MARQUETTE -Every fourth grader in Michigan knows that the robin is the state bird. But not everyone knows Michigan has a state fish, too: the brook trout.
Native to the Upper Peninsula and northern Lower Peninsula, brook trout are colorful, speckled fish - some people even call them "specks"- that inhabit clean, cold water. Over the years, brook trout have been widely stocked around the state and are now found almost everywhere there is appropriate habitat.
Although brook trout are capable of attaining large sizes, they typically do not live long enough to grow very large. Brook trout are vulnerable to predation from other fish, birds and mammals, and, of course, anglers. They are often caught in small, jump-across streams that do not lend themselves to harboring large individuals. But there is a notable exception; brook trout that migrate out of the rivers and into the Great Lakes (mostly Lake Superior) are capable of reaching large sizes.
These fish are known as "adfluvial" brook trout or, more commonly as "coaster brook trout" or simply "coasters." These brook trout spend time in the big lakes where they "cruise the coast," then migrate up rivers to spawn.
"Brook trout do not have the same strong migratory tendencies as other species in the trout and salmon family," said Tammy Newcomb, who heads up the research staff of the Michigan Department of Natural Resources and Environment's Fisheries Division. "Their migrations are less ingrained and seem to be highly unpredictable when compared to species such as steelhead or Chinook salmon, which are noted for their migratory runs."
Coaster brook trout have been the subject of significant study and management in recent years. Regardless of their ability to grow to more than two feet in length, scientists have been unable to distinguish them genetically from the brook trout that spend their entire lives in streams.
"It's easy to understand why people would want to have these fish as a component of the fishery," Newcomb said. "A big brook trout is a remarkable creature and makes a great fish story."
Scientists continue to study brook trout across the state, trying, among other things, to determine where these populations historically existed.
"Even in the 1800s there was large-scale stocking of brook trout, particularly in the Lake Superior watershed," Newcomb said. "You could say that any stream that is connected to the Great Lakes could have had some fish that exhibited an adfluvial life history strategy at some point in time."
Brook trout are the subject of debate nationwide. In the West, where they have been widely transplanted, brook trout are considered an invasive species in some waterways, where fisheries managers are actively trying to eliminate them.
On the East Coast, ocean-run brook trout (known colloquially as "salters") are a highly desirable game fish, but they are managed in a similar fashion to how Michigan manages brook trout populations.
As part of an experiment that began in the late 1990s to see if brook trout populations could be rehabilitated and potentially exhibit an increase in migratory behavior, management agencies participated in the high-density stocking and restrictive harvest regulations on a number of Lake Superior tributaries.
In Michigan, those experiments have failed to bear fruit. As a result, the experimental harvest regulations were lifted on many of the streams, though regulations that require larger minimum size limits and a restricted harvest season continue for research purposes in three others, including the Salmon Trout River in Marquette County.
Meanwhile, there is a 20-inch minimum size limit with a one-fish creel limit in Lake Superior as well as a 4 1/2-mile zone out from the shoreline of Isle Royale where no brook trout harvest is allowed.
Biologists hope these regulations will provide an environment to foster a migratory life history strategy in the brook trout population.
As Michigan re-examines its trout regulations, it will continue work with partners to investigate the potential for coaster brook trout. In the meantime, regulations will focus on adequate protection for brook trout populations while providing adequate opportunity for recreational harvest.
To find out where to fish for brook trout, visit the DNRE website at www.michigan.gov/dnr.