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