The story
Australian Tuna Fisheries Pty Ltd was founded by Hagen Stehr and registered in 1963. In the year 2000 it was renamed The Stehr Group and established Clean Seas.
The company successfully controlled the life-cycle of the Yellowtail kingfish and invested substantial research and development effort in trying to achieve the same for the Southern bluefin tuna from 2005 onwards. The company suffered unsustainable stock losses of its Yellowtail kingfish between 2009 and 2011 after which the company suspended its Southern bluefin tuna breeding project in 2012. The company has posted significant annual losses in many financial years, and has had its social licence challenged by recreational fishers and Spencer Gulf residents due to its handling of kingfish escapes, garbage, pollution and shared use facilities, including the Point Lowly North marina. Conversely, the company has won various awards and accreditations that acknowledge their product and market development achievements and its founder has an Order of Australia Medal and is a member of the Australian Seafood Hall of Fame.
Yumbah Aquaculture Purchase
In July 2025, Clean Seas Seafood Limited was acquired by Australian shellfish producer Yumbah Aquaculture and was subsequently delisted from the ASX.
Yumbah Aquaculture is South Australian-headquartered and paid nearly $30 million for Clean Seas.
Yumbah said at the time that adding kingfish to its abalone, oyster and mussel portfolio would provide further resilience against the inherent risks of aquaculture through diversification.
At the same time Yumbah Aquaculture became the first oyster producer in Australia to attain Best Aquaculture Practices (BAP) certification, an internationally recognised benchmark for responsible aquaculture.
BAP certification provides independent assurance that Yumbah’s oyster farming operations meet the highest global standards, reinforcing the company’s dedication to quality, sustainability, and continuous improvement across all aspects of aquaculture.
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In April 2025 Yumbah was awarded the Aquaculture Stewardship Council’s coveted Responsible Seafood Producer award for its regenerative approach and engagement with local communities and First Nations stakeholders.
Southern bluefin tuna
In 2005, Clean Seas was awarded an AUD $4 million grant from the Australian Government to develop a system for the land-based production of young Southern bluefin tuna. Clean Seas Tuna Ltd was floated on the ASX that year, with the ambition of controlling the lifecycle of the Southern bluefin tuna. In March 2007, the company announced it has successfully stimulated the release of sperm in a captive Southern bluefin tuna and captured it on video. Further developments were announced in 2008, with Stehr stating that the development "will give us a sustainable blue fin industry, that nobody around the world will be able to attack us in the future." Clean Seas announced that they had closed the lifecycle of the Southern bluefin tuna after successfully producing eggs from captive mature fish. They airlifted mature fish into their land-based facility at Arno Bay in May for breeding purposes. By mid-2009, the company had raised young Southern bluefin tuna to roughly 20 cm long, and members of the Norwegian aquaculture sector were expressing interest in their progress.
In March 2010, the Australian Securities and Investments Commission investigated Clean Seas for failing to disclose the deaths of Southern bluefin tuna fingerlings to the market. The company said that the fingerlings were not of material value and that the breeding program was ongoing.
The company's efforts appeared in the documentary film Sushi - The Global Catch. Research and development was eventually discontinued as the company had difficulty raising the larvae which have complex water temperature requirements, eat each other and injure themselves in captivity. The company officially suspended its Southern bluefin tuna propagation research as a cost-cutting measure after it revealed it had made a $34 million statutory loss for the last half of 2012. In February 2013, Stehr remained optimistic about Clean Seas' future prospects for closing the life-cycle of the Southern bluefin tuna.
Yellowtail kingfish development
In 2006, Clean Seas struck a deal to export Yellowtail kingfish to Russia. The following year, a deal to stock Yellowtail kingfish in Sainsbury's supermarkets in the United Kingdom was finalised. The company was optimistic that it could achieve spawning of Southern bluefin tuna the following year. The company was also attempting to accelerate the Yellowtail kingfish's growth by artificially increasing water temperature for fish held in tanks at Arno Bay.
In 2008, Stehr told the ABC that he had expansion plans for the company. He said "We got the marina [in] close proximity to Adelaide, and it is a natural progression for our company to move that side... We either move to Wallaroo or direct to Adelaide."
In 2009, the company employed 90 people in Whyalla, according to its CEO. At that time it was using the Whyalla marina but had plans to develop a marina for dedicated use in Fitzgerald Bay.
Financial losses and fish mortalities
The company reported a $12 million loss in 2009, having lost feed and equipment during a fire. Hagen Stehr, the founder of Clean Seas, stepped down from his position as Chairman of Clean Seas Tuna that year. At the time, he said that the company was transitioning from a research and development company to commercialisation.
In April 2010, Clean Seas announced that it would close its Whyalla kingfish processing facility. In May 2010, the twenty-two people employed there lost their jobs. The company decided to consolidate its processing in Port Lincoln.
