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''An Introduction to Parasitology''
Page 73–74. Cambridge University Press. . The female worm, with her now-fertilized eggs, then finds a cod, or a cod-like fish, such as a haddock or whiting. There, the worm clings to the
Atlantic cod act as intermediate, paratenic, or definitive hosts to a large number of parasite species; 107 taxa are listed by Hemmingsen and MacKenzie (2001)Perdiguero-Alonso D., Montero F. E., Raga J. A. & Kostadinova A. (2008). "Composition and structure of the parasite faunas of cod, ''Gadus morhua'' L. (Teleostei: Gadidae), in the North East Atlantic". '' Parasites & Vectors'' 1: 23. with seven new records by Perdiguero-Alonso ''et al.'' (2008). The predominant groups of cod parasites in the northeast Atlantic were trematodes (19 species) and nematodes (13 species), including larval anisakids, which comprised 58.2% of the total number of individuals. Parasites of Atlantic cod include copepods, digeneans, monogeneans, acanthocephalans, cestodes, nematodes, myxozoans and protozoans:
Monogenea
* '' Diclidophora merlangi''
Cod
Cod (: cod) is the common name for the demersal fish genus ''Gadus'', belonging to the family (biology), family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gad ...
and related species in the family Gadidae are susceptible to a variety of diseases and parasites.
''Laenaeocera branchialis''
'' Lernaeocera branchialis'', the "cod worm", is acopepod
Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...
that infects gadoids. The first host used by cod worm is a flatfish
A flatfish is a member of the Ray-finned fish, ray-finned demersal fish Order (biology), suborder Pleuronectoidei, also called the Heterosomata. In many species, both eyes lie on one side of the head, one or the other migrating through or around ...
or lumpsucker, which it captures with grasping hooks at the front of its body. It penetrates the lumpsucker with a thin filament, which it uses to suck the host's blood. The nourished cod worm then mates with another one on the lumpsucker.Matthews B (1998''An Introduction to Parasitology''
Page 73–74. Cambridge University Press. . The female worm, with her now-fertilized eggs, then finds a cod, or a cod-like fish, such as a haddock or whiting. There, the worm clings to the
gill
A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...
s while it metamorphoses into a plump, sinusoidal, worm-like body, with a coiled mass of egg strings at the rear. The front part of the worm's body penetrates the body of the cod until it enters the rear bulb of the host's heart
The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...
. There, firmly rooted in the cod's circulatory system, the front part of the parasite develops like the branches of a tree, reaching into the main artery
An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...
. In this way, the worm extracts nutrients from the cod's blood, remaining safely tucked beneath the cod's gill cover until it releases a new generation of offspring into the water.
Parasites of Atlantic cod
Atlantic cod act as intermediate, paratenic, or definitive hosts to a large number of parasite species; 107 taxa are listed by Hemmingsen and MacKenzie (2001)Perdiguero-Alonso D., Montero F. E., Raga J. A. & Kostadinova A. (2008). "Composition and structure of the parasite faunas of cod, ''Gadus morhua'' L. (Teleostei: Gadidae), in the North East Atlantic". '' Parasites & Vectors'' 1: 23. with seven new records by Perdiguero-Alonso ''et al.'' (2008). The predominant groups of cod parasites in the northeast Atlantic were trematodes (19 species) and nematodes (13 species), including larval anisakids, which comprised 58.2% of the total number of individuals. Parasites of Atlantic cod include copepods, digeneans, monogeneans, acanthocephalans, cestodes, nematodes, myxozoans and protozoans:
Monogenea
* '' Diclidophora merlangi''
Trematoda
Trematoda is a class of flatworms known as trematodes, and commonly as flukes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is a mol ...
– metacercariae
* Bucephalinae gen. sp.
* '' Cryptocotyle lingua''
* '' Otodistomum'' sp.
* '' Prosorynchoides gracilescens''
* '' Prosorhynchus crucibulum''
* '' Rhipidocotyle'' sp.
Trematoda – adult
* '' Derogenes varicus''
* '' Fellodistomum'' sp.
* '' Gonocerca phycidis''
* '' Hemiurus communis''
* '' Hemiurus levinseni''
* '' Hemiurus luehei''
* '' Lecithaster'' sp. ?''gibbosus''
* '' Lepidapedon elongatum''
* '' Lepidapedon rachion''
* '' Opechona bacillaris''
* '' Podocotyle reflexa''
* '' Stephanostomum'' spp.
* '' Steringotrema'' sp.
Cestoda – larval forms
* '' Grillotia'' sp.
* '' Hepatoxylon'' sp.
* '' Lacistorhynchus'' sp.
* '' Scolex pleuronectis''
* Pseudophyllidea fam. gen. sp.
* '' Schistocephalus gasterostei''
* Trypanorhyncha fam. gen. sp.
* Unidentified plerocercoids
Cestoda – adult
* '' Abothrium gadi''
Nematoda
The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitism, parasitic. Parasitic ...
– larval forms
* '' Anisakis simplex'' (s.l.)
* '' Contracaecum osculatum'' (s.l.)
* '' Hysterothylacium aduncum''
* '' Hysterothylacium rigidum''
* '' Pseudoterranova decipiens'' (s.l.)
* '' Rhapidascaris'' sp.
Nematoda – adults
* '' Ascarophis morrhuae''
* '' Ascarophis crassicollis''
* '' Ascarophis filiformis''
* '' Capillaria gracilis''
* '' Cucullanus cirratus''
* '' Cucullanus'' sp.
* '' Hysterothylacium aduncum''
* '' Spinitectus'' sp.
Acanthocephala – post-cystacanths
* '' Corynosoma semerme''
* '' Corynosoma strumosum''
Acanthocephala – adults
* '' Echinorhynchus gadi'' (s.l.)
Hirudinea – adults
* '' Calliobdella nodulifera''
* '' Johanssonia arctica''
Copepoda - larval forms
* '' Caligus'' sp. copepodite
* Copepoda fam. gen. sp. copepodite
Copepoda – adults
* '' Acanthochondria soleae''
* '' Caligus curtus''
* '' Caligus diaphanus''
* '' Caligus elongatus''
* '' Chondracanthus ornatus''
* '' Clavella adunca''
* '' Holobomolochus confusus''
* '' Lernaeocera branchialis''
Amphipoda
Amphipoda () is an order (biology), order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods () range in size from and are mostly detritivores or scavengers. There are more than 10,700 amphip ...
* '' Lafystius sturionis''
Isopoda
* '' Gnathia elongata'' (praniza larva)
References
This article incorporates CC-BY-2.0 text from the reference: Perdiguero-Alonso D., Montero F. E., Raga J. A. & Kostadinova A. (2008). "Composition and structure of the parasite faunas of cod, ''Gadus morhua'' L. (Teleostei: Gadidae), in the North East Atlantic". '' Parasites & Vectors'' 2008, 1: 23. doi:10.1186/1756-3305-1-23Further reading
* * * {{fish disease topics Fish diseases Gadidae