[Federal Register Volume 62, Number 114 (Friday, June 13, 1997)]
[Proposed Rules]
[Pages 32268-32284]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-15584]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
RIN 1018--AE29
Endangered and Threatened Wildlife and Plants; Proposal to List
the Klamath River Population Segment of Bull Trout as an Endangered
Species and Columbia River Population Segment of Bull Trout as a
Threatened Species
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
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SUMMARY: The U.S. Fish and Wildlife Service (Service) proposes to list
the Klamath River population segment of bull trout (Salvelinus
confluentus) as endangered from south-central Oregon; and the Columbia
River population segment of bull trout as threatened from the
northwestern United States and British Columbia, Canada, with a special
rule, pursuant to the Endangered Species Act of 1973, as amended (Act).
The Klamath River population segment, comprised of seven bull trout
populations from south-central Oregon, is threatened by habitat
degradation, irrigation diversions, and the presence of non-native
brook trout. The Columbia River population segment, comprised of 386
bull trout populations in Idaho, Montana, Oregon, and Washington with
additional populations in British Columbia, is threatened by habitat
degradation, passage restrictions at dams, and competition from non-
native lake and brook trout. The special rule allows for take of bull
trout within the Columbia River population segment if in accordance
with applicable State fish and wildlife conservation laws and
regulations. Pursuant to a court order, this rule is based on the 1994
administrative record. All available information, including current
data, will be considered prior to promulgation of a final rule. If,
after consideration of all available data, this proposal is made final,
it would extend protection of the Act to these two fish population
segments.
DATES: Comments from all interested parties must be received by August
12, 1997. Public hearings locations and dates are set forth in
SUPPLEMENTARY INFORMATION.
ADDRESSES: Comments and material concerning this proposal should be
sent to the U.S. Fish and Wildlife Service, Snake River Basin Field
Office, 1387 S. Vinnell Way, Room 368, Boise, Idaho 83709. Comments and
material received will be available for public inspection, by
appointment, during normal business hours at the above address.
FOR FURTHER INFORMATION CONTACT: Robert Ruesink, Field Supervisor,
Snake River Basin Field Office (see ADDRESSES section) (telephone 208/
378-5243; facsimile 208/378-5262).
SUPPLEMENTARY INFORMATION: Public hearings locations and dates are:
1. Tuesday, July 1, 1997, from 2:00-4:00 p.m. and 6:00-8:00 p.m.,
Ramada Inn Portland Airport, 6221 N.E. 82nd Avenue, Portland Oregon.
2. Tuesday, July 8 1997, from 2:00-4:00 p.m. and 6:00-8:00 p.m.,
Shilo Inn, 923 East Third Avenue, Spokane, Washington.
3. Thursday, July 10, 1997, from 2:00-4:00 p.m. and 6:00-8:00 p.m.,
Doubletree Hotel Edgewater (formerly Village Red Lion Inn), 100 Madison
Street, Missoula, Montana.
4. Tuesday, July 15, 1997, from 2:00-4:00 p.m. and 6:00-8:00 p.m.,
Shilo Inn, 2500 Almond Street, Klamath Falls, Oregon.
5. Thursday, July 17, 1997, from 2:00-4:00 p.m. and 6:00-8:00 p.m.,
Doubletree Hotel Riverside (formerly Red Lion Hotel), 2900 Chinden
Blvd., Boise, Idaho.
Background
Bull trout (Salvelinus confluentus) were first described by Girard
in 1856 from a specimen collected on the lower Columbia River. Cavender
(1978) presented morphometric, meristic, osteological, and
distributional evidence to document the separation between dolly varden
(Salvelinus malma) and bull trout. Based on this work, taxonomists have
recognized this separation since 1978 (Bond 1992). Bull trout and dolly
varden were officially recognized as separate species by the American
Fisheries Society in 1980 (Pratt 1992).
Although the bull trout is well accepted as a species among
specialists in the evolution and classification of salmonid fishes (R.
Behnke, in litt., 1993), some uncertainty remains regarding the
taxonomic status of bull trout among fisheries managers and industry
(WDW 1992, Platts et al. 1993). When discriminate function values were
used to separate populations of bull trout from dolly varden in the
Puget Sound, a normal distribution resulted rather than a bimodal
curve, which indicated that a clear separation of these species does
not exist (C. Kraemer, in litt. 1993). In addition, Kraemer (in litt.
