THERE WAS A MORNING, back in time, when this region of British Columbia they call the Kootenays changed from ice and rock to land and water, from Pleistocene to Holocene. This morning can be described neatly in multiples of ten; at the beginning of the morning, some ten millennia ago, the glaciers lay across the landscape a thousand metres thick. At the end of the postglacial morning, a thousand years later, the continental glaciers were gone.
One of the very first inhabitants of the region, arriving literally on the melt-waters of receding glaciers, is a fish. This fish is an extravagant gift from the Pacific Ocean to the interior. It is an elusive flash of molten silver, a lustful reproductive torrent of fire-engine red, a marvel of adaptation, an icon of regional culture, and a pawn of industry. Its name has cycled through various cultures as kukeni, redfish, kickininee, silver, Oncorhynchus nerka, kokanee. These cultures have depended on it, studied it, even brought it close to annihilation, but none has ever completely possessed it.
In the early 1960s, the diminutive kokanee of Kootenay Lake began a radical transformation. Once herring-sized, kokanee were now achieving lengths up to 45 centimetres and weights of 3.5 kilograms, nearly as large as their saltwater cousins, the sockeye salmon. The kokanee's fine red flesh and sportiness made them a welcome addition to the creels of both local and visiting anglers, who now could chase the bulked-up kokanee as well as fish for the world-class Gerrard rainbow trout.
This transformation was attributed to the work of biologist Peter Larkin of the BC government's Game Commission. He felt that the fishery at Kootenay Lake, in southeastern British Columbia, was not reaching its full potential, and he had an idea how to enhance it.
In the spring of 1949, Larkin made a trip to Waterton Lake, Alberta. Using a fine-meshed net, he trawled the bottom of Waterton Lake and captured a small population of a tiny crustacean called Mysis. This organism was found in Waterton and other lakes east of the Rockies, but not in BC lakes. Larkin's idea was that Mysis (also known as the "opossum shrimp," for its nocturnal habits) would be an ideal food source for the Gerrard rainbow trout.
The Gerrards fed on plankton when they were fry, then switched to a diet of kokanee once they were mature. Larkin felt that the crustacean might become an intermediate food source that would help the growing rainbows as they moved from juvenile to adult food. Accordingly, he released Mysis into Kootenay Lake in 1949, and again in 1950.
As the newcomer slowly worked its way into the lake's ecology, biologists duly included it in their periodic monitoring regime. Kootenay Lake is remarkable in many ways, but one of the unique aspects of this rather remote mountain lake is its lengthy legacy of monitoring. Beginning as early as the 1930s, scientists from as far away as Ontario have made the trek to the lake with their sample bottles and trawling nets, making the time-consuming and often tedious measurements that form the basis of limnology, the scientific study of inland waters.
For the first several years, Larkin's species introduction was written off as a failure since the monitoring found Mysis in only vanishingly small quantities. This was not unexpected. In the lengthy history of aquatic introductions around North America, certain species caught on and others didn't, and it was hard to predict outcomes in advance.
Far off in the East Kootenay community of Kimberley, another interference was taking place. In 1953, Cominco's massive Sullivan lead-zinc mine began producing phosphate fertilizer as a by-product.
In the industrial style of the day, the fertilizer plant was a messy operation, producing large quantities of phosphorous-laced wastewater, which was dumped unceremoniously into the adjacent Saint Mary River. Tumbling down the rapids of the Saint Mary and into the Kootenay River system, this concentrated pulse of phosphorous acted like an ecological steroid. Quickly snapped up by ravening algae and spiralled upward into Kootenay Lake's food chain, Cominco's phosphorous boosted kokanee numbers as well as their size at maturity.
By 1962, fertilizer production was in full swing. Phosphorous fertilizer tonnage, as well as phosphorous pollution, increased steadily to a peak in 1967. Around Kootenay Lake, people noticed a decrease in the renowned clarity of the lake's water, and during hot summers, floating algae mats appeared, which no one could remember seeing before.
Meanwhile, the Mysis had been biding its time in the lake, slowly adapting to the conditions of its new home. In the early 1960s it began to show up in the monthly monitoring reports, and scientists belatedly realized that the Mysis transplant had indeed been successful.
Peter Larkin was belatedly applauded for his pioneering Mysis work. The media picked up the story, and soon Mysis was the instant solution for overfished and unproductive lakes. Based on the Kootenay Lake example, Mysis introductions were made in Okanagan Lake, the Arrow Lakes and several other lakes in BC, the United States and even Scandinavia.
By the early 70s, however, the Mysis data began to set off alarm bells in the scientific community. The shrimp were now multiplying rapidly and feeding on Daphnia, the primary food of the kokanee, yet very few Mysis were showing up in the guts of either rainbows or kokanee. The normal algae to Daphnia to kokanee to rainbow food chain was being disrupted by what the biologists dubbed "the Mysis shunt," which was algae to Daphnia to Mysis, period.
In other words, the Mysis were happily consuming, but rarely being consumed. Exploring further, the scientists stumbled onto a fundamental problem: the daily migrations of the light-shy Mysis were completely out of phase with the daily migrations of both kokanee and rainbows. The cagey, opossum-like shrimp would rise at nightfall to feed and then migrate back down to the bottom to avoid predation during the day. The fish, in their turn, carried out the opposite diurnal migration, feeding in the surface layers in the mornings and moving to intermediate depths later in the day and at night. Because of the great depth of the lake, the Mysis were able to avoid being eaten by either kokanee or rainbow.
