Where is the seagrass going?

16 June 2004

A study investigating the recent changes in natural marine-life habitats in the Torres Strait region has found that tides, waves and winds are responsible for dramatic movements of underwater sandwaves - or sandbanks.

Federal Industry Parliamentary Secretary and Member for the Far North Queensland electorate of Leichhardt, Warren Entsch MP, said the Torres Strait Islands community relies heavily on dugong, green turtles and juvenile rock lobsters, whose habitats include local seagrass beds.

"With these habitats so vulnerable to the impacts of sand movement and the effects this has on the seagrass, clearly it is an issue of importance," Mr Entsch said.

"The results from the first of two studies to be conducted this year by Geoscience Australia into seabed stability, sediment movement and seagrass dieback in the Torres Strait Islands region have produced some interesting findings."

Scientists from Geoscience Australia and the Queensland Department of Primary Industries and Fisheries, filmed sand wave movements at 69 underwater locations in north-central Torres Strait near Turnagain Island from March 28 to April 17.

Geoscience Australia's Dr Andrew Heap said: "Seagrass beds are important habitats for dugong and green turtle, which the Islanders fish, so we wanted to work out why the seagrass disappears over short time frames."

"The cameras showed that some of the sandwaves, up to three metres high, could move the length of two cars from their original position in one week," Dr Heap said.

Another survey of the sites at Turnagain Island will be conducted by Geoscience Australia at the end of the trade wind season in October. Data collected from both surveys will assist in characterising seabed ecosystems, and provide crucial information on the nature of the seabed for developing models of physical and biological processes, and also provide inputs into management strategies for the Torres Strait community.

The surveys are part of a larger program managed and funded by the CRC Torres Strait based in Townsville aimed at identifying and quantifying the key physical and biological processes occurring in Torres Strait.

Results of the completed first study and maps showing Torres Strait seagrass locations can be obtained from the Torres Strait Regional Authority, 1800 079 093.

Topic contact: media@ga.gov.au Last updated: October 4, 2013