Australian Southern Bluefin Tuna Association president Brian Jeffriess said Japanese boats would arrive and sit near pontoons to collect tuna from Australian farmers who would kill and gut the fish.

He said he expected it to be a "reasonable" harvest but certainly not the best given the weaknesses in the Japanese market.

"The Japanese market is not as strong due to the recession and the strength of the Australian dollar doesn't help that much either, which is a similar situation to any primary producer."

However, he said the fish were of an improved quality when they were first brought in from the Great Australian Bight.

"The quality of the fish when they are first brought in, is the best we have seen in a long time."

He said this was a result of more feed in the bight, which was a result of climate change. Rougher weather and upwellings produced more feed for sardines, which meant for feed for tuna.

Mr Jeffriess said the demand for southern bluefin tuna this year was stronger than first expected, but was still weak when compared with earlier this decade.

"This year would be the worst of the five years since 2004, but we do expect a strong recovery next year."

He said the industry was always looking at other markets and some success had been achieved with new exports to the United States, Europe and some parts of Asia.

"The incentive to sell to other markets has become stronger ... because of the lower Japanese price, these markets have become more attractive to us."

The frozen harvest will continue throughout July and August.