Coaster Brook Trout

When I was at the Hurricane River the other day, they have an interpretive sign about coaster brook trout. There is something to be said about very large brook trout. They are the stuff of legends, and none has gained so fair a reputation over the decades as what is commonly referred to as the coaster brook trout.

Although a coaster is indeed a brook trout, complete with all the flashy markings and sweet-tasting flesh, these remarkable fish live most of their lives in the very competitive environment of Lake Superior.

The nickname, coaster, came about because these fish spawn, as brook trout do, in rivers and streams, but then they go out into the big lake, where they live most of their lives roaming along the coastline of Lake Superior, foraging, hopefully avoiding predators and growing large. In fact, coaster brook trout commonly grow to more than 26 inches. Brook trout that remain in the streams and rivers are significantly smaller.

The Michigan Department of Natural Resources for many years has been cooperating with numerous other agencies in the Lake Superior Basin to rehabilitate what has become a dwindling coaster brook trout population. Stocking and inventory programs have been the common thread with Michigan, Wisconsin, Minnesota and Ontario, but recently Michigan enacted further angling restrictions, especially in the area around Isle Royale National Park, where it is believed that remnants of unique strains of coaster brook trout still live.

The first map shows data about the coaster (red). The second map shows the current distribution of coasters (darker colors) compared to the historical range (lighter gray).

On Lake Superior, the minimum size limit for brook trout is 20 inches and the possession limit is one fish. Within four and one-half miles of Isle Royale National Park, catch-and-release fishing only is allowed and no fish can be kept.

Before European settlement, these beautiful fish were abundant in Lake Superior's tributaries and coastal regions. Their decline echoed that of the native grayling, and for the last century they have been locally extirpated or are extremely rare. Biologists think that extensive logging during the late 19th century destroyed a good deal of coaster brook trout stream reproduction habitat with the infiltration of sand and other sediments. Over-fishing and the invasion of the sea lamprey in the 1950s also are factors believed to have played a role in collapsing the Lake Superior coaster brook trout fishery.

Fisheries managers from around the basin established a working group in 1997 and have been closely coordinating everyone efforts ever since.   Raised from wild stock in government-operated hatcheries, some young trout are fixed with a passive integrated transponder tag, released when they reach four inches long and tracked to determine movement and mortality. The PIT tags have shown that coaster brook trout come and go from their home streams with frequency. The fish will move in and out of the home waters over the course of a few hours up to several days and more.

Here are photos from the interpretive sign at the Hurricane.