In the Bedrooms of the Bull Trout
Lorne Fitch, P. Biol.
The tug upstream seems inexorable, an urge not to be denied or ignored. Up bull trout swim, from the wide expanses of river, from the comparative security of deep pools and boulder-choked riffles. Upstream, against a rapidly increasing current, in a channel that narrows and gets shallower. Upstream, where water temperatures drop perceptibly and the medium becomes so clear fish appear to be suspended rather than immersed.
Streamlined, appearing much like a baseball bat with fins, bull trout move in a timeless migration. Their destinations are the spots where each emerged from the stream gravels some five to ten years earlier. Each survivor has bulked up substantially. Nothing escapes them; suckers, mountain whitefish, big stoneflies and the occasional mouse, vole and snake. To get big you have to eat big.
Bull trout are the ultimate aquatic predator, at the top of the watery food chain. Think of them as scaled grizzlies, with gills. Nowadays a big one might top out at four kg. In earlier days, remembered still by elderly anglers, a big one might stretch over a saddle and dangle nearly from stirrup to stirrup. In the waters of their spawning tributaries these giants would only be partially submerged.
Their movements upstream are anything but random. The magnet that pulls, attracts them, is the unique combination of cool ground water bubbling up from some subterranean reservoir through gravels shaped from the persistent grinding action of erosion. Context here is everything. It takes a watershed, not just a stream, to meet bull trout needs for the biological imperative of replacing themselves.
Forests, generally of the old growth variety, with thick underlays of absorbent mosses capture and store snowmelt and rainfall. This water, the unheralded treasure of forests, slowly is entrained below the surface. There it is then meted out just as slowly to add to streamflow. That these streams flow in the winter when all else seems frozen is the magic of this unseen supply of water. Bull trout appreciate it more than we seem to, for their eggs are deposited in the gravels in the fall and survival is dependent on this interplay between surface and ground water.
The seeps and springs are not often obvious to our eyes. What was obvious to early hunters, trappers and anglers was the autumn splashing of female trout absorbed in moving gravels. Around them, like teenagers at a high school dance, the males vied with each other for position. Often these fish were of a size that the shallow riffles couldn’t provide enough depth. Heads, fins and backs would protrude into the alien environment of air. To be successful in the dance of sex requires bull trout to comprehend the nuances of water movement, depth, velocity and changes during the time of egg incubation. The combination must be one of hydrological experience and clairvoyance.
From the memories of early outdoorsmen a faint picture of bull trout ecology and abundance emerged. More detailed biological investigations, done recently, have validated early observations of bull trout migration and favored destinations. Alarmingly, more comprehensive inventories have shown diminishment in bull trout populations generally and extirpation of some.
In the Oldman River watershed bull trout are missing from 70% of their former range. Historically trout populations (both bull trout and westslope cutthroat trout) were to be found as far downstream as present day Lethbridge. A combination of overfishing and dramatic habitat shifts pushed these populations into the far reaches of the Oldman watershed. Even there, in isolated spots there is no security from persistent land uses that continue to threaten their existence.
I get to play fisheries biologist again, for a few days, on one of the ongoing inventories of bull trout in the upper Oldman watershed. This work, done jointly by the Alberta Conservation Association and Fish and Wildlife, represents the systematic collection of good data to inform better land use decisions. On a late and crisp September day I pull on my chest waders and accompany Matthew Coombs, the only fisheries biologist for southwestern Alberta. On paper Matthew has a small area in which to ply his trade- just the entire headwaters of the Oldman watershed from the US border to the boundary with the Bow watershed. It reminds me, painfully, of the minimal priority placed on fish by the province of Alberta.
Matthew warns me the waters of Hidden Creek, a tiny and seemingly insignificant tributary to the upper Oldman River, are very cold. Fresh snow ices the peaks of the continental divide and frost coats the ground. None of this registers until my feet desert me on the slick boulders and I stick an arm in the water to steady myself. The water is numbingly cold. As I wring out my shirt sleeve I marvel at creatures that make this glacial medium their home.