1992; undated U.S. Forest Service (USFS) survey) observed the two
species spawning together, and suggested introgression may be
occurring. In contrast, Phillips et al. (1992) and Pleyte et al. (1992)
examined evolutionary relationships among six species of Salvelinus
using ribosomal DNA analysis, and found clear distinctions among all
six species. Their results suggested that dolly varden are more closely
related to arctic char than bull trout, and that bull trout
evolutionarily diverged from a line that gave rise to S. leucomaenis (a
char indigenous to Japan) rather than the line that gave rise to dolly
varden or arctic char. In addition, Cavender (1984) concluded that the
evolutionary distance between bull trout and dolly varden is
significant based on at least four separate chromosomal changes that
separate the two taxa, and that the two species cannot be considered
sister species based on those differences. As a result, the 1994 record
supports the distinction between bull trout and dolly varden.
Bull trout populations are known to exhibit four distinct life
history forms: resident, fluvial, adfluvial, and anadromous. Resident
bull trout spend their entire life cycle in the same (or nearby)
streams in which they were hatched. Fluvial and adfluvial populations
spawn in tributary streams where the young rear from 1 to 4 years
before migrating to either a lake (adfluvial) system or a river
(fluvial) system, where they grow to maturity (Fraley and Shepard
1989). Anadromous fish spawn in tributary streams, with major growth
and maturation occurring in salt water. Diverse life history strategies
are important to the stability and viability of bull trout populations
(Rieman and McIntyre 1993).
Bull trout display a high degree of sensitivity at all life stages
to environmental disturbance and have more specific habitat
requirements than many other salmonids (Fraley and Shepard 1989, Howell
and Buchanan 1992, Rieman and McIntyre 1993). Bull trout growth,
survival, and long-term population persistence appear to be
particularly dependent upon five habitat characteristics: (1) cover,
(2) channel stability, (3) substrate composition, (4) temperature, and
(5) migratory corridors (Rieman and McIntyre 1993).
All life history stages of bull trout are closely associated with
various forms of cover, including large woody debris, undercut banks,
boulders, and pools
[[Page 32269]]
(Fraley and Shepard 1989; Goetz 1989; Hoelscher and Bjornn 1989; Oliver
1979; Pratt 1984, 1985, and 1992; Shepard et al. 1984b; Thomas 1992).
Cover provides critical rearing, foraging, and resting habitat, and
protection from predators (Bryant 1983, Meehan 1991, Salo and Cundy
1987, Sedell and Everest 1991).
Several bull trout life history features make them exceptionally
sensitive to activities directly or indirectly affecting stream channel
integrity and altering natural flow patterns. Juvenile and adult bull
trout frequently inhabit areas of reduced water velocity, such as side
channels, stream margins, and pools that are often eliminated or
degraded by management activities (Rieman and McIntyre 1993). Length
and timing of incubation to emergence (200 days or more during winter
and early spring), the strong association of juvenile fish with stream
channel substrates, and a fall spawning period, make bull trout
particularly vulnerable to altered stream flow patterns and associated
channel instability (Fraley and Shepard 1989, Pratt 1992, Pratt and
Huston 1993, Rieman and McIntyre 1993).
Preferred spawning habitat consists of low gradient streams with
loose, clean gravels (Fraley and Shepard 1989). Fine sediments fill
spaces between the gravel that are needed by incubating eggs and fry.
An extremely long period of residency in the gravel (200 or more days)
makes bull trout especially vulnerable to fine sediments and water
quality degradation (Fraley and Shepard 1989). Juveniles also live on
or within the streambed cobble (Oliver 1979, Pratt 1984). High juvenile
densities were observed in Swan River tributaries with a diverse cobble
substrate and low percentage of fine sediments (Shepard et al. 1984a).
Successful bull trout spawning and development of embryos and
juveniles requires very cold water temperatures (Bjornn and Reiser
1991, Goetz 1989, McPhail and Murray 1979, Pratt 1992). Additionally,
water temperature influences the distribution of juveniles (Fraley and
Shepard 1989, Pratt 1992). Such strict temperature tolerances
predispose bull trout to declines from any activity occurring in a
watershed that leads to increased stream temperatures.
Extensive migrations are characteristic of the species (Fraley and
Shepard 1989, Oregon Department of Fish and Wildlife (ODFW) 1993).
Migratory bull trout facilitate the interchange of genetic material
between populations, ensuring sufficient variability within
populations. Migratory forms also provide a mechanism for restoring
local populations extirpated due to natural or human-caused events
(Rieman and McIntyre 1993, citing others). Migratory forms are more
fecund and larger than non-native brook trout, potentially reducing the
risks associated with hybridization (Rieman and McIntyre 1993). The
greater fecundity of these larger bull trout also enhances the ability
of a population to persist in the presence of introduced fishes (Rieman
and McIntyre 1993). Migratory bull trout have been restricted and/or
eliminated due to stream habitat alterations, including seasonal or
permanent obstructions, detrimental changes in water quality, increased
temperatures, and the alteration of natural stream flow patterns.
