Boundaries

This ecoregion includes the Koryakiya Plateau and Northern Kamchatka, which drain to both the Sea of Okhotsk and the Bering Sea. The ecoregion extends south to include the drainages of the Voyamp’olka and Ozernaya rivers. The northern border follows the southern slopes of the Anadyrskoye Ploskogor’e Upland and northern slopes of the Koryakskiy Range, which divides the Anadyr’ and Bol’shaya drainages (in Anadyr [610]) and Koryakiya rivers. In the northwest, the border with Kolyma [609] (Omolon River headwaters) and Okhotsk Coast [614] (rivers of Gizhiginskaya Guba Bay) runs along the Kolymskiy Range and Taygonosskiy Range on the Taygonos [Tainykot] Peninsula. The southern border (with Kamchatka and Northern Kurils [613]) divides the Ozernaya and Kamchatka river drainages in the east and the Voyampolka and Tigil’ drainages in the west.

Topography

The ecoregion lies on the Koryakiya Plateau and extends from the northern part of the Sredinny (“Central”) Range on Kamchatka to the Koryak Range in the north. Elevations vary from sea level to over 3000 m.

Freshwater habitats

Rivers are generally short, with the largest basin being the Penzhina River basin. All of the rivers are mountainous in their upper reaches, and have a plain character in their lower reaches. Lakes and anabranches are numerous in the lower part of the Penzhina River floodplain.

Terrestrial habitats

Three main terrestrial ecoregions comprise Koryakiya. Bering tundra covers all of the northern half of the ecoregion. In the south Kamchatka mountain tundra and forest tundra occurs in the mountains and Kamchatka-Kurile meadows and sparse forests line the coast. The ecoregion is devoid of arboreal vegetation. Flat and low interfluvial areas are covered by huge swamps with abundant small lakes. Small islands of tundra with elevated relief (130-160 m altitude) occur among the extensive marshes.

Description of endemic fishes

The endemic Coregonus subautumnalis is a migratory char spawning in the Penzhina River. Specific data is not known.

Other noteworthy fishes

Coregonus anaulorum is a near-endemic that is distributed in the Anadyr River drainage, rivers of the Anadyr Liman, and rivers of the Sea of Okhotsk coast of Koryakia. It is a relict of the Anadyr Penzhna River system, which in the pre-Pleistocene time flowed into the Sea of Okhotsk.

Coregonus levanidovi is a near-endemic that is only distributed in some rivers of the north and northwest coasts of the Sea of Okhotsk. It is a typical migratory char that is threatened by severe overfishing in its spawning sites.

Justification for delineation

The ecoregion is intermediate between the East Siberian ecoregions (with such typical rivers as Kolyma and Anadyr) and Kamchatka, which has only one primary freshwater fish. Along the Bering Sea coast, the border is clearly defined by a lack of species such as Salvelinus taranetzi, humpback whitefish (Coregonus pidschian), and slimy sculpin (Cottus cognatus); and appearance of cherry salmon (Oncorhynchus masou), whitespotted char (S. leucomaenis), and starry flounder (Platichthys stellatus) (the latter two species also occur in rivers along the ecoregion’s Okhotsk coast). The most peculiar river is Penzhina, which supports an endemic species, Coregonus subautumnalis.

Level of taxonomic exploration

Poor