| Aega psora | |
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| Dorsal and ventral views of A. psora | |
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| Species: | A. psora |
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| Aega psora | |
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Aega psora is a species of isopod crustacean that parasitises a number of fish species in the North Atlantic. It is a serious ectoparasite of larger species of fish, particularly when they are injured. [2]
Aega psora is the type species of the genus Aega and was first described by Carl Linnaeus in 1758. [1] It reaches 15 mm (0.6 in) in length and is mostly grey, with a faint dorsal stripe. [2] It has slender mandibles and maxillae adapted for sucking blood and some of the setae (bristles) are hooked. The front three pairs of pereiopods (legs) cling on to its host, it inserts its mouthparts and blood is pumped rapidly into the gut. Other adaptations for this method of feeding include strong muscles in its oesophagus and large salivary glands. [3]
Aega psora is widespread throughout the North Atlantic Ocean and has been found in the Baltic Sea, the North Sea and the Irish Sea. [4] In the northwestern Atlantic it is found between the Bay of Fundy and Cape Cod. [1]
Aega psora is a facultative parasite which temporarily attaches itself to its host and is able to survive independently. [4] It probably spends the rest of the time resting on the seabed.
It has been found as an external parasite on the Atlantic cod (Gadus morhua), [5] the Greenland shark (Somniosus microcephalus), a shark in the genus Squalus , the common skate (Raja batis), the thorny skate (Amblyraja radiata) and the barndoor skate (Dipturus laevis). [6] Large numbers have also been found in the stomach of a Greenland shark, though whether living as a parasite or as a commensal is unclear. [6] It was also found for the first time on the goldstripe sardinella (Sardinella gibbosa) off the coast of Egypt in 2007. [7]
Cod is the common name for the demersal fish genus Gadus, belonging to the 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 Gadus is commonly not called cod.
The Atlantic cod is a benthopelagic fish of the family Gadidae, widely consumed by humans. It is also commercially known as cod or codling. Dry cod may be prepared as unsalted stockfish, and as cured salt cod or clipfish.
The Greenland cod, commonly known also as ogac, is a species of ray-finned fish in the cod family, Gadidae. Genetic analysis has shown that it may be the same species as the Pacific cod. It is a bottom-dwelling fish and is found on the continental shelf in the Arctic Ocean and northwestern Atlantic Ocean, its range extending from Alaska to West Greenland, then southwards along the Canadian coast to the Gulf of St. Lawrence and Cape Breton Island. It is a commercially harvested food fish, but landings have been greatly reduced in recent years.
Gadus is a genus of demersal fish in the family Gadidae, commonly known as cod, although there are additional cod species in other genera. The best known member of the genus is the Atlantic cod.
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax.
Saduria entomon is a benthic isopod crustacean of the family Chaetiliidae. It is distributed along the coasts of the Arctic Ocean and of the northern Pacific Ocean. It is also found in the brackish Baltic Sea, where it is considered a glacial relict. Moreover, it is present in a number of North European lakes, including Ladoga, Vänern and Vättern. It has been introduced into the Black Sea.
The Gnathiidae are a family of isopod crustaceans. They occur in a wide range of depths, from the littoral zone to the deep sea. The adults are associated with sponges and may not feed. The juvenile form is known as a 'praniza', and it is a temporary parasite of marine fish. These forms are not larvae; Gnathiidae instead become parasitic during the manca stage. Mancae of the Gnathiidae closely resemble the adult form, however they lack the final pair of pereiopods.
The blacktailed spurdog is a dogfish, a member of the family Squalidae, found around New Caledonia in the central Pacific Ocean, at depths from 320 to 320 m. Its length is up to 75 cm.
The Cymothoidae are a family of isopods in the suborder Cymothoida found in both marine and freshwater environments. Cymoithoids are ectoparasites, usually of fish, and they include the bizarre "tongue-biter", which attaches to a fish's tongue, causing it to atrophy, and replaces the tongue with its own body. Ceratothoa oestroides is one of the most devastating ectoparasites in Mediterranean aquaculture. Around 40 genera and more than 380 species of cymothoid are recognised. Species of the Cymothoidae are generally found in warmer waters and rarely in the cool and cold climates.
Ceratoserolis is a genus of isopods in the family Serolidae from the Southern Ocean around Antarctica and some Sub-Antarctic Islands. They prefer to live on soft bottoms and range of least between 24 and 950 m (80–3,120 ft) in depth. They are superficially similar to the unrelated, extinct trilobites and reach up to about 8 cm (3.1 in) in length. They were once considered to be part of the genus Serolis and for a long time only Ceratoserolis trilobitoides was recognized. The validity of the other species has been disputed, but there are some morphological and genetic differences between them and C. trilobitoides, and there are indications that additional, currently unrecognized species of Ceratoserolis exist.
The Aegidae are a family of isopod crustaceans. The adults are temporary parasites of fish, feeding on their hosts' blood before dropping off to digest the meal. They differ from members of the family Cirolanidae in having only three pairs of hook-like pereiopods, whereas in Cirolanidae all seven pairs of pereiopods are hooked. The family contains the following genera:
Gnathia marleyi is a species of crustacean in the family Gnathiidae. It is named after reggae musician Bob Marley. It is a parasite that infests and feeds on the blood of such fish as the French grunt. This tiny species is only found in the Caribbean Sea. It only eats while in the juvenile stage. It can be found hiding among sea sponges, algae, and pieces of dead coral.
Aega antarctica is a species of isopod crustacean. It is a temporary ectoparasite of fish, feeding on the fish's blood and then dropping to the seabed to digest its meal over a period of several months. It is found in the seas around Antarctica.
Loma morhua, also known as Loma branchialis, is a species of microsporidian parasite, infecting fish. It forms xenoparasitic complexes of the cell-hypertrophy tumour type, and is found in the gills of the Atlantic cod Gadus morhua. It is apansporoblastic, unikaryotic, disporoblastic and undergoes partial development in parasitophorous vacuoles, while lacking plasmodial stages. It produces one or two spores in a vacuole, having tubules in the parasitophorous vacuoles.
Aega is a genus of isopods in the family Aegidae, containing the following species:
Nerocila is a genus of parasitic isopod crustaceans, with 11 species, which have been found parasitizing Indian marine fishes.
Anilocra capensis is a species of parasitic isopod in the family Cymothoidae. It is endemic to southern Africa. The species preferentially attaches itself to the hottentot seabream.
Ceratothoa oestroides is a crustacean isopod, obligate ectoparasite of marine fish that dwells in the buccal cavity. It is the causative agent of various pathologies including tissue damage at the parasitisation site (tongue), growth defects, decrease in mean host weight and size and increases mortalities in farmed and wild fish populations. It has been recorded in six different fish families: Sparidae, Carangidae, Clupeidae, Maenidae, Scorpenidae, and Mugilidae.
Ceratothoais a genus of isopod ectoparasites of teleost fish, first described by James Dwight Dana in 1852. Infection by Ceratothoa can cause anaemia, lesions, growth retardation, emaciation, and mortality in their fish hosts.