Fisheries

Sturgeon

Sturgeon

Sturgeon

Rearing systems for Siberian sturgeon, a species classified as vulnerable on the Red List published by the International Union for Conservation of Nature, were developed in the 1970s in the former USSR. It was during this same period that the first specimens were introduced into France, as part of a scientific cooperation programme. Siberian sturgeon was chosen because its reproductive cycle is one of the shortest in this family of fish (7 to 8 years rather than 15) and because it can be reared only in fresh water, unlike other sturgeons that migrate between the sea and rivers. Siberian sturgeon is now farmed in other European countries (Belgium, Italy, Germany, etc.). The number of farms is growing as operators aim to produce caviar, a highly lucrative luxury product.

Basic facts

Siberian sturgeon © ScandFish

Latin nameAcipenser Baerii
Production (EU-27) – Meat: 201 t (2007) – Caviar: 12 t (2007).
Value (EU-27) – Meat: EUR 0.9 million (2007).
Main EU producer countries – France (Europe’s leading producer of caviar), Poland, Germany.
Main producer countries worldwide – Russia, China.
Fact sheeet

Reproduction

The reproduction of Siberian sturgeon is complicated by the fact that the females do not ovulate every year and are not all synchronous. The number of females mature enough to ovulate can range from 35 to 63 % of the stock. By controlling the water temperature, however, it is possible to obtain eggs over a relatively long period, namely from December to May.

The eggs are harvested by repeated abdominal massaging every two hours or by making a small incision in the female’s abdominal cavity. The male’s sperm is collected using a small tube inserted into the genital orifice. The fertilised eggs have to be treated to keep them from clumping together during incubation: they are placed in an aqueous clay suspension or sometimes in milk. After rinsing, the eggs are placed in incubators in water maintained at 13-14°C.

Rearing

Six days later, normal larvae can be selected. The fry are fed for the first time when they are 9 to 11 days old.

Fattening

Siberian sturgeons can be reared in raceways, circular tanks, ponds or cages. They are carnivorous and are fed pellets similar in composition to that of the pellets used for trout (fishmeal and fish oil plus vegetable extracts).

The average rearing time for sturgeon cultured for their meat is 14 months to obtain a fish weighing 700 g. At harvesting time, the sturgeons are caught in nets and the biggest can even be caught by hand.

Caviar

The selection of females is the most important stage of caviar production.

Exploitation for caviar production is costly because the females cannot reproduce until they are at least seven years old. They are reared during these years in tanks of running fresh water. The females used to be slaughtered and their eggs removed. In recent years, though, fish farmers have developed techniques to remove the caviar without killing the fish, which reduces production costs by improving the females’ yield. Up to five such caesareans can be performed on a female sturgeon.

Consumption

The meat of Siberian sturgeon has no bones, which makes it appealing to consumers. European consumers, however, are not yet familiar with this fish which can be sold live, filleted or smoked.

The rearing of Siberian sturgeon in Western Europe has been encouraged by the recent ban on exporting caviar from wild specimens to protect sturgeons in danger of extinction owing to the construction of dams, overfishing and pollution.