Hidden Creek enters the Oldman River tumbling over bedrock and boulders. Not much wider than I am tall, it joins the larger river discretely, without fanfare. It seems to fit its name well. Before a logging bridge over the Oldman River provided easier access a watery moat kept the creek secure, free from all but the most persistent explorer. The headwaters of the stream wrap themselves around the base of Tornado Mountain, the highest peak of the southern High Rock range, part of the continental divide. Hidden Creek’s watershed is not untouched, but at most is only nibbled at with old seismic lines and small clearcuts in the shadow of Tornado Mountain. Compared with the logging footprint in drainages to the north and south, Hidden Creek looks relatively pristine.
Except, of course, for the mouth of the valley, where a large clearcut focuses the eye as Hidden Creek enters the Oldman. Walking from the marginal buffer of unlogged forest adjacent to the stream into the clearcut is like a trip from soft broadloom to a city sidewalk. One is soft, spongy and shaded; the other hard, unyielding and bright. The buffer seems like an administrative abstraction rather than a logical solution to protecting water quality. How can we think the answer is to parcel the landscape into discrete, unrelated bits when all work together in unity? Bull trout might see this industrial dismemberment of the landscape as reductionist and an anathema.
A fence of aluminum rods directs fish into a mesh trap. The materials of the trap are modern but the technology is of the Stone Age. One bull trout has been fooled by the labyrinth. We net it and anesthetize it with clove oil- a similar formulation has been used for generations to sooth the pain of toothache in humans.
The gills open and close, breathing in the aqueous tranquilizer until the fish no longer struggles and is quiescent. Scarred from life in a turbulent environment it is as long as my arm and likely heavier than it as well. Matthew gently squeezes along its sides and announces it is a spent male, probably returning from earlier action. Using the equivalent of a grocery store scanner Matthew determines it has an imbedded chip- an identity device- from an encounter with another fisheries biologist. Like a can of corn this bull trout has a number and few secrets. The world of electronics has taken much of the mystery out of the lives of wildlife. Conversely, the use of technology has sensitized us, with better data, to issues of species biology and survival, especially those critters hovering on the edge.
Measurements done the trout is placed in a tub of fresh water and gently rocked back and forth. The anesthetic wears off quickly. Holding him to recover, he seems like 100% muscle, arching and twisting in my grip, displaying a power disproportionate to size. On return to the stream, with a disdainful flip of his tail he disappears downstream amid the turbulence. I have touched and connected with a creature that represents the outcome of 10,000 years of trial, error, adaptation and evolution. It fits here perfectly.
One bull trout does not a story tell though. The number of bull trout that seek out Hidden Creek to spawn does. Extensive trapping over a two year period by the Alberta Conservation Association indicates that amid all of the tributary streams Hidden Creek is the hands down bedroom of choice for nearly 8 out of every 10 bull trout. Hidden Creek is the epicenter for about half of all bull trout reproduction in the upper Oldman River watershed. We may not understand all of the virtues of this one tiny stream, but bull trout do.
Yet, a population cannot afford to put all its eggs in one basket or, as is the case for bull trout, in one stream. Bull trout have hedged their bets, over time, by spawning in a number of streams in the upper Oldman. By spreading out, disaster in one stream is compensated for by success in another. The choices have narrowed however. In the upper Oldman the list of streams that attracted spawning bull trout has shrunk by at least three since the late 1950’s. The quality of many of the remainder is dubious.
Dutch Creek, the next downstream tributary to the Oldman is a river by comparison to Hidden Creek. Despite its size less than one out of 10 bull trout choose it as a spawning destination. In Dutch Creek the stories of big bull trout and many of them from the dusty archives stored in the memories of elderly anglers are hard to square with today’s reality. Dutch Creek (and its near twin, Racehorse Creek) are watersheds checker-boarded with clearcuts. A little cyber trip on Google Earth shows the footprint of logging in these watersheds to be extensive.
