Aquaculture, the farming of fish and other aquatic organisms, has become a crucial pillar of global food security, particularly in Sub-Saharan Africa. Faced with a growing demand for fish protein, this sector is experiencing rapid expansion. However, this intensification comes with a major challenge: the excessive and often inappropriate use of antibiotics, which poses significant risks to human health, the environment, and the sustainability of the industry itself.

The Rise of Aquaculture and the Antibiotic Dilemma

Aquaculture is the fastest-growing food sector in Sub-Saharan Africa. To meet the needs of a growing global population, aquaculture production is projected to increase by 62% by 2030 . This growth is crucial for food security and poverty reduction, but it is accompanied by practices that can compromise these long-term goals.

In many fish farms, antibiotics are used not only to treat diseases but also preventively, or even systematically. This approach is often driven by several factors :

• Lack of training and technical knowledge among fish farmers.
• Difficulty in accessing specialized veterinary diagnostics.
• Fear of economic losses due to epidemics, leading to widespread antibiotic administration.
• Intensive farming conditions: high fish density in ponds, poor water or feed quality, and inadequate sanitary management, which favor the rapid spread of diseases.

The Alarming Consequences of Antibiotic Misuse

The widespread and indiscriminate use of antibiotics in aquaculture has profound and negative repercussions at several levels.

For Aquaculture Producers

1. Emergence of Resistant Bacteria (Antibiotic Resistance): Constant exposure to antibiotics selects for the most resistant bacteria. Eventually, medications become ineffective, making diseases more difficult and costly to treat. A farm dependent on antibiotics enters a vicious cycle of increasing diseases, treatments, and production costs .
2. Decreased Profitability: Repeated purchase of antibiotics represents a significant expense. Moreover, epidemics caused by resistant bacteria can lead to massive mortalities and reduced fish growth, thereby lowering yields and revenues .
3. Loss of Market Access: International markets impose strict standards regarding antibiotic residues in aquaculture products. Fish containing excessive residue levels may be rejected, leading to significant economic losses and damaging the industry’s reputation .

For Human Health: Antibiotics on Our Plates

When fish are marketed too soon after treatment, antibiotic residues can persist in their flesh. Consumers then unknowingly ingest small quantities of these substances. Repeated ingestion of these sub-therapeutic doses can have serious consequences :

• Development of Antimicrobial Resistance (AMR): Bacteria in the human body adapt and mutate, rendering medical treatments ineffective when real infections occur. AMR is considered by the Food and Agriculture Organization of the United Nations (FAO) as one of the greatest threats to global health, potentially causing up to 10 million deaths per year by 2050.
• Disruption of Gut Microbiota: Even at low doses, antibiotic residues can destroy the “good” bacteria in the gut, weakening the immune system and causing digestive disorders and other health problems.

For the Environment

Approximately 80% of antibiotics administered to aquatic animals disseminate into surrounding environments (water and sediments), contributing to the spread of resistant bacteria and resistance genes in aquatic ecosystems. Studies have shown that up to 90% of marine bacteria can be resistant to at least one antibiotic .

Towards Sustainable Aquaculture: Solutions to Reduce Antibiotic Use

The solution lies in disease prevention rather than systematic treatment. Several strategies can be implemented to reduce reliance on antibiotics and promote more sustainable and safer aquaculture :

1. Improved Water Quality: Rigorous management of water parameters (dissolved oxygen, pH, ammonia levels) significantly reduces fish stress and the risk of disease.
2. Avoid Overcrowding in Ponds: Appropriate fish densities minimize stress, improve animal welfare, and limit the rapid spread of infections.
3. Use of Quality Feed: A balanced and nutritious diet strengthens the fish’s immune system, making them more resistant to pathogens.
4. Enhanced Biosecurity: Strict hygiene and management measures, such as equipment disinfection, access control to ponds, isolation of sick fish, and proper disposal of dead fish, are essential to prevent the introduction and spread of diseases.
5. Prudent Use of Antibiotics: Antibiotics should only be used after accurate disease diagnosis, under the advice of a technician or veterinarian, and strictly adhering to prescribed dosage and duration.
6. Development of Antibiotic Alternatives: Innovative solutions are emerging, such as probiotics and prebiotics (beneficial microorganisms that improve gut health and fish immunity), improved nutrition, selection of more resistant fish strains, vaccination, phage therapy, and Biofloc technology .
7. Respect Withdrawal Periods Before Marketing: Each antibiotic has a specific withdrawal period, the time required for drug residues to disappear from the fish’s body. It is imperative to read the drug label, strictly observe this period, and never market fish before its expiration. Failure to comply with this rule endangers consumer health and the reputation of the entire aquaculture sector.

The Future of African Aquaculture

The future of aquaculture in Sub-Saharan Africa depends on its ability to reconcile production growth with sustainable practices. By adopting preventive approaches and investing in antibiotic alternatives, the sector can not only preserve consumer health and drug efficacy but also ensure its own long-term economic viability. Antibiotics must once again become an exceptional treatment tool, not a systematic solution.