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Despite the name, lake sturgeon live in both rivers and lakes in Canada and the eastern half of the United States. It is an ancient fish and is characterized by the 5 rows of boney plates covering its body, its heavy torpedo-shaped body, 4 smooth barbels on the lower snout, and its cartilaginous body structure. Large lake sturgeon can exceed 8 feet in length and weigh as much as 800 pounds. Mostly it lives on the bottom of clean freshwater lakes and rivers, although some have been observed in brackish waters.
In the spring or early summer, depending on local water temperature, lake sturgeon migrate upstream in rivers to spawn. Females release 50,000-700,000 eggs that are fertilized by nearby males and then stick to rocky surfaces. If the eggs aren’t eaten by other fish, they hatch in 5-8 days. Lake sturgeon grow rapidly the first 10 years of their lives, but reach sexual maturity more slowly than any other freshwater fish. Males reach sexual maturity around 15-20 years, females around 20-25 years. They are extremely long-lived, reaching ages of 100 years or more.
Lake sturgeon generally eat leeches, snails, small clams, insects, and sometimes small fish and plants. They swim slowly across the river or lake bottom, dragging their sensitive barbels. When they sense food, their tubular, toothless mouth extends to suck up dinner and sediment, expelling the sediment through their gills.
Although lake sturgeon were once overexploited and some local populations are threatened or endangered, global populations are healthy. The IUCN lists the species as one of Least Concern. The Great Lakes and St. Lawrence River basin are home to the largest populations.
Nature picture credits (left to right): Photo © Eric Engbretson (above rocks); Photo © Eric Engbretson (pair).
