Antibiotics in shrimp farming: Identifying Critical Control Points

The use of antibiotics in aquaculture is an essential tool for controlling bacterial diseases that can severely impact production. In the farming of white shrimp (Penaeus vannamei), one of the world’s most important aquaculture species, this practice is common for mitigating economic losses. However, its extensive use raises growing environmental and public health concerns, prompting questions about the fate of unabsorbed antibiotics and the moments of greatest risk during the cultivation cycle.

A recent study in the Journal of Hazardous Materials by researchers from Ningbo University and the Ningbo Academy of Agricultural Sciences delves into a complete P. vannamei production cycle to answer these questions. Through dynamic and periodic monitoring, the researchers analyzed water, feed, additives, and the shrimp themselves at various developmental stages. Their goal was to precisely identify the “critical control points” for antibiotic management, offering a roadmap for a more sustainable and secure aquaculture industry.

Key findings

• Antibiotic concentrations in pond water increased progressively throughout the culture cycle, particularly during the final stages.
• Juvenile shrimp accumulate up to 1.6 times more antibiotics than adults, making this a high-vulnerability stage.
• Current effluent (wastewater) treatment is ineffective at removing certain antibiotics, creating a medium-to-high ecological risk.
• Despite their presence in the environment, antibiotic residues detected in shrimp muscle remained below the risk thresholds for human health and antimicrobial resistance.

How were the antibiotics tracked?

To understand the dynamics of these compounds, the scientists implemented an innovative experimental design. They monitored the entire shrimp farming cycle, from the post-larval phase to maturity, dividing it into five stages (S1 to S5) marked by changes in feed.

Periodically, they collected samples from various points in the system: the water source, storage pond, culture pond, effluent pond, and purification pond. They also analyzed samples of juvenile, adult, and mature shrimp, as well as the feed and additives used. This comprehensive approach enabled them to trace the journey of 45 different antibiotics, understanding their origins, accumulation patterns, and associated risks.

Progressive accumulation and risk hotspots

Pond water: A growing reservoir of antibiotics

The study detected eleven antibiotics, with florfenicol, enrofloxacin, and trimethoprim being the most prevalent. A crucial finding was that the total concentration of antibiotics in the culture ponds increased significantly over time, particularly in the later stages of the cycle (S3-S5).

Levels in the culture ponds were notably higher than in the water source, confirming that aquaculture activities are the primary source of these residues. The combined use of trimethoprim (TMP) and sulfamethoxazole (SMX), mainly for disease treatment, was responsible for much of this increase in the final phases.

Juveniles under scrutiny: Higher bioaccumulation capacity

Perhaps the study’s most revealing discovery is the difference in antibiotic accumulation capacity based on the shrimp’s developmental stage. The analysis of bioaccumulation factors (BAF) demonstrated that juvenile shrimp have a significantly higher accumulation capacity than adults and mature specimens.

This is likely because juveniles have lower levels of biotransformation enzymes and a higher lipid content, which facilitates the retention of these compounds. Sulfamethoxazole (SMX), in particular, showed a strong potential for bioaccumulation during this juvenile stage. This finding positions the juvenile phase as a critical point requiring precise monitoring and management of inputs.

Effluent treatment: An insufficient barrier

The study also highlighted a significant weakness in current practices: the ineffectiveness of effluent treatment systems. Neither the sedimentation pond nor the ecological purification pond managed to effectively remove key antibiotics like trimethoprim and florfenicol.

These systems, primarily designed to remove nutrients like nitrogen and phosphorus, do not perform optimally for eliminating pharmaceutical compounds. Consequently, significant concentrations of antibiotics are discharged into the environment, where trimethoprim and florfenicol pose a medium-to-high ecological risk.

Implications for shrimp farmers and the aquaculture industry

The results of this research have direct practical implications for the management of shrimp farms:

• Critical point 1: The Juvenile Phase (S3). This is the stage where shrimp are most susceptible to accumulating antibiotics. The management of feed, additives, and prophylactic treatments during this period must be extremely careful and precise.
• Critical point 2: Late-Stage Treatments (S3-S5). The use of antibiotics to treat diseases during the grow-out phases is the primary cause of increased concentrations in the water. It is essential to optimize dosages and explore alternatives.
• Critical point 3: Effluent Treatment. Current systems are inadequate. The industry needs to invest in more effective technologies for treating wastewater, such as extending hydraulic retention time or implementing constructed wetlands, to minimize ecological impact.

Is the shrimp safe for consumption?

Despite the presence of these compounds in the farming system, the study offers reassuring news for consumers. The human health risk assessment determined that the levels of antibiotic residues detected in shrimp muscle at all stages remained below safety thresholds.

However, the researchers caution against ignoring the long-term risk of antimicrobial resistance (AMR). Constant exposure, even at low levels, can promote the development of resistant bacteria in the aquatic environment—a global public health concern.

Conclusion: Towards a more precise and responsible shrimp production

This study underscores that sustainability in Penaeus vannamei aquaculture is not about eliminating antibiotics, but about managing them intelligently and strategically. The research clearly identifies the juvenile phase and effluent treatment as the two most critical control points requiring immediate attention.

Implementing precise monitoring, optimizing management practices during high-vulnerability stages, and developing more robust water treatment systems will not only reduce the ecological impact of shrimp farming but also strengthen product safety and long-term consumer confidence.

Contact
Rongrong Zhang
School of Marine Sciences, Ningbo University
818 Fenghua Road, Ningbo 315211, PR China.
Email: zhangrongrong@nbu.edu.cn

Reference
Xu, F., Yang, C., Liu, H., Liu, H., Chen, M., Wu, Y., Shi, X., Zhang, Z., & Zhang, R. (2025). Critical control points in Penaeus vannamei aquaculture: Dynamic tracking and comprehensive risk assessment of antibiotics. Journal of Hazardous Materials, 496, 139256. https://doi.org/10.1016/j.jhazmat.2025.139256

Milthon Lujan

Editor at the digital magazine AquaHoy. He holds a degree in Aquaculture Biology from the National University of Santa (UNS) and a Master’s degree in Science and Innovation Management from the Polytechnic University of Valencia, with postgraduate diplomas in Business Innovation and Innovation Management. He possesses extensive experience in the aquaculture and fisheries sector, having led the Fisheries Innovation Unit of the National Program for Innovation in Fisheries and Aquaculture (PNIPA). He has served as a senior consultant in technology watch, an innovation project formulator and advisor, and a lecturer at UNS. He is a member of the Peruvian College of Biologists and was recognized by the World Aquaculture Society (WAS) in 2016 for his contribution to aquaculture.