The history of large scale, commercial logging dates back 60 some odd years, following construction of the Forestry Trunk Road. In many respects, this trail, with an initial rationale for forest protection from fire lit a fire storm of resource exploitation that hasn’t cooled yet. Extracting the wealth of our forests is a largely one way affair; resources go out and the legacy of their removal lingers to haunt subsequent generations. Past generations of bull trout had to contend with poachers using a variety of contrivances. Angling isn’t the issue of today. What is troubling today is the change in landscape integrity and stream quality from decades of industrial (and recreational) use.
We slip on our chest waders again to count bull trout redds in a reach of Dutch Creek. Redds are the “nests” bull trout mothers excavate in the gravels. First on their minds is the selection of an appropriate spot, an inscrutable science to we who live in air, not water. What seems evident is the female must sense the presence of an intergravular flow of water. That flow is crucial to provide oxygenated water to the incubating eggs and to flush away metabolic wastes. Additionally, that flow must persist throughout the overwinter incubation period until the eggs hatch in the spring. This explains why ground water is so key to bull trout.
If the water-witching is successful the female then turns on her side and with a vigorous wave-like undulation of her body and tail uses a hydraulic shock wave of water to dislodge stream bed gravels and cobbles. This blast of water flushes away sediment and creates a depression. Into this depression she lays some of her eggs, attended to by a randy male who completes the conjugal unit. The process is repeated, moving upstream, covering the previous excavation and creating a new one for more eggs. Over the course of this the female will move several times her own weight of gravels and cobbles. Counting these redds provides an indication of population size; monitoring year to year helps gauge population trends.
This is one of those clear, bright blue days of Indian summer. Snow capped peaks give evidence the summer season is ending but the day tells the lie it will persist. Dutch Creek is clearing; a rainstorm the previous day clouded the water with sediment. What happens in the uplands of a watershed inevitably follows the fundamentals of gravity. The footprint of disturbed land, the clearcuts, roads and trails, continues to bleed sediment and even a slight rainstorm mobilizes that sediment.
We walk upstream, in the channel, looking for the telltale signs of redds- oval signatures of stream gravels cleaned of their patina of algae and silt. On reach after reach I mentally challenge myself to discern the signs that would indicate a bull trout would find the place pleasing. So many of the reaches seem to have the right stuff; suitable water depth, sufficient velocity, appropriately sized substrate and overhead cover. But we find few redds.
Stymied, we consider the reasons for trout rejection. The gravel holds a clue. It is solid under our feet and when we probe it with our measuring sticks it yields only to excessive force. Despite the appearance of being clean it takes a human scaled effort to excavate a depression. This is not the usual loose, friable substrate where a step leaves a footprint behind. Alarmingly, this is pavement, aggregate cemented together with an outward appearance of a roughed surface. Without pickax or jack hammer no trout could penetrate this stuff.
The count for a six km wade is a disappointing 10 redds. In Hidden Creek nearly 10 times as many redds were counted in a four km stretch in 2008. None of this is surprising when one connects the dots between land use and fish populations. Logging, the predominant land use has a greater impact on streams than on forests because of the long term nature of effects in and on streams. A subtle and less evident change is in runoff- both the amount and the speed of delivery. For a species like bull trout that are reliant on ground water, subtle shifts in hydrologic response from forest harvest is a problem.
The connection between logging and streams is less subtle when roads are considered. The scientific literature abounds with information on the effects of logging and associated roading on trout populations. Roads funnel, streamline and contribute to sediment delivery. It is evident that wherever studied the impacts are real, measurable and negative.
A clear conclusion, across the research is that as road densities (and the number of stream crossings) increase, the proportion of streams that support strong, healthy populations of trout diminish. All aquatic species have adapted to periodic disturbance but roading increases sediment delivery sometimes by an order of magnitude greater than the natural background levels. But, sediment delivery is just the tip of the problem.
