Introduction
Fish polyculture is defined as the concurrent rearing of two or more species within the same aquaculture system at the same time. It is one of the oldest and most adaptable approaches for increasing aquatic food production. Despite its long history and recognized ecological and economic benefits, a comprehensive understanding of global research trends in fish polyculture has been lacking. Through a systematic review of scientific literature published between 1968 and 2023, we analyzed 889 peer-reviewed studies and produced the first global overview of fish polyculture research. This presentation synthesizes these trends and discusses how decision-support tools can facilitate the development of future polyculture systems.
Global Research Trends
The review revealed a strong geographic imbalance in research effort, with most studies conducted in Asia, while Africa, Europe, and the Americas remain comparatively underrepresented. Freshwater pond systems overwhelmingly dominated the literature, reflecting the historical importance of carp- and tilapia-based farming systems. Research objectives were primarily centered on growth performance, biomass yield, and feed utilization, whereas fewer studies investigated ecological processes, fish welfare, economic resilience, or social acceptability.
Temporal analysis nevertheless indicates an important transition in recent years. Increasing numbers of studies now address sustainability-oriented systems, including integrated multi-trophic aquaculture, biofloc-based production, and rice–fish farming. Emerging themes also link species diversity with nutrient recycling, improved trophic efficiency, and reduced environmental impacts. These developments suggest that polyculture is evolving from a productivity-driven practice toward a multifunctional strategy aligned with circular economy principles.
Future Development of New Polycultures
Although interest in polyculture is increasing, designing new fish species combinations remains complex because species may interact positively through niche complementarity or negatively through competition, stress, or predation. To overcome these constraints, structured decision-support approaches are needed. We developed an integrative three-step workflow consisting of: (1) selection of promising fish species combinations according to stakeholder objectives, (2) evaluation of environmental compatibility, welfare, and interaction risks, and (3) pilot-scale validation under farming conditions. We operationalized this workflow through several decision-support tools using in silico approaches. AquaDesign is an in silico tool that identifies abiotic farming conditions suitable for individual species and species combinations using ecological niche modeling. It can rapidly screen candidate species for new environments or emerging farming sectors. Predish is a complementary tool that estimates predation risk between fish species based on body-size relationships, helping to avoid combinations with high predation risk before experimental trials. Competifish is a third tool that uses functional fish trait information from public databases to estimate the risk of interspecific competition for trophic and spatiotemporal resources.
Conclusion
The global literature demonstrates that fish polyculture research has expanded substantially but remains geographically uneven and strongly focused on conventional freshwater production metrics. Future progress should prioritize underrepresented regions, broader production systems, and indicators linked to ecosystem functioning, welfare, and socioeconomic sustainability. Decision-support tools such as AquaDesign, Predish, and Competifish offer practical means to accelerate innovation while reducing costly empirical testing. Combining evidence from past research with predictive tools can help develop the next generation of resilient and sustainable fish polyculture systems.
Acknowledgments
This research is part of an international partnership between the University of Lorraine and the University of Namur, funded by Lorraine Université d'Excellence (LUE). The PhD thesis of M.L.T. is supported by Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement and the University of Namur. This work was also supported by PolyRAS (INTGR0100025), an Interreg Grande Région 2021–2027 project funded by the European Regional Development Fund (FEDER). The PhD thesis of S. Lévy was supported by a CIRAD grant.
References
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