Kronotskoye Lake

Kronotskoye Lake. Kronotskoye Lake is the largest freshwater lake (242 km2) and drainage basin (2,330 km2) on Kamchatka; it is the second largest in terms of water volume (12.4 km3) and the third deepest on Kamchatka. It has a maximum depth of 48 meters, and a mean depth of 51 m.  

The first information on the lake and its environs was recorded by S.P. Krasheninnikov (based on surveys). The first researchers on the lake were members of P.Yu. Schmidt’s expedition.  

Kronotskoye Lake was formed after the ancient Paleokronotskaya River was dammed by a massive (200 m) lava flow and pyroclastic sediments from eruptions of the Kronotsky and Krasheninnikov volcanos. The mountain watershed was formed in the late Pleistocene at the base of one of the most beautiful volcanoes in the world — the Kronotsky Volcano. The altitude of the lake’s surface is 372 meters above sea level.  

The lake is also unique because of the natural ecosystems within its watershed. A population of kokanee (a freshwater form of the sockeye) with about 30 million fish evolved here from anadromous sockeye as a result of long-term isolation. For the same reason, a group of char with three different types also evolved; at least one of them is believed to be a separate species which diverged from the others due to adaptation and specialization. Mechanisms of speciation in this closed ecosystem warrant close attention of geneticists and fish biologists.  

Eleven picturesque islands rise 25–50 meters above the lake-mirror in the eastern part of the lake. They were all named for members of the Kamchatka Complex Expedition of F.P. Ryabushinsky’s Russian Royal Geographical Society — Komarov Island, Konrad Island, Baer Island, etc.  

Colonies of slaty-backed gulls (numbering about 600 pairs) nest on the islands, 34–40 km from the sea coast. Such abundant breeding sites of this species, situated this far away from the coast, are found elsewhere on Kamchatka only on Kuril and Azabachye lakes. Bears swim to the islands to feast on the gull’s eggs, at times even reaching the distant Baer Island.  

The lake freezes over from late December to mid-May. The thickness of the ice sheet reaches one meter. 

The Kronotskaya River is the only outflow from the lake. The first 12 kilometers are characterized by massive rapids, which block entry for salmon to the lake. However, a few freshwater and anadromous dolly vardens ascend to the upper reaches of the river to spawn each year. Surprisingly, KamchatNIRO fish biologists also noted several cases of Coho salmon reaching the lake. 

The ecosystem of the Kronotskoye Lake basin is of special significance. It is here that a Kamchatka larch forest thrives with small groups or — more often — individual specimens of Jezo spruce.  

Nesting sites of osprey and Steller’s sea eagle have been found in the larch forest. In the mountains surrounding the lake, nests of peregrine falcon have been observed, as well as, possibly, those of gyrfalcon and golden eagle. 

Swans are an irreplaceable adornment and symbol of the lake. In summer, these wary and beautiful birds are unobtrusive — in the huge basin of the lake, there are only 2–4 places that these capricious birds choose for nesting. But in late autumn, numerous birds fly here from the north. Year after year, they overnight in the headwaters of the Kronotskaya River, on unfrozen patches of water. At first the birds were concerned about the human activity at the reserve ranger station, located only 200 m from their daily resting spot, but in winter they get used to it and become completely trusting.  

In sum, the ecosystems of Kronotskoye Lake are worthy of special protection and further scientific study.