Acipenser fulvescens Rafinesque, 1817

Barbel and Lip Structure

The lake sturgeon (Acipenser fulvescens Rafinesque, 1817) has taste buds on and around its barbels, which sit near its rubbery, prehensile lips.

Feeding Mechanism

It extends these lips to suck up soft live food, and swallows prey whole because it has no teeth.

Core Diet Components

Its typical diet includes insect larvae, worms (including leeches), and other small, primarily metazoan organisms it finds in mud.

Diet Shift from Invasive Species

Some populations have fish as a significant part of their diet, a shift that has occurred largely since the invasive round goby was introduced in the early 1990s.

Feeding Ecology Comparison

Because this large species survives by feeding on very small organisms, its feeding ecology has been compared to that of large filter-feeding marine animals such as some whales.

General Distribution Range

This species is distributed across much of central and eastern North America.

Southern and Eastern Drainage Range

It lives in the Mississippi River drainage basin, ranging south to Alabama and Mississippi and east to the French Broad River in western North Carolina.

Great Lakes and St. Lawrence Range

It also occupies the Great Lakes, the Lake Winnebago System, and the Detroit River, extending east down the St. Lawrence River to the furthest extent of fresh water.

Western Range

In the west, its range reaches Lake Winnipeg and the North Saskatchewan and South Saskatchewan Rivers.

Northern Range

In the north, it can be found in the Hudson Bay Lowland.

Eastern Vermont Range

In the east, it inhabits Lake Champlain and several Vermont waterways, including the Winooski, Lamoille, and Missisquoi rivers, as well as Otter Creek.

Historical Range Context

This current distribution aligns with the range of large proglacial lakes that formed as glaciers retreated from North America at the end of the last ice age, such as Lake Agassiz and Lake Iroquois, which once connected all these areas.

Migration Drivers

Lake sturgeon often migrate to search for food, find suitable spawning sites, or respond to seasonal environmental changes.

Age-Based Habitat Depth

Juveniles typically live in pools deeper than around 6 feet, while adults usually occupy deep water in large lakes.

Habitat Selection Factors

Most individuals do not stray far from appropriate spawning locations, and the availability of plentiful prey is also a major factor in habitat selection.

Lifespan

Lake sturgeon have a very long lifespan. Males typically live up to 55 years, while females can live between 80 and 150 years.

Juvenile Growth Pattern

They grow quickly during their extended juvenile stage.

Male Sexual Maturity

For reproduction, male lake sturgeon usually reach sexual maturity between 8 and 12 years old, though some take as long as 22 years.

Female Sexual Maturity

Females reach sexual maturity between 14 and 33 years old, most often between 24 and 26 years.

Spawning Site and Timing

These sturgeon spawn on clean gravel shoals and in stream rapids, usually between April and June. They prefer spawning in water temperatures between 55 and 64 °F (13 and 18 °C).

Spawning Courtship Behavior

To reproduce, lake sturgeon swim in circles around each other before shaking violently. After the male finishes circling and releases his sperm, the female lays her eggs.

Egg Production

Females produce 4,000 to 7,000 eggs per pound of their body weight.

Spawning Frequency

Males spawn every 2 to 7 years, while females spawn every 4 to 9 years.

Annual Breeding Proportion

Only 10 to 20 percent of adult lake sturgeon are sexually active in any given season.

Mating System

Lake sturgeon are polygamous, which maximizes their genetic diversity.