Sturgeon is the common name used for some 26 species of fish in the family Acipenseridae, one of the oldest families of bony fish in existence, all found in the northern hemisphere. Sometimes Sturgeon is used more exclusively to refer to species in the two best-known genera, Acipenser and Huso. Sturgeon are distinctive for their elongated bodies, lack of scales and rows of bony plates including covering the head. Most sturgeons are anadromous bottom-feeders, spawning upstream and feeding in river deltas and estuaries. While some are entirely freshwater, very few venture into the open ocean beyond near coastal areas. All sturgeon are slow-growing & late-maturing. Young sturgeon primarily feed on algae and bottom- living aquatic invertebrates while remaining in rivers and estuarine environments. Adult sturgeon primarily feed on fish, shellfish and other aquatic invertebrates including amphipods, and shrimp. White sturgeon Acipenser transmontanus is one of the most important sturgeon species in the American continent inhabiting the whole Pacific Coast. The largest freshwater fish in North America ,it can weigh over 1,500 pounds, be 20 feet in length, and live for over 100 years. White sturgeon reach maturity in 15-25 years . Moving into large rivers in the spring, spawning usually takes place in swift current with a rocky bottom, near rapids. White sturgeon can spawn multiple times during their life, and apparently spawn every 4-11 years as they grow and mature. Females can produce from 100,000 to several million eggs each. Eggs are broadcast in the water column and the fertilized eggs sink and attach to the bottom to hatch. Research indicates that water flow is one of the key determinants of larval survival. Siberian or Long-nosed sturgeon, Acipenser baeri, is a freshwater species, but it migrates long distances in the rivers where it is found. Found in all of the major Siberian river basins that drain northward into the Kara, Laptev and East Siberian seas, including the Ob, Yenisei (which drains Lake Baikal via the Angara River) the Lena and Kolyma rivers. It is also found in Kazakhstan and China in the Irtysh River, a major tributary of the Ob. Though variable between and within river basins this species is large; the maximum recorded weight was 210 kg. Long-lived (up to sixty years), and late to reach sexual maturity (males at 11-24 years, females at 20-28 years). They spawn in strong current main stem river channels on stone or gravel substrates. The species has been in steep decline in its natural range due to habitat loss, degradation and poaching. Up to 40% of the Siberian sturgeon spawning habitat has been made inaccessible by damming.