Herd Management for Bull Trout A Historical Reconstruction
HSTS 470X
For Drs Minear and Robbins
By Ben Walczak
INTRODUCTION
The bull trout is a very sensitive indicator of overall riverine ecosystem health in
the Pacific Northwest. Many biologists believe that bull trout are particularly sensitive to
environmental change. As Rieman and McIntryre point out, “They are recognized as a
‘species of special concern’ by State management agencies and the American Fisheries
Society (Williams and others 1989) and as an ‘indicator species’ by the Forest Service,
U.S. Department of Agriculture.”
Until recently, the bull trout was considered an inland form of the Dolly Varden
(Salveninus malmo), an anadromous trout found in coastal streams. In 1978 biologists
decided it was a separate species, and named it Salvenlinus confluentus. The original
range of the bull trout is the Pacific Northwest, including western Canada, southeastern
Alaska, Washington, Oregon, Idaho, and western Montana. (See Figure 1 distribution
map).
The general life history of bull trout is characteristic of chars. Like other char,
bull trout have multiple life-history forms. There are two distinct forms, resident and
migratory. Resident populations are often found in small headwater streams were they
spend their entire lives. Migratory forms live in tributary streams for several years before
migrating downstream to a larger river. Migratory bull trout spend several years in larger
rivers or lakes before returning to tributaries to spawn. Anadromy has not been
demonstrated in bull trout but may have been important in the past.
Other physiological aspects of bull trout are that migratory bull trout tend to be
much larger than resident fish. Bull trout mature when they are between 5 and 7 years of
age. These mature fish may spawn each year or in alternate years. Bull trout require a
narrow range of temperature conditions to rear and reproduce. Water that is warmer than
15C is thought to limit bull trout distribution. Many researchers have concluded that
water temperatures represent a critical habitat characteristic for bull trout. Bull trout eat
terrestrial and aquatic insects, macrozooplankton, mysids, and fish. Fish are common in
the diet of individuals greater than 110 mm. Large bull trout may feed exclusively on
fish.
Populations of bull trout are prone to habitat disruption and fragmentation
because they appear to have more specific habitat needs than other salmonids. Channel
stability, cover, temperature, and migratory corridors all influence bull trout distribution
and abundance. Dambacher and Jones (1997) found that seven habitat variables were
significant descriptors of the presence of bull trout: high levels of shade, high levels of
undercut banks, large wood debris volume, large woody debris pieces, high levels of
gravels in riffles, low levels of fine sediment in riffles, and low levels of bank erosion.
Figure 2 contains many of these characteristics. When these seven factors are degraded
or removed bull trout suffer. Habitat degradation and its link to the decline of bull trout
are well established; “Only 18 percent of all bull trout populations and stream segments
rangewide are not threatened by degraded conditions. It should come as no surprise that
fisheries biologists frequently report that bull trout spawning strongholds are associated
with unmanaged watersheds with near pristine streams.” (Knowles and Gumtow)
AGRICULTURE
Knowles and Gumtow feel that, “The bull trout’s problems almost certainly began
with impoundments for irrigation.” Irrigation creates major problems for bull trout.
Irrigation reduces instream flows. Additionally, the water that returns to streams tends to
be significantly warmer than the water that was taken out. This may create a thermal
barrier that can serve to behaviorally block fish from spawning areas. Up to ninety
percent of the flow in the lower portions of some rivers is irrigation return flow.
Irrigation also adds sediment to streams. Lastly, unscreened irrigation diversions
frequently kill migrating juvenile bull trout.
The construction of the dams on the Columbia River drainage system added to the
loss of free flowing streams because corridors for migrating bull trout were closed.
Between irrigation and the dam building many, if not most, of the migratory bull trout
were wiped out. These migratory bull trout linked the resident bull trout to much of the
gene pool making the populations highly fragmented and isolated. Passage barriers delay
or even block upstream migration of adult bull trout to their spawning areas.
Many of these problems can be traced back to federal programs to supply
electricity to the region and irrigation water for agricultural crops. Agriculture began in
the Columbia River basin during the 1830s. These first agricultural practices did not
impact the region much but by the 1840s the Pacific Northwest was on the verge of
tremendous change. The discovery of gold in California was the catalyst for this change.
Wheat began to become a major export crop; “in 1867 Walla Walla merchants
experimented in shipping both flour and wheat to Portland” (Robbins and Wolf). This
was to be the first of many shipments of grain down the Columbia River. Railroad
construction in the 1880s led to an increase in wheat production to more than 2,500,000
acres within the decade. All of these water developments leading to increased
agricultural production also helped lead to bull trout’s present-day problems.
