The powan is a kind of freshwater whitefish

Freshwater whitefish

The freshwater whitefish are fish of the subfamily Coregoninae in the salmon family Salmonidae. Along with the freshwater whitefish, the Salmonidae includes the freshwater and anadromous trout and salmon species as well as graylings...

 endemic to two lochs in Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

, Loch Lomond

Loch Lomond

Loch Lomond is a freshwater Scottish loch, lying on the Highland Boundary Fault. It is the largest lake in Great Britain by surface area. The lake contains many islands, including Inchmurrin, the largest fresh-water island in the British Isles, although the lake itself is smaller than many Irish...

 and Loch Eck

Loch Eck

Loch Eck is a loch located on the Cowal peninsula, north of Dunoon, Argyll and Bute, Scotland. It is seven miles long. Apart from Loch Lomond, it is the only naturally occurring habitat of the powan.-External links:*...

. It has been successfully introduced in two other sites, Loch Sloy

Loch Sloy

Loch Sloy was a Scottish sailing barque that operated between Great Britain and Australia from the late 19th century until 1899. Her name was drawn from Loch Sloy, a freshwater lake which lies to the north of the Burgh of Helensburgh, in the region of Argyll and Bute, Scotland.In the early hours of...

 and the Carron Valley Reservoir.

Powan populations are relatively healthy, but may have been negatively impacted by the introduced ruffe

Ruffe

The Eurasian Ruffe or simply Ruffe 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...

, which eats powan eggs and fry.As a conservation action, an attempt to establish populations in four additional lakes 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

Gwyniad

The gwyniad is a freshwater whitefish native to Bala Lake in northern Wales.The population is threatened by deteriorating water quality and by the ruffe, a fish introduced to the lake in the 1980s and now eating the eggs and fry of gwyniad...

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

Schelly

The schelly is a designation for four populations of freshwater whitefish in the English Lake District, Cumbria. The native populations of this fish inhabit the Brothers Water, Haweswater, Red Tarn and Ullswater, and occupy a total area of about 20 square kilometers...

, are generally considered belonging to the widespread Eurasian common whitefish

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 number of species in the genus Coregonus and the delimitation of the species Coregonus lavaretus.-Lavaret:In a narrow...

 (Coregonus lavaretus). This accords with the close genetic similarity among these units.
The FishBase

FishBase

FishBase is a comprehensive database of information about fish species . It is the largest and most extensively accessed online database on adult finfish on the web...

 and IUCN however classify the Scottish powan as a distinct species, Coregonus clupeoides.