As the biologists pored over their reams of lake and fish data, a new and disturbing picture emerged. They realized the Mysis was actually not responsible for the overall enhancement of the fishery. Cominco's phosphorous pollution was in fact the main engine behind the increase, and the Mysis introduction was actually a tragic mistake.
Not long after Mysis and Cominco, a further interference was added to this already complex and volatile mix. In 1972, Libby Dam was installed across the Kootenay River near the bottom of its southward loop into Montana. This dam administered the coup de grace for the artificially inflated kokanee fishery. The long stretch of dead water created behind the Libby Dam, euphemistically named "Lake Koocanusa", caused virtually all the nutrients to settle out, not only those from the Cominco plant, but the naturally occurring ones as well.
In a final and ironic twist to the story, settling ponds were finally installed at the Cominco fertilizer plant in 1969, removing most of the phosphorous from the wastewater, and in 1987 the fertilizer plant was shut down altogether. Cut off from its phosphorous supply and disrupted by the Mysis, the lake's food chain started into freefall. Kokanee populations dropped dramatically. The kokanee-dependent Gerrard rainbows, the trophy fish of Kootenay Lake, suffered much the same fate. Fishing success rates were pathetic. The same charter, tackle, moorage, food and accommodation businesses that had done so well during the phosphorous pollution years were now either out of business or complaining loudly. What happened to the vaunted Mysis solution? Why wasn't it working? they asked.
The scientists who had worked on the lake over the years were called in and began poring over data on nutrient loading, temperature gradients, zooplankton, Mysis and fish reproduction, looking for a solution. One unique proposal that came out of this process, and which was actually seriously considered, was to install a string of swimming pool lights along the bottom of the lake. The light would drive the Mysis back up toward the surface, where they could be eaten by fish.
Another blue-sky proposal was to install a giant circular air bubbler on the bottom, creating an upward current that would sweep helpless Mysis into the waiting jaws of kokanee and juvenile Gerrards. However, one of the mathematically inclined scientists pulled out a calculator and showed that a bubbler of a scale large enough to bring shrimp to the surface would also create a huge downward vortex powerful enough to suck in canoes and water-skiers.
Ken Ashley, a bright young fisheries scientist from UBC, proposed the radical solution of fertilizing the lake. With support from the fledgling Columbia Basin Fish and Wildlife Compensation Program, the Fish and Wildlife Branch approved a five-year pilot fertilization experiment. It was to be the largest lake-fertilization project ever undertaken anywhere. A pair of huge fertilizer tanks were mounted on a barge with a pusher tug behind it, and beginning in April 1992, this bizarre craft, with a mixture of dissolved phosphorous and nitrogen in its tanks, made a weekly ten-kilometre run down the middle of the North Arm of Kootenay Lake, dribbling the mixture overboard at a predetermined rate. The scientific community held its collective breath and waited for the results. Contrary to expectations, the kokanee did respond positively to fertilization.
Arriving in Nelson just as the Kootenay Lake fertilization program was being proposed, I was deeply offended by it. Knowing nothing of the local situation, but having had my fill of decades of industrial solutions to ecological problems (problems largely caused by industrial development to begin with), I went storming into the Fish and Wildlife office, demanding to talk to a fisheries person. Jay Hammond, the regional fisheries biologist, received me and patiently walked me through the basics of the phosphorous history of Kootenay Lake. An hour later I had the picture and remember making the comment, "So there's really only three options here. Either you let the fishery die, you blow up Libby Dam or you fertilize."
The Kootenay Lake phosphorous story, as well as the Libby Dam experience, are ecological moral tales, modern fables. They show that once we touch a system, it seems we have to keep on touching it. When we have damaged an ecosystem (a river, for instance) with technology (a dam), we may have to use more technology (fertilization) to repair it. This runs counter to a strong current in contemporary thinking, which is that the best way to manage or repair an ecosystem is to leave it alone. The Kootenay Lake experience suggests a different, more interventionist paradigm.
The Mysis tale is a parallel one, teaching us a history lesson. It is easy to condemn Peter Larkin for an unwise and destructive biological introduction, to write him off as an unthinking ecological cowboy. It is more difficult, but more instructive, to recognize that Larkin was a well-respected scientist at the time; that he was following a lengthy tradition of purposeful alien biological introductions; and that his example was eagerly copied by his peers across North America and elsewhere. As Tom Northcote, another early Game Commission biologist admitted, they were looking for a "quick fix," and the Mysis seemed to be it.
Noted fisheries scientist Carl Waiters feels that Larkin's idea of filling a perceived gap in the food chain was innovative and imaginative. The problem, Waiters says, was that scientists were focused on "first-order" impacts on ecosystems and had no understanding of second-order, indirect effects. Waiters does fault Larkin for not asking the obvious question about Mysis while it was still confined to Waterton, its home lake: if this shrimp is such perfect fish food, how come it is so rarely eaten?
Folktales and children's stories help ease young people into the complex and ambiguous world of adult life. Perhaps these ecological moral tales of fish and shrimp can help ease us adults into the complex and ambiguous world of living with nature, rather than in spite of it. They help us understand that ecosystems are complex, our actions upon them are far-reaching, human arrogance comes at a price, and that we are not god-like in our wisdom.
This is an excerpt from Kokanee: The Redfish and the Kootenay Bioregion, published by New Star Books in 2002. Don Gayton is an ecologist and author.…