Fifteen-thousand yellowtail kingfish fingerlings have arrived in Tasmania from Western Australia.
Their arrival marks the next stage of a three-year aquaculture research trial in Bass Strait, which aims to "generate evidence about what it takes to grow a new species" and "build Australia's capability in offshore aquaculture".
The trial will run until 2028, after which the pens will be decommissioned and the viability of an aquaculture industry assessed.
Placed in oxygenated bags then packed into insulated boxes, 15,000 juvenile kingfish have made the 3,000-kilometre journey from Fremantle to Hobart.
The arrival of the small fish, known as fingerlings, marks the next stage of aquaculture trial underway in Bass Strait, 12 kilometres off the coast of Burnie.
Researcher and kingfish impact lead for the company running the trial, Blue Economy CRC (Cooperative Research Centre), Maxi Canepa, said the journey was "an interesting exercise".
"We didn't have mortalities. They are fantastic. They looked very healthy on arrival," he said.
"These fish grow really fast. That's why it's a very nice species for aquaculture."
The fingerlings will grow on land at the Institute of Marine and Antarctic Studies (IMAS) in Taroona for three months until they weigh between 100 and 150 grams.
The not-so-tiny fish will then be transported to the trial site, where they will be acclimatised to the water and released into a sea pen where they are expected to grow to 4 kilograms before being harvested.
Dr Canepa said it would be the first time kingfish are farmed offshore in Australia.
"It's a site that is going to offer some challenges but also opportunities," he said.
The three-year research trial, dubbed the Blue Economy Zone (BEZ), is the country's first aquaculture trial in Commonwealth waters, led by independent not-for-profit Blue Economy CRC.
The company is part of the federal government's CRC program, which supports industry-led collaborations between industry, researchers and the community.
The project aims to trial the viability of multi-species offshore aquaculture in Commonwealth waters.
In 2028 the site will be decommissioned; and any commercial operation will then be a question for aquaculture companies and will require government approvals.
Three months after pens were established in 2025, 15,000 Atlantic salmon were introduced. Last week, the fish were harvested.
Blue Economy CRC chief executive Angela Williamson says the salmon "performed really well" in the rough waters of Bass Strait.
"They grew above the predicted modelled weight. Unlike within the state waters, they did not need to be bathed. We did experience regular mortalities across that time period," she said.
"All our information was put on our website on a dashboard. We know transparency is a really important component of this trial and (the public) understanding and trusting the process," she said.
Ms Williamson said infrastructure had also held up against the "wild and windy" conditions.
"We've had to really make sure that our mooring grid, our nets and our floating equipment meet those standards, not just of government, but also of keeping the fish safe, keeping people who are operating safe, and ensuring that marine debris is eliminated as much as possible."
According to the project's dashboard, the BEZ has recorded 13 pieces of marine debris and eight "wildlife interactions".
A public meeting hosted by Blue Economy CRC was held when the project at the start of the trial last year, with attendees opposed to the trial expressing concerns about environmental impacts.
Tasmanian independent Braddon MP Craig Garland is staunchly opposed to the trial.
"We never wanted any salmon or any finfish aquaculture in our waterways," he said.
"One in five people are coming here for the tourism experience. They're not coming to see a flow-through hatch with algae growing downstream. They're not coming to see 20,000 ton of dead fish rotting and floating around the place."
From January to April 2025, a bacterial disease known as Piscirickettsia salmonis caused the mass deaths of salmon in pens in south-east Tasmanian waters.
Data reported to the Environment Protection Authority (EPA) showed almost 15,000 tonnes of dead salmon during that period went to waste facilities.
Ms Williamson said there are a "variety of perspectives" on aquaculture across coastal communities.
"I think the debate about aquaculture more broadly across Australia is a strong debate," she said.
"At the end of the day, what we're looking to do is learn from all of those and provide for a regulatory environment, a policy environment that makes sense for Commonwealth waters, which are further offshore."
After the kingfish are harvested in May 2028, the site will be decommissioned and the research findings will inform future governance of aquaculture in government waters.
Harvested salmon, kingfish and seaweed products are allowed to be sold under the project's permit arrangement, with profits fed back into the CRC program to offset research costs.
"There'll be a wealth of information and knowledge available for industry and government to make decisions on what's next and whether that is unlocking Commonwealth waters right around Australia, what that looks like, how that will be done," Ms Williamson said.