Brown Trout

Salmo trutta

  • First stocked in Great Lakes in 1880s
  • Popular sport fish

Etymology

The brown trout’s scientific name translates to “trout-salmon.” The Atlantic salmon and brown trout both belong to the genus Salmo. Rainbow trout, coho salmon, and Chinook salmon belong to a different genus – Oncorhynchus.

Life History

Great Lakes brown trout typically enter tributaries to spawn during late fall. Reef spawning also has been documented in Lake Superior and Lake Michigan. Although naturally reproducing populations of brown trout exist in Michigan waters, most are maintained through stocking. Unlike Chinook and coho salmon, brown trout do not necessarily die after spawning and can live for up to 13 years in Lake Michigan.

Browns can tolerate warmer water than other trout species, which adds to their popularity as a gamefish in rivers that are not suitable for native brook trout. In the Great Lakes, brown trout stay near shore in waters less than 50 feet deep, which makes them an ideal gamefish for shallow bays such as Lake Huron’s Thunder Bay.

Diet

The diet of brown trout varies greatly depending on its environment and available food sources. In the Great Lakes, brown trout prey mostly on forage fish such as alewife, rainbow smelt, and round goby. In rivers, small browns eat a variety of aquatic invertebrates. Larger fish transition to a diet of small fish, large insects, and even small rodents. Big browns are notorious for their wariness and nocturnal feeding habits.

Size and Master Angler Entries

The bar for maximum brown trout size was recently set in Michigan, by a 41.45 pound giant that measured 43 3⁄4 inches long. This new IGFA all-tackle world record and Michigan state record was caught in the Manistee River, but had almost certainly spent most of its life in Lake Michigan. Minimum size for entry in Michigan’s Master Angler program is 33 inches or 16 pounds.

Management Issues

The first stocking of brown trout into public waters of the U.S. occurred on April 11, 1884 in the Baldwin River, which was then known as the North Branch of the Pere Marquette River. Although brown trout are not native to North America, they have been widely stocked in streams and lakes due to their popularity with anglers.

The cost of rearing and stocking a single brown trout was $0.73 in 1991, compared to $0.12 for each Chinook salmon. This is because Chinooks are released during their first spring, while brown trout are typically held for an additional year in the hatchery and stocked as spring yearlings. Furthermore, survival of Chinook salmon in Lake Michigan is much higher than brown trout. Brian Gunderman of the MDNR found that each brown trout harvested by an angler costs the state of Michigan $39.88, while each Chinook salmon harvested by an angler costs the state only $0.88.

Low survival of Great Lakes brown trout has led to changes in stocking strategies, including experimentation with fall fingerling stockings in Lake Huron bays, and stocking of Sturgeon River strain brown trout that began in 2009 with 68,000 spring yearlings stocked in Grand Traverse Bay.