Parasitology of Marine Fish Species

Marine fish harbour a remarkable diversity of parasitic organisms, spanning protozoa, helminths (cestodes, trematodes and nematodes) and crustaceans. These parasites complete complex life cycles involving multiple hosts, from invertebrate first intermediates to fish as second intermediates or definitive hosts, and in some cases marine mammals or birds as final hosts. Environmental change, globalised seafood trade and intensification of aquaculture have altered parasite prevalence and distribution, with some species emerging in previously unaffected regions. Parasites influence fish health, growth and survival, with direct effects on wild populations and farmed stocks alike. Many fish-borne parasites pose zoonotic risks when infective stages survive processing or enter the human food chain, provoking gastrointestinal or allergic reactions. Advances in molecular diagnostics, ecological modelling and targeted control strategies—such as selective breeding for resistance and novel processing technologies—have improved our capacity to detect, monitor and mitigate parasitic threats. Understanding host–parasite dynamics in marine ecosystems is essential for sustainable fisheries, food safety and the preservation of aquatic biodiversity.

Research from Nature Portfolio

Recent studies have applied quantitative risk assessment models to anisakid infections in commercially important fish products. One seminal analysis developed a probabilistic framework for the anchovy value chain, integrating fishery landings, infection rates and consumption patterns to estimate human anisakiasis burden. This work revealed that post-harvest migration of nematode larvae from viscera to flesh can multiply disease risk and demonstrated that simple freezing protocols could reduce annual cases by up to eighty per cent. These outcomes inform policy interventions, drive consumer education and underpin improved industry guidelines for parasite control.

Parasitology of Marine Fish Species publication trend

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

Technical terms

Anisakiasis: Human disease caused by ingestion of live anisakid nematode larvae from infected fish or seafood.

Definitive host: Organism in which a parasite reaches sexual maturity and reproduces.

Intermediate host: Organism that supports the developmental stages of a parasite but does not allow it to mature sexually.

Paratenic host: Transport host in which a parasite remains viable without further development, awaiting transmission to the definitive host.

Quantitative risk assessment: Probabilistic modelling approach to estimate likelihood and severity of adverse outcomes in public health or food safety contexts.

Pulsed electric fields (PEF): Non-thermal processing technology using short bursts of high voltage to inactivate microorganisms or parasites in food matrices.

References

1. Assessing the risk of an emerging zoonosis of worldwide concern: anisakiasis. Scientific Reports (2017).
2. Dependence of anisakid larva inactivation by pulsed power on various parameters. Journal of Food Engineering (2024).
3. Evaluation of Pulsed Electric Fields (PEF) Parameters in the Inactivation of Anisakis Larvae in Saline Solution and Hake Meat. Foods (2023).
4. Effects of anisakid nematodes Anisakis simplex (s.l.), Pseudoterranova decipiens (s.l.) and Contracaecum osculatum (s.l.) on fish and consumer health. Food and Waterborne Parasitology (2016).