golomyanka

The golomyanka, scientifically known as Comephorus baikalensis and Comephorus dybowskii, are a pair of closely related species of fish endemic to Lake Baikal in Siberia. These unique fish are renowned for their unusual biology and ecological role. Golomyankas are the only freshwater fish in the world that are viviparous, meaning they give birth to live young rather than laying eggs. They are also notable for their extremely high fat content, which can constitute up to 50% of their body weight. This high fat content makes them buoyant, and they are often found at various depths throughout the lake.

The two species, the big golomyanka (C. dybowskii) and the small golomyanka (C. baikalensis), differ primarily in size. The big golomyanka can reach lengths of up to 25 centimeters, while the small golomyanka is typically smaller, reaching around 15 centimeters. Their coloration is generally a pale, translucent pink or white. They inhabit the deep waters of Lake Baikal, with the small golomyanka preferring shallower areas and the big golomyanka found in deeper zones.

The golomyankas are a vital food source for the Baikal seal, the world's only exclusively freshwater seal species. Their high fat content makes them a calorically rich meal, essential for the seals' survival in the cold environment. Despite their abundance, golomyankas are not commercially fished due to their soft, oily flesh and rapid decomposition. Their peculiar adaptations and central position in the Baikal food web make them a fascinating subject of study in limnology and evolutionary biology.