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Stellate sturgeon. © Wild Wonders of Europe / Lundgren / Nature Picture


Prehistoric fish


There is no set of species on the planet more endangered than the fish collectively known as sturgeons. They are an example of so-called ‘living fossils’ – a reference to how long these extraordinary fish have graced the planet. Sturgeons have literally been around since the age of the dinosaurs, but that’s no reason to take their survival for granted. Today, these incredible creatures from the Cretaceous face a perfect storm of threats. Time may finally be catching up with them.

Sturgeons even look prehistoric, an impression reinforced by their beady eyes, barbels and their built-in body armour made of bony external plates, known as scutes. These giants among freshwater fish can reach gargantuan proportions. The largest sturgeon species can measure over seven metres – that’s as long as a minibus – and weigh up to one-and-a-half tons.

Sturgeons are renowned for their highly prized roe, which is widely harvested, cured in salt and sold for eye-watering sums of money, particularly in Russia. But this caviar comes with a caveat; the sturgeon is paying an even higher price for the popularity of its eggs.

Fascinating facts about sturgeon

    1.5 tons

    Maximum weight of the world’s heaviest sturgeons

    Russian sturgeon. © Wild Wonders of Europe / Lundgren / Nature Picture Library

    7 metres

    Length of the world’s biggest sturgeons

    200 million years

    Sturgeons’ time on Earth

    Russian sturgeon. © Olga Kamenskaya / Nature Picture Library

    Vacuum cleaners

    Sturgeons have no teeth, but suck up their prey and swallow it whole.


    Sturgeons can live for more than a century.

    The Rioni river, the last known refuge of the Colchic sturgeon © Kakha Gogichashvili / Fauna & Flora

    The Rioni river, the last known refuge of the Colchic sturgeon © Kakha Gogichashvili / Fauna & Flora

    Sturgeon run

    Like salmon, most sturgeons are anadromous, meaning ‘upward running’. In other words, they migrate upriver from the sea to spawn.

Where do sturgeons live?

Sturgeons are found in the subtropical and subarctic waters of the northern hemisphere from North America to Eurasia and as far east as the Pacific coast of Russia and China. Europe’s sturgeons have declined to the point where they are rarely encountered outside the major rivers that flow into the Adriatic, Black, Caspian and Azov seas.

How many sturgeons are left?

Population size is not easy to assess, but every single one of the world’s remaining 26 sturgeon species is now officially at risk of extinction according to the IUCN Red List. Two other species – the Chinese paddlefish and Yangtze sturgeon – were recently declared extinct.

Juvenile Colchic sturgeon © Tamar Edisherashvili / Fauna & Flora

Juvenile Colchic sturgeon © Tamar Edisherashvili / Fauna & Flora

One of the juvenile Colchic sturgeons found during surveys in the Rioni River.

Why are sturgeons endangered?

All the world’s sturgeons face an upstream battle for survival, but those in Europe are particularly at risk. Once widespread throughout the continent’s major river systems, they have been decimated by unsustainable levels of fishing, poaching and the loss of traditional spawning grounds as a result of habitat destruction.

Sturgeons are nominally protected under CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora), but enforcement of these regulations is not easy, because it’s hard to distinguish between wild-sourced and farmed products. The thriving black market in caviar poses a serious threat to Europe’s dwindling wild sturgeon populations.

As if that wasn’t enough to deal with, sturgeons are now faced with another, potentially terminal, threat to their survival in the shape of hydropower dams, which cut off access to traditional spawning grounds.

How can we help save Europe’s sturgeons?

Of the main rivers draining into the Black Sea, only a handful still offer suitable spawning habitat for sturgeons. One of these, the Rioni River in Georgia, is the last known refuge of the Colchic sturgeon and supports crucial populations of five other critically endangered sturgeon species.

Until Fauna & Flora intervened in 2017, this vital haven had no sturgeon conservation programme. Since conducting the very first baseline studies for these fish in Georgia, we have worked with the government and a range of local and regional partners to combat poaching, trafficking and the other grave threats to sturgeons in the Rioni.

As part of this programme, we have established monitoring teams comprising ‘citizen inspectors’ drawn from communities along the river, whose role is to inform governmental agencies about incidences of poaching. These individuals also engage with fishers, encouraging them to report and release any sturgeon they catch, to stick to legal fishing methods, and to help collect data on wild sturgeon. Fauna & Flora works closely with these local people – from schoolchildren to fish traders – to raise awareness of the plight of the sturgeons in the Rioni – and emphasise their global importance.

Research is a vitally important aspect of this project, and local fishers have played a critical role in this regard, vindicating our efforts to engage constructively with local people and engender widespread support for sturgeon conservation.

Tamar Edisherashvili, Sturgeon Researcher. © Kakha Gogichashvili / Fauna & Flora

Fauna & Flora's Tamar Edisherashvili, Sturgeon Researcher, checking nets in Georgia's Rioni River.

River phoenix

During the course of this work, Fauna & Flora and our local partners have made some astounding discoveries. In 2018, the capture of a baby stellate sturgeon provided proof positive that this critically endangered species was still breeding in the Rioni.

More recently, two juvenile specimens of the critically endangered ship sturgeon – widely feared to be extinct – were found and reported by local anglers within the space of a single month. Just a week later, the Rioni yielded a third juvenile, provisionally identified as a vanishingly rare Colchic sturgeon.

The positive relationship that Fauna & Flora has developed with local fishers has had a hugely beneficial impact on the success of this project. Anglers often notify us when they have caught sturgeons, and we have managed to take genetic samples from the vast majority of these fish.

Ship sturgeon, Rioni River. © Irakli Tsulaia

An extremely rare ship sturgeon caught in the Rioni River by a local fisher and photographed before release.

Dammed to death

Unfortunately, all this great work is in danger of being undermined by a potentially disastrous new development. The proposal to construct a 100-metre-high hydrodam has caused dismay among the conservation community and drawn widespread condemnation within Georgia, including unprecedented mass demonstrations in major towns and cities. Astoundingly, the environmental impact assessment conducted as part of the proposed scheme made no mention of the sturgeon.

The Rioni River has already been adversely affected by existing hydrodams, gravel extraction and industrial pollution, threatening the last viable spawning grounds for sturgeons in the eastern Black Sea. Any further deterioration in water quality and spawning conditions could be the final straw for the stranded sturgeon, scuppering any hope of recovery and causing Europe’s flagship fish to sink without trace. Fauna & Flora and our partners are working to ensure that this doesn’t happen.

Juvenile Colchic sturgeon © Tamar Edisherashvili / Fauna & Flora

Sturgeon SOS

Please help us to reverse the dramatic decline of these incredible fossil fish.

Together, we can bring sturgeons back from the brink.


Juvenile Colchic sturgeon © Tamar Edisherashvili / Fauna & Flora