What fish are in Lake Superior?

Lake Superior, the largest and deepest of the five Great Lakes, is known not only for its stunning landscapes but also for its rich biodiversity. As a cold, oligotrophic lake, its waters support a wide variety of fish species, both native and introduced. The diverse habitats of Lake Superior, including deep waters, rocky shorelines, sandy bottoms, and cold, clear environments, are home to more than 80 species of fish. Whether you're a fisherman, naturalist, or simply curious about the lake’s aquatic life, understanding what fish inhabit this vast body of water offers a glimpse into the health of the ecosystem and the interconnectedness of aquatic life.

Native Fish Species in Lake Superior

Lake Superior has a rich history of native fish species that have evolved and adapted to the lake's cold, nutrient-poor waters. These species form the foundation of the lake's aquatic ecosystem.

1. Lake Trout (Salvelinus namaycush)

One of the most iconic fish species in Lake Superior, the lake trout is a cold-water fish that thrives in deep, oxygen-rich waters. Native to the lake, these fish are important both ecologically and economically. Lake trout can grow to impressive sizes, with some individuals reaching lengths of 3 to 4 feet. They are opportunistic predators, feeding on other fish such as ciscoes, whitefish, and smaller lake trout. Overfishing in the past, along with invasive species, caused a decline in lake trout populations, but efforts to restore this species through stocking programs have been successful.

2. Brook Trout (Salvelinus fontinalis)

The brook trout is another native cold-water fish species found in Lake Superior, primarily in its tributaries and nearshore areas. A member of the salmon family, brook trout are well-suited to the lake's clear, cool waters. They are highly sought after by anglers for their striking appearance and delicious taste. Brook trout are typically smaller than lake trout but are known for their vibrant colors, with males displaying brilliant orange and red markings during the spawning season.

3. Whitefish (Coregonus clupeaformis)

The whitefish is a cold-water species that is native to Lake Superior. It inhabits deep, clear waters and feeds primarily on zooplankton and other small organisms. Known for its delicate flavor and firm texture, whitefish is an important commercial and recreational catch. Whitefish populations in Lake Superior are healthy, and they play a key role in the food web, serving as prey for larger fish like lake trout and predatory birds.

4. Walleye (Sander vitreus)

The walleye is a popular fish in Lake Superior's shallow waters, especially in the spring and fall. While walleye are not native to the lake, they have established a healthy population due to stocking efforts in the 20th century. Known for their large, predatory nature, walleyes are highly sought after by anglers for their tasty, firm white meat. They prefer sandy or rocky lake bottoms and are often found in areas with submerged structures, where they can ambush prey like yellow perch and minnows.

5. Yellow Perch (Perca flavescens)

The yellow perch is a smaller fish species that inhabits both the shallow and deeper parts of Lake Superior. Known for its distinctive yellow and green stripes, this species is abundant in the lake and an important food source for larger predators like lake trout and walleye. Yellow perch are popular among anglers due to their abundance and tasty flesh.

6. Cisco (Coregonus artedi)

The cisco, also known as lake herring, is a small, schooling fish that is native to Lake Superior. It inhabits deeper, cooler parts of the lake, where it feeds on plankton and smaller invertebrates. Ciscoes are a key prey species for larger fish such as lake trout and are important in maintaining the health of the lake’s ecosystem. They are also a commercial fishery species and are used as bait for larger fish species.

7. Northern Pike (Esox lucius)

The northern pike is a predatory fish that can be found in the shallow, weedy areas along the shores of Lake Superior. Native to the lake, pike are known for their elongated bodies and sharp teeth. They are ambush predators, often lying in wait among vegetation to strike at smaller fish like yellow perch, minnows, and even juvenile trout. Northern pike are an important species for both recreational fishing and ecosystem balance.

Invasive Fish Species in Lake Superior

While Lake Superior has a wide variety of native fish, invasive species have also made their way into the lake. These species often disrupt the natural balance, outcompeting native fish for resources and altering the ecosystem.

1. Sea Lamprey (Petromyzon marinus)

The sea lamprey is perhaps the most notorious invasive species in Lake Superior. Native to the Atlantic Ocean, sea lampreys entered the Great Lakes system through the Welland Canal in the early 20th century. These parasitic fish attach themselves to other fish and feed on their blood and tissues. The presence of sea lampreys has significantly reduced the populations of native fish, particularly lake trout, and is a primary reason for the decline in many fish species in the lake. Efforts to control sea lampreys include chemical treatments and the construction of barriers to prevent their movement into tributary rivers.

2. Alewife (Alosa pseudoharengus)

The alewife is another invasive species that was introduced into the Great Lakes, including Lake Superior, in the 19th century. This small, schooling fish competes with native species like ciscoes and yellow perch for food resources. Alewives are considered a threat to the native fish populations because they reproduce rapidly and can outcompete native species, leading to a decline in biodiversity.

3. Rainbow Trout (Oncorhynchus mykiss)

The rainbow trout, though not native to Lake Superior, has been introduced to the lake in various areas. Unlike lake trout, rainbow trout are more adaptable to warmer water temperatures and often compete with native fish species for food. Despite their non-native status, rainbow trout have become a popular species for anglers due to their size, fighting ability, and excellent taste.

Conclusion: A Rich and Diverse Ecosystem

Lake Superior’s fish populations are diverse and abundant, thanks to the lake’s unique characteristics, including its cold, clear waters and varied habitats. The lake’s native species, such as lake trout, brook trout, and whitefish, play important roles in the ecosystem, while introduced species like the rainbow trout and alewife present challenges to the delicate balance of the lake's aquatic environment. Conservation efforts, including controlling invasive species and restoring native populations, are crucial for maintaining the health of Lake Superior’s fishery and its surrounding ecosystems.

Whether you are an angler hoping to catch a prized lake trout, a naturalist marveling at the diversity of species, or simply someone who appreciates the beauty and wonder of the Great Lakes, the fish of Lake Superior remain an important part of what makes this body of water so unique and remarkable.