Gyrodactylus salaris

Gyrodactylus salaris

Scientific classification
Kingdom:	Animalia
Phylum:	Platyhelminthes
Class:	Monogenea
Order:	Monopisthocotylea
Family:	Gyrodactylidae
Genus:	Gyrodactylus
Species:	G. salaris
Binomial name
*Gyrodactylus salaris* Malmberg, 1957

A warning sign in Scotland

Gyrodactylus salaris is a small monogenean ectoparasite (about 0.5 mm long) which mainly lives on the skin of freshwater fish, especially Atlantic salmon. This species is a leech-like parasite that has been implicated in some diminution of Atlantic salmon populations in the Norwegian fjords.^[1] Its common name is salmon fluke.^[2] Other species that can be parasitized include rainbow trout, Arctic char, North American brook trout, grayling, North American lake trout and brown trout.^[3]

The parasite attaches to the fish by a large specialized posterior attachment organ, the haptor which has sixteen sharp hooks located around its margin. The parasite cannot be seen with the naked eye, but it can be seen with a hand held lens.^[4] When feeding, the parasite attaches its anterior end to the fish with cephalic glands. It everts its pharynx through the mouth and releases a digestive solution with proteolytic enzymes which dissolves the salmon skin. Mucus and dissolved skin are then sucked into the gut. Attachment of many parasites can cause large wounds and the epidermis of the host fish can be damaged which allows secondary infections. The parasites give birth to live young nearly as big as themselves and at this time, a further generation is already growing inside the neonates.^[3]

Catastrophic losses of Atlantic salmon occurred in Norway in the 1970s following the introduction of G. salaris. By 2001, the salmon populations of 41 Norwegian rivers had been virtually wiped out in this way.^[3]

The parasite cannot survive in the high salinity of sea water, so the infection is not spread by the migration of fish.^[2]^[3] Historically, Gyrodactylus-infected rivers have been treated with the indiscriminate pesticide/piscicide rotenone. A newer method of treatment employs dosing small volumes of aqueous aluminium and sulfuric acid into the river. A huge advantage of this method is its ability to kill the parasites without harming the hosts. This new method has shown promising results in Batnfjordelva and Lærdalselva, two rivers in Norway.

References

↑ C.Michael Hogan. 2011. Norwegian Sea. Encyclopedia of Earth. Eds. P.Saundry & C.J.Cleveland. National Council for Science and the Environment. Washington DC
1 2 Mitchin, Dan. "Gyrodactylus salaris" (PDF). DAISIE - europe-aliens.org. Retrieved 11 November 2010.
1 2 3 4 Gyrodactylus salaris, Scotland.gov, accessed 11 November 2010
↑ "Do not spread salmon parasite Gyrodactylus salaris" (PDF). Finnish Ministry of Agriculture and Forestry. Retrieved 11 November 2010.

External links

Fish diseases and parasites

Pathogens	Aeromonas salmonicida Columnaris Enteric redmouth Fin rot Fish dropsy Flavobacterium Hematopoietic necrosis Heterosigma akashiwo Hole in the head Hypodermal and hematopoietic necrosis Infectious pancreatic necrosis Koi herpes virus Mycobacterium marinum Novirhabdovirus Pfiesteria piscicida Photobacterium damselae ssp piscicida Salmon anemia Streptococcus iniae Spring viraemia of carp Taura syndrome UDN VHS White spot Yellowhead

Parasites	Abergasilus Amoebic gill disease Anisakis Carp lice Ceratomyxa shasta Clinostomum marginatum Dactylogyrus vastator Diphyllobothrium Cymothoa exigua Eustrongylidosis Epizootic ulcerative syndrome Flukes Glugea Gyrodactylus salaris Henneguya zschokkei Ich (freshwater) Ich (marine) Kudoa thyrsites Lernaeocera branchialis Microsporidia Monogenea Myxobolus cerebralis Myxosporea Nanophyetus salmincola Pseudorhabdosynochus spp. Salmon lice Saprolegnia Schistocephalus solidus Sea louse Sphaerothecum destruens Swim bladder disease Tetracapsuloides bryosalmonae Velvet Xenoma

Fish groups	Diseases and parasites in cod Diseases and parasites in salmon Disease in ornamental fish List of aquarium diseases

Related topics	Amnesic shellfish poisoning Brevetoxin Ciguatera Diarrheal shellfish poisoning Fish kill Neurotoxic shellfish poisoning Paralytic shellfish poisoning Saxitoxin

Salmon

Groups and species	Salmon Salmonidae Adriatic salmon Atlantic salmon Black Sea salmon Pacific salmon Chum salmon Chinook salmon Coho salmon Masu salmon Pink salmon Steelhead Sockeye salmon Taiwanese salmon Danube salmon Sabertooth salmon Genetically modified salmon

Fisheries and management	Aquaculture of salmon Fly fishing bibliography Environmental issues with salmon Old McKenzie Fish Hatchery Pre-spawn mortality in coho salmon Puget Sound salmon Putcher Putcher fishing Alaska salmon fishery Salmon conservation Salmon run June hogs

As food	Salmon as food Cured salmon Gravlax Lohikeitto Lomi salmon Lox Rui-be Salmon burger Salmon cannery Salmon tartare Smoked salmon Images

Diseases and parasites	Diseases and parasites in salmon Amoebic gill disease Ceratomyxa shasta Gyrodactylus salaris Henneguya zschokkei Infectious salmon anemia virus M74 syndrome Myxobolus cerebralis Nanophyetus salmincola Salmon louse Sea louse Salmon tapeworm Sphaerothecum destruens Tetracapsuloides bryosalmonae

Organisations	Atlantic Salmon Federation Cook Inlet Aquaculture Association North Atlantic Salmon Conservation Organization Pacific Salmon Commission Welsh Salmon and Trout Angling Association Wild Salmon Center Yakima Klickitat Fisheries Project

Other	Ceasg H. Forman and Son (salmon smokehouse) Salmon (color) Salmon of Knowledge Salmon Fishing in the Yemen The Salmon Fly

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