Migratory corridors tie seasonal habitat together for anadromous,
adfluvial, and fluvial forms, and allow for dispersal of resident forms
for recolonization of rebounding habitats. The disruption of migratory
corridors, if severe enough, will result in the loss of migratory life
history types and isolate resident forms from interacting with the
metapopulation (U.S. Department of Agriculture (USDA) 1993).
Distinct Population Segments
Pursuant to a court order, the Service evaluated the distribution
of bull trout throughout the species' range for the presence of
distinct population segments in our reconsidered 12-month finding using
the 1994 administrative record. This approach was undertaken because
bull trout occur in widespread but fragmented habitats and have several
life history patterns. In addition, the threats to the fish are
diverse, and the quantity and quality of information regarding the
population status and trends of bull trout varies greatly.
The Service has considered three elements when evaluating the
status of potential distinct population segments--discreteness,
significance, and conservation status. Discreteness refers to the
separation of a population segment from other members of the species
based on either (1) physical, physiological, ecological, or behavioral
factors, or (2) international boundaries that result in significant
differences in exploitation control, habitat management, conservation
status, or regulatory mechanisms. Significance refers to the biological
and ecological importance or contribution of a discrete population to
the species throughout its range. Examples of significance include
persistence of a discrete population segment in a unique or unusual
ecological setting, evidence that loss of discrete segment would result
in a significant gap in the range of the species, or evidence that the
discrete segment differs markedly from other populations of the species
in genetic characteristics.
Based on the 1994 administrative record and as discussed in the
reconsidered 12-month finding, numerous bull trout populations are
isolated from each other because of unsuitable habitat and/or
impassable dams and diversions. Though these isolated populations could
be considered discrete, few populations of bull trout are significant
to the species as a whole. The 1994 record provided evidence of
significance for five distinct population segments: (1) Coastal/Puget
Sound; (2) Klamath River; (3) Columbia River; (4) Jarbidge River; and
(5) Saskatchewan River. Based on the 1994 administrative record, the
Service determined in the reconsidered 12-month finding that listing is
not warranted for the Coastal/Puget Sound, Jarbidge River, and
Saskatchewan River population segments. However, listing is warranted
for the Klamath River and Columbia River population segments based on
the 1994 administrative record.
Klamath River Population Segment
The Klamath River originates in south-central Oregon near Crater
Lake National Park, and flows southwest into northern California where
it meets the Trinity River and empties into the Pacific Ocean. Bull
trout in this drainage are discrete because of physical isolation due
to several small mountain ranges in central Oregon (separating this
population from that of the Columbia River) and the Pacific Ocean.
Leary and Allendorf (1991) determined the genetic structure of bull
trout in the Klamath and Columbia River drainages with the use of
protein electrophoresis. This study concludes that not only are these
two groups of fish reproductively isolated, but also evolutionarily
distinct. In addition, Williams et al. (abstract in: Friends of the
Bull Trout Conference, 1994) separated the Klamath and Columbia River
populations into different clades based on mtDNA diversity patterns. As
a result, the Klamath River population segment is significant to the
taxon because of substantial genetic differences from the Columbia
River populations.
Columbia River Population Segment
The Columbia River population segment includes the entire Columbia
River basin and all its tributaries, excluding the isolated bull trout
populations found in the Jarbidge River
[[Page 32270]]
in Nevada which comprises the Jarbidge population segment. Though
Williams et al. (abstract in: Friends of the Bull Trout Conference,
1994) identified two distinct clades (taxonomic groupings of
descendants by common ancestors) in the Columbia Basin (Upper and Lower
Columbia) based on mtDNA diversity patterns, a discrete geographical
boundary between the two clades was not documented in the record. The
Columbia River population segment is significant because the overall
range of the species would be substantially reduced if this discrete
population were lost.
Status and Distribution
The base of information contained in the 1994 administrative record
regarding the status and trends of bull trout populations throughout
the species' range varies in quantity and quality. The criteria for
defining populations and estimating extinction risks were not
standardized among individual states. Bull trout information from the
state of Montana (primarily Thomas 1992) was the most organized and
complete. In Idaho, with the exception of Lake Pend Oreille and its
tributaries that support an important bull trout fishery, bull trout
status information was incomplete. The status of a majority of Oregon
bull trout populations is unknown. Similar patterns in quality of data
were found for bull trout populations in Canada. Interpretation of
``status unknown'' was the primary problem in status information
contained in the 1994 administrative record.
In 1993, the U.S. Department of Agriculture produced a working
draft concerning the status and conservation needs for bull trout (USDA
1993). This publication, entitled ``An Assessment of the Conservation
Needs for Bull Trout,'' surveyed biologists from State, Federal, and
Tribal agencies, and private industry in the range of bull trout.
