Young Fish
Most sturgeon species exhibit rapid growth during their early years, typically between 4 and 9 years, depending on the species. The California Department of Fish and Game reports that white sturgeon grow to a 12-inch fork length during their first year, and reach a 46-inch fork length by the time they are 9 to 16 years old. Fork length is the measurement from the tip of the nose to fork of the tail fin.
Mature Sturgeon
Different sturgeon species mature at different ages. Age at maturity is also affected by environmental conditions. After the initial growth spurt during the early years, white sturgeon grow about 1 to 2 1/2 inches annually. The Environmental Protection Agency says that pallid sturgeon grow about 4 inches per year between the ages of 5 and 10. Shortnose sturgeon are a smaller species overall, and these fish reach a mature fork length of 17 to 21 inches, but the latitude of the waters they inhabit affects their rate of reaching maturity.
Water Temperatures
Faster growth occurs when water temperatures are at 68 F compared to 59 F, according to the California Department of Fish and Game, but increasing temperatures to 77 have little impact on growth. The NOAA Fisheries Service describes delayed maturity ages in northern climates versus southern climates, largely a result of water temperatures. While shortnose sturgeon mature at 2 to 3 years of age in Georgia rivers, they do not reach mature fork lengths until ages 10 to 11 in Canadian waters.
Maximum Lengths and Ages
All sturgeon species can grow very large. Even the shortnose species can reach nearly 5 feet in length and weigh up to 50 lbs. At a length of more than 20 feet and an estimated weight of about 1300 lbs., a shortnose would be dwarfed next to the largest white sturgeon. The fish are long-lived as well. Pallid sturgeon live around 40 years or so, while female shortnose achieve about 67 years. White sturgeon, however, can live beyond 100 years.