The Use of Antibiotics in Sustainable Aquaculture: Safety & Biological Implications

Why Antibiotic Use in Aquaculture Matters

Recently, a study by the National Institute of Oceanography (NIO) revealed some troubling news: the water near Mumbai’s popular beaches contains bacteria resistant to more than 12 types of antibiotics.

Even worse, bacteria levels were found to be ten times above the safe limit.

This isn’t just a local concern—it’s a global red flag.

These antibiotic-resistant bacteria can spread through water, enter the food chain, and potentially reach humans.

And one major contributor to this resistance?

The use of antibiotics in aquaculture.

Understanding Antibiotic Resistance

Bacteria are incredibly adaptable.

When exposed to antibiotics too often or in the wrong way, they can evolve and develop resistance.

This means infections that were once easy to treat can become much harder to manage.

Resistance can even spread from harmless bacteria to harmful ones, posing a significant threat to human health.

Aquaculture—where fish and seafood are farmed—can become a hotspot for this resistance.

The high density of bacteria, frequent use of antibiotics, and other chemical treatments create the perfect environment for resistance genes to spread.

The Growth of Aquaculture & the Need for Safer Practices

As the global demand for seafood increases, so does the pressure on aquaculture to deliver affordable, protein-rich food.

But this comes with a responsibility: to ensure that farming practices don’t compromise food safety, environmental health, or public health.

Antibiotics are commonly used in aquaculture to treat and prevent disease.

However, overuse or misuse can lead to antibiotic residues in the water, fish, and surrounding environment—sometimes even in the seafood we eat.

The Environmental Impact

Research shows that antibiotics used in aquaculture can affect marine ecosystems.

Some antibiotics, like oxytetracycline and florfenicol (used to treat salmon), have been found to harm algae like Tetraselmis chuii, which are essential to the ocean food web.

Even more concerning is that many developing countries, which account for 90% of global aquaculture, lack strong regulations around antibiotic use.

This leads to inconsistent and often excessive use, further increasing the risk of antibiotic resistance.

How Antibiotic Resistance Spreads

Antibiotic-resistant genes can spread quickly among bacteria in water and sediment.

Even after antibiotic use stops, resistant bacteria can remain in the environment for a long time.

And with fish waste and uneaten feed carrying antibiotic residues into the water, the cycle continues.

Studies show that up to 90% of marine bacteria are resistant to at least one antibiotic, and 20% are resistant to five or more.

Exploring Safer Alternatives

Thankfully, many countries have started regulating antibiotic use in aquaculture.

For example, the EU banned the non-therapeutic use of antibiotics in 2001.

Norway, through strict oversight and increased use of vaccines, reduced antibiotic use in aquaculture by 99% from 1987 to 2013, despite a 20-fold increase in production.

Other promising alternatives include:

• Vaccination to prevent disease.
• Immune-boosting feed additives made from natural sources.
• Phage therapy (using viruses to kill harmful bacteria).
• Quorum sensing disruption, which reduces bacterial virulence.
• Biofloc technology, which recycles waste nutrients into beneficial bacteria that both clean the water and feed the fish.

The Role of Probiotics

Probiotics are live microorganisms that support gut health and immunity in farmed fish.

They can also help reduce the need for antibiotics.

However, even probiotics aren’t entirely risk-free—there’s a chance they could pick up and spread antibiotic resistance genes, especially when used in large amounts.

Still, probiotics are a major step forward in making aquaculture more sustainable.

Organica Biotech: Leading the Way in Organic Aquaculture

One company making a real impact in this space is Organica Biotech.

Through research-based probiotic solutions, they are helping transform traditional fish farming into a cleaner, healthier, and more sustainable practice.

Organica’s soil and water probiotics reduce organic waste and clean up pond environments.

At the same time, their feed probiotics support gut health in fish, boosting immunity, improving growth, and reducing the need for antibiotics.

The result?

Higher-quality seafood, healthier ponds, and a significantly smaller environmental footprint.

Their work shows how science and sustainability can go hand in hand, paving the way for a future where organic aquaculture isn’t just possible—it’s powerful and scalable.