Results from this survey represented the most thorough attempt to date
at rangewide classification of bull trout. Survey participants were
requested to fill out forms to provide information on life history,
status, factors influencing status, and whether individual bull trout
populations were considered remnant. The authors noted, that
``[a]lthough the quality of available data was not always consistent
across sources, no attempt was made to account for that variability.''
Many of these data could be described as anecdotal, though a systematic
attempt was made to address the entire species' range.
The appropriate interpretation of the ``remnant'' classification
was the most difficult aspect of the survey to analyze. The 1993
publication classified a remnant population as one in which ``the fish
are known to be present but in very low numbers.'' Additionally, a
remnant classification included the caveat that ``[a]lthough long-term
viability is questionable, the population may constitute a significant
portion of the species gene pool.'' Lacking any population status data
(i.e. declining, stable, secure, or increasing), the Service
interpreted a remnant classification by itself as a ``gap'' in status
information. When a remnant classification was accompanied by status
information other than ``unknown'', the Service generally considered
these data reliable and accurate.
Where population status or trends are known but only for a portion
of a distinct population segment (i.e., there are informational gaps in
1994 record), the Service considered documented trends within a
distinct population segment to be representative of the entire
population segment.
Klamath River Population Segment
Historical accounts suggest that the bull trout was once widely
distributed and exhibited diverse life history traits in the Klamath
Basin. The earliest records of bull trout in the Klamath Basin were
from the late 1800's (Oregon Chapter of the American Fisheries Society
(OCAFS) 1993, citing Cope) and suggested that an adfluvial life history
form occurred in Klamath Lake. Migratory fluvial bull trout evidently
were present in some of the larger streams in the basin as recently as
the early 1970's (Ziller in litt. 1992). Goetz (1989) suggested that
bull trout occurred in 15 separate drainages between 1948 and 1979. By
1989, the distribution of the species had been restricted to 10 streams
in the basin (author unknown, FWS notes, 1993). The most recent data
provided in the 1994 record suggested that in 1991, only seven
segregated resident populations still occurred in the basin and were
confined to headwater streams in the Sprague, Sycan, and Upper Klamath
Lake subbasins. The largest area occupied by any of the seven
populations is 2.5 stream miles, and basinwide, only 12.5 miles of
stream is inhabited by bull trout (Ziller in litt. 1992).
Bull trout occur in four tributaries to the Sprague River subbasin.
Ziller (in litt. 1992) compared abundance estimates between samples
taken in 1979 and 1989 at seven 30-meter sites on Deming, Boulder,
Brownsworth, and Leonard creeks. Ziller found the abundance of bull
trout was relatively unchanged at five sites, increased at one site,
and decreased at one site. In 1991 and 1992, ODFW estimated a total
population size of 3,310 individuals within the 4 segregated
populations of the Sprague River subbasin (OCAFS 1993). The effective
population size was estimated to be 140 to 462 mature fish, with 43
percent of these fish associated with Deming Creek. The remaining 57
percent were split unequally among Boulder, Brownsworth, and Leonard
creeks. Although the Sprague River subbasin contains the healthiest
remaining populations in the Klamath population segment, these
populations are considered to be at a moderate to high risk of
extinction (Ratliff and Howell 1992).
Long Creek may be supporting the only remaining bull trout
population in the Sycan River subbasin. Ratliff and Howell (1992)
suggested that the extinction risks of Long and Coyote creeks were
moderate and high, respectively, based on sampling efforts in 1989.
Sampling efforts in 1990 and 1991 suggest that populations previously
identified in Coyote Creek and the Upper Sycan River are probably
extinct (OCAFS 1993). The total population size in Long Creek was
estimated at 842 individuals with an effective population size of 36 to
119.
Populations in the Upper Klamath Lake subbasin are at precarious
abundance levels, and at a high risk of extinction (Ratliff and Howell
1992). Small populations remain in Sun and Threemile creeks.
Populations in Cherry and Sevenmile creeks are likely to be extinct
(OCAFS 1993). The Sun Creek population was estimated at 133 total
individuals in 1991, with an effective population size of only 11 to 35
mature fish. No abundance estimates were reported for Threemile Creek,
but only nine fish were sampled in the stream during recent surveys.
Because the resident life history trait prevails in the remaining
Klamath River, bull trout populations, size at maturity and associated
fecundity have been reduced in the population from historic conditions.
Average fecundity in 1989 was only 170 eggs/female, and a predominance
of males in the sample suggested a skewed sex ratio of 2.5 males/female
(Rode 1990). These data suggest that the natural recovery potential of
these populations is poor.