MINING
Gold was discovered in the interior during the 1860s and was the cause for a great
influx of people to the region. Gold was found on tributaries of the Snake River and
along streams in the Blue Mountains. The gold rush was brief but mining activities
impacted bull trout. Mining in the 1800s was ecologically very disruptive. Entire
hillsides were logged and then sluiced away, streams were silted, and riparian habitats
were destroyed. Bader et al. point out this problem, “Mine-related diversions often
dewater entire streams, and toxic discharges from improper mining operations and failed
tailing ponds are responsible for large fish kills.” Robbins and Wolf further emphasize
the environmental impact of gold mining:
Theodor Kirchoff, who passed through the mining country around Mormon Creek in 1868, offered a glimpse of the new ecological reckoning that was dawning on the eastern country: ‘elevated troughs, long sluices, uprooted ground, raw piles of sand and tailings, heaps of cleanly washed stone, and water for mining rushes in ditches and wooden conduits among boulders and trees. In her book Nancy Langston goes one step further when she stated, “When
miners started using steam dredges, they did not just alter riparian zones-they completely
removed them.” Due to the large population influx of miners, large cattle herds were
brought into the Columbia Basin to feed the miners and timber was logged to supply
mining timbers.
LOGGING
The demand for timber from mining brought the first large-scale cutting of
forests. Gildemeister makes the point that, “There was a limit of 30 fish per day and 60
per week on the Silvies river until logging came in the 1930s. After that there was heavy
siltation in the streams, the limit was dropped to 10, and it was difficult to catch that
many.” Before 1900 most of the logging of lumber was only for local demand, primarily
mining timbers. This was because there were abundant forests in the Great Lakes states
and the eastern United States and there was no means of transporting the timber to a
market. Once the transcontinental railroad was completed in 1884, the pace of logging in
eastern Oregon began to pick up. New entrepreneurs, such as David Eccles, began to
construct rail lines along streams and into the mountains. Along these railways, huge
amounts of timber were harvested. In many areas timber was taken from every gulch and
creek that was accessed by the railways. By 1910 the timber market was glutted and
remained that way until the Second World War. However, logging still went on because
of the amount of debt lumbermen had. At the end of World War Two, timber companies
began to utilize the gas-powered chain saw and became more efficient with its addition
and that of other mechanized tools. Logging in this period switched to clearcutting
because it was more efficient.
Over a period of time, these intensive logging practices helped to induce
landslides. Forest Service inventories of landslides indicate that most were associated
with logging roads, many were associated with clearcuts, and few took place in pristine
forests. A good example of this is Karen Pratt’s work. Karen Pratt has studied bull trout
in Lightening Creek, a tributary to the Pend Oreille River in northern Idaho, for more
than a decade and documented the periodic landslides resulting from logging and roads.
During her period of study, Lightening Creek became a braided stream due to large
sediment loads from landslides and bull trout numbers declined.
GRAZING
To feed the miners entrepreneurs began to move large numbers of sheep and
cattle into the Columbia River basin. Cattle and sheep grazed throughout the Northwest
by the 1870s. In the Blue Mountains, “Grass was so thick that cattle could survive the
winter without being fed hay. People could make a living just by reaching out their
hands for it.” (Langston). However ten years after settlers first drove their cattle into the
lush, bunchgrass filled valleys the range was already becoming degraded. Soon hay had
to be supplied during the winters and competition became intense. The summer alpine
range was the source of competition between three major groups; the small local cattle
ranchers, immigrant sheepherders running corporate owned sheep, and large out-of-state
cattle ranchers. This caused grasses to be trampled and eaten before they could grow or
even seed. Occupation meant possession so herders were reluctant to move their cattle of
the range even with the signs of overuse; “4,000 sheep would spend a month at a time in
one small meadow until nothing was left but dust and rock.” (Langston). Railroads
opening in the 1880s, in addition to increasing the wheat production increased the
pressure on the range. Railroads increased access to eastern markets. With so many
cattle in the area there was intensive use. Cattle, unlike sheep, are water-loving animals
and need constant sources of water. Cattle prefer to graze in creeks and wet meadows. In
addition to riparian vegetation destruction, improper grazing often leads to collapsing
streambanks, increasing sediment loads, and increasing the streams width-to-depth ratio.
Streams suffering such affects warm faster because they are wider and shallower.
