Fishing Vessels and Alternative Fuels: Reducing Emissions from Purse Seiners

Discover how purse seine fishing vessels are adopting alternative fuels to reduce emissions. Explore technologies, challenges, and future trends in sustainable fishing.

When you think of the global fight against climate change, fishing vessels may not be the first image that comes to mind. Yet the world’s fishing fleet—nearly 4.1 million vessels, ranging from artisanal boats to massive tuna purse seiners—plays a significant role in greenhouse gas (GHG) emissions. While cargo ships and tankers often dominate the headlines, purse seiners, which target high-demand species like tuna, mackerel, and sardines, also burn large volumes of marine fuel every year.

These vessels are essential for global food security. According to the UN Food and Agriculture Organization (FAO), tuna and tuna-like species account for more than 10% of the total value of internationally traded fish products. But this economic value comes at an environmental cost: heavy fuel oil (HFO) and marine diesel still dominate the purse seine fleet, leading to CO₂, NOₓ, SOₓ, and particulate emissions.

As governments tighten environmental regulations and consumers demand greener seafood, purse seiners are facing growing pressure to decarbonise. The question is: how?

This is where alternative fuels enter the story. Technologies like LNG, methanol, ammonia, hydrogen, and advanced biofuels are already being tested in commercial shipping. Could these same fuels chart a new, cleaner course for fishing vessels? Wärtsilä, DNV, Lloyd’s Register, IMO, and other industry leaders suggest they can. This article explores how purse seiners can adapt, the opportunities ahead, and the very real challenges of greening one of the world’s most important food-harvesting fleets.

Why Purse Seiners and Alternative Fuels Matter

Purse seiners are some of the most fuel-hungry fishing vessels. Unlike small coastal boats, they operate across vast oceanic ranges, chasing migratory species. A single voyage may last weeks, with fishing grounds often far from bunkering hubs. This operational profile creates three key issues:

High fuel consumption – Large main engines and auxiliary power demands make purse seiners significant emitters relative to their size.
Global mobility – They move across international waters, often operating under multiple jurisdictions, which makes emissions regulation complex.
Food supply impact – With tuna and pelagic fish central to diets worldwide, the sustainability of purse seiners affects global nutrition.

Decarbonising purse seiners is therefore not just an environmental issue—it’s about securing the long-term future of sustainable seafood.

Key Alternative Fuels for Purse Seiners

Liquefied Natural Gas (LNG)

LNG has become the leading “bridge fuel” in deep-sea shipping, and its potential for purse seiners is significant. It offers:

20–25% CO₂ reduction compared to HFO.
Near elimination of SOₓ and particulate matter.
Lower NOₓ emissions, especially with dual-fuel engines.

Several Norwegian fishing vessels, including pelagic trawlers, already run on LNG. For purse seiners, LNG requires space for cryogenic tanks, which may reduce fish storage capacity. Still, with expanding LNG bunkering in ports like Singapore, Rotterdam, and Spanish tuna hubs, LNG could be a viable transitional step.

Methanol

Methanol is emerging as a promising option for both commercial ships and fishing vessels. Its advantages include:

Liquid at ambient temperatures, simplifying storage compared to LNG or hydrogen.
Biodegradability, reducing risks in case of spills.
Compatibility with existing two-stroke and four-stroke engines through retrofits.

Maersk has already ordered methanol-fuelled container vessels, and fishing companies are watching closely. For purse seiners, methanol could be especially appealing in regions like Northern Europe, where renewable e-methanol production is scaling up.

Ammonia

Ammonia is attracting intense interest as a zero-carbon fuel (when produced with renewable energy). Wärtsilä and MAN are already testing ammonia-capable engines. For purse seiners, ammonia’s appeal lies in its energy density and potential global production through green hydrogen and nitrogen.

The challenge is toxicity: leaks onboard a fishing vessel present risks to crews. Handling protocols and training would be essential. Yet with international investment in ammonia bunkering infrastructure, purse seiners may not be far behind.

Hydrogen

Hydrogen is often viewed as the ultimate clean fuel. Used in fuel cells or internal combustion engines, hydrogen offers zero CO₂ emissions at point of use. Pilot projects in Norway and Japan already involve hydrogen-powered ferries and fishing boats.

For purse seiners, the hurdles include:

Low volumetric energy density (requiring large tanks).
High costs of green hydrogen production.
Safety concerns during long voyages.

Despite these, as hydrogen hubs grow (North Sea, California, Japan), hydrogen could become a long-term solution.

Advanced Biofuels

Biofuels such as FAME (Fatty Acid Methyl Ester), HVO (Hydrotreated Vegetable Oil), and biogas offer drop-in potential for existing purse seiner engines. They are:

Immediate solutions without major engine retrofits.
Capable of reducing lifecycle GHG emissions by up to 80%, depending on feedstock.

The caveat: sustainability. Not all biofuels are equal. Palm oil-based biodiesel, for example, can increase emissions due to deforestation. Certification and traceability will be crucial for fisheries marketing themselves as sustainable.