In summary, all seven of the remaining populations in the Klamath
River Basin are currently disconnected from each other, and are
considered to be isolated, remnant groups from a historically larger,
more diverse metapopulation. Ratliff and Howell
[[Page 32271]]
(1992) determined each population to be at a moderate or high risk of
extinction. Bull trout occur in three primary subbasins, with the fish
residing in the Upper Klamath Lake subbasin the most precarious. The
Sprague River and Sycan River subbasins each contain isolated
populations within limited available habitat of 2.5 miles or less.
Recent extinctions reportedly have occurred in Coyote Creek and the
Upper Sycan River of the Sycan subbasin, and Cherry and Sevenmile
creeks of the Upper Klamath Lake subbasin (Ratliff and Howell 1992).
Columbia River Population Segment
The Columbia River population segment encompasses a vast geographic
area including portions of Idaho, Montana, Oregon, Washington and
British Columbia. For discussion purposes, this segment was split into
three areas: 1) the Columbia River upstream from the confluence with
the Snake River, 2) the Snake River and its tributaries, and 3) the
Columbia River downstream of the Snake River confluence.
Upper Columbia River
The upper Columbia River portion of the distinct population segment
was separated into four subareas to aid in describing status and
distribution: (1) Kootenai River basin, (2) Clark Fork/Pend Oreille
basin, (3) Spokane River Basin, and (4) Washington tributaries. The
Kootenai River drains the southeastern portion of British Columbia west
of the continental divide, and flows through the extreme northwestern
section of Montana and northern Idaho, before flowing north back into
Canada where it joins the Columbia River. The Clark Fork drains the
majority of area west of the continental divide in Montana before
flowing into Idaho and Lake Pend Oreille. The Pend Oreille River,
including the Priest River and tributaries, flows north and joins the
Columbia River just north of eastern Washington. The Spokane River
drains both the Coeur d'Alene and St. Joe basins and flows west joining
the Columbia River in western Washington. Major Washington tributaries
in the upper Columbia River portion of the distinct population segment
include the Entiat, Wenatchee, Methow, and Yakima rivers.
Kootenai River Basin
Historically, bull trout were likely distributed throughout the
Kootenai River basin (Thomas 1992). Construction of Libby Dam and the
formation of Lake Koocanusa functionally separated bull trout into
different populations. The bull trout population in Lake Koocanusa is,
generally, small in size and constitutes a minor portion of angler
harvest (Thomas 1992). These fish have limited access to spawning
tributaries putting this population at risk (Thomas 1992).
Below Libby Dam, bull trout populations are separated by Kootenai
Falls. Kootenai Falls serves as a natural barrier to upstream migration
(Thomas 1992). Bull trout between Libby Dam and Kootenai Falls rely on
two remaining tributaries, Quartz and Pipe creeks, for spawning.
Historically, bull trout were likely distributed throughout the Fisher
River (tributary to the Kootenai below Libby Dam) since no physical
barriers prevent dispersal. However, Thomas (1992) considered the
status of fluvial bull trout in the Fisher River to be non-viable, or
extinct. Information on bull trout populations in Montana below
Kootenai Falls is incomplete. Several remnant populations are thought
to occur in tributaries including the Yaak River. Of the 99 bull trout
populations evaluated in the Kootenai River basin, all were at least at
moderate risk of extinction, and 47 percent of these were considered to
be at high risk of extinction (Thomas 1992).
Bull trout are considered uncommon in the Idaho portion of the
lower Kootenai River (Esch and Hallock, citing others, 1993). Status is
based on the relatively few individuals that contribute to the sport
catch (1 percent). Based on limited surveys and harvest catch, the
population trend in this portion of the Kootenai River appears to be
declining. Bull trout populations in Kootenay Lake in British Columbia
are considered stable with historic and current harvest rates remaining
relatively high (Esch and Hallock, citing others, 1993).
Clark Fork/Pend Oreille River Basin
The Clark Fork/Pend Oreille River basin drains the largest area in
the Columbia River population segment. Major tributaries of the Clark
Fork are the Flathead, Bitterroot, and Blackfoot rivers. Historically,
strong fluvial, adfluvial, and resident populations of bull trout were
likely distributed throughout the system (Thomas 1992). The healthiest
remaining bull trout populations are adfluvial because passage from
stream to lake environments is unimpeded. Resident populations of bull
trout are remnant and exist in the headwater reaches of tributaries
(Thomas 1992, USDA 1993). Fluvial populations have shown the greatest
decrease concurrent with the construction of mainstem impoundments. For
discussion purposes, the Clark Fork/Pend Oreille Basin is separated
into five areas: Upper Clark Fork (including the Bitterroot and
Blackfoot rivers); Lower Clark Fork (from the Bitterroot confluence
downstream to Lake Pend Oreille, including the Flathead River below
Flathead Lake); Flathead Lake and its tributaries; Lake Pend Oreille
and its tributaries; and Lower Pend Oreille River.