In the mid 1880s the bubble broke. There was no grass left for anyone. By the
mid-1890s, the situation was ready to explode. Large corporations were running cattle on
public land and denying the small ranchers and sheep herders from water sources. Vast
bands of sheep and herds of cattle were crossing through the mountains to market.
Eventually all concerned parties recognized that unregulated grazing was devastating the
landscape and government intervention was welcomed.
FISHERIES MANAGEMENT DECISIONS
In 1906 the Eastern Oregon Fish and Game Association, which was organized just
two years earlier, released one million brook and rainbow trout into the streams of Union
county. Around the turn of the century brook trout were introduced into the rivers and
streams without consideration of the impacts this would have on native salmonids
through competition and hybridization. The brook trout is genetically close enough to the
bull trout to permit hybridization. Offspring of the bull trout/brook trout crosses are
infertile. Dave Buchanan stated that, “Brook trout have a higher fecundity rate and lower
age at first reproduction (2years old vs. 4 years old) so that when a bull trout and brook
trout occur in the same waters, the brook trout will numerically swamp the bull trout
because of their greater reproductive potential.” The introduction of additional other
non-native salmonids such as lake trout may also be a limiting factor.
“Throughout history, human overharvest of animals has been a factor in
extirpation.” (Buchanan et al.) Overfishing is a problem due to the fact that bull trout are
aggressive feeders and readily take lures or bait. This makes them susceptible to angling
pressures. In Gildemeister’s book, a long-time resident tells a story about the fishing in
the region:
Dolly Varden [bull trout] were common in Eagle creek in the 1940s and 50s with many over 2 feet long. They are no longer found there…. Early in the 1920s fishing was very good in the Minam river and the high lakes and it was always easy to catch fish, mostly rainbow trout and Dolly Varden [bull trout]. In the 1940s there were large populations of Dolly Varden in the Wallowa river during the fall when spawning started; this is when all of the native Dolly Varden were killed. Lastly, many fish managers regarded bull trout as a pest species because they
were such voracious feeders and specifically tried to exterminate it. Fish managers
deliberately tried to exterminate bull trout as early as 1913 and as late as 1990 by not
setting bag limits and in some cases netting them.
CONCLUSIONS
Bull trout were more widely distributed historically than currently. Bull trout
require high quality habitat to survive. Humans have degraded the environment through
agricultural expansion, logging and grazing practices, mining, and poor fisheries
management decisions. The degradation of uplands and riparian areas through overuse
for the lure of quick profits is the main factor causing distribution to shrink.
Bibliography
1) Buchanan, D., M. Hanson and R. Hooton. 1997. Status of Oregon’s Bull Trout: Life History, Limiting Factors, Management Considerations, and Status. Oregon Department of Fish and Wildlife. Portland, OR. 168pp.
2) Dambacher, J.M. and K.K. Jones. 1997. Stream habitat of juvenile bull trout
populations in Oregon, and benchmarks for habitat quality, Proceedings of the Friends of Bull Trout Conference. Calgary, Alberta.
3) Gildemesiter, Jerry. 1992. Bull Trout, Walking Grouse, and Buffalo Bones: Oral
Histories of Northeast Oregon Fish and Wildlife. Oregon Department of Fish and Wildlife. La Grande, OR.
4) Knowles, Craig and R. Gumtow. Saving the Bull Trout. The Thoreau Institute.
Oak Grove, OR. http://www.teleport.com/~rot/gumtow.html. Last accessed 06/04/01.
5) Langston, Nancy. 1995. Forest Dreams, Forest Nightmares: the Paradox of Old
Growth in the Inland West. University of Washington Press, ISBN: 0295974567 6) Pratt, K.L. 1992. A Review of Bull Trout Life History. In: Howell, P.J. and D.V.
Buchanan eds. Proceedings of the Gearhart Mountain bull trout workshop; August 1992, Gearhart Mountain, OR. Corvallis, OR: Oregon Chapter of the American Fisheries Society.
7) Rieman, Bruce and J. McIntyre. Demographic and Habitat Requirements for
Conservation of Bull Trout. Microfiche. Pp1-11. 8) Robbins, William and D. Wolf. 1994. Landscape and the Intermontane
Northwest: An Environmental History. U.S. Department of Agriculture, Forest Service. Pacific Research Station. General Technical Report PNW-GTR-319.
Figures and Cover Images
1) www.icbemp.gov. GIS Published Graphics. Ch2-28. Last accessed 06/05/01.
Figure 1. 2) www.bulltrout.org/picts/tean.jpeg. Last accessed 06/05/01. Cover and Figure
2.
Figure 1: Distribution
Figure 2: Example of Bull Trout Habitat