Scientists investigating deep sea life in a supposedly pristine area of the Southern Ocean near eastern Antarctica have been shocked to find what they believe is evidence of illegal fishing there.
ABC TV's Catalyst program will tonight air the evidence, collected by a team of marine scientists on the Aurora Australis research vessel.
The scientists were using an experimental "benthic trawl" net fitted with cameras to get their first look at an unexplored undersea plateau within Australian Antarctic Territory, known as Bruce Rise.
But the first photos of the sea floor from about 1500 metres depth were not what the team expected to see.
"We were expecting reasonably complex rocky reefs, perhaps more coral reefs like were observed further to the east ... however, we didn't find anything like that - it was mud," says project leader Dr Andrew Constable, from the Australian Antarctic Division (AAD) in Hobart.
"But what was really interesting as well is that on that mud were a whole bunch of long straight furrows. And we repeatedly encountered those."
Constable believes the furrows are marks gouged by bottom longlines set to catch Patagonian toothfish - all the more surprising because that area of Bruce Rise is closed to fishing.
"We were very surprised, firstly that we observed them, but secondly, we couldn't believe the number of them. The intensity of fishing in the area was certainly beyond what we would expect," he says.
Under the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR), an international agreement between 32 nations, including Australia, the eastern half of Bruce Rise is closed to fishing, while the western half is open to fishing.
"We thought our research would be able to better understand how to manage not only the existing fishery, but also what the potential impacts might be in the future if the fishery was allowed to expand into the closed area," says Constable.
"What's clear is that the evidence suggests there's been a large degree of illegal, unreported, and unregulated fishing in [the closed] part of the CCAMLR area."
A key focus for CCAMLR is the management of illegal, unreported, and unregulated (IUU) fishing within its jurisdiction, a major cause of pressure on toothfish stocks and seabird populations in the Southern Ocean.
Illegal catch rates
In the 1996/1997 fishing season, CCAMLR estimated that 72.4% of the total toothfish catch came from IUU fisheries. The illegal catch was still 10.2% in the 2007/2008 season.
The information from Constable's benthic trawl project will be presented to CCAMLR for consideration.
"One of the things that is going to be important for CCAMLR to address is how the open and closed area system is operating and what might need to be done in the future about that," says Constable.
Unlike other fisheries agreements that focus only on the status of the commercial target species, CCAMLR requires that all species in the ecosystem and their ecological relationships be conserved.
"We need to think about not just the benthic fauna that sit on the seabed, but also those fauna that live inside the sediments as well," says Constable.
The researchers used fishing gear such as beam trawls and longlines modified to carry specialised camera equipment.
This was developed in collaboration with the fishing industry, the Australian Fisheries Management Authority and the Fisheries Research and Development Corporation.
"The two commercial fishing operators that work out of Heard Island are partners in this project, and very keen to see if we can come up with measures for allowing fishing to occur while maintaining the conservation values of the sensitive habitats," says Constable.