The Great Lakes, a vast freshwater system including Superior, Michigan, Huron, Erie, and Ontario, hold a significant portion of the world’s surface freshwater. This expansive ecosystem supports diverse aquatic life, with certain fish species reaching impressive sizes.
Identifying the Great Lakes’ Largest Fish
Several fish species in the Great Lakes are notable for their size. The Lake Sturgeon is the largest, a prehistoric fish reaching up to 8 feet and 200 pounds, with some historical records over 300 pounds. The Chinook Salmon is another substantial resident, with the Great Lakes record at 47.86 pounds.
Lake Trout also grow to impressive sizes, with individuals recorded up to 100 pounds. The Muskellunge, often called the “musky,” is another large predator, with some specimens reaching 70 pounds. A Michigan state record weighed 58 pounds and measured 59 inches.
Profiles of the Lake Giants
The Lake Sturgeon (Acipenser fulvescens) has a distinctive appearance with rows of bony plates instead of scales, giving it an armored, torpedo shape. These bottom-dwelling omnivores use four sensory barbels near their shovel-like snout to locate prey like insects, crustaceans, and small mussels. Lake Sturgeon are long-lived, with some females reaching 150 years.
Chinook Salmon (Oncorhynchus tshawytscha) are silvery fish that spend their early lives in freshwater streams before migrating to the Great Lakes. As adults, they are primarily piscivorous, feeding on other fish like alewives and smelt. These salmon return to their natal rivers to spawn, after which they die.
Lake Trout (Salvelinus namaycush), a native cold-water species, are predators in the deeper, cooler parts of the Great Lakes. Their diet shifts from plankton and invertebrates when young to various fish as adults, including alewives, round gobies, and sculpins. Lake Trout help maintain the food web balance.
The Muskellunge (Esox masquinongy) is an elongated, ambush predator with a flat head and camouflaged markings. They prefer shallow, vegetated areas, with Lake St. Clair a noted habitat. Muskies are opportunistic feeders, consuming various fish species like yellow perch, white suckers, and cisco. They can swallow prey up to two-thirds their body length.
Why These Fish Grow So Large
Several factors contribute to the impressive size of Great Lakes fish. The lakes’ vastness and depth provide ample space and support large populations of prey fish like alewives and smelt, offering abundant food for predators such as salmon and lake trout. Long lifespans, particularly for species like the Lake Sturgeon, also allow more time for growth. The cold, oxygen-rich waters are ideal for supporting the metabolic needs of large, cold-water fish, promoting efficient growth. Complex food webs, including invasive species like round gobies as a food source, further support their growth.