Sterlet

The sterlet (Acipenser ruthenus), a small sturgeon species native to Eurasia, inhabits large rivers flowing into the Black Sea, Azov Sea, Caspian Sea, and Siberia as far east as the Yenisei River. Once anadromous populations existed but have since been extirpated. Overfishing for its meat, caviar, and isinglass; pollution; and dams have led to a decline in populations, making it vulnerable according to the IUCN. Restocking efforts are ongoing, though introduced populations rarely sustain themselves.

The sterlet typically weighs up to 16 kg and measures between 100-125 cm, with rare individuals exceeding 90 cm. Its coloration is variable but often features a yellowish underside. It is distinguished by numerous whitish lateral scutes, fringed barbels, and an elongated, narrow snout.

Feeding primarily on benthic organisms such as crustaceans, worms, and insect larvae, the sterlet requires large ponds with good water quality and may entangle in aquatic plants like blanketweed. In captivity, it often needs specialized feed, such as sterlet sticks, due to its inability to digest typical commercial fish food.

In Russia, the sterlet is valued for its high-quality meat, contributing to premium caviar and isinglass production. Once prevalent in the Middle and Upper Danube River, its population has significantly declined due to habitat degradation, affecting spawning and foraging grounds.