Roes with a thickness higher than 2.5 mm. The biggest and the most appreciated between the culture of caviars.Sturgeon, the fish from which the roes-caviar- are extracted is on the verge of extinction. The white and hard meat of sturgeon, like the roes, have been very appreciated by the human being from old times. Due to over-fishing and environmental alterations of the fluvial habitat (contamination, reservoir construction, etc.) in many places of the territory, this specie has experimented a decline and started disappearing in many regions until gather together, almost exclusively in the Caspian Sea and the Black Sea. One has to keep in mind that sturgeon is an anodromous fish: it reproduces and is born the rivers, going to sea afterwards where it needs for spawning a deep and pebbly sea with fast flow and well oxygenized waters.Regarding that sturgeon family consists of 23 species, only four of them are suitable for caviar production and its meat consumption (which all reside in the Caspian Sea): -Beluga us the world's biggest fish in fresh water, with maximum 8 m long and a superior weight of a metric ton. -Asetra is averaging 1.2 m long and its weight ranges between 20 and 80 Kg -Sevruga is the smallest from the three and the most elegant-. Karaburun lives in the south of Caspian Sea and its roes are very similar to the ones from Asetra.