by Xin He, Regional Policy and Technical Specialist

At the port in Suva, fishing vessels arrive after weeks at sea, carrying tuna destined for markets across the world. Crews move quickly—offloading, sorting, preparing the catch for export. Within hours, the catch begins its journey to markets in Japan, Europe and the United States.

What is less visible—but just as critical—is what happens below deck. Hidden behind metal panels, refrigeration systems work relentlessly to keep tuna at temperatures as low as –60°C. Without them, the catch would quickly lose much of its export value. With them, Fiji’s fishing industry continues to power livelihoods, exports and economic resilience. However, these same systems are now at the center of a different challenge.

An industry under pressure

Fiji’s tuna industry has long been a pillar of its economy. In 2022, the national longline fleet landed close to 11,000 metric tonnes of catch, with tuna accounting for around 90 percent. [1]

Yet behind these numbers lies a sector navigating increasing uncertainty.

Many of the vessels operating today are more than two decades old, and according to industry stakeholders, some have been operating for as long as 40 to 50 years. Owners continue to repair and maintain them, stretching their lifespan as long as possible. Replacing them is costly, and for many, not financially viable.

At the same time, companies are grappling with rising fuel prices, shifting global markets and the impacts of climate change on fish stocks.

And now, another transition is underway—one that reaches deep into the heart of every vessel.

The invisible dilemma below deck

Most of Fiji’s fishing vessels rely on refrigerants like HCFC-22, which have long been used in the refrigeration systems that preserve the catch at sea. However, because HCFC-22 damages the ozone layer and has a high global warming potential (around 1,810 times more potent than CO₂), it is now being phased out globally.

Yet replacing them is not as simple as swapping one chemical for another. The alternative refrigerants available today often come with trade-offs. Some are better for the ozone layer but worse for the climate. Many of these alternatives are usually hydrofluorocarbons or HFCs, which were introduced as replacements for ozone-depleting substances but have very high global warming potentials, often hundreds to thousands of times higher than CO₂. Others are more climate-friendly but significantly more expensive, or require entirely new systems.

And on a fishing vessel, space is tight, conditions are harsh and safety is critical.

“Protecting the catch is our top priority,” one industry stakeholder explained during field consultations. “If a system cannot operate reliably, then it is not an option for us.”

Why the toughest challenge is the coldest

The challenge becomes even more complex when it comes to tuna bound for export markets.

To meet strict quality standards for long-term storage, tuna must be stored at around –47°C. Keeping fish at that temperature for weeks at sea is no small task. Refrigeration systems need to reach temperatures as low as –60°C – not just to keep the catch frozen, but to preserve the colour and texture required for sashimi-grade quality throughout a voyage.

At these temperatures, options are limited.

Many low-global-warming alternatives show promise, but have not yet been sufficiently tested under the demanding conditions required for ultra-low-temperature storage, especially on smaller vessels. Others require large, complex systems that simply cannot fit onboard and be safely operated without specialized training.

For now, many vessel owners are left with difficult choices: invest in costly upgrades, adopt interim solutions or delay changes altogether.