The powan (''Coregonus clupeoides'') is a kind of

freshwater whitefish The freshwater whitefish are fishes of the subfamily Coregoninae, which contains whitefishes (both freshwater and anadromous) and ciscoes, and is one of three subfamilies in the salmon family Salmonidae. Apart from the subfamily Coregoninae, ...

endemic to two lochs in

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

Loch Lomond Loch Lomond (; ) is a freshwater Scottish loch which crosses the Highland Boundary Fault (HBF), often considered the boundary between the lowlands of Central Scotland and the Highlands.Tom Weir. ''The Scottish Lochs''. pp. 33-43. Published by ...

and

Loch Eck Loch Eck (Gaelic: ''Loch Eich'') is a freshwater loch located on the Cowal Peninsula, north of Dunoon, in Argyll and Bute, west of Scotland. It is long. It is oriented in a north-south direction. Its main inflow, at the northern end, is the ...

. It has been successfully introduced in two other sites, Loch Sloy and the Carron Valley Reservoir. Powan populations are relatively healthy, but may have been negatively impacted by the introduced

ruffe The ruffe (''Gymnocephalus cernua''), 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 as an invasive species ...

, which eats powan eggs and fry. As a conservation action, an attempt to establish populations in four additional lochs has been undertaken. The taxonomic status of the British whitefish populations, including powan, is a matter of debate. Currently the Scottish powan, along with the Welsh

gwyniad The gwyniad (''Coregonus pennantii''), or Welsh whitefish, is a species of freshwater Actinopterygii, ray-finned fish belonging to the Family (biology), family Salmonidae, which includes the salmon, trouts and related fishes. This species is End ...

known from a single lake, and four similar populations in England known as

schelly The schelly (''Coregonus stigmaticus'') 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 t ...

, are generally considered belonging to the widespread Eurasian

common whitefish ''Coregonus lavaretus'' is a species of freshwater whitefish, in the family Salmonidae. It is the type species of its genus ''Coregonus''. There are widely different concepts about the delimitation of the species ''Coregonus lavaretus'' and abou ...

(''Coregonus lavaretus''). This accords with the close genetic similarity among these units, and the absence of clear morphological differences between them.

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

and the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

continue to recognize the Scottish powan as a distinct species, ''Coregonus clupeoides''.

Ecology

This fish is

benthopelagic The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

, 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 The brown trout (''Salmo trutta'') is a species of salmonid ray-finned fish and the most widely distributed species of the genus ''Salmo'', endemic to most of Europe, West Asia and parts of North Africa, and has been widely introduced globally ...

(''Salmo trutta''),

common roach The roach, or rutilus roach (''Rutilus rutilus''), also known as the common roach, is a fresh- and brackish-water fish of the family Cyprinidae, native to most of Europe and western Asia. Fish called roach can be any species of the genera ''Rut ...

(''Rutilus rutilus''), other powan and ''

Phryganea ''Phryganea'' is a genus of giant caddisflies in the family Phryganeidae. Species in the genus are found throughout the northern hemisphere (especially Europe and Asia), of which about 13 are found in N. America. Species The Global Biodi ...

'' larvae, and the adult powan are heavily predated by the

northern pike The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (pikes). They are commonly found in brackish water, moderately salty and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). T ...

(''Esox lucius'') at breeding time.

References

External links

* {{Taxonbar, from=Q2705955 Coregonus Freshwater fish of Europe Fish described in 1803 Endemic fauna of Scotland Cowal