Sturgeon: The Caviar Fish — Species, Breeding, and Why It Costs What It Costs

What is Sturgeon? The living fossil that produces caviar

The sturgeon is a fish from the Acipenseridae family, a lineage that has been on the planet for over 200 million years. To put it in perspective: sturgeons were already swimming when dinosaurs roamed the Earth. They are, literally, living fossils.

There are 27 recognized species of sturgeon, distributed across the northern hemisphere: from the Caspian Sea and the Black Sea to the rivers of North America and Asia. All share unmistakable traits:

• Elongated body with five rows of bony plates (scutes) instead of scales.
• Pointed snout with four sensory barbels to detect food on the bottom.
• Cartilaginous skeleton, like sharks, instead of true bone.
• Protrusible ventral mouth (toothless in adults) adapted to suck invertebrates from the riverbed.
• Slow growth and extreme longevity: some species live over 100 years.

But what has made the sturgeon the most coveted fish in the world is not its flesh —which is also prized— but its roe. Sturgeon roe, once processed and salted, becomes caviar: the most exclusive and expensive gourmet food in existence.

Not just any fish roe is caviar. By strict definition (and European regulation), only sturgeon roe can be called caviar. Everything else —salmon roe, lumpfish roe, trout roe— are substitutes or "caviar of [species]", but not simply caviar.

Main sturgeon species: each, a distinct caviar

Of the 27 sturgeon species, only a handful produce commercially relevant caviar. Each species yields roe with unique characteristics in size, color, flavor, and price. These are the ones you need to know:

Beluga (Huso huso) — The king of caviar

The beluga is the largest sturgeon in the world. It can exceed 5 meters in length and 1,000 kg in weight, although current specimens rarely reach these dimensions due to historical overfishing. It mainly inhabits the Caspian Sea and the Black Sea.

Its caviar is the most highly prized: large roe (3-4 mm in diameter), pearl grey to dark grey in color, with a buttery, complex, and persistent flavor. A kilogram of beluga caviar can exceed €10,000 on the international market.

The problem: beluga females do not reach sexual maturity until 18-25 years of age. This means a fish farm needs to keep a fish for two decades before obtaining a single gram of caviar. This is the main reason for its astronomical price.

Osetra (Acipenser gueldenstaedtii) — The chefs' favorite

For many experts, osetra (also spelled oscietra or ossetra) is the sturgeon with the most gastronomically interesting caviar. It reaches 2 meters and about 80-200 kg. It is found in the Caspian Sea, Black Sea, and Azov Sea.

Its caviar features medium-large roe (2.5-3 mm), with an exceptional color range: from amber gold to dark brown, including green and grey tones. The flavor is nutty, with hints of walnut and a clean marine aftertaste. Osetra caviar is the most appreciated by professional chefs for its versatility.

It matures between 12-15 years, making it somewhat more economically viable than beluga, but still a long-term investment for producers.

Sevruga (Acipenser stellatus) — The most intense

The sevruga is the smallest of the three great Caspian sturgeons: it rarely exceeds 1.5 meters and 25-30 kg. It is easily recognized by its elongated and narrow snout, almost like a sword.

Its caviar has the smallest roe (under 2 mm) but the most intense and iodized flavor of all. Dark grey to black in color, with a firm texture that bursts in the mouth. It matures in 7-10 years, which historically made it the most accessible of the three classic caviars. Even so, its price is around €3,000-€5,000/kg.

Baerii (Acipenser baerii) — The aquaculture workhorse

The Siberian sturgeon or baerii is, by far, the most cultivated species in aquaculture worldwide. Originally from Siberian rivers, it adapts well to controlled farming conditions and matures relatively quickly: between 5 and 8 years.

Its caviar is medium-sized (2-2.5 mm), dark grey to black, with a mild, slightly nutty, more accessible flavor than beluga or osetra. It is the caviar you will most frequently find in restaurants and gourmet shops as an entry point into the world of caviar.

France, Italy, Germany, and China are the main producers of baerii caviar. Its price ranges from €1,500-€3,000/kg, making it the option with the best value for money.

Adriatic Sturgeon (Acipenser naccarii) — The Spanish sturgeon

Acipenser naccarii is a species endemic to the Adriatic and Southern Europe. In Spain, it is the basis of caviar production for Nacarii, the pioneering Spanish caviar company, and Riofrío, the world's first organic caviar fish farm.

It reaches 1.5-2 meters and about 20-25 kg. Its caviar is medium-sized, greenish-grey to brown, with a delicate, clean flavor, with herbaceous notes. It matures in 8-12 years. It is a critically endangered species in the wild, which means its aquaculture production has added conservation value.

