Powan | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Salmoniformes |
Family: | Salmonidae |
Genus: | Coregonus |
Species: | C. clupeoides |
Binomial name | |
Coregonus clupeoides Lacépède, 1803 | |
Synonyms [2] | |
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The powan (Coregonus clupeoides) is a kind of freshwater whitefish endemic to two lochs in Scotland, Loch Lomond and Loch Eck. [1] It has been successfully introduced in two other sites, Loch Sloy and the Carron Valley Reservoir. [3]
Powan populations are relatively healthy, [1] but may have been negatively impacted by the introduced ruffe, which eats powan eggs and fry. As a conservation action, an attempt to establish populations in four additional lochs has been undertaken. [4] [5]
The taxonomic status of the British whitefish populations, including powan, is a matter of debate. Currently the Scottish powan, along with the Welsh gwyniad known from a single lake, and four similar populations in England known as schelly, are generally considered belonging to the widespread Eurasian common whitefish (Coregonus lavaretus). [3] [6] This accords with the close genetic similarity among these units, [7] and the absence of clear morphological differences between them. [8] FishBase and the IUCN continue to recognize the Scottish powan as a distinct species, Coregonus clupeoides. [1] [9]
This fish is benthopelagic, feeding on the lakebed on insect larvae and crustaceans. In Loch Lomond, this fish exhibits a pattern of daily migration to feeding sites and of seasonal migration to breeding grounds. Before the breeding season, the mature males begin to congregate in deep water near the spawning beds; these are shallow areas of gravel and pebbles washed by waves. In late December and January they move into the shallows where they are joined by the ripe females, and spawning is completed by early February, after which the fish disperse to other parts of the loch. The eggs are eaten by brown trout (Salmo trutta), common roach (Rutilus rutilus), other powan and Phryganea larvae, and the adult powan are heavily predated by the northern pike (Esox lucius) at breeding time. [10]
Coregonus is a diverse genus of fish in the salmon family (Salmonidae). The Coregonus species are known as whitefishes. The genus contains at least 68 described extant taxa, but the true number of species is a matter of debate. The type species of the genus is Coregonus lavaretus.
Coregonus lavaretus is a species of freshwater whitefish, in the family Salmonidae. It is the type species of its genus Coregonus.
The ruffe, also known as the Eurasian ruffe or pope, is a freshwater fish found in temperate regions of Europe and northern Asia. It has been introduced into the Great Lakes of North America, reportedly with unfortunate results, as it is invasive and is reproducing faster than other species. Its common names are ambiguous – "ruffe" may refer to any local member of its genus Gymnocephalus, which as a whole is native to Eurasia.
The ciscoes are salmonid fish that differ from other members of the genus Coregonus in having upper and lower jaws of approximately equal length and high gill raker counts. These species have been the focus of much study recently, as researchers have sought to determine the relationships among species that appear to have evolved very recently. The term cisco is also specifically used of the North American species Coregonus artedi, also known as lake herring.
The gwyniad is a freshwater whitefish native to Bala Lake in northern Wales.
The shortnose cisco is a North American freshwater whitefish in the salmon family Salmonidae. One of the members of the broader Coregonus artedi species complex of ciscoes, it is native to the Great Lakes of Canada and the United States. Its population has been declining and it has disappeared from some of its earlier haunts. The last reported population was restricted to Georgian Bay off Lake Huron in Canada. It is thought that declines in the population of this fish may be linked with the arrival of the sea lamprey, in the Great Lakes. The International Union for Conservation of Nature has rated the conservation status of this fish as "critically endangered", and possibly extinct.
The pollan or Irish pollan is a freshwater whitefish known only from five Irish lakes, Lough Neagh, Lower Lough Erne, Lough Ree, Lough Derg and Lough Allen. The pollan faces competition from introduced species such as pike, roach and zebra mussel, and the populations rely on restocking for survival.
Coregonus albula, known as the vendace or as the European cisco, is a species of freshwater whitefish in the family Salmonidae. It is found in lakes in northern Europe, especially Finland, Latvia, Lithuania, Sweden, Russia and Estonia, and in some lakes of Norway, the United Kingdom, northern Germany, and Poland. It is also found in diluted brackish water in the Gulfs of Finland and Bothnia, both of which are in the Baltic Sea.
The broad whitefish is a freshwater whitefish species. Dark silvery in colour, and like a herring in its shape. Its distinctive features includes: a convex head, short gill rakers, and a mild overbite. It is found in the Arctic-draining streams, lakes, and rivers of far eastern Russia and North America. Its prey includes larval insects, snails, and shellfish. It is eaten by humans and brown bears.