Upper Clark Fork
Historically, fluvial and resident populations of bull trout
probably inhabited the entire upper mainstem Clark Fork (Thomas 1992).
However, due to mining related stream degradation, these populations
have become increasingly rare, or, in some cases, extirpated entirely
from former habitats (Thomas 1992). Natural recolonization of these
populations seems remote due to continued habitat problems and the
absence of strong fluvial populations downstream. Bull trout are
considered rare in many tributaries with most remaining populations at
a high risk of extinction (Thomas 1992).
The healthiest remaining Clark Fork tributary population of bull
trout is Rock Creek (Thomas 1992). Rock Creek generally has had
relatively few impacts from humans, which undoubtedly has positively
influenced this population. Conversely, Flint Creek has experienced a
substantially higher degree of perturbation and consequently, this
population is considered to be in perilous condition (Thomas 1992).
However, the majority (86 percent) of bull trout in Flint and Rock
creeks combined are considered to be at moderate risk of extinction.
The Blackfoot River is one of the largest tributaries to the upper
Clark Fork River. Historically, the Blackfoot contained resident and
fluvial populations of bull trout. The fluvial component is thought to
have had connections with the mainstem Clark Fork. This connection was
broken in the early 1900's by the construction of Milltown Dam, which
effectively isolated bull trout in the Blackfoot from populations in
the mainstem Clark Fork (Thomas 1992). Fluvial populations of bull
trout still use the mainstem Blackfoot; however, their population
status is unknown. Isolated populations of adfluvial and resident fish
still exist within the basin. In the Blackfoot River, Peters (1990)
found juvenile bull trout in only 40 percent of tributary streams
surveyed in 1989, leading to a conclusion that Blackfoot bull trout
[[Page 32272]]
were in jeopardy. None of the remaining populations are classified as
abundant, and only three populations within the system are considered
common. Overall, 66 percent and 32 percent of bull trout populations in
the Blackfoot River were considered at a moderate and high risk of
extinction, respectively (Thomas 1992).
Bull trout were historically distributed throughout the mainstem
Bitterroot River and its tributaries (Thomas 1992). Bull trout now
appear to be extinct in the majority of the mainstem Bitterroot River.
Though tributary streams contain small isolated populations of bull
trout, many are sympatric with non-native brook trout. Bull trout are
considered abundant or common in 30 percent of the surveyed Bitterroot
stream reaches, and uncommon or rare in 70 percent (Thomas 1992).
Ninety-six percent of the bull trout populations in the Bitterroot
system are considered to be small, fragmented, and at a moderate to
high risk of extinction (Thomas 1992).
Lower Clark Fork
The Lower, or mainstem, Clark Fork River is segmented by several
impoundments that do not provide fish passage. Above Lake Pend Oreille,
Cabinet Gorge, Noxon Rapids, and Thompson Falls facilities separate the
mainstem river. Historically, a natural barrier existed at Thompson
Falls that prevented upstream passage. Prior to mainstem impoundments,
migrating bull trout from Lake Pend Oreille likely used the tributaries
below Thompson Falls for spawning (Thomas 1992). In addition, this area
probably supported fluvial and resident populations of bull trout.
Currently, bull trout are uncommon in the mainstem Clark Fork River,
and all remaining populations are considered at moderate risk of
extinction (Thomas 1992).
Populations of fluvial bull trout probably occurred historically
throughout the drainage above Thompson Falls (Thomas 1992). Adfluvial
fish from Lake Pend Oreille probably did not use this area due to the
natural barrier created by Thompson Falls. Thomas (1992) suggested that
adfluvial bull trout from Flathead Lake may have migrated downstream.
The construction of Kerr Dam blocked passage between Flathead Lake and
the lower Flathead and Clark Fork rivers. Bull trout in the mainstem
Clark Fork are considered rare or uncommon (Thomas 1992). Several
important tributaries still serve as spawning grounds with many
tributary populations existing at low numbers. Limited information
exists on bull trout status in the lower Flathead River. Currently,
bull trout are the least common salmonid found in the Flathead River
below Kerr Dam. Of the 199 populations evaluated in the Lower Clark
Fork and Flathead rivers, Thomas (1992) reported that 44 percent were
at high risk of extinction and 56 percent were at moderate risk of
extinction.