White Sturgeon (Acipenser transmontanus) — The American giant

The Pacific white sturgeon is the largest freshwater fish in North America: it can exceed 6 meters and 800 kg. It is found on the west coast, from Alaska to California.

Its caviar features large roe, light to dark grey in color, with a clean, buttery, and slightly sweet flavor. The aquaculture of this species has grown significantly in the United States, with producers in California and Oregon. It matures between 10-15 years.

Comparison Table: 6 Sturgeon Species and their Caviar

Why is sturgeon so expensive? The 5 real reasons

The price of caviar —and by extension, sturgeon— is not a market whim. There are very specific biological, regulatory, and economic reasons that explain it:

1. Extremely long reproductive cycle

A female sturgeon needs between 5 and 25 years to reach sexual maturity, depending on the species. In aquaculture, this means feeding, maintaining, and caring for a fish for years —sometimes decades— before obtaining a single gram of caviar. No other food product requires a comparable time investment.

For a fish farm working with beluga, the return on investment begins to arrive 20 years after the first stocking. With baerii, the period is reduced to 5-8 years, which explains why it dominates global production.

2. CITES Regulation and International Protection

All sturgeon species are included in CITES Appendices I or II (Convention on International Trade in Endangered Species). This implies:

• All legally traded caviar needs a CITES traceability code on the tin.
• Exports require government permits from both the country of origin and destination.
• Wild sturgeon fishing is prohibited or severely restricted in virtually all countries.

These regulations are necessary for the survival of the species but add significant bureaucratic and logistical costs to the final product.

3. High aquaculture costs

Raising sturgeon is not like raising trout or salmon. Requirements include:

• High-quality water: sturgeon need clean, oxygenated water, ideally from a spring or river.
• Space: they are large fish that need ample ponds.
• Feeding: specific high-protein diets for years.
• Sexing: until they reach a certain age, males cannot be distinguished from females. Males do not produce caviar and represent approximately 50% of the stock.
• Health control: strict and constant throughout the fish's life.

4. Low yield per fish

The roe represents between 10% and 15% of the female's body weight. A 10 kg baerii sturgeon can produce 1-1.5 kg of caviar. After processing (cleaning, salting, moisture loss), the net yield is even lower. If a fish farm has invested 7 years in raising that fish, the cost per kilo of resulting caviar is considerable.

5. Artisanal processing

Caviar is processed by hand. A master caviar maker evaluates the roe, separates it from the ovarian membrane, washes it, salts it precisely (between 3% and 5% salt), and packages it. All of this must be done within minutes of extraction to preserve freshness. It is a specialized trade that requires years of experience.

The sturgeon crisis in the Caspian Sea

For centuries, the Caspian Sea was the world's epicenter of caviar. Russia and Iran produced more than 90% of the planet's caviar. But the recent history of sturgeon in the Caspian is an environmental tragedy:

Overfishing and collapse

After the fall of the Soviet Union in 1991, fisheries control in the Caspian plummeted. The newly independent republics (Kazakhstan, Turkmenistan, Azerbaijan) lacked effective regulation. The result:

• Illegal sturgeon fishing multiplied by 10-12 times compared to legal quotas.
• Beluga populations fell by 90% in two decades.
• Osetra and sevruga suffered similar declines.
• It is estimated that in the 1990s, for every kilogram of legal caviar, 8-10 kilograms of illegal caviar were traded.

Bans and regulation

The international response was forceful:

• 2006: CITES temporarily suspended all caviar exports from the Caspian Sea.
• 2010: Russia imposed a total moratorium on commercial sturgeon fishing in the Caspian.
• 2020: The five Caspian countries signed enhanced protection agreements.

Iran has been the relative exception: it maintained restocking programs and more controlled fishing management on the southern Caspian coast. That's why Iranian caviar maintains its reputation for superior quality, and its supply —though limited— was never completely interrupted.

Are populations recovering?

Slowly. Restocking programs (releasing captive-bred fry into rivers and the Caspian itself) are showing results, but sturgeon reproduce so slowly that full recovery will take decades. Meanwhile, aquaculture has taken over as the primary source of caviar worldwide.

Aquaculture: How sturgeon is farmed today

Sturgeon aquaculture has gone from being a curiosity to becoming the source of 95%+ of the world's caviar. China is now the largest producer (yes, China), followed by Italy, France, Germany, Spain, the United States, and Iran.

