The Sturgeon

Natural Habitats

The natural habitat of sturgeons is the rivers and seas of the Northern Hemisphere. Many sturgeon species are anadromous fish – meaning they migrate from the seas upriver to spawn. They are found primarily in the Caspian and Black Seas.

REPRODUCTION

It takes a relatively long time for sturgeons to reach reproductive maturity, and this occurs at different times among the various species. Furthermore, it depends significantly on the sum of degree-days. Sturgeon of the same species reach sexual maturity more quickly in warmer waters. A female Siberian sturgeon (A. baerii) takes 9-11 years to reach sexual maturity in the North German climate, while a beluga sturgeon (Huso huso) takes even 25-30 years.

In their natural habitat, sturgeons migrate upriver to spawn, where they lay their eggs on sandy-gravelly bottoms. The damming of rivers presents significant obstacles, in some places insurmountable for the fish.

As early as the 1950s, the Soviets began artificially breeding sturgeon in facilities and releasing the hatched fish back into the wild to manage the stocks sustainably. With the collapse of the Soviet Union and the resulting unregulated fishing of sturgeon stocks, the population numbers plummeted in the 1990s. The flourishing caviar smuggling trade during this period and the lack of restocking exacerbated this decline.

SPECIES CONSERVATION

On April 1, 1998, sturgeon were placed under the protection of the Washington Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and trade was only permitted according to CITES regulations. Sturgeon stocks were then fished according to quotas, and the caviar trade was subject to specific marking and documentation requirements. However, these measures were unable to sustainably halt the decline of wild sturgeon populations. Since 2008, no more fishing quotas have been issued, which is why wild caviar can no longer be processed, and trade is now limited to farmed caviar.

MARKING AND DOCUMENTATION REGULATIONS

All primary containers – that is, packaging that comes into direct contact with the caviar, e.g., jars or tins – must be sealed with a
band and/or a label containing the species protection code.

Anyone who trades in caviar today must, according to Section 6 of the Federal Species Protection Ordinance, maintain up-to-date inventory records in the form of a receipts and dispatches book, whereby private customers purchasing caviar with a value exceeding €250.00 must be recorded with their name and full address.

The respective species protection code – or Universal Labeling Code – is explained as follows:

STURGEONS IN AQUACULATION

Since the early 1990s, sturgeons have been farmed in aquaculture. Initially, almost exclusively the Siberian sturgeon (A. baerii), but soon after, other sturgeon species as well.

Today, aquaculture not only raises a wide variety of sturgeon species but has also become a source of knowledge for restocking measures and the necessary sturgeon reproduction. Its unique feature lies primarily in the long rearing periods of the fish. No other fish are kept in aquaculture for such an extended period before processing. Consequently, achieving specific breeding goals is correspondingly time-consuming and challenging. Fish growth and ovarian development are highly dependent on water temperature. Sturgeon grow significantly faster and reach sexual maturity earlier in warm water. Therefore, sturgeon are often kept in heated, recirculating aquaculture systems. Alternatively, there is pond fishing or raising sturgeon in tanks fed with fresh river water. The changing temperature and light throughout the year, the proportion of natural food, and the fish's freedom of movement promote the development of the roe. Before processing, all sturgeon from any rearing method are transferred to tanks or ponds circulated by cool spring water. This prevents any foreign Flavors from entering the product.

How to read the label

STURGEON SPECIES / SIGNIFICANCE FOR CAVIAR PRODUCTION

With a phylogenetic age of over 250 million years, sturgeons are among the oldest fish on our planet. The family Acipenseriformes comprises 27 species of sturgeon, which are further divided into two species of paddlefish and 25 species of true sturgeons (Acipenseridae).

However, only a few of these sturgeon species are used for caviar production. Currently, some species are selectively crossbred, for example, Acipenser schrenckii x Acipenser dauricus. The aim is to achieve advantages for the final product. One sturgeon species grows quickly, and the other reaches sexual maturity quickly—both desirable traits in aquaculture.

BELUGA / HAUSEN (Huso huso)

The beluga is the largest freshwater fish in the world. The largest specimens caught have weighed over 1.5 tons. Their natural habitat is the Caspian and Black Seas. In our latitudes, in open waters, the fish takes 25 to 30 years to reach spawning maturity. The fine, delicate-shelled, large roe makes it one of the most sought-after suppliers of caviar.

