Australian Antarctic marine science voyage

7 December 2009

The impacts of bottom fishing and ocean acidification are two of the key research projects being undertaken on the Australian Antarctic Division's marine science voyage leaving Hobart today.

Nearly 40 scientists will sail on the icebreaker Aurora Australis for a six week trip covering 7000 nautical miles of the Southern Ocean.

Antarctic Division Principal Research Scientist, Dr Andrew Constable, is leading a program to use new camera technology developed by the Antarctic Division, to investigate the effects of demersal fishing practices on sea-floor habitats around Antarctica.

Aaron Spur deploying long line camera
Aaron Spur deploying long line camera
Photo: Robbie Kilpatrick
View of the sea floor
Collaborative East Antarctic Marine Census (CEAMARC)
Photo: Martin Riddle

Demersal fishing in Antarctica is undertaken primarily with longlines, while bottom trawling is currently prohibited.

Dr Constable said little is known about the effects of the fishing on Antarctic benthic, or bottom-dwelling, communities which are often diverse and vulnerable and a vital part of marine ecosystems.

"On this voyage we'll deploy new camera technology fitted to demersal gear used on commercial fishing vessels to directly measure the types of impacts that could be caused by bottom fisheries on vulnerable habitats in Antarctica," Dr Constable said.

Funding of $1.2 million has been allocated by the Australian Government's Fisheries Research and Development Corporation for the joint project between AAD, the Australian Fisheries Management Authority (AFMA) and industry partners, Austral Fisheries and Petuna Sealord.

It is hoped the information gathered on the voyage will assist with assessing the potential impacts of demersal fishing in Antarctica and, if necessary, the development of management strategies to mitigate these impacts on marine benthos.

The second major project of the voyage will look at ocean acidification.

Increased levels of man-made carbon dioxide in the atmosphere are being absorbed by the ocean surface, increasing acidity and reducing the ability of microscopic marine organisms to make their shells.

Coccolithophorid (Emiliania huxleyi)
Coccolithophorid (Emiliania huxleyi)
Photo: J. Cubillos
Coccolithophorid (Emiliania huxleyi)
Incomplete growth of shell plates in sea water containing higher CO2 concentrations
Photo: J. Cubillos

Antarctic Climate and Ecosystems Cooperative Research Centre Oceanographer, Will Howard, said while the impacts of acidity at the ocean surface are becoming apparent, little is known about what's happening deeper down.

"We think that at different times of the year some of the organisms are actually doing a lot of their shell making and growth at 40-100 metres below the surface," Dr Howard said.

"So we really want to capture the organisms at those depths and get a better idea of their shell-making activities and the impact of acidification," he said.

Dr Howard's team will use plankton tows to sample the water column over 2000 kilometres between Hobart and the Antarctic coastline.

"We will focus on single-celled organisms and microscopic snails about the size of a grain of sand," Dr Howard said.

"We want to start building a baseline of the health of these organisms in the ocean so we can come back and assess change in the future," he said.

It is unknown what the impact of the acidification changes may have on animals further up the Antarctic food-chain, such as penguins and seals.

The voyage is scheduled to return to Hobart at the end of January. 


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This page was last modified on 7 December 2009.