The schelly is a living fresh water fish of the salmon family, endemic to four lakes in the Lake District, England. Its taxonomy is disputed with some recognizing it as a distinct species and others as a variant of the widespread Eurasian whitefish species Coregonus lavaretus. It is present in Brothers Water, Haweswater, Red Tarn and Ullswater, and the population seems stable in all of these except for Haweswater where it seems to be declining. The main threats it faces are seen to be water abstraction and cormorants, and the fish-eating birds are being culled from Haweswater. The International Union for Conservation of Nature has rated the conservation status of this fish as "endangered".
Coregonus vandesius, the vendace, is a freshwater whitefish found in the United Kingdom. Population surveys since the 1960s have revealed a steady decline and the fish is no longer present in some of its previous haunts but is still present in Bassenthwaite Lake and Derwent Water. The main threats it faces are eutrophication and the introduction of alien species of fish which eat its eggs and fry. The International Union for Conservation of Nature has rated its conservation status as "endangered".
The Atlantic whitefish is a coregonine fish inhabiting some freshwater lakes within Nova Scotia, Canada. It is known to survive only in the Petite Rivière watershed as landlocked populations. Earlier it was also found in the Tusket and Annis rivers of Nova Scotia. Those populations were anadromous, migrating to the estuary to feed while breeding in freshwater.
The freshwater whitefish are fishes of the subfamily Coregoninae, which contains whitefishes and ciscoes, and is one of three subfamilies in the salmon family Salmonidae. Apart from the subfamily Coregoninae, the family Salmonidae includes the salmon, trout, and char species of the subfamily Salmoninae, and grayling species of the subfamily Thymallinae. Freshwater whitefish are distributed mainly in relatively cool waters throughout the northern parts of the Northern Hemisphere.
The gravenche, also known as the Lake Geneva whitefish or the little fera, is a presumably extinct freshwater fish from Lake Geneva in Switzerland and France.
Coregonus fera, commonly called the true fera, is a presumed extinct freshwater fish from Lake Geneva in Switzerland and France.
Loch Eck is a freshwater loch located on the Cowal Peninsula, north of Dunoon, in Argyll and Bute, west of Scotland. It is seven miles long. It is oriented in a north-south direction. Its main inflow, at the northern end, is the River Cur, and its main outflow, at the southern end, is the River Eachaig, which meanders somewhat within the confines of the broad strath before flowing into the head of Holy Loch, about 5 km further south.
Coregonus bavaricus, the Ammersee kilch, is a species of freshwater whitefish endemic to Lake Ammersee in the German state of Upper Bavaria. A small, silver-colored fish, it typically lives between 60–85 m (197–279 ft) deep, though shallower in the summer months. In the early 20th century the Ammersee kilch was an important commercial species, but its population declined drastically in the 1930s onward due to overfishing and eutrophication of the only lake in which it is found. Today it is listed as Critically Endangered by the International Union for Conservation of Nature (IUCN) and may be on the verge of extinction.
Coregonus maraena, referred to in English as the maraene, maraena whitefish, vendace, cisco, lake herring, lake whitefish or the whitefish, is a whitefish of the family Salmonidae that occurs in the Baltic Sea basin - in the sea itself and the inflowing rivers, and in several lakes as landlocked populations. It is found in Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Netherlands, Norway, Poland, Slovakia, Russia and Sweden. As of 2013, it has been listed as a vulnerable species by the IUCN and as endangered by HELCOM. It is an extremely important fish within the Baltic Sea ecosystem, both for population equilibrium and for the local diets of the surrounding human population. Due to a variety of factors, mostly overfishing, the maraena's population dwindled to near-extinction levels. Thus, rampant repopulation was enacted to preserve this important fish.
The Peipsi whitefish is a freshwater whitefish of the family Salmonidae that naturally occurs in Lake Peipus on the border of Estonia and Russia, from where it also ascends to Lake Võrtsjärv to spawn. It has been introduced in Lake Burtnieks (Latvia), Gulf of Riga, many lakes of northern Russia, Poland, Germany, Netherlands, Japan, Lake Sevan (Armenia) and Balkash (Kazakhstan). It is a benthopelagic fish up to 60 cm long.
Coregonus widegreni, also called the Valaam whitefish, is a putative species of freshwater whitefish, a part of the common whitefish complex from Northern Europe. It is a demersal form of freshwater whitefish that feeds on benthic invertebrates. It spawns in late autumn, and can reach a length of 55 cm maximum. It is characterized by a low gill raker density.