Sea louse
family of copepods
Sea lice (singular: sea louse) are copepods (small crustaceans) of the family Caligidae within the order Siphonostomatoida. They are marine ectoparasites (external parasites) that feed on the mucus, epidermal tissue, and blood of host fish. The roughly 559 species in 37 genera include around 162 Lepeophtheirus and 268 Caligus species.
The genera Lepeophtheirus and Caligus parasitize marine fish. Lepeophtheirus salmonis and various Caligus species are adapted to salt water and are major ectoparasites of farmed and wild Atlantic salmon. Several antiparasitic drugs have been developed for control purposes. L. salmonis is the best understood in the areas of its biology and interactions with its salmon host.
Caligus rogercresseyi has become a major parasite of concern on salmon farms in countries including Chile and Scotland. Studies are under way to gain a better understanding of the parasite and the host-parasite interactions. Recent evidence is also emerging that L. salmonis in the Atlantic has sufficient genetic differences from L. salmonis from the Pacific to suggest that Atlantic and Pacific L. salmonis may have independently co-evolved with Atlantic and Pacific salmonids respectively.
Begin with the source’s own compact description: “Sea louse” is family of copepods. The dossier treats that line as a proposition to test through louse, family and copepods, not as a finished interpretation.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Mar 26, 2026. The linked authority identifier is Q3808922. The Library of Congress control number is sh87020532. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank.
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This entry incorporates text from “Sea louse” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.