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Lake Sturgeon (Acipenser fulvescens) Spawning in the Wolf River near Shiocton, WI

spawning Lake Sturgeon

 

Lake Sturgeon (Acipenser fulvescens) are the largest fish species endemic to the Great Lakes Basin. There are 24 species of Sturgeon (family Acipenseridae) in the world, 5 of which occur in North America. Sturgeon species as we know them now have remained relatively unchanged from their ancestors of 125,000,000 years ago. They lack scales like more modern fishes and instead are covered with five rows of bony plates sometimes called scutes. They are slow maturing and long-lived. Females do not spawn until they are at least 14 years old, but usually not until they are 20 years old. Males matures earlier, between 8 and 17 years of age. Like many fishes they continue to grow as they age, eventually weighing about 80 lbs, but the Wisconsin record catch was a fish weighin 170 lbs. Lake Sturgeon have average life spans of 80 years for females and 55 years for males, but individuals over 150 years have been caught. They usually weigh between 10 and 80 lbs. They feed by siphoning small animals including insect larvae, crayfish, snails, clams, and leeches

Spawning occurs during April and May when water levels and temperatures are favorable. The fish migrate to clean shallow rocky reefs in larger rivers or along islands. The fish will often perform "staging" displays where they roll on their sides and jump out of the water. Females only lay eggs every 4 or 5 years so that in any given year only 15% of the population is reproducing. Each female will lay 100,000-800,000 eggs in shallow rocky river bottoms during the spawning season, but most of these will be eaten by predators, like crayfish and carp.

Highly prized in Wisconsin in the late 1800s for their eggs, as well as for gelatin, oil, and glue, the population was fished to 10% of its original size. In 1903 the first size limit restrictions were imposed and in 1915 Wisconsin began the first sturgeon fishery management program when it closed the fishery to allow the population to recover. In 1931 a regulated spearing fishery opened and a scientifically regulated fishery based on population estimates and spawning estimates has been in place since the 1940s. Sturgeon are under continuous threat from dams, pollution and habitat degradation, as well as from fishing. Because sturgeon are bottom feeders and are at risk from pollutants that accumulate in the sediments that they feed from. They are also at risk during spawning if there is not enough suitable habitat for eggs to survive and hatch. Today, the sturgeon spearfishery is highly regulated so that only a small proportion of reproductive adults are removed from the population each year.

Lake Sturgeon Spawning Viewing Sites (from WI DNR):

  • Wolf River - Over 50 places to watch along river.
  • Fox River - Over 50 places to watch along river.
  • Pfeifer Park, New London - Take Hwy. 45 north and turn right onto Waupaca St. Follow Waupaca St. to Embarrass Dr. and turn left. Walk the south shoreline of the Embarrass River.
  • Mukwa Wildlife Area, New London. Take County road X west from New London for 2 miles. Park in the Mukwa Wildlife Area parking lot and walk along the south shoreline of the Wolf River.
  • Shawano Dam, Shawano. Take Hwy. 29 west through Shawano to the bridge crossing the Wolf River.
  • Shiocton, "Bamboo Bend". Take Hwy. 54 near "Bamboo Bend" where Old Hwy. 54 crosses the Wolf River. Overpasses and riverbanks allow public viewing. (Our photos were taken at Shiocton)

 

 

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Last updated on May 12, 2014