The discovery was made on the North West Shelf of Western Australia when 22 mystery circles were spotted on video footage collected by Fugro during an inspection of the Echo Yodel subsea infrastructure – operated by Woodside on behalf of the North West Shelf Project participants – and while surveying fish along the ancient coastline.

The circles, which are the first to be found in Australia, were recognised by the researchers as the complex underwater structures created by the white-spotted pufferfish previously thought to be found only in southern Japan.

Most notably the size, number of ridges and presence of an intricate central circle with two outer rings makes them comparable to those found in Japanese waters.

Originally found at depths of less than 30m in Japan, the finding in the north-west extends their depth occurrence to 137m.