Hybrid Solutions (Batteries + Fuels)

In coastal operations, hybrid systems combining batteries with alternative fuels can reduce fuel burn and emissions. For large purse seiners, batteries may support peak shaving during fishing maneuvers, reducing engine loads and emissions.

Challenges Facing Purse Seiners in Fuel Transition

Space and Storage
Alternative fuels like LNG, ammonia, and hydrogen require more space than diesel. Purse seiners must balance tank size with fish storage capacity.
Cost Barriers
Alternative fuel engines and retrofits are expensive. Smaller fishing companies may struggle without subsidies or financing.
Infrastructure
Unlike containerships that frequent major ports, purse seiners often operate in remote regions. Without reliable bunkering for LNG, methanol, or ammonia, uptake will be slow.
Safety & Training
Toxicity (ammonia), cryogenics (LNG, hydrogen), and handling risks demand new crew competencies. Training under the STCW Convention will need updating.
Regulatory Uncertainty
The IMO’s decarbonisation roadmap applies globally, but regional fisheries organisations and coastal states may enforce additional fuel rules. Vessel owners face complex compliance landscapes.

Case Studies and Real-World Applications

Norway’s Green Fishing Fleet

Norwegian companies are pioneers in alternative fuels for fishing. Several pelagic trawlers and longliners already use LNG. Pilot projects are testing hydrogen-hybrid fishing boats, offering a glimpse of what purse seiners could adopt.

Spanish Tuna Purse Seiners in the Pacific

Spain’s tuna fleet, among the largest purse seine operators in the Pacific, is exploring biofuels as a near-term solution. Collaborations between shipowners and fuel suppliers are underway to certify emissions reductions for export markets like the EU and US.

Japan’s Hydrogen Demonstrators

Japan has invested in hydrogen-powered ferries and small fishing boats, with government-backed R&D funding. While these are not yet purse seiners, the knowledge gained is transferable.

Pacific Island Initiatives

Small island states dependent on tuna fisheries are pushing for greener fleets. Development banks and regional fisheries management organisations are exploring financing for low-emission purse seiners, recognising the link between sustainability, climate resilience, and food security.

Future Outlook

The path to decarbonising purse seiners is not linear. Near-term solutions (biofuels, LNG, hybrid systems) will dominate the 2020s. By the 2030s, methanol and ammonia could see greater uptake. By the 2040s, hydrogen and synthetic e-fuels may become widespread, provided infrastructure and costs align.

Importantly, consumer demand for sustainable seafood will accelerate change. Retailers in Europe and North America increasingly require carbon footprint disclosures. Purse seine operators who adopt cleaner fuels early may gain market access advantages.

The next decade will be a testing ground—where technology, regulation, and market forces converge. Those purse seiner fleets that innovate will not only reduce emissions but also secure their long-term viability in a changing seafood market.

Frequently Asked Questions

Why focus on purse seiners specifically?
Because they are among the most fuel-intensive fishing vessels, often operating across vast distances. Their fuel choices have an outsized impact on emissions.

Which alternative fuel is most promising today?
Biofuels and LNG are the most immediate, with methanol and ammonia gaining traction for the near future. Hydrogen is likely a long-term solution.

Will alternative fuels increase operating costs?
Yes, initially. But as production scales up and carbon pricing spreads, alternative fuels are expected to become more cost-competitive.

How does this affect fish prices?
Greener fuels may raise costs slightly, but consumer demand for sustainable seafood is growing. In premium markets, buyers may pay more for low-carbon tuna.

What role do governments play?
Governments can offer subsidies, green financing, and updated training standards. Without policy support, adoption will be slow.

Are there safety risks for crews?
Yes. Fuels like ammonia and hydrogen pose handling risks. This is why training, new safety protocols, and updated vessel designs are essential.

Conclusion

Purse seiners are the workhorses of global tuna and pelagic fisheries. Their role in global food supply is undeniable, but so is their environmental footprint. As the shipping industry accelerates its decarbonisation, purse seiners cannot afford to be left behind.

The transition will not be simple: challenges of cost, infrastructure, and safety are real. Yet the opportunities are greater. From LNG and biofuels already in play to ammonia and hydrogen on the horizon, alternative fuels offer a way to align purse seine fishing with a low-carbon future.

The stakes are high—not just for shipowners or regulators, but for every consumer who relies on seafood as part of a sustainable diet. By embracing innovation, collaboration, and training, purse seiners can navigate toward a cleaner horizon—ensuring that the fish on our plates come not only from healthy oceans, but from a healthy planet.

References

International Maritime Organization (IMO). Initial GHG Strategy.
Food and Agriculture Organization (FAO). The State of World Fisheries and Aquaculture.
Wärtsilä. Future Fuels Development for Shipping.
DNV. Maritime Forecast to 2050.
Lloyd’s Register. Fuel for Thought Series.
European Commission, DG MOVE. Alternative Fuels Infrastructure.
UNCTAD. Review of Maritime Transport.
International Council on Clean Transportation (ICCT). Fishing Vessel Emissions Studies.

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