Humane Slaughter of Aquatic Farmed Animals
Yoriko Otomo, Global Research Network
Background
Every year, more than ten billion aquatic animals are farmed and slaughtered for food. Yet their welfare remains almost entirely unregulated. Most fish are killed using methods that cause prolonged suffering—asphyxiation, gill-cutting without stunning, live chilling, or freezing in ice slurries. Most of these practices would be illegal for any land animal. Despite this, fish and other aquatic animals have long remained invisible in both legislation and public debate.
Global Research Network
In 2024, the Global Research Network (GRN) convened an international team of researchers in law, ethics, economics, and animal welfare science to address this gap. Our purpose was to make the case—empirical, ethical, and economic—for humane slaughter of farmed aquatic animals worldwide.
The GRN has produced a report to show that humane slaughter not only is possible but practical. The science is clear, the technologies exist, and the financial cost is negligible compared to the moral and reputational costs of inaction.
Main Findings
1. The Growing Context
Aquaculture now supplies more fish than all wild-capture fisheries combined. It is one of the fastest-growing food sectors in the world, valued at over 670 billion US dollars annually and expanding by 6–8 percent per year. As aquaculture grows, public awareness of animal welfare is also increasing. Consumers are beginning to ask how fish are killed and whether their treatment is humane. In particular, younger generations expect ethical and sustainable practices from food producers. In every region studied, the direction of change is the same: higher expectations for transparency and welfare standards in food production. Humane slaughter is increasingly viewed as a baseline requirement, not an optional add-on.
2. Humane Slaughter Technologies
The report evaluates three main methods that can ensure farmed fish lose consciousness rapidly and permanently before death:
- Percussive stunning: a mechanical blow to the head, causing immediate unconsciousness. Highly effective for large fish such as salmon and cod;
- Dry electrical stunning: direct current applied to fish in air. Effective when properly calibrated for medium-sized fish but requires careful handling;
- Wet electrical stunning: immersion in electrified water, allowing multiple fish to be processed quickly. When voltage and frequency are correctly adjusted, this is a humane and efficient method for smaller species.
Each method is already commercially available and technically feasible. The challenge is not technology but implementation. In many countries, regulation lags behind science, and producers lack incentives to invest in equipment that would eliminate suffering at slaughter.
3. Existing Regulatory Protection
The report analyses legal protection of fish and other aquatic species globally and found significant variation across jurisdictions, depending on each country’s recognition of sentience as reflected in its existing welfare laws and enforcement mechanisms. Protection ranges from mandatory stunning practices, implemented in countries such as Norway or New Zealand due to the acknowledged sentience of fish, to the exclusion of fish from enforcement mechanisms in countries including China, Vietnam or Bangladesh. Although varying degrees of protection and enforcement are present in all regions, the global demand for fish continues to rise annually. It is therefore imperative to standardise and secure humane slaughter practices for key species of farmed fish worldwide. The World Organisation for Animal Health’s Aquatic Animal Code 2019 and the Aquaculture Stewardship Council’s standards could serve as the basis for a proposed Model Law on humane slaughter for farmed aquatic animals, mandating stunning before killing using methods that ensure an immediate and irreversible loss of consciousness.
4. The Financial Case
A detailed financial analysis shows that introducing humane slaughter systems changes production costs by only –2.1 percent to +2.5 percent—in some cases reducing costs through improved efficiency and product quality. Capital investment requirements range from 140,000 to 625,000 euros per facility, depending on species and system size. Once installed, humane slaughter systems often lower staff injury rates, improve product shelf life, and facilitate compliance with export standards. Consumer research shows that people are willing to pay more for ethically produced seafood—typically 8–20 percent more, and sometimes as high as 40 percent in high-income markets. Even if humane slaughter accounts for a fraction of this premium, the shift is economically sound.
The evidence suggests that humane slaughter is not a financial burden but a strategic opportunity. Collective adoption would eliminate competitive disadvantages and accelerate market transformation.
Key Recommendations
1. Governments
- Establish clear legal requirements for stunning before slaughter across all farmed fish species, modelled on the standard provided in the Aquatic Animal Code 2019. Stunning methods must, where possible, result in an immediate and irreversible loss of consciousness.
- To ensure humane slaughter, species-specific methods of killing should be explicitly mandated. Provide transitional funding or tax incentives to help smaller producers adapt.
- Align national inspection standards with validated welfare science, using measurable indicators of unconsciousness and death.
2. Certification and Standards Bodies
- Integrate humane slaughter into the criteria for eco-labels and certification schemes.
- Existing programs such as the Aquaculture Stewardship Council already influence consumer behaviour; adding welfare standards, such as the ASC’s standard, which requires oversight of effective stunning and killing, for example by verifying the absence of opercular, eye or body movements, will make these schemes more credible and consistent.
3. Industry and Producers
- Treat humane slaughter as a core operational standard rather than an optional welfare measure.
- Transparent adoption of humane slaughter methods enhances efficiency, product quality, and brand integrity. Early adopters will be best positioned for regulatory change and consumer trust.
4. Researchers and Academics
- Close remaining data gaps through collaborative studies on species-specific welfare indicators, cost-benefit analyses, and consumer behaviour.
- Evidence-based standards are essential for consistent regulation and implementation.
5. Civil Society and Consumers
- Continue to hold governments and producers accountable. Public awareness and advocacy are vital in ensuring that welfare reforms are implemented, monitored, and enforced.
A humane food system is not only possible—it is within reach. The time to act is now. The full report is available here.
Brought to you in partnership with Global Research Network Think Tank
