Oral Presentation Australian Society for Fish Biology Conference 2025

Understanding of fish welfare in small-scale mariculture: practices and perceptions in snubnose pompano Trachinotus blochii farming in Vietnam (124783)

Linh P. Pham 1 , Manh V. Ngo 1 , Anh T. Pham 1 , Cuong T. Le 1 , Dai T. Vu 1 , Phu M. Tran 2 , Sunil Kadri 3
  1. Institute of Aquaculture, Nha Trang University, Nha Trang, Vietnam
  2. College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
  3. Research Institute for Northern Agriculture, Chales Darwin University, Darwin city, Northern Territory, Australia

Background

Vietnam is the second largest pompano exporter globally, underscoring the potential of marine aquaculture for the country. However, fish welfare, especially in smaller operations, remains understudied.

Aims

This study explored current practices associated to pompano farming and transportation around Nha Trang in Central Vietnam, alongside stakeholder perceptions of fish welfare.

Methods

Interviews with 75 individuals (hatchery operators, grow-out farmers, transporters) revealed insights into operational practices (farm scale, stocking density, feeding, environmental factors, health management, and handling) and understanding of welfare (perceptions of biological needs, stress indicators, influencing factors, responsibilities, and the importance of welfare).

Results

Hatcheries generally showed practices supporting biological needs: reasonable stocking density, good water quality, health management reducing disease stress, and live feed aligned with behaviour-based feeding decision. Fasting durations was less than 7 hours and 24 hours before grading and transport, respectively.

Grow-out farms, relying on ambient water conditions, faced potential environmental fluctuations. Often, less care is taken during handling of fish in grow-out than in hatcheries because farmers believe that fish have become accustomed to their handling procedures, so mitigating stress responses. In both hatcheries and grow-out, while negative impacts of grading were uncertain, it likely improves welfare by optimizing density, feeding, and acclimating fish to handling, reducing any future stress. Inconsistent chemical and antibiotic use raised concerns about physiological impacts (microbiome disruption, resistance) upon fish regardless of production stage.

Transport personnel lacked comprehensive aquaculture knowledge, hindering their understanding of species-specific biological needs and stress responses, thus limiting their ability to implement welfare-focused practices during transit. High stocking densities during transport are a potentially stressor, impacting water quality, oxygen, and causing physical injury. Farm operators intuitively linked welfare to stock health and sustainability, recognizing the biological impact of stress, while transporters, who focused on survival, overlooked how reducing stress benefits the fish during transport.

Conclusion

Current research suggests partial welfare implementation in pompano farming. Future studies should quantify stress, improve disease control, and emphasize welfare across all stages to inform best practices and stakeholder training, promoting the biological, ethical, and economic value of fish welfare in aquaculture.