Lernaeocera branchialis
| Lernaeocera branchialis | |
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| The gills of a whiting infested by two blood-sucking Lernaeocera branchialis
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Copepoda |
| Order: | Siphonostomatoida |
| Family: | Pennellidae |
| Genus: | Lernaeocera |
| Species: | L. branchialis
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| Binomial name | |
| Lernaeocera branchialis | |
| Synonyms[1] | |
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Lernaeocera branchialis, sometimes called cod worm, is a
Lernaeocera branchialis is
of cod-like fish.Life stages
The life-cycle of a cod worm involves a complex progression of life stages, including two successive hosts. It comprises "two free-swimming
The cycle begins with the females laying eggs which hatch into a
The next stage is finding a secondary or
When they locate such a fish, they capture it with grasping hooks at the front of their body. They penetrate the fish with a thin filament which they use to suck its blood. The nourished cod worms then progress via four moults from the naupliar stage to the mature chalimus stage. At this point the males transfer sperm to the females. Both sexes develop swimming setae, detach from the flounder or lumpfish and again swim freely as pelagic organisms.[4][5]
The female cod worm still resembles a copepod and is 2 to 3 mm long. Females undergo another pelagic quest, searching this time for a definitive or
When a suitable definite host is located, females enter the gill chamber. There, while attached to a gill, the female develops a plump, sinusoidal, worm-like body, with a coiled mass of egg strings at the posterior end.[4] Females now measure about 20 mm long, but can grow up to 50 mm.[6] The oral end of the female copepod penetrates the body of the cod until it enters the rear bulb of the host's heart. There, firmly rooted in the cod's circulatory system, the front part of the parasite develops in the shape of antlers or branches on a tree, reaching into the main artery. In this way, while safely tucked beneath the cod's gill cover, the female's deeply embedded oral end can feed on blood while eggs develop and are released into the water column from the posterior end.[4][5]
Behaviour
It is not known how L. branchialis searches for its fish hosts, but it probably uses chemoreceptors and mechanoreceptors, and follows physical clues in the water column such as those provided by haloclines and thermoclines.[3]
Effects on fisheries
The most serious parasitic crustaceans among fish in general are
References
- ^ Geoff Boxshall (2011). T. Chad Walter & Geoff Boxshall (ed.). "Lernaeocera branchialis (Linnaeus, 1767)". World Copepoda database. World Register of Marine Species. Retrieved March 11, 2011.
- .
- ^ a b c Adam Jonathan Brooker (2007). Aspects of the biology and behaviour of Lernaeocera branchialis (Linnaeus, 1767) (Copepoda : Pennellidae) (PDF) (PhD thesis). University of Stirling.[permanent dead link]
- ^ ISBN 978-0-521-57691-8.
- ^ ISBN 978-0-313-33922-6.
- ISBN 978-0-903874-05-2.
- ^ PMID 10456421. Archived from the original(PDF) on 2011-07-18.
- ISBN 978-0-85198-845-0.
- ISBN 0-9546490-8-7
Further reading
- Adam J. Brooker, Andrew P. Shinn & James E. Bron (2007). "A review of the biology of the parasitic copepod Lernaeocera branchialis (L., 1767) (Copepoda: Pennellidae)". PMID 18063099.
- Larry S. Roberts, John Janovy & Gerald D. Schmidt (2009). Foundations of Parasitology (8th ed.). ISBN 978-0-07-128458-5.
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