Cod worm
| Lernaeocera branchialis | |
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| The gills of a whiting infested by two blood-sucking Lernaeocera branchialis | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Maxillopoda |
| Subclass: | Copepoda |
| Order: | Siphonostomatoida |
| Family: | Pennellidae |
| Genus: | Lernaeocera |
| Species: | L. branchialis |
| Binomial name | |
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Lernaeocera branchialis (Linnaeus, 1767) |
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| Synonyms | |
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Lernaeocera branchialis, sometimes called cod worm, is a parasite of marine fish, found mainly in the North Atlantic. It is a marine copepod which starts life as a small pelagic crustacean larvae. It is among the largest of copepods, ranging in size from 2–3 millimetres when it matures as a copepodid larva to more than 40 millimetres (1.6 in) as an adult.
Lernaeocera branchialis is ectoparasitic, which means it is a parasite that lives primarily on the surface of its hosts. It has many life stages, some of which are motile and some of which are sessile. It goes through two parasitic stages, one where it parasites as a secondary host a flounder or lumpsucker, and another stage where it parasites as a primary host a cod or other fishes of the cod family (gadoids). It is a pathogen that negatively impacts the commercial fishing and mariculture of cod-like fish.
The life-cycle of a cod worm involves a complex progression of life stages, including two successive hosts. It comprises "two free-swimming nauplius stages, one infective copepodid stage, four chalimus stages and the adult copepod, each separated by a moult".
The cycle begins with the females laying eggs which hatch into a nauplius, the usual early larval stage of crustaceans. This nauplius moults about 10 minutes after hatching to produce nauplius II, and 48 hours later, nauplius II moults to a copepodid stage. At this point the copepodid is pelagic and free-swimming with an average length of about 0.5 mm.
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Wikipedia