Pathogen-Associated Diseases in Tuna Aquaculture: Current Challenges and Future Research Directions

Tuna aquaculture faces significant challenges from various pathogen-associated diseases, including bacterial, fungal, viral, and parasitic infections, which threaten both the health of farmed tuna and the economic viability of the industry. This review provides an overview of the current status of these diseases in tuna farming, with a focus on the pathogenic mechanisms, environmental stressors, and management strategies. Bacterial infections, particularly those caused by Vibrio species and Photobacterium damselae, remain major threats, often exacerbated by environmental stressors such as high water temperatures and poor water quality. Fungal diseases, which impact the gills of yellowfin tuna, and viral diseases, notably Nervous Necrosis Virus (NNV), present additional risks that result in high mortality rates, especially among juvenile fish. Parasitic diseases, including infestations by flatworms like Cardicola forsteri and ectoparasites such as Caligus species, also contribute to significant losses in tuna farming. Despite progress in understanding these pathogens, critical research gaps remain, particularly in the areas of immune system responses, pathogen-host interactions, and the development of sustainable disease control measures. The overuse of antibiotics and chemicals in disease management has led to growing concerns over antimicrobial resistance and environmental pollution. Future research should prioritize integrated disease management systems, including the development of eco-friendly control strategies such as probiotics, immunostimulants, and vaccines. Furthermore, the impact of environmental factors on disease dynamics requires more in-depth investigation, alongside the development of predictive models and real-time monitoring systems for better disease management. Addressing these challenges with a multidisciplinary approach will be crucial to improving the health and productivity of farmed tuna, thereby ensuring the sustainability of the tuna aquaculture industry.