Lake Superior, often referred to as an inland sea, is the largest freshwater lake in the world by surface area, covering over 31,700 square miles. It holds an extraordinary volume, making it the third-largest freshwater lake globally. With an average depth of 483 feet and a maximum depth reaching 1,332 feet, its cold, clear waters create a unique environment supporting diverse aquatic life. The lake’s vastness naturally sparks curiosity about its largest inhabitants.
Identifying the Largest Resident Fish
The largest fish species consistently residing in Lake Superior is the Lake Sturgeon (Acipenser fulvescens). This remarkable fish is considered the oldest and largest native species found throughout the Great Lakes system. Its lineage traces back at least 150 million years, classifying it as a prehistoric fish. While once abundant, the Lake Sturgeon is now rare and protected in many areas due to historical overharvesting and habitat loss. Its continued presence highlights the lake’s ecological significance.
Defining Its Immense Size
The Lake Sturgeon is the largest fish in Lake Superior due to its impressive physical dimensions and longevity. These fish can grow to lengths of up to 7.25 feet and weigh over 240 pounds, with some individuals potentially reaching 8 feet long and 300 pounds. Typically, adult Lake Sturgeon encountered today range from 4 to 6 feet in length and weigh between 30 and 80 pounds. They are characterized by a streamlined body, a partly cartilaginous skeleton, and rows of bony plates on their sides and back instead of scales.
The Lake Sturgeon’s immense size results from its exceptionally long lifespan and slow growth rate. Males commonly live for about 55 years, while females can survive for 80 to 150 years. This species matures slowly, with males taking approximately 15 years to reach reproductive maturity and females requiring 20 to 25 years. Females also spawn intermittently, typically only once every four or five years, contributing to the species’ vulnerability. Lake Sturgeon are bottom feeders, using their spade-like snout and four sensory barbels to locate small invertebrates like snails, crustaceans, and aquatic insects.
Other Notable Large Fish Species
While the Lake Sturgeon holds the record for size, Lake Superior is home to other substantial fish species. The Lake Trout (Salvelinus namaycush) is another prominent large fish in the lake. While the largest recorded Lake Trout globally weighed nearly 102 pounds, those typically caught in Lake Superior range from 7 to 12 pounds. Impressive catches have been documented, with one notable Lake Superior specimen estimated at 51.6 pounds, and the largest recorded in the lake weighing 63 pounds. Lake Trout inhabit cold, deep waters and can live for many decades, with the oldest recorded in the Great Lakes being 62 years old.
Walleye (Sander vitreus) are a significant large fish species in Lake Superior. As the largest member of the perch family, Walleye are popular among anglers and are abundant in certain areas, particularly near river mouths. Fishing regulations often specify minimum lengths, such as 18 inches, for harvest. Northern Pike (Esox lucius) are another large predatory fish found in Lake Superior, known for their aggressive feeding habits. These fish can grow to over four feet in length, with average sizes around 2 to 5 pounds, though much larger individuals have been caught, including a Wisconsin record of 38 pounds.