The Atlantic sturgeon (Acipenser oxyrinchus) occupies the coastal regions of the U.S. and Canada from Labrador to Florida with breeding populations existing in at least 14 Atlantic Coast rivers in the U.S. from Maine to Georgia, and several other rivers in Canada, including the St. Lawrence and St. John. Atlantic sturgeon are found within rivers, estuaries, nearshore marine environments, and shelf regions occurring at depths of at least 200 m along the coast.
This species of sturgeon can attain extremely large sizes (4.3 m, 268 kg) and live for longer than 60 years. Sexual maturation of Atlantic sturgeon varies by gender and latitude. In the Mid-Atlantic males are known to mature at 6-10 years whereas females mature at 10-20 years. At higher latitudes (e.g., St. Lawrence River), males mature at 16-24 years while being approximately 150 cm FL, and females reach maturity after 27-28 years at 180-200 cm FL. Spawning periodicity ranges from 2-6 year intervals, however males may spawn annually. Atlantic sturgeon are a highly migratory fish. Juveniles use freshwater and brackish habitats and can be found seasonally throughout estuarine environments, while adults and sub-adults migrate along the east coast of North America until migrating into estuaries and rivers during the autumn or spring to reproduce. Their diet consists mostly of benthic macro-invertebrates and occasionally small fish. Atlantic sturgeon have also been known to cease feeding during spawning runs.
The Atlantic sturgeon has suffered drastic population declines due to overfishing for the caviar market and the installation of dams which subsequently impede spawning migration and habitat. The IUCN Red List classifies these fish as ‘near threatened’, however, they are currently experiencing population increases throughout their range. The Atlantic sturgeon is not considered to be endangered or threatened in Canada, however a few sub-populations may be extinct.
The biology of these fish is relatively well known, however regions in Canada lack detailed fisheries survey information regarding abundances of river populations. Although a few regions have properly assessed their Atlantic sturgeon populations, a comprehensive evaluation on the abundance of Atlantic sturgeon does not currently exist. Management plans that have been implemented in some regions (e.g., St. Lawrence River) will most likely promote population increases in the future. The U.S. has restricted harvest of Atlantic sturgeon since 1998 and has further helped to rehabilitate adjacent Canadian populations. The removal of tidehead dams will also help to re-establish populations in the Kennebec River, U.S. The enactment of the Ocean Dumping Act in Canada has also led to improvement of estuarine habitat which will further benefit Atlantic sturgeon populations. Overall, the historic threats that have affected Atlantic sturgeon populations have been reduced (pollution, dams, commercial overharvest), and many populations are considered stable or recovering.
Photo Credit: James Crossman
Photo Credit: Bill Post
FishBase FAO IUCN