Parasitic Copepoda in Marine Fish Systems

Parasitic copepods represent a diverse assemblage of crustaceans that colonise marine teleosts and elasmobranchs worldwide. Among these, the sea lice (family Caligidae) and related siphonostomatoid lineages deploy specialised mouthparts and adhesive structures to attach to skin, gills or buccal cavities, where they feed on blood, mucus and epithelial tissues. Their lifecycles typically comprise two free-swimming naupliar stages, an infective copepodid that locates a host, immobilised chalimus stages and free-moving pre-adult and adult phases. Host specificity ranges from highly selective to broadly generalist, influencing parasite dispersal patterns and the risk of epizootics in both wild and cultured stocks. Infection can provoke osmoregulatory disruption, epidermal damage and secondary bacterial invasion, with consequent economic losses in aquaculture and ecological impacts on wild populations. Advances in molecular phylogenetics have begun to resolve relationships among genera such as Caligus, Lepeophtheirus and Bomolochus, while experimental studies illuminate host immune responses and environmental drivers of infestation intensity. Integrated management strategies now draw on precision farming, targeted therapeutic treatments and predictive modelling of parasite population dynamics under changing oceanic conditions.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Parasitic Copepoda in Marine Fish Systems publication trend

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

Technical terms

Copepodid: Infective post-naupliar stage of a copepod that seeks a host for attachment.

Chalimus: Immobilised developmental stage of parasitic caligids, characterised by a frontal filament attaching it to the host.

Caligidae: Family of parasitic copepods commonly known as sea lice, of major significance in wild and farmed fish.

Siphonostomatoida: Order of copepods distinguished by a specialised oral siphon adapted for feeding on host tissues and fluids.

References

1. The caligid life cycle: new evidence from Lepeophtheirus elegans reconciles the cycles of Caligus and Lepeophtheirus (Copepoda: Caligidae). Parasite (2013).
2. Discovery of the fish host of the ‘planktonic’ caligid Caligus undulatus Shen & Li, 1959 (Crustacea: Copepoda: Siphonostomatoida). Biodiversity Data Journal (2020).
3. Sea lice (Copepoda: Caligidae) from South Africa, with descriptions of two new species of Caligus. Systematic Parasitology (2021).
4. A new parasitic copepod (Copepoda; Cyclopoida; Chondracanthidae) from two pomacentrid fishes caught on the Great Barrier Reef, Queensland, Australia. Systematic Parasitology (2022).