OSCIETRA / RUSSIAN STURGEON (Acipenser gueldenstaedtii)

Oscietra sturgeons can grow to over two meters in length, weighing more than 100 kg. They also inhabit the Caspian and Black Seas. Spawning maturity is reached at 12-14 years of age. Their firm, large roe, which ranges in color from golden yellow through various shades of brown to anthracite, has made these fish the "primary suppliers" of caviar.

SIBERIAN STURGEON (Acipenser baerii)

As a purely freshwater fish, the Siberian sturgeon played a pioneering role in aquaculture – the first aquaculture caviar was produced from this species. Its roe is typically grey-black and medium-sized; in general, the roe is considered to have a slightly more delicate shell than that of the Siberian sturgeon (Acipenser baerii).

CAVIAR

Caviar varieties are generally named after the fish from which the roe was harvested – for example, "Beluga" or "Oscietra." However, individual names have also emerged from various retailers and producers, often based on the fish species.

Clarity can be achieved by looking at the Universal Labeling Code or the scientific name of the sturgeon species. Terms like "Selection" or "Imperial" originally referred to selection processes, but are now also used independently to describe other types of caviar.

In addition, the label sometimes indicates the different processing methods used. "Malossol" is the most common and refers to caviar produced with a maximum of 5% salt. This caviar is therefore only lightly salted and remains grainy. "Pressed" and "barrel caviar" are now less common and are processed with significantly higher salt concentrations.

Furthermore, the label sometimes indicates the different processing methods used for the caviar. Proper salting of the roe is not only important for the taste of the caviar, but primarily for its preservation. Borax, which is only permitted for caviar production, is used as an additional preservative. The addition of this natural mineral allows for processing with a lower salt content, resulting in a milder flavor.

Another method for extending the shelf life of the product is pasteurization. In this process, the sealed container – usually a glass jar – is heated briefly and precisely. This inactivates any potential germs.

FROM FISH TO CAVIAR

Once the female sturgeon has developed its ovary after several years, it is placed in cool, clear spring water for a few weeks to allow the roe to shed any foreign flavors and mature slowly. When the roe has reached the correct degree of ripeness, the fish is slaughtered, the ovary is removed, and the roe is then separated using a sieve. After rinsing in cold water, the roe is salted and packed into traditional hinged-lid tins for maturation. Only when the roe is bound to the salt is it considered caviar. At -4°C, the caviar matures for several months, developing into the desired high-quality product. Besides the caviar master's extensive experience, the correct salt, which can originate from the most diverse countries, is of paramount importance in production.

The question often arises as to why the sturgeon's eggs cannot be harvested live – for example, by stripping them. It's important to understand that the roe develops a softer shell as it matures. Such a mature roe is called an ovulated egg. In nature, for the fish to release this egg, it requires spawning with a male sturgeon – the milt. In aquaculture, hormones would have to be injected as a substitute, after which the roe can be stripped. The thin-skinned roe must then be chemically hardened, as it would burst during the subsequent salting process. However, such a method is fundamentally prohibited for caviar production in Germany!

Companies that produced "caviar" using this method were forced to cease operations.

STORAGE AND TRANSPORTATION

Caviar should always be transported and stored under a well-chilled environment. In retail practice, it has proven effective to store the product in a refrigerator/cold storage room at a consistent temperature and to use empty jars and containers for display in the counter.

IDEAL SERVING ACCESSORIES

Buttered toast, crusty baguettes, baked potatoes, or potato “rösti” with crème fraîche are ideal accompaniments that perfectly complement the caviar's flavor.

In Russia, caviar is served with sour cream and buckwheat pancakes – known as blinis.

You should absolutely avoid any accompaniments with a strong flavor of their own, such as onions and lemon. They would completely overpower the delicate caviar aroma. Avoid silver spoons – these would also impair the caviar's flavor. Mother-of-pearl, gold, plastic, or horn spoons are excellent choices.

THE PERFECT DROP

Ideally, the drinks should complement the delicious taste of the caviar. Champagne is a very popular choice with caviar. A light white wine is also highly suitable, as it allows the caviar's aroma to fully develop. In Russia vodka is, of course, the preferred choice.

Pictures: Anja Behrens