Sturgeon Species: The Fish Behind the Tin

Huso huso — beluga

The largest freshwater fish on earth: historically over 1,000 kg and 100 years old, though nothing like that survives in the wild now. Females mature at 15 to 20 years. Yields the largest, palest, softest grain in caviar. Listed as critically endangered; wild Caspian product is barred from the US market and effectively from legitimate trade generally.

Huso dauricus — kaluga

The Amur River basin's answer to beluga, and nearly its equal in size. Matures at ten to fifteen years and gives a large grain with a firmer membrane than beluga. Most commercial product is the kaluga × amur hybrid farmed in China, which is now the dominant large-grain caviar worldwide.

Acipenser gueldenstaedtii — russian sturgeon

The source of ossetra. Matures at eight to twelve years. Produces the widest colour range of any caviar species, from near-black through brown and amber to the rare gold that comes from the oldest fish, and the most distinctive nutty flavour. Farmed extensively in Israel, China, and across Europe.

Acipenser baerii — siberian sturgeon

The species that made farmed caviar economically viable. Matures in six to eight years — fast, by sturgeon standards — adapts well to European water temperatures, and yields a clean, nutty, medium-small grain. France, Italy, Germany, Belgium, Poland and Uruguay all farm it at scale.

Acipenser stellatus — stellate sturgeon

Sevruga. A smaller, distinctively long-snouted sturgeon that matures at around seven to ten years and yields small, dark, intensely flavoured grains. Critically endangered in the wild; farmed production is limited relative to demand.

Acipenser transmontanus — white sturgeon

North America's largest fish and the backbone of the Californian caviar industry since the 1980s, now also farmed in Italy. Matures at eight to twelve years, giving a medium-large dark grain with a buttery, clean profile. The most successful sturgeon aquaculture story outside the Caspian species.

Acipenser ruthenus — sterlet

The small one, and the fast one: mature in three to five years, rarely exceeding a few kilograms. Small delicate grains, historically the caviar of the Russian court. Its albino strain produces the pale golden roe sold as Almas, the most expensive caviar in the world. Widely used as a hybrid parent for exactly this reason — it drags maturation times down.

The rest

Acipenser naccarii, the Adriatic sturgeon, is Italy's native species and the basis of a protected domestic industry. Acipenser persicus is the Persian sturgeon of the southern Caspian. Acipenser schrenckii is the Amur sturgeon and the other half of the kaluga hybrid. Scaphirhynchus platorynchus, the shovelnose or hackleback, supports one of the few legal regulated wild fisheries in the United States. Polyodon spathula, the American paddlefish, is not a sturgeon but a close Acipenseriform relative and is CITES-listed on the same basis.

How sturgeon farming works

Fish are raised in flow-through or recirculating systems, sexed by ultrasound at two to three years (roughly half of any cohort is male and diverted to meat), then monitored by biopsy until the ovary reaches optimal maturity. Timing is everything: harvested early the grain is underdeveloped, harvested late it goes soft. From harvest, the roe is screened, rinsed, salted, drained, and tinned — usually within fifteen minutes.

A growing number of farms now use no-kill "stripping" methods that milk ripe eggs from a live fish via massage or a small incision, allowing repeat harvests. The technique is commercially proven but yields a slightly different texture, and the fish must still be brought to full maturity first.

Common questions