With fish accounting for 17% of all animal protein consumed globally and aquaculture representing the fastest-growing food production system worldwide, the need for humane seafood farming standards has become increasingly urgent. Reports show that almost half of the seafood consumed today is derived from farms, yet fewer than 1% of farmed fish have fish-specific legal protection when it comes to slaughter, despite scientific evidence that fish experience pain and stress.
The Aquaculture Stewardship Council (ASC) has launched a unified farm standard that consolidates 12 species-specific standards into a single comprehensive framework, with enhanced animal welfare requirements taking center stage in response to growing market demands for responsible seafood sourcing.
The new ASC Farm Standard, officially launched in May 2025, represents a significant evolution in aquaculture certification, introducing what the organization calls “Principle 4” – responsible animal health and welfare practices that address longstanding industry concerns about fish welfare in farming operations.
“This is not something that has just come out of the blue,” explains Maria Filipa Castanheira, Health and Welfare Standards Manager at ASC, speaking exclusively to Sustainable Food Business. “This stems from discussions that have been going on for many years, backed by scientific research and different stakeholders.”
The timing of the enhanced welfare requirements reflects a convergence of scientific advancement and market pressure. While ASC’s previous species-specific standards included basic health and welfare indicators covering water quality and veterinary planning, Castanheira notes that increased scientific evidence and “much more robust knowledge” from both research facilities and farm-scale operations has enabled the organization to take this significant step forward.
Four core operational welfare indicators drive daily farm management
At the heart of the new welfare principle are four operational welfare indicators designed to provide farmers with real-time assessment tools for animal welfare outcomes. These indicators focus on water quality monitoring, body condition assessment through morphological scoring, feeding behavior evaluation, and mortality tracking with segregation according to causes.
“These indicators are going to help the farmers to spot issues early on, making sure that conditions are appropriate for each species and for the system already established at the farm,” Castanheira explains. The approach represents a shift from reactive to proactive welfare management, allowing farmers to identify and address welfare concerns before they escalate.
The welfare management framework requires farms to develop health and welfare management plans that serve as guides for day-to-day practices. Crucially, these plans must be reviewed annually by veterinarians to ensure they remain relevant and effective for specific farm conditions and species requirements.
“This approach helps the farmers to move from a more reactive to proactive welfare management,” says Castanheira. “This is backed by real-time data. They access the data and then make plans according to the unique needs of their fish that will be specific for this species and for this farm.”
Addressing the industry’s most contentious welfare issues
The welfare challenges ASC’s new standard addresses reflect broader industry problems. Research indicates that inhumane slaughter practices often cause suffering for farmed fish, with 70-72% having no legal welfare protection. Farmed fish are frequently subject to overcrowding, starvation (with food withheld for two weeks or more before transport or slaughter), and unethical slaughter methods including gassing with carbon dioxide, cutting gills without stunning, or being processed while still alive.
The standard directly tackles three major welfare concerns that have become focal points for retailers: slaughter practices, eyestalk ablation in shrimp farming, and antibiotic use. On slaughter requirements, the standard mandates stunning before killing across all species, addressing what Castanheira describes as practices where fish are “placed in a slurry bed, in which they are left for minutes or even hours to die.” The new requirements, based on scientific evidence that fish can feel pain and suffer during slaughter, require stunning through percussion or electrical methods before processing.
For shrimp farming, the standard phases out eyestalk ablation – a practice where one eyestalk is removed from female shrimp to increase egg production. “According to scientific evidence, it was noted that eyestalk ablation doesn’t work as effectively, and they need to have more tanks and more female brood stocks instead,” Castanheira explains.
The antibiotic approach takes a “one health” perspective, restricting prophylactic treatment while maintaining flexibility for therapeutic use when necessary. For shrimp farms specifically, all antibiotics are forbidden, making ASC-certified shrimp products antibiotic-free.
ASC’s species-specific implementation recognizes industry diversity
Implementation timelines vary by species and practice, with the salmon industry leading adoption of welfare improvements. “The salmon industry is moving much more quickly, compared to all the other fish,” notes Castanheira. “For them it’s much easier to comply with these stunning and slaughter requirements. All the other ones are a bit behind, but we are happy to begin discussions.”
The standard incorporates time-bound indicators that allow farms adaptation periods for practices requiring significant infrastructure or procedural changes. This approach acknowledges that welfare improvements often require substantial investment in equipment, training, and facility modifications.
“We understand that not all farmers or countries are ready to make the move right now,” Castanheira says. “So we call this a time-bound indicator. This allows the farms to have a period to adapt until they have implemented conditions that require different procedures at the farm, different training, different equipment.”
ASC has established a two-year transition period until May 2027, supported by what Castanheira describes as extensive resources to prevent leaving farmers adrift. The support system includes an interpretation manual that provides guidance on requirement compliance, regional teams offering direct farmer support, and planned workshops specifically focused on health and welfare implementation.
The organization is also conducting mock audits to help farms assess their readiness for certification under the new standard. “We understand that the new farm standard involves a lot of changes in terms of procedures, staff, training and infrastructure as well,” Castanheira explains.
Regional workshops aim to engage directly with different countries and regions to understand implementation challenges specific to health and welfare requirements. This feedback-driven approach recognizes that welfare concerns may manifest differently across various farming systems and geographic locations.
Market-driven transformation with measurable outcomes
The enhanced welfare requirements respond directly to retailer demands for stronger animal welfare assurance mechanisms. Retailers including Tesco, Sainsbury’s, Albert Heijn, and Iceland have welcomed the welfare principle as part of their responsible sourcing commitments.
“Many retailers have welcomed the ASC animal welfare principle, and we have had a lot of discussions with them. They are very happy with the principle,” says Castanheira. The third-party certification scheme provides what she describes as “assurance value” that enables retailers to meet customer expectations and corporate responsibility goals.
Looking ahead, Castanheira anticipates measurable improvements in mortality and injury rates, better health monitoring through proactive rather than reactive approaches, and progress toward 100% humane slaughter practices across species. The data collection requirements built into the standard will enable ASC to demonstrate improvements over time compared to non-certified farms.
“The main goal is really to measure the progress,” she explains. “When you start to have the data coming in, it becomes possible to show that it’s not just a promise — we can show over time that welfare data will be better.”
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