Lake Sevan - Fauna

Fauna

Fish

Sevan trout (Salmo ischchan) was an endemic species of the lake, but it is endangered as some competitors were introduced into the lake, including common whitefish (Coregonus lavaretus) from Lake Ladoga, goldfish (Carrasius auratus), and crayfish (Astacus leptodactylus). If the Sevan trout is likely to become extinct in its "home" lake, it seems that it will survive in Issyk-Kul Lake (Kyrgyzstan) where it was introduced in the 1970s.

Due to anthropogenic impact, changes have occurred in all the biologycal components of the lake, including bacteria, benthos, and of course fish. Thus, the benthic mass increased 10-fold in 1940, due to oligochetes and chrinomices. Today, the former prevail and multiply the oxygen-rich residue at the bottom of the Lake.

The bojak and winter bakhtak species of the Sevan-endemic trout have already disappeared. The summer bakhtak occurs rarely; the gegharkuni is still capable of reproducing naturally. In 1980s, the quantity of Sevan koghak significantly decreased. There are numerous reasons for this:

• The level of the water lowered, the patches of rivers changed, the trout (gegharkuni and Aestivalis species) lost its natural spаwning place. Changes in the areas near the shore (mossing, disappearance of macrophyte plants) also had a negative impact on the trout lays. The trout spawns only in certain areas, where there is oxygen-rich underground water at the depth of 25–30 meters.
• Deoxidization of the bottom is extremely detrimental for salmon, which are used to more than 4 mg O2 per liter.
• In the last 10 years, poaching rapidly increased, which significantly reduced the amount of fish in the lake.

Other species

The lake is an important breeding ground for the Armenian Gull (Larus armenicus) with about 4,000–5,000 pairs. Other birds which visit the lake include Bewick's swan (Cygnus columbianus), lesser white-fronted goose (Anser erythropus), red-crested pochard (Netta rufina), ferruginous duck (Aythya nyroca) and great black-headed gull (Larus ichthyaetus). The mouflon are suffering a great population decline due to poaching and habitat loss. The Sevan trout, which made up thirty percent of the fish in Lake Sevan, have virtually disappeared. Another endangered visitor to the lake is the Armenian leopard or panther (Panthera pardus tullianus).