The prized southern bluefin tuna industry, worth hundreds of millions of dollars to Australia, could be heading for a major collapse unless a moratorium on fishing the species is adopted.

That is the view of TRAFFIC, a program of the conservation organisation WWF, and several scientists who are becoming increasingly concerned at the low level of spawning stock and the low levels of annual recruitment of young fish to that of breeding stock.

The issue will come to a head at the annual Commission for the Conservation of the Southern Bluefin Tuna (CCSBT), which meets in South Korea next week.

Lateline understands the scientific report to be presented at the meeting is expected to show a dramatic fall in stocks.

The delegates to the commission have all signed confidentiality agreements and the true state of the stock will only be revealed once the meeting finishes on Friday, October 23.

One of the delegates to the CCSBT, CSIRO scientist Campbell Davies, cannot reveal the latest scientific data but says the information from the 2008 reports shows the stock is not recovering, despite significant cuts to quotas over the past 10 years.

He says "this level is below the level of many nationally and internationally recognised limit points for fisheries management". In other words, below this point is crisis time.

The global marine program leader for TRAFFIC, Glenn Slant, puts the situation more bluntly: "The southern bluefin tuna is at an all-time low, below 10 per cent of its original population size, and what that means is at any time it could collapse."

"Just this week the Australian Government released its status report ... and I can tell you there is a lot of red ink in it which represents continued overfishing and overfished levels."

The report Mr Sant is referring to is the Fishery Status Reports 2008, put out by the Australian Bureau of Agricultural and Resource Economics.

But Lateline believes the evidence to be presented to the CCSBT next week may show the southern bluefin tuna is now in a worse state than its northern cousin - the northern bluefin tuna, which has just been submitted by the Prince of Monaco for what is known as a CITIES listing.

The CITIES parties will now consider whether the tuna should be listed as an "endangered species". If accepted it would ban the trade in the species for commercial purposes, placing much more pressure on the southern bluefin tuna.

Scientists are improving their methods of stock assessment. Since the 1990s, electronic tags have revealed information about how the southern bluefin tuna migrates over large distances and how it hunts for food.

This information is helping scientists to more accurately determine the size of the spawning stock. Also, there is some hope that the use of genetic tags - a type of DNA fingerprinting technology - will allow scientists to estimate the size of the spawning stock independent of fishery reports.

Data questioned

The Australian Tuna Association, which represents the Port Lincoln community, disputes the scientific claims. Chief executive Brian Jefferies says the current data is not "transparent".

"The stock is recovering, there is no question about that. What everyone agrees on is that the stock is not at risk. Where people disagree is how quickly will it take to recover."

Australian tuna fishermen are angry the benefits that should have flowed from large cuts to the quota in 1990, and then by 50 per cent in 2006, were cancelled out by years of illegal overfishing by Japan.

Several years ago, the Japanese Government admitted it had illegally taken more than 120,000 tonnes of tuna above their total allowable catch (TAC). The figure is believed to be closer to 200,000 tonnes.

Mr Jefferies says the Japanese Government is "pulling their fishermen into line" and should be given credit for that.

However, Mr Jefferies say there should be a debate about whether Japan needs to pay back the thousands of tonnes of tuna it was illegally catching and selling.

"They should pay back 200,000 tonnes, when they only have a quota of 6,000 tonnes - this is a political issue for the two countries. Let's see if the Government takes into account other issues such as the health of the Australian tuna industry."

But Mr Jefferies does not believe next week's CCSBT meeting in South Korea will decide to significantly cut the total allowable catch for south bluefin tuna.

"The season is about to start, the boats and pontoons are in the water already. That is not realistic. That is not going to happen," he said.

"The real debate will be 2011, but it will be informed by the data available in 2010. We shouldn't panic and be driven by short-term decisions."

The Australian Tuna Association says it could cope with a cut to quotas if it was given enough time to adapt and the market conditions were right.

"If we were given plenty of notice, and the prices in the market were right, we will do what's best for the long-term of the resource," Mr Jefferies said.

"Australia is the only country that relies on this resource. Other countries have other fish and remember Port Lincoln has 5,000 working families relying on this resource.

"The data is not transparent enough. By 2011 we will have a better idea of where the stock actually is instead of just speculating."

Crunch time

But Mr Sant says there is enough evidence on the public record to show the stock is in severe decline.

"Unfortunately, when we talk about fisheries we are talking about communities and people," he said.

"Here we are in a fishing port, this port 20 years ago was dependent on eastern gem fish catches. The management of that stock was too little and too late, so the stock collapsed. At some stage we have to make hard decisions if we want a long-term future for the industry and the communities."

Mr Sant says he has been attending CCSBT meetings for 16 years but now it is "crunch time".

"What we would like to see in Korea is for the commissioners at this meeting to substantially reduce the catch of tuna and consider a zero catch for the next couple of years. We need to get the southern bluefin tuna on a firm footing if we are going to see a recovery of the stock and the industry."

For more on this issue watch Lateline tonight at 10:30pm on ABC 1.