Sturgeon (European) - Acipenser sturio
Status: Critically Endangered … If landed in the UK, the sturgeon is the property of the Queen
Location: Once very wide-ranging - from the North and (Eastern) north Atlantic and Mediterranean coast of Europe to the Black Sea. The last remaining viable breeding population is in the Garonne River in France.
Size: Up to 6m long and 400kg, males are slightly smaller than females.
Habitat: Sturgeon are anadromous - spending part of their life in salt water and returning to rivers to breed.
European sturgeon are also known as Baltic or, ironically, Common sturgeon. Once widespread in Europe, there is now only one population of European sturgeon left in the whole continent. This too is declining. Yet not many people know that the magnificent, pre-historic sturgeon, known for its caviar, is now as endangered as the black rhino.
The adults spawn in freshwater. Juveniles then slowly make their way downstream and reach the estuary of the river of their birth at about 1 year old. They then go to sea after 2-6 years, and alternate movement between the sea while over-wintering in the estuary. For the next 4-6 years, they spend the summer in the estuary and return to the sea during the autumn. Adults stay close to shore in the sea, and are rarely found in waters deeper than 200m.
This species of sturgeon now breeds only in one location, the Garonne River in France, where it last spawned in 1994. Bycatch is the major threat and the extraction of gravel in the Garonne is also a potential threat to the species. Dam construction, pollution and river regulation have led to loss and degradation of spawning sites. The current population size is now between just 20-750 wild, mature individuals. In recent years there has been substantial stocking, but these fish will not reproduce until around 2016.
The sturgeon was an important commercial fish until the beginning of the 20th century when populations crashed. Prior to this, juvenile sturgeon were harvested as animal food in Poland and Germany. The European sturgeon is not the source of the very expensive Beluga caviar. This comes from its relative the Beluga (Siberian) sturgeon, Huso huso, (also classified as critically endangered by the IUCN.)
Under UK law, whales and sturgeons are ‘royal fish’, and when taken become the personal property of the monarch of the United Kingdom, although the Queen rarely accepts sturgeon when they are offered.
The sturgeon is occasionally found in British seas, although most experts believe our fish to be vagrants from other larger European rivers. The Environment Agency will only begin to consider granting a license to reintroduce the fish if it can be established that there were self-sustaining populations of sturgeon in British rivers in the past. Throughout the 19th century there were numerous records of its occurrence far up British rivers, which suggests that spawning may have taken place in the larger British rivers at one time.
Although called the ‘common sturgeon’ there are now only 20 - 750 mature fish left in the wild.
Did you know?
The sturgeon was common over 200 years ago in large UK rivers including the Severn, Avon, Ouse, some Scottish rivers and the Thames, with remnants of sturgeon found in the medieval remains of Westminster Abbey.
Fossilised sturgeons have been found in deposits dating over 54 million years old. They possess many primitive features, including a heterocercal tail (the spine continuing along the upper lobe), a cartilaginous skeleton, and a spiral valve in the lower intestine.
The head is covered with hard bony plates that meet to form visible seams.
In September 2013, two boys caught a sturgeon near Pembroke Dock. Steve Colclough, of the Institute of Fisheries Management said, “Where it came from is at present a mystery.” Two months later, the Daily Express reported a Siberian sturgeon caught in the Thames. Steve Colclough explained the fish could possibly be one lost from cages in the Gironde River in France some years ago during a caviar farming experiment. But, he said, “We think it is more likely to be an escapee from the UK pet trade. These exotic species are imported and this may show that some are now escaping into the wild.”
What MCS is doing:
- Working as part of an International coalition to reduce marine pollution;
- Campaigning at EU level for more effective regulation of fisheries that can impact sturgeon.