Flathead Lake
As in other areas in Montana, the actual historic distribution of
bull trout in the Flathead Lake system is unknown. However, with few
natural barriers and abundant interconnected habitat, bull trout likely
were distributed throughout the system (Thomas 1992). Undoubtedly,
resident and fluvial forms occupied areas within the drainage, but in
the Flathead Lake system the adfluvial lifestage would most likely have
had a distinct advantage. The larger adult size and increased
reproductive potential would probably have made this the dominant life
history form. Primary tributaries of Flathead Lake included the North,
South, and Middle forks of the Flathead River, Swan River, and
Stillwater River.
The interconnectedness of the Flathead system has been disrupted by
the construction of several hydroelectric facilities that block
historic migration corridors. Big Fork Dam on the Swan constructed in
1902 blocked bull trout passage into the Swan River drainage.
Similarly, the completion of Hungry Horse Dam in 1953 on the South Fork
Flathead River further isolated bull trout populations. As previously
mentioned, Kerr Dam blocks passage from the lower Flathead River into
Flathead Lake. The North and Middle forks of the Flathead River still
have relatively unimpeded passage into Flathead Lake.
Thomas (1992) reported that the Flathead system contained one of
the most viable populations of adfluvial bull trout left in the
coterminous United States. The viability of bull trout in the Flathead
system should be qualified given more recent monitoring data that
suggest certain populations within the system are declining.
Spawning redd counts in the North Fork (1991) and Middle Fork (1990
and 1991) Flathead rivers have decreased. The 1991 redd count
information in the North Fork was 34 percent below the annual average.
Redd counts in the Middle Fork during 1990 and 1991 were 43 percent and
28 percent below the annual average, respectively (Thomas 1992). Trend
analysis, including redd count surveys from 1992 and 1993, indicate a
significant decline in redd counts over a 15-year monitoring period
(Weaver 1994). Moreover, the recent estimated rate of decline (7-year
period) is significantly greater than the 15-year rate of decline. Bull
trout redd counts reached the lowest observed levels in 1992 and 1993.
Annual rate of decline was estimated at 16 redds per year based on the
15-year observation period, and 60 redds per year using the recent 7-
year period of record.
Analysis of redd count trend information for four North Fork
Flathead tributaries found a moderate level of annual variability
within the system (Rieman and McIntyre 1993). Using the same
information, the authors calculated a probability of 100-year
persistence for each population, based on an extinction threshold of 10
redds, alternate year spawning, and an instantaneous growth rate of
zero. Of the four populations examined, all were below 50 percent
probability of persistence. When actual estimates for instantaneous
growth rate were used, all four populations were still below the 50
percent probability of persistence over the next 100 years.
Rieman and McIntyre (1993) conducted the same analysis of redd
count trend information for four Middle Fork Flathead tributaries and
found a low to moderate level of annual variability within the system.
Of the four populations examined, two populations were below 50 percent
probability of persistence (40 percent and 29 percent), while fish in
two tributaries had moderate to high probabilities for persisting (60
percent and 71 percent). When actual estimates for instantaneous growth
rate were used, all four populations were below the 50 percent
probability of persistence over the next 100 years.
Despite this apparent decline, and uncertain probabilities for
persistence in bull trout populations in the North and Middle forks of
the Flathead, each tributary still contains areas of pristine habitat
and healthy bull trout (Thomas 1992). Adfluvial populations of bull
trout in Glacier National Park reside in high quality habitat with
little or no exposure to non-native species. Similarly, the Middle Fork
of the Flathead still contains viable populations of bull trout (Thomas
1992). Overall, while referred to as a bull trout stronghold, Thomas
(1992) reported that 91 percent of the populations in the North and
Middle Fork of the Flathead River are at a moderate risk of extinction.
The remaining 9 percent are judged to be at low risk of extinction.
Little population information was available from the 1994
administrative record regarding bull trout population status in the
South Fork of the Flathead River prior to the construction of
[[Page 32273]]
Hungry Horse Dam. As previously stated, Hungry Horse Dam was built
without allowing for fish passage, and this functionally isolated
adfluvial populations of bull trout which would have migrated to
Flathead Lake. This blockage resulted in a net loss of 38 percent of
the available bull trout spawning habitat (Thomas 1992). Fish that were
trapped behind Hungry Horse Dam established a new adfluvial population
using the newly formed reservoir. Remote spawning locations in the Bob
Marshall Wilderness Area have hampered collection of redd count
surveys. However, where information is available, 83 percent of the
remaining bull trout populations in the South Fork of the Flathead
River are considered to be at a moderate risk of extinction (Thomas
1992).