The farming process

1. Broodstock selection: the best specimens are chosen for genetics and roe quality.
2. Incubation: fertilized eggs are incubated under controlled temperature and oxygenation conditions.
3. Fry stage: the first few months are critical. High natural mortality (30-50%).
4. Growth: juveniles are transferred to larger ponds. Fed high-protein feeds.
5. Sexing (year 2-4): sex is determined by ultrasound or biopsy. Males are destined for meat; females continue until maturity.
6. Maturation (year 5-25, depending on species): females are monitored periodically to assess roe development.
7. Extraction: when the roe reaches optimal ripeness, extraction proceeds (more detail below).

Sustainable vs. conventional aquaculture

Not all fish farms are the same. The difference between a sustainable operation and a conventional one lies in:

• Water source: natural spring/river vs. treated water.
• Stocking density: fewer fish per cubic meter = less stress = better caviar.
• Feed: organic vs. conventional feeds.
• Certification: organic (like Riofrío) or conventional.

Sustainable aquaculture caviar is not only better for the environment, but many tasters agree that it produces a cleaner-tasting caviar.

From sturgeon to caviar: extraction process

The moment of roe extraction is the culmination of years of breeding. The process is fast, precise, and artisanal:

Traditional method (sacrifice)

1. Evaluation: a roe sample is taken by biopsy to verify it is at the optimal maturation point (size, firmness, color).
2. Sacrifice: the fish is humanely sacrificed. The roe must be processed immediately.
3. Extraction: the ovarian sacs are opened, and the roe is carefully removed.
4. Sieving: the roe is passed through a calibrated mesh to separate it from the ovarian membrane, without breaking it.
5. Washing: gently washed with cold water to remove residues.
6. Salting: the master caviar maker adds between 3% and 5% salt. The Malossol category (from Russian "little salt") indicates less than 3%: the purest and most delicate caviar.
7. Packaging: packaged in classic metal tins with airtight seals, under vacuum.
8. Maturation: the caviar matures for 1 to 3 months in refrigeration (0-4 °C) before commercialization.

All this process —from sacrifice to packaging— must be completed in less than 15-20 minutes to ensure the freshness and integrity of the roe.

Non-lethal method (stripping/milking)

Some fish farms use an alternative method that does not require sacrificing the fish: ovulation is induced with hormones, and the roe is extracted by abdominal massage. The female survives and can produce caviar again in 2-3 years.

The debate about quality is open: some experts believe that caviar obtained by stripping has a slightly inferior texture, while others argue that the difference is imperceptible. What is undisputed is its ethical and economic advantage (the same female can produce caviar multiple times).

Sturgeon in Spain: Nacarii and Riofrío

Spain is one of the most interesting caviar producers in Europe, with two names you should know:

Riofrío: the world's first organic caviar

The Riofrío fish farm in Granada has the distinction of being the first in the world to obtain organic certification for its caviar. Located next to the source of the Riofrío river, it uses spring water at a constant temperature (14-15 °C) all year round.

• Species: Acipenser naccarii (Adriatic sturgeon).
• Certification: organic (CAAE, equivalent to EU Organic).
• Production: limited, a few tons per year.
• Distinction: the natural spring water gives the caviar an exceptionally clean flavor profile.

Nacarii: premium Spanish caviar from Lleida

Nacarii operates in Lleida and also works with Acipenser naccarii, as well as osetra. It has managed to position Spanish caviar in international fine dining, with a presence in Michelin-starred restaurants.

• Range: from classic naccarii caviar to premium osetra.
• Recognition: awarded in international gastronomy competitions.
• Philosophy: controlled production, low stocking density, selected feed.

What is relevant is that Spain demonstrates that you don't have to go to the Caspian to find top-tier caviar. The combination of exceptionally high-quality water (springs of Granada, rivers of the Pyrenees) and accumulated know-how over two decades has put Spanish caviar on the world map.

Nutritional value of sturgeon and its caviar

Beyond luxury, sturgeon and its caviar are foods with an exceptional nutritional profile:

Caviar (per 100g)

Sturgeon meat (per 100g)

Sturgeon meat is also notable: 105 kcal, 16 g protein, 4 g fat (rich in omega-3), no carbohydrates. It has a firm, almost meaty texture, reminiscent of beef or swordfish. In Russia and Caspian countries, it is consumed roasted, smoked, grilled, or in stews.

Key benefits

• Omega-3: caviar is one of the most concentrated sources of EPA and DHA, essential fatty acids for cardiovascular and brain health.
• Vitamin B12: a 30 g serving of caviar covers more than 250% of daily needs. Fundamental for the nervous system.
• Selenium: powerful antioxidant. Caviar provides more selenium than most oily fish.
• Complete protein: contains all essential amino acids in optimal proportions.

The only point of attention is sodium: caviar is a salty food by definition. People with high blood pressure should moderate their consumption, although typical amounts (10-30 g per serving) do not pose a risk for the general population.

Frequently asked questions about sturgeon