Sterlet
| Sterlet | |
|---|---|
 | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Acipenseriformes |
| Family: | Acipenseridae |
| Genus: | Acipenser |
| Species: | A. ruthenus |
| Binomial name | |
| Acipenser ruthenus Linnaeus, 1758 | |
The sterlet (Acipenser ruthenus) is a relatively small species of sturgeon from Eurasia. It is native to large rivers that flow into the Black Sea, Azov Sea and Caspian Sea, as well as rivers in Siberia as far east as Yenisei. Populations migrating between fresh- and saltwater (anadromous) have been extirpated.[1]
Due to overfishing (for its flesh, caviar and isinglass), pollution and dams, the sterlet has declined throughout its native range and is considered vulnerable by the IUCN.[1] There are ongoing re-stocking projects and it has been introduced to some regions outside its native range, but the latter have generally not become self-sustaining.[1] Today the majority of the international trade involves sterlets from aquaculture.[1]
Physical appearance
- The sterlet may reach 16 kg in weight and 100 to 125 cm in length, rarely exceeding a length of 3 ft.
- It is quite variable in coloration, but usually has a yellowish ventral side.
- It is distinguishable between other European species of sturgeons by the presence of a great number of whitish lateral scutes, fringed barbels, and an elongated and narrow snout, highly variable in length.
Feeding habits
The sterlet's main source of food is benthic organisms; they commonly feed on crustaceans, worms, and insect larvae.
Life span
The sterlet commonly reaches the age of 22 to 25 years.
Sexual maturity
- Males: 3–7 Years Old
- Females: 4–12 Years Old
Fecundity
Females may lay from 15,000–44,000 eggs.
Spawning period
- Middle of April – End of May—Beginning of June.
Spawning requirements
- Sexually mature adults
- Within spawning period
- Water temperature preferably 12–17 °C (54–63 °F).
As pond fish
Sterlets require relatively large ponds with good water conditions, and may get entangled in plants such as blanketweed. Sterlets may require specialist food such as sterlet sticks, as they are unable to digest the vegetable proteins usually found in commercial fish foods.
As food
In Russia, it is held in high esteem on account of its excellent flesh, contributing also to the best kinds of caviar and isinglass.
Sturgeon hybrids
- Sterlet x Beluga (Huso huso) = (Bester)
- Sterlet x Siberian [Russian (Acipenser gueldenstaedtii)]
- Sterlet x Diamondback
- The most common sturgeon hybrid is Diamondback x Siberian.
- There is also Italian x Diamondback.
- Hybrids are hardier than their parents.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Gesner, J., Freyhof, J. & Kottelat, M. (2010). "Acipenser ruthenus". IUCN Red List of Threatened Species. Version 2012.2. International Union for Conservation of Nature.