Marine futures project reveals ocean's hidden depths

Ancient shorelines containing possible Indigenous sacred sites from thousands of years ago have been discovered during a research expedition around Rottnest Island, along with shipwrecks, canyons and an old delta stream bed.

Like charting new territory, this hidden ocean floor is being mapped for the first time as part of the Securing WA's Marine Futures project.

The collaborative project is being managed in partnership with regional groups - with the South Coast Natural Resource Management Inc. taking the lead - by the University of Western Australia, marine survey company Fugro, the WA Museum and other agencies.

Funding

The $4.2 million initiative is the largest marine investment in the state by the Australian Government. The State Government has also provided support.

Activities

Project Manager Dr Jessica Meeuwig said despite centuries of large-scale human use of the ocean, there had never been a clear, historical baseline by which to measure healthy marine ecosystems.

"Most of us measure ocean health against the best we remember in our own lifetimes, yet today in many parts of the world, including Australia, the sizes and abundance of species has changed so dramatically they would be unrecognisable to our great-grandparents," Dr Meeuwig said.

"This is known as 'shifting baselines', which presents a challenge to marine resource managers because our lack of historical perspective on ocean condition makes it difficult to understand what management is needed."

At Cape Naturaliste and Geographe Bay researchers discovered 20 metre high mounds on the ocean floor up to a few hundred metre wide and not shown on commercial charts. Deepwater seagrasses and sponges were also documented - the characteristics of which may have never been described before.

"Seasoned local fishermen can tell you yarns about massive Blue Gropers and Dhufish caught off the Perth coast 50 years ago, that you don't see the likes of today," Jessica said. "We need to understand these changes if we're to know what implications they have for our children."

Habitat is slowly being mapped across 1,000 square kilometres from the cool waters off Eucla to the sub-tropical waters of Kalbarri. The vessel for this historic voyage is the Kimberley Quest I, which has a multibeam attached to her hull to explore depths from 10 to 120 metres plus. When the multibeam signals come back to the ship, they provide a full-coverage, highly accurate map of depth and the texture of the seabed.

The next step is to add visuals to the multi-beam interpretation by using underwater video. This is followed by a detailed assessment of human marine resource use patterns to uncover relationships between habitats, the biodiversity values associated with them and our uses of these resources.

More information

1. Heather Taylor, University of Western Australia: (08) 6488 5800 or marinefutures@uwa.edu.au
2. Securing WA's marine futures website: www.marinefutures.com.au

Australian Government Land and Coasts
GPO Box 787
Canberra ACT 2601 Australia
1800 552 008 (toll-free)

Caring for our Country is an Australian Government initiative jointly administered by the Australian Government Department of Agriculture, Fisheries and Forestry and the Department of the Environment, Water, Heritage and the Arts