Parasitic Dynamics in Freshwater Aquaculture

Parasites exert profound influences on the productivity, sustainability and biosecurity of freshwater aquaculture. A diverse array of protozoan, metazoan and crustacean parasites can impair fish growth, reproduction and marketability, with impacts ranging from subclinical effects on feed conversion to acute outbreaks with high mortality. The dynamics of these host–parasite systems are shaped by intensive rearing practices, translocation of cultured species and interactions with wild fish populations. Environmental drivers such as water quality, stocking density and seasonal fluctuations modulate parasite transmission and virulence, while global trade facilitates co-introduction of exotic pathogens. Integrating clinical diagnostics, molecular characterisation and ecological monitoring has revealed complex webs of infection, including mechanical vectors and cross-species spillover. Contemporary research emphasises holistic management strategies that combine improved biosecurity, targeted therapeutics, selective breeding for resistance and ecosystem-level safeguards under a One Health paradigm.

Research from Nature Portfolio

Recent investigations have used integrated clinical, histopathological and molecular approaches to elucidate parasite–host interactions in ornamental and food-fish species. One study characterised the sessile ciliate Epistylis wuhanensis attached to the crustacean Lernaea cyprinacea in farmed guppies and mollies, revealing granulomatous lesions in skin and muscle and identifying the copepod as a mechanical vector. Molecular phylogeny informed improved diagnostic protocols and reinforced the importance of quarantine measures to prevent mixed parasite burdens. In a separate nationwide survey of farmed tilapia, researchers performed detailed morpho-molecular analyses of Gyrodactylus monogeneans. They demonstrated that multiple African monogenean species have been co-introduced with cultured tilapia and have spilled over into native fish. This work highlighted widespread distribution of pathogenic species, underscoring the ecological risks of parasite translocation and the need for routine molecular surveillance in production systems.

Parasitic Dynamics in Freshwater Aquaculture publication trend

The graph below shows the total number of articles in parasitic dynamics in freshwater aquaculture across all publications each year (not limited to Nature Index journals).

Technical terms

Epibiont: An organism that lives attached to the surface of another organism, often influencing host health.

Monogenean: A class of flatworms typically infecting fish, often as gill or skin parasites.

Transcriptomics: The study of the complete set of RNA transcripts produced by an organism, used to reveal gene expression patterns.

Oxidative phosphorylation: The mitochondrial process of ATP production, often up-regulated in parasites to meet energy demands.

Mechanical vector: A non-biological carrier that transmits a parasite to a host without being infected itself.

References

1. Clinico-histopathological and phylogenetic analysis of protozoan epibiont Epistylis wuhanensis associated with crustacean parasite Lernaea cyprinacea from ornamental fish in Iran. Scientific Reports (2023).
2. Morpho-molecular characterization of Gyrodactylus parasites of farmed tilapia and their spillover to native fishes in Mexico. Scientific Reports (2021).
3. A global review of problematic and pathogenic parasites of farmed tilapia. Reviews in Aquaculture (2023).
4. Comparative Transcriptomics of Chilodonella hexasticha and C. uncinata Provide New Insights into Adaptations to a Parasitic Lifestyle and Mdivi-1 as a Potential Agent for Chilodonellosis Control. International Journal of Molecular Sciences (2023).
5. Aquaculture of Animal Species: Their Eukaryotic Parasites and the Control of Parasitic Infections. Biology (2024).