© 2001 Michael Furtman

The Case of the Stolen Jewels

(How coaster brook trout disappeared and why they may return.)

 By Michael Furtman

We were robbed. 

Over one hundred years ago, thieves came to Lake Superior and stole one of its crown jewels. The thieves operated in full daylight, and indeed, their efforts were either heralded as positive economic development, or journaled as the exploits of the adventuresome. 

The jewel was the “coaster” brook trout, a Lake Superior-dwelling version of that lovely little ruby-spotted fish many of us know from our region’s small streams. This race of brook trout (it is not known yet whether they constitute a separate subspecies) has a life history similar to anadromous salmon or steelhead. That is, they spawn in tributary streams where the young remain for a period of time, before out-migrating to Lake Superior, where adults spend their lives. 

The crooks were lumbermen, who turned rivers into sluiceways, destroying habitat, and whose dams (for floating logs downstream) blocked spawning access. Logging also stole streamside shade, and the widespread loss of forest cover on the uplands, with the slash fires that followed, changed whole watersheds, altering the flow regime and destroying groundwater seeps so critical to these fish. 

Other thieves came as “sports” – wealthy anglers who came to Lake Superior as early as 1850 to enjoy the seemingly unlimited fishing opportunity for “coasters.” Old accounts are rife with stories of boatloads of fish being caught in the streams or along the shorelines, and it is thought this intense angling pressure – even without the changes wrought by logging – may have been enough to cause the fishery’s collapse. 

Growing larger than the stream-bound  brook trout, coasters attracted thousands of anglers, even though Lake Superior was still difficult to reach. The world record brook trout of  just over 14 pounds was taken from Ontario’s Nipigon River, and was likely a coaster. Although few coasters ever attained such size, the chance to catch brookies that averaged about two pounds was sufficient to draw boatloads of anglers who would leave Duluth to fish Minnesota’s streams, camping at river mouths and harvesting the trout as they returned to spawn. The St. Mary’s River was said to hold astounding numbers of coasters, and besides the Nipigon region streams, Michigan’s Salmon Trout River, and Wisconsin’s Bois Brule all attracted passionate trout anglers. The Bayfield area was well known for its “rock trout” fishing – the term locals used for coasters that inhabited the inshore waters in and around the Apostle Islands. It is thought that 118 streams around the lake sustained viable populations of coaster brook trout. 

That all came to an end by about 1930. Today, only a handful of Ontario streams and two on Isle Royale contain anything resembling viable populations. No populations are known to exist in Wisconsin or Minnesota’s waters, though a few coasters still linger to spawn in Michigan’s Salmon Trout River. 

With Lake Superior’s lake trout population now considered restored, conservationists have turned their attention to restoring the coaster. State and provincial fisheries agencies, along with the U.S. Fish and Wildlife Service and conservation groups like Trout Unlimited, are marshalling this effort. If they succeed, not only will an important and beautiful native predator be returned to the Lake Superior basin, but the environment for humans and other creatures should benefit. 

No one is sure what the prospects for success are, especially because it is unknown whether sufficient stocks of coasters are available for rehabilitation efforts (or even if stocks from one part of the lake will work in another), whether enough good habitat still exists, and whether coasters can now thrive in a lake with an entirely different fish community than that in which it evolved. 

When coasters roamed the lake in numbers, there were no coho or chinook salmon, or brown and rainbow trout. Some of these fish, especially the coho, have spawning requirements similar to that of coasters, and so could pose stiff competition. While it is certain that the decline of coasters can’t be attributed to these introduced (and now naturalized and self-sustaining) species, since coasters had all but disappeared before these species were first stocked, efforts to re-establish coasters may be complicated by the presence of these fish. 

There is hope in this regard. In some Ontario streams, where coasters never disappeared, they seem to be holding their own against these exotic species. In fact, they’ve begun recently to increase in numbers, now that Ontario has greatly reduced angling bag limits. 

Any recovery will depend upon such restrictions. Brook trout are not known as the brightest of salmonids, and are easy to catch. This led to their decline, and could thwart recovery, unless resource agencies, anglers, and tribal authorities all work to reduce harvest. 

The most critical factor may be environmental issues. With so much road and home building, logging, and farming going on in the watersheds of the nursery streams, the very nature of many rivers has changed. Some streams, especially on the south shore, are “flashier” than in historic times. Higher than historic peak flows causes course woody debris to blow out of the streams. Without the debris to slow the water, beneficial smaller sediments (to form spawning gravel), and the organic materials (such as leaves) on which aquatic invertebrates feed (which in turn feed the trout), can’t settle out, leaving the lower reaches of these rivers much less friendly to spawning coasters and their offspring than they once were. 

Because of this, restoring these fish will mean, in some cases, rehabilitating whole watersheds. Although doing so will not only benefit coaster brook trout, but all the other animals (including people) and fish that depend on healthy streams, it also will mean working with numerous landowners – private and public. Such landscape level projects take time, determination, and considerable financial resources. 

In other locations, progress will mean protecting existing quality habitat, which will also require landowner cooperation. In these locales, stocking of genetically-correct brook trout, combined with harvest restrictions, could be all that is needed. 

Before this can happen, however, serious scientific research into coaster genetics and ecology will need to take place – some of which is already being done. Although much is known about brook trout as a species, little is known about the biology and natural history of the apparently unique coasters, since they largely disappeared before professional resource managers could study them, and the few remaining populations are in remote locations where research is difficult to do. 

All of these concerns are known to coaster advocates, and are built into the restoration plan. Despite a good plan, and good intentions, the question remains: will viable populations of coasters ever return to the streams and shores of Lake Superior? 

There is reason to be hopeful, given the determination of natural resource managers and conservationists, and the resiliency of nature. Although it is unlikely that in this now altered lake, coaster brook trout will ever again enjoy the population status of pre-settlement times, chances seem realistic that they can be snatched from near oblivion and returned to viability. After all, native species, given half a chance, tend to thrive in the environment in which they evolved.

 If they do, it’ll be a sign that the lake’s basin is growing healthier. 

It’ll also mean we righted a wrong and restored the glistening jewels to the crown of the greatest of lakes.

This article originally appeared in  Superior Vision, Summer 2001

  © 2001 Michael Furtman