Sterlet
A small Eurasian sturgeon found in rivers flowing to the Black, Azov, and Caspian seas.
The sterlet is a small sturgeon native to large Eurasian river systems. It faces threats from overfishing and habitat loss, leading to its endangered status despite ongoing conservation efforts.
- Reaches up to 125 cm in length and 16 kg in weight.
- Native to rivers flowing into the Black, Azov, and Caspian Seas.
- Spawns between April and June at water temperatures of 12–17 °C.
- Listed as Endangered by the IUCN due to overfishing and habitat loss.
- Most international trade now comes from aquaculture sources.
What it is
The sterlet belongs to the sturgeon group and represents one of the smaller members of this ancient lineage. Adults typically measure between 90 and 125 centimetres in length, with a maximum recorded weight of 16 kilograms. The body exhibits variable colouration, though a yellowish underside is common. Key physical identifiers include a narrow, elongated snout that varies in length, fringed barbels near the mouth, and numerous whitish lateral scutes along the sides. These features help distinguish it from other European sturgeon species. It is classified within the genus Huso, having been moved from Acipenser due to taxonomic revisions highlighting paraphyletic relationships.
Where it lives
This species originates from Eurasia, inhabiting large river systems that empty into the Black Sea, the Azov Sea, and the Caspian Sea. Its range extends eastward into Siberia, reaching as far as the Yenisei River. Historically, some populations were anadromous, migrating between fresh and salt water. However, these migratory groups have been extirpated from most areas. While introduced to regions outside its native range, these populations rarely become self-sustaining. The fish relies on specific riverine habitats for survival, making it vulnerable to changes in water flow and quality.
How it lives
Sterlets feed primarily on benthic organisms found at the bottom of water bodies. Their diet consists mainly of crustaceans, worms, and insect larvae. They can live for 22 to 25 years. Sexual maturity is reached relatively early, with males maturing between three and seven years of age, and females between four and twelve years. In captivity, they require large ponds with excellent water conditions. They may struggle with commercial fish foods containing vegetable proteins and sometimes need specialized diets like sterlet sticks to avoid digestive issues or entanglement in plants like blanketweed.
Breeding and life cycle
Spawning takes place from mid-April through early June. Females produce between 15,000 and 44,000 eggs during this period. Successful reproduction requires water temperatures between 12 and 17 degrees Celsius. The eggs develop in river environments, supporting the next generation of the population. Due to habitat degradation and barriers such as dams, natural spawning grounds have declined significantly, impacting recruitment rates in the wild.
Fish and people
In Russia, the sterlet is highly valued for its flesh, which contributes to various culinary preparations. It is also a source of caviar and isinglass, a gelatinous substance derived from swim bladders used in clarifying beverages. Overfishing for these products has historically contributed to population declines. Today, much of the international trade involves sterlets raised in aquaculture facilities rather than caught in the wild. Restocking projects aim to support wild numbers, though success varies. The species holds cultural significance in regions where it was once abundant.
Status and threats
The sterlet is listed as Endangered by the IUCN. Populations have declined across its native range due to overfishing, pollution, and the construction of dams that block migration routes and degrade spawning habitats. Conservation efforts include restocking programmes and aquaculture development to reduce pressure on wild stocks. Despite introductions to new areas, these have not established self-sustaining populations. Protection measures focus on preserving remaining river habitats and managing fishing activities to allow recovery.
Questions people ask about Sterlet
What does the sterlet eat?
The sterlet feeds on benthic organisms found at the bottom of rivers. Its diet includes crustaceans, worms, and insect larvae. In captivity, it may require special food because it cannot digest vegetable proteins found in standard commercial fish foods.
How big does a sterlet get?
Adult sterlets typically reach lengths between 90 and 125 centimetres. The maximum recorded weight is 16 kilograms. While size can vary, individuals rarely exceed 125 cm in total length.
Why is the sterlet endangered?
The sterlet faces threats from overfishing for its flesh, caviar, and isinglass. Pollution and the construction of dams further degrade its habitat and block migration routes. These factors have caused significant population declines across its native range.
Where does the sterlet spawn?
Spawning occurs from mid-April to early June. Females lay eggs in freshwater rivers when water temperatures are between 12 and 17 degrees Celsius. Each female can produce between 15,000 and 44,000 eggs during this period.
Good reading and sources
The facts on this page come from the Wikipedia article "Sterlet", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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