Sturgeon are a group of ancient, long-lived fish known for their impressive size and distinctive appearance. These remarkable creatures have existed for over 200 million years, earning them the nickname “living fossils” due to their largely unchanged form since the time of dinosaurs. They are characterized by elongated, spindle-like bodies covered with five rows of bony plates called scutes, rather than scales. Their unique armor and large dimensions contribute to their reputation as some of the most imposing fish in aquatic environments.
The Giants Among Fish
Among the various sturgeon species, the Beluga sturgeon (Huso huso) and White sturgeon (Acipenser transmontanus) stand out for their exceptional sizes, holding records for the largest documented individuals. The largest accepted record for a Beluga sturgeon is a female caught in the Volga estuary in 1827, measuring 7.2 meters (23 feet 7 inches) long and weighing 1,571 kilograms (3,463 pounds). This makes it the largest freshwater fish in the world and rivals some of the most massive bony fish. While unconfirmed reports suggest even larger Belugas, this catch remains a benchmark.
For White sturgeon, the largest recorded individual was caught in the Fraser River, British Columbia, in 2012. This fish measured 11 feet 7 inches in length and weighed approximately 1,100 pounds. While historical accounts mention White sturgeon potentially reaching 20 feet and over 1,500 pounds, this 2012 catch is a verified modern record. These record-breaking specimens highlight the growth potential within these species.
Factors That Determine Sturgeon Size
Sturgeon achieve their large sizes due to a combination of biological and environmental factors. Their remarkable longevity is a primary reason; many sturgeon species can live for 50 to 100 years, with some individuals exceeding 150 years. This extended lifespan allows for continuous growth throughout their lives, as they do not stop growing once they reach maturity. Their slow maturation rates also contribute, as some species do not reach sexual maturity until well into their second decade of life.
Their diet and habitat quality also play a significant role. Sturgeon are primarily bottom feeders, using sensitive barbels to locate prey such as invertebrates, crustaceans, and small fish. Consistent access to abundant food sources in large, healthy aquatic environments, such as expansive rivers and lakes, supports their sustained growth. Undisturbed environments with suitable water quality and ample space are important for these fish to reach their full potential.
Varying Sizes Across Sturgeon Species
While some sturgeon grow very large, individual size varies across the more than 25 sturgeon species. The average adult size for many sturgeon species ranges from 7 to 12 feet in length and 400 to 800 pounds. For instance, the Atlantic sturgeon can typically grow to 14 feet long and weigh up to 800 pounds, with an average length of 6 to 9 feet. Siberian sturgeon, another large species, can reach lengths of up to 7 feet and weigh around 440 pounds in the wild.
In contrast, other species are smaller. Lake sturgeon typically measure 4 to 6 feet long and weigh 30 to 80 pounds, though older individuals can reach 7 feet and 300 pounds. Green sturgeon usually range from 4 to 6 feet in length, reaching up to 7 feet and 350 pounds. The Shovelnose sturgeon is among the smallest North American species, typically around 3 feet long and weighing approximately 5.5 pounds, with a maximum recorded weight of about 20 pounds. This diversity shows that while sturgeon are known for their size, not all species achieve the record-breaking dimensions of the Beluga or White sturgeon.