In this edition of our Industry Voices series, we had the pleasure of speaking with Maria Filipa Castanheira, the Health and Welfare Standards Manager at Aquaculture Stewardship Council (ASC). Maria’s journey is not just about career milestones—it’s her story of passion, curiosity, and a deep commitment to marine life. Read the full interview below, or scroll to the end to watch the video.

 

Kurt Cobain once sang “It's okay to eat fish 'cause they don't have any feelings”. His words, emblazoned across T-shirts and posters in the nineties, captured the feelings of the day. But attitudes around the sentience of fish and marine animals have changed massively in the past thirty years. So, if the Nirvana frontman were writing now, he’d have to amend his lyrics.  

This change in opinion is due in part to Aquaculture Stewardship Council (ASC) and similar industry bodies, which have worked hard to drive the adoption of welfare as a core value in the seafood sector.  

It’s a topic very close to Maria Filip Castanheira’s heart. As Fish Health and Welfare Standards Manager for  ASC, her work centres on promoting fish and crustacean welfare and advancing sustainable practices within the aquaculture industry.  

Discovering a love of marine life 

Based in Singapore, Castanheira plays an integral role in ASC's Standards Team, developing welfare-related topics for fish and crustaceans within the ASC Farm Standard. She focuses her efforts on integrating science, policy and ethical practice to improve the life of animals and ensure sustainable seafood production.  

When we chat, she is back in her native Portugal visiting family - the place where her love of the sea began. As a child, Castanheira lived in a small city and dreamt of the ocean. She longed to work with marine life, a passion which she says was instilled in her by her grandfather, a science teacher. That dream translated into a career in marine biology, taking her round the world, specialising in advanced animal welfare and sustainability in agriculture. 

Understanding the sentience of seafood 

So why does she think that attitudes around fish and crustacean welfare fell so far behind land animal standards? She puts it down to a perception problem. “Historically fish and seafood were perceived as less sentient compared to terrestrial animals. This has delayed things a bit in terms of welfare considerations.”  

She puts it another way. “A cow can express when it’s in discomfort, but it’s much harder to tell when a fish is in pain. That lack of facial expression can be a stumbling block.” 

Certification as a catalyst for change 

So how to fix this disparity? That’s where certification schemes like ASC come in. They work to instill confidence in consumers, ensure accountability throughout the supply chain and have practical results. 

“I think farmers’ opinions are changing” she says, “because our animal welfare standards are really making a difference for them.” But getting one farmer to adopt the ASC standards doesn’t mean that all will – especially when dealing with different fish breeds. And it’s not always easy changing the attitudes of “non-believers”. So, demonstration is key.  

“It's very important to support and demonstrate to the farmers the value across the board,” says Castanheira. 

"If we go to the salmon sector, it’s completely different to people farming tropical marine species. But the idea is to just start implementation – to start training the farmers. At the end they will understand that controlling these small steps will be beneficial for the fish, for themselves, and they will have fewer issues to solve on a daily basis. The results are fewer troubles and better fish to sell at the end. "

Castanheira believes the starting point is better education – not just for the farmers but also understanding the touch points that will resonate with them. “Sometimes we need to adjust the language we use for different cultures. I can’t say to some people that this is about welfare, because they don't understand what welfare means.  

“They respect the fish. They pray before taking them. So, we need to take into consideration the environment, the culture of the country and the people. Instead of welfare, we talk about sustainability or quality of the product - something we know they will understand much more easily.”  

Tackling the big challenges in aquaculture 

Convincing the fish farmers to change how they operate isn’t the only challenge facing ASC. Antibiotic usage, climate change impact and water quality are all expected to cause problems in the upcoming years says Castanheira.  

“We still have a lot of issues relating to disease and the use of antibiotics. Even if we do have better biosecurity controls in place. If you are in an open field miles from anywhere it is not so easy to control that many factors. There’s the soil, algae blooms and predators all to consider. Plus, we are also anticipating climate change impacts.” 

The big worry here is the water starting to warm up. It’s a problem already in the consumer consciousness due to the coral bleaching of the Great Barrier Reef in Australia. “It’s clear this is going to create a lot of issues with aquaculture systems, including the possibility of new diseases occurring due to the changes in temperature,” the Fish Health and Welfare Standards Manager explains.  

The other big issue is an ongoing one. Overfishing. “We are moving in a good direction with this,” says Castanheira, “but we still have some way to go before we get rid of it. Mainly because we still have a dependence on fish oil and fish meal.” 

Castanheira is also aware that they must get the basic animal welfare standard challenges sorted first. A remote farm might not have access to electricity, or a fishing boat might be too small for monitoring equipment. These small challenges can make implementing the big changes harder to achieve.  

But Castanheira is feeling cautiously positive for two reasons - people and tech. The latter will play its part in bringing about some of the changes the industry needs.

“I’m expecting a broader adoption of welfare technologies this year. A lot of artificial intelligence and basic monitoring systems. These should help transparency, issues with skin lesions, and just be much more systematic.” 

She’s also hopeful that these automations will help in terms of water quality. “So, if the oxygen goes down, there’s an automatic way to inject more in.” 

Consumer awareness as a driver of change 

Consumers today are not just buying products—they’re buying into practices. The desire for ethical and sustainable food will drive shifts leading to a broader adoption of all things animal welfare related.  

“Consumers are very aware about what is going on – and they are looking for labels telling them what's happened with the fish and understand the conditions before the fish reached their plate.” 

Castanheira knows this because answering consumer questions is also part of her role. She’s been asked to explain about eyestalk ablation – the practice of removing eyestalks from female shrimps to improve productivity - and even when the shrimps included in the ASC supply chain will be ablation free. “We know that people know and are aware about a lot of issues in terms of welfare and they want to make sure that the products that come to the table are free of this or that.” 

So, Castanheira is hopeful. “I think we have the theoretical tools now. So, it's just the time to make them practicable – every day we can see it's possible to do more and more. That’s how we are going to make change. One step at a time.” 

The broader picture: sustainability and fair practices 

While much of Maria’s work focuses on aquatic welfare, she is equally aware of the broader social and environmental implications of aquaculture. “Something that comes together that is not really welfare related for the animals is ensuring fair labour practices across the supply chain for the aquaculture sector,” she explains. “It is something that we noted that is a challenge of the aquaculture sector.” 

Her observations highlight a critical point: sustainability isn’t just about the environment—it’s also about people. Fair labour practices, ethical sourcing, and community impact must all be part of the equation. The challenge, then, is balancing these priorities in an increasingly globalised industry. 

Looking ahead: a vision for the future 

Maria is optimistic about the future of aquaculture and its potential to become a model of sustainability. But she is also realistic about the work that lies ahead. 

“The good news is, we’re heading in the right direction—working together, finding new solutions, and listening to what consumers care about"  

Her words serve as both a call to action and a reminder of the progress already made. As the aquaculture industry continues to evolve, Maria’s dedication and expertise will undoubtedly play a key role in shaping its future. 

Watch Maria discuss the sector in her own words in our Industry Voices video. 

 

If you'd like to discover more interviews in our Industry Voices series, you can read them here.