Most caviars from Europe are farmed in a similar process. Natural water is channeled from rivers or reservoirs to the farm, allowing a constant in-flow and out-flow of natural, temperate water. The sturgeons are raised in pens or tanks, fed a carefully controlled diet and living conditions are created to closely replicate that of their natural environment.
One would notice that some European caviars have a very clean taste. This is because the sturgeon were bred in pens or tanks, or transferred later from river beds into large tanks where clean, well-oxygenated (usually using a pump system) water is used. This process cleans out any river elements that would adversely affect the caviar's taste.