Bringing Back The Giants

We called them "coasters" and "salmon trout" because they patrolled the coastlines of Lakes Superior, Huron, Michigan and Nipigon, and because they were the size of salmon. Then, before we had a chance to learn much about how they lived and reproduced, we essentially wiped them out. We caught and killed a lot of these giant brook trout-but that doesn't mean there had been a lot of them. Few if any species are as vulnerable to angling pressure. As with so many brook trout extirpations, this one was also accomplished by ripping up landscapes so silt and sand buried streambed spawning gravel, and by razing tree cover that shaded, cooled and slowed runoff.

Today there are only three recognized strains of wild coasters in the United States, all in Lake Superior and all in Michigan: the two stream-spawning populations of the Upper Peninsula's Salmon Trout River and Isle Royale's Big and Little Siskiwit rivers, and the shoal-spawners of Isle Royale's Tobin Harbor. There are countless rills in Minnesota that funnel brook trout into the lake at which point, by definition, they become coasters. Most of these fish aren't much over a pound and a half. Ontario provides eggs from its Lake Nipigon coaster strain to Ojibwa Indian and state managers around the Superior Basin.

Attempts at coaster rehabilitation began in 1890. It was going to be easy-just cluster-bomb the lake with hatchery brook trout. During the next 100 years Wisconsin alone stocked about 23 million fry, fingerlings and adults. Despite those efforts, the state is apparently without wild coasters. And the populations that persist in Michigan's, Ontario's, and Minnesota's Lake Superior shorelines are tiny remnants. In Ontario's Lake Nipigon (60 miles long and 40 miles wide) recovery is well underway.

Whether coasters can be restored to lakes Huron and Michigan is questionable, but there is reason for much optimism in Lake Superior. Since I last reported on coasters (in the July 2001 FR&R) Superior's Canadian and American partners-27 governmental, tribal, university and non-profit organizations-have pooled coaster research and coordinated management. At this writing working groups are about to publish papers that will answer some of our many questions about stream habitat, lake habitat, ecology, populations and genetics.

In 2001 it grieved me to report that Wisconsin and Michigan were thumbing their noses at coaster rehabilitation by permitting Lake Superior anglers to kill three fish a day, which only had to measure 15 inches in Wisconsin and 10 inches in Michigan. But now all partners have implemented strict lake-wide harvest regulations-one fish over 20 inches per day in the states; and one fish over 22 inches in Ontario. The tribes are doing even better-having basically committed to no-kill and, as has been their traditional practice, refusing to stock exotic species. Although Wisconsin and Michigan still allow the mass slaughter of potential coasters in most of their tributaries, Minnesota and Ontario have applied their one-fish limit in every stream at least up to the first migration barrier. The new state and provincial regs, which went into effect in 2005, are by far the best news coaster advocates have ever received. Minnesota and Ontario anglers report more and bigger coasters already, though it will probably be at least five years before they see dramatic results.

The only good coaster data we have comes from Lake Nipigon, but it is applicable to Superior because growth and maturity rates are identical. The previous limit on Lake Nipigon (in place from 1990 through 2004) of two coasters over 18 inches protected only 22 percent of the fish on South Bay Shoal, a major spawning bed. The year-old limit of one fish over 22 inches (also in effect in Ontario's Lake Superior waters) is protecting 87 percent. Rob Swainson of the Ontario Ministry of Natural Resources, the godfather of North American coaster rehabilitation, predicts a "huge" and speedy improvement in the Nipigon population and a slower but still impressive one in Superior's. When he took over coaster management in 1988 the fish were presumed extirpated from the Nipigon River (which meets Lake Superior north of Thunder Bay). When he asked his colleagues for coaster data they told him there weren't any.

Destroying brook trout habitat has long been a criminal offense in Ontario, but because managers assumed there was none left they'd been allowing Ontario Power Generation to flush and fill the river as if it were a toilet bowl, stranding eggs, fry and invertebrate prey in the process. Swainson got that stopped two years after he arrived, then set about the Herculean task of convincing the angling community that you can catch lots of brook trout or eat lots of brook trout, but that if you do the latter, you won't do either for long.

In 1989, despite an ugly confrontation with the fillet-and-release crowd-namely the Ontario Federation of Anglers and Hunters (OFAH)-he implemented a limit of two fish over 18 inches in Lake Nipigon and the Nipigon River. Seven years later-after another ugly confrontation with OFAH-he implemented a one-fish, 20-inch limit in the Nipigon River and Superior's Nipigon Bay. A year ago, when he proposed the one-fish, 22-inch limit for all Canadian coaster waters including Superior's tributaries to the first migration barrier, OFAH shrieked louder than ever, claiming that such a limit at the bottom of the tribs was anti-sportsmen and anti-father-and-son. So Swainson and his colleagues suggested that perhaps the trib limit could be one fish over 22 inches or one fish under 10 inches. This time, however, there was so much support for coasters among enlightened anglers that they shouted the proposal down.

Some coasters-the Tobin Harbor and Lake Nipigon strains, for example-are known to spawn in the lake (on shoals at the mouths of rivers or over upwellings of groundwater). But others-maybe most-spawn in feeder streams. In order to shut down the slaughter, not just in Canada but in Minnesota as well, managers had to show doubters such as OFAH that coasters need tributaries. Providing the evidence was graduate student Silvia D'Amelio of Trent University in Peterborough, Ontario. D'Amelio compared the DNA of trout captured in the tribs to that of trout captured in the lake and found that fish from both habitats were part of the same population, thereby dismantling the widespread superstition that coasters depend only on the lake. "My research showed that not all tributaries within Lake Superior contribute to the coaster presence within the lake," she writes me. "However, all the tributaries I looked at seem to have the potential to do so. Because coasters are not unique unto themselves, it is not possible to create a coaster broodstock. You can, however, create a broodstock with the potential to produce coasters. The key is in finding the trigger(s) that cause some brook trout to make the switch from resident to coaster. The most important point to remember for rehabilitative stocking is that to maintain the long-term integrity of these populations, closely related populations should be used to rehabilitate each individual tributary. Using a single source for the whole lake could greatly hamper the long-term survival of these fish."

One of the environmental triggers is obviously weather. Many of the small North Shore rills that ripple with brookies in May dry up in July. The fish don't have a choice; they have to go out into the lake, at which point they become coasters even if they're two inches long. In some cases fish above the barriers are genetically distinct from fish below, but when they get swept over the falls they apparently migrate to the lake also. There's a coldwater trickle collected by Superior near Swainson's house that produces no trout of its own; yet every spring it is full of young of the year brookies. In summer they're gone. "Brook trout have very plastic life histories," observes Trout Unlimited's watershed programs director Laura Hewitt. "Full siblings can be two inches and living under an ice shelf and two feet and living in open water."