With a size that can exceed seven meters and a mass of more than 1.5 tonnes, the large sturgeon, or European beluga, is the largest freshwater fish. The species is unfortunately in very bad shape.
It took three people to extract, measure and mark the fish, which was then released into the river. A few weeks ago, biologists captured one of the largest freshwater fish ever identified in the United States: a lake sturgeon (Acipenser fulvescens) measuring 2.1 meters long and weighing 109 kilos on the scale. . These measurements are very impressive, but there are even larger fish in other rivers.
According to the US Geological Survey, the largest freshwater fish on the planet remains the large sturgeon (Huso huso), which has been on Earth for approximately 250 million years.
That being said, you will find these fish between Europe and Asia in the Black, Azov and Caspian seas and tributary rivers. Some specimens can indeed measure more than seven meters long and weigh more than 1.5 tonnes. The largest accepted report is of a female measuring 7.2 meters and weighing 1,571 kg, isolated in 1827 in the Volga estuary. The sturgeon thus competes with the great white shark, the tiger shark and the Greenland shark for the title of largest predatory fish.
These sturgeons feed on roach, whiting, anchovies and other carp, but also on crustaceans and molluscs. Some also sometimes attack young Caspian seals. Just like the lake sturgeon, the beluga sturgeon can live more than a hundred years.
A species threatened by humans
The species is unfortunately classified as “critically endangered” on the IUCN Red List. Their population is in fact seriously fragmented and there is a decline in mature individuals.
The main threats are transportation and service corridors, dams that prevent fish from swimming upstream to reach their spawning grounds, and water pollution. Without obviously forgetting overfishing. Adult females are indeed very appreciated for their eggs sold in the form of caviar.
Note that they are included in the category of freshwater fish because they are born and reproduce in fresh water, but also occupy salty environments. Concerning fish that only live in fresh water, the giant Mekong catfish (Pangasianodon gigas) is now breaking all records, with some specimens being able to reach the three meters long and more than 250 kilos. Like the great sturgeon, these fish are also considered critically endangered by the IUCN, for the same reasons.
The beluga sturgeon, in addition to its impressive physical characteristics, plays a crucial ecological role in its habitat. As a top predator, it helps regulate fish populations and maintain the balance of the aquatic ecosystems of the rivers and seas it inhabits. Its disappearance could thus have cascading effects, affecting not only biodiversity but also human communities that depend on these ecosystems for fishing or other resources.
