi, it is sung in its place, after songs about rain and brolgas, and a woman’s connection to the water of eternal life. But where pi is an immutable chronology, Yolngu song cycles are sprawling maps of scientific encyclopedias, rhythmic astrological and seasonal charts, glossaries of language and its semantics, spiritual tomes of ancestry, and practical guides for human survival. Songs about ecosystems are their own ecosystems: heterarchies of spiritual, geological and cultural knowledge that comprise human substance. To sing gunmarra is to fill up with, and focus briefly on a moment of being, and relive its purpose. It is a story of much more than where to find a small, bony fish in an estuary.