Decades of research in experimental watersheds shows only a fraction of the sediment eroded will work its way downstream, out of the stream system. Measurement in the usual short monitoring period consistently underestimates sediment yield from land use. Much, especially the bedload sediment is stored in the streambed and within the substrate. Researchers term the residence time for that sediment as “centennial” time. There it lingers, migrating downstream as little as a few meters a year to perhaps a kilometer a year in larger rivers. Mike Miles, a fluvial geomorphologist, calls it “a slow moving train of sediment”.
The impacts are neither fleeting nor transitory. As the sediment settles in for the long haul it reduces the depth and quality of pools. Less evident is the infilling of the interstitial spaces between the gravels, where trout eggs incubate and insects (the building block of fish flesh) live. As it infiltrates the gaps some of the sediment bonds, effectively cementing together the substrate materials. This cemented layer, which may extend down some distance into the substrate, becomes resistant to periodic flushing flows. Reduced permeability of the substrate, the ability of water to percolate up or down, becomes another impact on bull trout. Like tar in a smoker’s lungs the accumulated sediment squeezes the life out of streams. So the forest may regrow quickly but the legacy of logging will persist as an influence on streams and all the aquatic creatures over centennial time.
Work done by biological consultants on the cumulative effects of access roads in the upper Oldman watershed indicates the problem faced by bull trout (and westslope cutthroat trout). In 1950 there were 177 stream crossings in the entire upper watershed. By 2001 this had ballooned to 2803 crossings. Most of the upper Oldman watershed had, in 1950, a very low density of crossings- from 0 to 0.5/km². By 2001 only a tiny fraction of the watershed (notably Hidden Creek) had such a low density of crossings. Dutch and Racehorse creeks have stream crossing densities that range from two to more than 4/km². The road densities for Dutch and Racehorse creeks exceed any threshold recommended for the continued survival and viability of bull trout by a wide margin.
We may have inadvertently doomed trout populations in logged watersheds to a slow, drawn-out and anticlimactic end, like a candle finally burning out. The overwhelming and unfortunate legacy of landuse decisions and their cumulative effects will haunt these watersheds until the last native fish slips away and all that remain are ghosts. Without an ecosystem approach and more balance in decisions about land use soon we might be arguing over the last bull trout. By then it will be too late. Watersheds with an extensive logging footprint need quick remedial actions and mitigation involving road closures and rehabilitation if native fish are to be saved.
We should be using bull trout as an indicator, an icon of the health and integrity of our headwaters. Their continued presence and increasing abundance would provide a strong signal we know how to manage these vital watersheds. And, to many of us who see bull trout (and all native species) in that context it is about sense of place, centuries old. Bull trout know place, know how to return home and they know where they came from. All they require of us is to acknowledge their presence and needs as well as share the watershed with them in ways that don’t contribute to them winking out of existence.
Sadly, our industrial focus for the Forest Reserve is not far removed from the pursuit of buffalo hides and tongues; the resource economy of logging is equally simplistic, rapacious and blind. It would appear the decline of bull trout provincially and in the Oldman watershed has slipped beneath the consciousness and conscience of the land manager, the Forest Service. In the words of David Brower, founder of the Sierra Club, it is as if “the relationship of everything to everything else and how it is not working is so comprehensive no one can comprehend it”.
Splashing up Dutch Creek puts into sharp focus the treasure that Hidden Creek represents. To log the Hidden Creek watershed, to liberate sediment for decades to come, to turn the stream into a small facsimile of Dutch Creek (and others) seems retrogressive. Neither the Forest Service nor the timber industry have yet demonstrated the soft, sensitive, careful touch required to maintain bull trout habitat and to keep sediment from streams.
In the case of Hidden Creek the cost of repeated mistakes in timber harvest is too high to let them keep trying. Pierre Trudeau, the bogeyman for Alberta, once famously said, “The state has no business in the bedrooms of the nation”. To paraphrase that, logging has no business in the bedrooms of the bull trout.
Lorne Fitch is a Professional Biologist, a retired Fish and Wildlife Biologist and an Adjunct Professor with the University of Calgary.