Parasitic Infections in Cultured Marine Fish

Parasitic infections represent a major constraint on the productivity, welfare and sustainability of marine aquaculture. Ectoparasitic flatworms (monogeneans), protozoans and myxozoans commonly colonise gills, skin and gastrointestinal tracts, causing tissue damage, impaired respiration and reduced growth rates. Intensive rearing conditions, high stocking densities and environmental fluctuations often exacerbate transmission, while escapees and wild populations constitute reservoirs of infection. Control strategies encompass chemotherapeutants, functional feeds, environmental management and biosecurity measures, yet resistance, residue concerns and welfare considerations drive the search for integrated approaches. Recent advances in immunological profiling, precision treatment scheduling and novel antiparasitic delivery systems are reshaping management, with global significance for food security, ecosystem health and trade standards.

Research from Nature Portfolio

Recent studies have demonstrated that natural dietary interventions can bolster mucosal defences against monogenean infestation. In gilthead sea bream challenged with Sparicotyle chrysophrii, feeding with microencapsulated blends of garlic, carvacrol and thymol elicited a coordinated up-regulation of genes associated with mucin secretion, vesicular transport and inflammatory responses. Histochemical analyses confirmed enhanced mucosal barrier integrity through increased glycoprotein deposition, and in-vivo challenges recorded a near 80 % reduction in parasite abundance. These findings underscore the potential of functional feeds to modulate host immunity and reduce reliance on chemical baths.

Parasitic Infections in Cultured Marine Fish publication trend

The graph below shows the total number of articles in parasitic infections in cultured marine fish across all publications each year (not limited to Nature Index journals).

Technical terms

Monogenean: A class of flatworm ectoparasites that typically complete their life cycle on a single fish host, attaching to gills or skin.

Ectoparasite: A parasite living on the external surface of its host, causing damage through attachment and feeding.

Microencapsulation: A technique for enclosing active compounds (e.g. drugs, essential oils) within biopolymer matrices to control release and improve stability.

Transcriptomic analysis: High-throughput profiling of gene expression in host tissues to reveal immune and metabolic pathways activated during infection.

Life cycle parameter: A developmental milestone or timing measure (e.g. hatching, maturation) used to model and interrupt parasite transmission.

References

1. Effects of Formulation on the Palatability and Efficacy of In-Feed Praziquantel Medications for Marine Finfish Aquaculture. Marine Drugs (2022).
2. Reared fish, farmed escapees and wild fish stocks—a triangle of pathogen transmission of concern to Mediterranean aquaculture management. Aquaculture Environment Interactions (2013).
3. Unveiling the effect of dietary essential oils supplementation in Sparus aurata gills and its efficiency against the infestation by Sparicotyle chrysophrii. Scientific Reports (2020).
4. In Vitro Testing of Alternative Synthetic and Natural Antiparasitic Compounds against the Monogenean Sparicotyle chrysophrii. Pathogens (2021).
5. A decision support tool for parasite management in fish aquaculture. Reviews in Aquaculture (2022).