| Sevan trout | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Salmoniformes |
| Family: | Salmonidae |
| Genus: | Salmo |
| Species: | S. ischchan |
| Binomial name | |
| Salmo ischchan Kessler, 1877 | |
TheSevan trout (Salmo ischchan) is an endemic fish species ofLake Sevan inArmenia, known asishkhan (իշխան,pronounced[iʃˈχɑn]) inArmenian. It is asalmonid fish related to thebrown trout.
The fish is endangered, because various competitors were introduced into the lake during theSoviet period, includingcommon whitefish (Coregonus lavaretus) fromLake Ladoga,goldfish (Carassius auratus) andnarrow-clawed crayfish (Astacus leptodactylus); and because of lake level change. On the other hand, the Sevan trout itself has been successfully introduced toIssyk Kul lake inKyrgyzstan.[2]
A resolution by Armenia's Council of Ministers in 1976 stopped thecommercial fishing of Sevan trout and organizedSevan National Park.[citation needed] The fish are nowadays also reared in hatcheries.[3]
The Sevan trout has four[3][2] (or two[4]) distinct strains differing in their breeding time and place, and growth rate:
The winter bakhtak is the largest form and can grow to considerable size, up to 90 cm and 15 kg. It breeds within the lake.[2] The summer bakhtak is smaller (<50 cm), and breeds naturally both in rivers and within lake near river mouths.[3] Gegharkuni is a migratory form that naturally breeds exclusively in rivers; it also feeds on plankton in addition tobenthos.[3] Bojak in turn is a dwarfed form that breeds within the lake in the winter, and does not exceed 33 cm and 0.25 kg.[2]
Water level regulation has been destructive for sevan trout reproduction. Currently, the summer bakhtak and gegharkuni are mainly propagated by hatcheries. The winter bakhtak and bojak may be extinct within the lake.[3]
From a study of historical samples, the four strains or forms were not diagnosable by theirmitochondrial DNA sequences.[5] Nevertheless, in the checklist of Armenian fish (2020) they were listed as different species.[6]
As a whole, the Sevan trout is phylogenetically very close to theCaspian trout, within thebrown trout complex.[5]
Trout and char of the world | ||
|---|---|---|
| Trout of Europe andAtlantic basin Salmo |   .png) | |
| Trout of thePacific basin Oncorhynchus | ||
| True char Salvelinus | ||
 Media related toTrout at Wikimedia Commons | ||
