The European eel is a species of eel. They are critically endangered due to overfishing by fisheries on coasts for human consumption and parasites.
Eels are any of several long, thin, bony fishes of the order Anguilliformes. They have a catadromous life cycle, that is: at different stages of development migrating between inland waterways and the deep ocean. Because fishermen never caught anything they recognized as young eels, the life cycle of the eel was long a mystery. Of particular interest has been the search for the spawning grounds for the various species of eels, and identifying the population impacts of different stages of the life cycle.
The short-finned eel, also known as the shortfin eel, is one of the 15 species of eel in the family Anguillidae. It is native to the lakes, dams and coastal rivers of south-eastern Australia, New Zealand, and much of the South Pacific, including New Caledonia, Norfolk Island, Lord Howe Island, Tahiti, and Fiji.
The Anguillidae are a family of ray-finned fish that contains the freshwater eels. Except from the genus Neoanguilla, with the only known species Neoanguilla nepalensis from Nepal, all the extant species and six subspecies in this family are in the genus Anguilla, and are elongated fish of snake-like bodies, with long dorsal, caudal and anal fins forming a continuous fringe. They are catadromous, spending their adult lives in freshwater, but migrating to the ocean to spawn.
The pouched lamprey, also known as the piharau in the North Island, korokoro,kanakana in the South Island, or wide-mouthed lamprey, is a species in the genus Geotria, which is the only genus in the family Geotriidae. The second species in the genus is the Argentinian lamprey, which was revalidated as a separate species in 2020. The pouched lamprey is native to the southern hemisphere. It spends the early part of its life in fresh water, migrating to the sea as an adult, and returning to fresh water to spawn and die.
The New Zealand longfin eel, also known as ōrea, is a species of freshwater eel that is endemic to New Zealand. It is the largest freshwater eel in New Zealand and the only endemic species – the other eels found in New Zealand are the native shortfin eel, also found in Australia, and the naturally introduced Australian longfin eel. Longfin eels are long-lived, migrating to the Pacific Ocean near Tonga to breed at the end of their lives. They are good climbers as juveniles and so are found in streams and lakes a long way inland. An important traditional food source for Māori, who name them ōrea, longfin eel numbers are declining and they are classified as endangered, but over one hundred tonnes are still commercially fished each year.
Anguillicoloides crassus is a parasitic nematode worm that lives in the swimbladders of eels and appears to spread easily among eel populations after introduction to a body of water. It is considered to be one of the threats to the sustainability of populations of European eel. It was introduced to the European continent in the 1980s, where it was reported independently from Germany and Italy in 1982, having probably been introduced from Taiwan. It is thought to have reached England in 1987 from continental Europe. It is a natural parasite of the Japanese eel in its native range.
Paracalliopiidae is a family of amphipods, containing the following genera:
Allorchestes compressa is a species of amphipod in the family Dogielinotidae. It is found around the coast of Australia from Western Australia to Tasmania and east to Illawarra, New South Wales.
Chiltonia is a genus of amphipod crustaceans endemic to New Zealand. Four species are known, three of which live in fresh waters. They were first discovered by Charles Chilton in 1898 and the genus Chiltonia was erected the following year by T. R. R. Stebbing in Chilton's honour.
Chaetocorophium is a monotypic genus of amphipods in the family Corophiidae, containing only the species Chaetocorophium lucasi. Chaetocorophium is very closely related to Paracorophium, and some researchers propose synonymising the two genera.
Paracorophium is a genus of amphipods in the family Corophiidae.
Paracrangonyx is a genus of amphipods in the family Paracrangonyctidae, comprising two species, Paracrangonyx compactus and Paracrangonyz winterbourni.
Phreatogammarus is a genus of amphipod crustaceans that are endemic to New Zealand. It is the only genus in the family Phreatogammaridae, and contains four species, three of which were described by Charles Chilton.
Abergasilus amplexus is a species of parasitic copepod endemic to euryhaline habitats in New Zealand. It is the only known species in the genus Abergasilus.
Eels are ray-finned fish belonging to the order Anguilliformes, which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage and are usually predators.
Hedruris spinigera is a parasite belong to phylum Nematoda, commonly found in the stomach of freshwater fish. The female Hedruris spinigera attaches itself onto the epithelium of the fishes' stomach using a hook at the curved tail. Meanwhile, the male swims freely until it finds a female that has already attached to a host, then the male curls around the body of that female so that sexual reproduction occurs within the host. Most fishes consume Paracorophium excavatum, the intermediate host for Hedruris spinigera; however, the prevalences of Hedruris spinigera are restricted to certain host range.
The Pacific shortfinned eel, also known as the Pacific shortfinned freshwater eel, the short-finned eel, and the South Pacific eel, is an eel in the family Anguillidae. It was described by Albert Günther in 1871. It is a tropical, freshwater eel which is known from western New Guinea, Queensland, Australia, the Society Islands, and possibly South Africa. The eels spend most of their lives in freshwater, but migrate to the Pacific Ocean to breed. Males can reach a maximum total length of 110 centimetres, but more commonly reach a TL of around 60 cm. The Pacific shortfinned eel is most similar to Anguilla australis, and Anguilla bicolor, but can be distinguished by the number of vertebrae.
Anguillicoloides novaezelandiae is a parasitic nematode worm that lives in the swimbladders of eels, particularly Anguilla australiensis, Anguilla anguilla and Anguilla dieffenbachii. Specimens have been located in Italy and New Zealand. The species is most similar to A. Australiensis. However, it differs from the latter species in the shape of the head end which is bulbously inflated, almost spherical, and followed by a marked neck constriction in A. Australiensis, whereas it is only slightly expanded in A. novaezelandiae. Also, the anterior ovary in A. australiensis females extends anteriorly to about the mid-length of the oesophagus, while it does not reach the end of the oesophagus in A. novaezelandiae. Both species differ in size and form. While the body of A. australiensis is long and relatively slender, that of A. novaezelandiae is much shorter and wider. The shape of the posterior end of the female body is different in these two species.
Hedruris is a genus of nematodes belonging to the family Hedruridae.