In September 2010, Clean Seas staff killed 80 tonnes of stock as a result of human error while "bathing" the fish in hydrogen peroxide at the wrong concentration. The stock had infestations of flukes on their skin and gills that such baths are intended to clear.
The company reported a first-half loss of $14 million that year, and a loss of over $15 million for the year to June 30.
In November 2010, Stehr told The Advertiser that he took responsibility for the over-production of kingfish which adversely impacted the company's finances. At that time, the company's Chairman was John Ellice-Flint, and its Managing Director was Clifford Ashby.
In late 2011, the ongoing fish mortalities raised concerns about water quality. Local Parliamentarian Lyn Breuer stated "I understand there are further issues down the peninsula where there's a bit of a shortage of other species so I think we need to have this looked at." Paul Steere from Clean Seas stated that a cause might be hard to find and "there are a lot of drivers that affect the fish. It's always difficult to isolate a particular cause and effect." ABC reported that Clean Seas was removing its operations to Arno Bay "to let its farming area recover."
In 2011, Clean Seas reported a $9.3 million loss for the latter half of 2010. 2011 also saw kingfish production in Fitzgerald Bay cease after two years of high levels of fish mortality. Clean Seas worked with research scientists to investigate the issue. Clean Seas tried to produce fish on land, but were producing weak fish and suspected a nutritional problem. Clean Seas reported that its farmed kingfish were afflicted with a "mystery illness" gut enteritis and that 38 percent of its stock had been lost in 2012 and 17 percent in 2011. Fish also had secondary health problems and were in a generally weak condition. Clean Seas directed blame for the losses at feed suppliers Ridley Corporation and Skretting Australia, serving both companies legal notice that it would be seeking damages to the value of "tens of millions" of Australian dollars in 2012.
Clean Seas reported a $34 million statutory loss for the second half of 2012. It suspended its tuna propagation efforts in order to focus on kingfish production exclusively. Financial pressure prompted restructuring and the sale of assets. Between January and September, its workforce halved in number.
Litigation, recovery and expansion plans
In mid 2012, Clean Seas was seeking an investment partner to help the company to expand and reach new markets. Later that year, the company's share price was near its all-time low value of two cents per share, following a series of fish health and mortality problems. Clean Seas workforce was halved to lower operating costs.
In 2013, Clean Seas founder and former Chairman Hagen Stehr was inducted into Australia's Seafood Hall of Fame.
In 2015, Clean Seas announced that it had served proceedings in the Supreme Court of South Australia against former feed supplier, Skretting Australia. Clean Seas alleged that the supplier's product was deficient in taurine which contributed to poor fish health and stock losses between 2009 and 2012. In 2016, Clean Seas estimated the financial losses related to alleged deficiencies in Skretting's product to be valued between AUD$34.5 million and AUD$39.1 million. The long-running legal dispute with Skretting was eventually settled out of court in 2019 with Clean Seas receiving AUD$15 million.
In 2015, Clean Seas was investigating the prospect of establishing fish farms for Yellowtail kingfish and Yellowfin tuna near the Abrolhos Islands in Western Australia and Yellowtail kingfish at Wallaroo in South Australia. At that time, the company's objective was to be able to grow and sell 3,000 tonnes of Hiramasa per year. Late 2015 saw the company appoint David Head as CEO, whose terms included some equity in the company.
In 2016, Clean Seas Tuna Ltd became Clean Seas Seafood Ltd, with the company refocusing entirely on Yellowtail kingfish. In 2017, it rebranded its product Spencer Gulf Hiramasa Kingfish and established new facilities at Royal Park, South Australia. As of September 2017, Hagen Stehr remains the company's largest shareholder, which he holds through the entity: Australian Tuna Fisheries.
In 2018, Clean Seas' directors were confident about the prospects for their Yellowtail kingfish business, and planned to resume farming in Fitzgerald Bay, near Whyalla in August of that year. In November 2018, Clean Seas signed a distribution agreement with Chinese seafood distributor, Hunchun Haiyun Trading Co Ltd. That year, the company received $2.5 million from the Australian Government in a program to support employment initiatives in regional areas. This supported Clean Seas' efforts to reestablish itself at Fitzgerald Bay in the upper Spencer Gulf region.
In 2020, Clean Seas entered a partnership with Norwegian company Hofseth with the objective of selling frozen kingfish into the US market.
In May 2021 Clean Seas halted trading on the ASX briefly, pending their secondary listing on the Oslo-based Euronext Growth Exchange in Norway. The listing is expected to occur in late May 2021.
As of May 2021, Clean Seas has not resumed kingfish farming in Fitzgerald Bay in South Australia though it has the required approvals to do so. The last approval to be granted was for the commercial use of the Point Lowly North marina. Councillors of the City of Whyalla felt that their "hand was forced" by the Government of South Australia on the matter, and some of them remain opposed to the project.
From Wikipedia’s article on Clean Seas Seafood, shared under CC BY-SA 4.0.3