Historically, the Swan River supported an adfluvial population of
bull trout that migrated to Flathead Lake (Thomas 1992). Construction
of Bigfork Dam in 1902 effectively blocked passage and isolated this
population. Subsequently, a new adfluvial population developed in Swan
Lake. The Swan Lake drainage also supports isolated resident
populations of bull trout (Thomas 1992). Thomas (1992) reported that
adfluvial bull trout in Swan Lake represent the healthiest population
in the Flathead system. Based on redd counts, Swan Lake bull trout
spawner densities appear to be higher than those in Flathead Lake
(Thomas citing others 1992). Trend analysis based on redd counts for
the Swan River system indicates that adfluvial bull trout populations
are increasing (Weaver 1994). In addition, the 1993 redd count was the
highest recorded, and represented a 57 percent increase over an 11-year
average. In spite of this, Thomas (1992) considered bull trout in Swan
Lake and Swan River to be at moderate risk of extinction.
Rieman and McIntyre (1993) conducted the same analysis of redd
count trend information for four Swan River tributaries and found a low
to high level of annual variability within the system. Of the four
populations examined using an instantaneous growth rate of zero, two
populations were below 50 percent probability of persistence (43
percent and 49 percent), while fish in two tributaries had moderate to
high probabilities for persisting (65 percent and 74 percent). When
actual estimates for instantaneous growth rate were used, all three
populations had high probabilities for persistence (two populations at
greater than 95 percent and 80 percent respectively) over the next 100
years (Rieman and McIntyre 1993). Conversely, one tributary had a low
probability of persistence (4 percent).
Bull trout populations in the Stillwater River are depressed and
are considered at a high risk of extinction (Thomas 1992).
Historically, bull trout were probably distributed throughout the
Stillwater system. While several lakes still contain adfluvial
populations of bull trout, poor habitat conditions and non-native
species interactions have made the occurrence of bull trout uncommon.
Lake Pend Oreille
The Lake Pend Oreille system in the upper Columbia River is
delineated upstream by Cabinet Gorge Dam on the Clark Fork River.
Constructed in 1951, Cabinet Gorge Dam blocked upstream passage and
functionally isolated adfluvial bull trout from numerous tributary
spawning areas. Similarly, the Lake Pend Oreille system is isolated
downstream by Albeni Falls Dam (1952) on the mainstem Pend Oreille
River. The major tributary to the Pend Oreille system in this area is
the Priest River, that enters the Pend Oreille River downstream of Lake
Pend Oreille.
Historical accounts indicate that bull trout were common throughout
the Pend Oreille system (Esch and Hallock, citing others). These
accounts undoubtedly included resident, fluvial, and adfluvial
lifecycles. As was the case with bull trout in the Flathead system, an
adfluvial lifecycle in Lake Pend Oreille would have been advantageous,
and annual spawner escapement may have reached 10,000 fish (Pratt and
Houston 1993). Annual population estimates indicated that between 1,100
and 2,000 adfluvial bull trout may occur in Lake Pend Oreille (Pratt
and Houston 1993).
Analysis of redd count trend information for six Lake Pend Oreille
tributaries found a high degree of annual variability within the system
(Rieman and McIntyre 1993). The authors calculated a probability of
100-year persistence for each population, based on an extinction
threshold of 10 redds, alternate year spawning, and an instantaneous
growth rate of zero. Of the six populations examined, four populations
were below 50 percent probability of persistence, while fish in the
remaining two tributaries had high probabilities for persisting (87
percent and greater than 95 percent). When actual estimates for
instantaneous growth rate were used, five of the populations were below
the 40 percent probability of persistence over the next 100 years. Only
one Lake Pend Oreille tributary had a high probability of persistence
(88 percent).
Since 1983, portions of 21 different tributaries to Lake Pend
Oreille have been surveyed for bull trout redds (Idaho Bull Trout
Survey, no date). Year to year consistency in sampling each site has
varied. Of the 21 tributary locations, only 6 index streams were
surveyed from 1983 through 1992. These tributaries are East Fork
Lightning, Johnson, Trestle, Grouse, North Gold, and Gold creeks. This
sampling represents some of the best trend information in the 1994
administrative record concerning Lake Pend Oreille. During this period,
redd counts in index streams varied from a high of 671 in 1985, to a
low of 290 in 1986. The 1992 stream index redd count of 344 is 31
percent below the 9-year average of 500.
Pend Oreille River
The Priest River is the only remaining tributary of the Pend
Oreille River below Lake Pend Oreille still supporting bull trout
(Pratt and Houston 1993). As recently as 1972, bull trout were
documented in seven tributaries of the Priest River below Priest Lake.
However, in 1987, only three of these tributaries were found to contain
bull trout. The reduction in bull trout abundance in Priest Lake has
been reflected in decreased annual harvest (Mauser 1985). Between 1956
and 1970, an annual average of 1,200 bull trout were harvested in
Priest Lake. In 1978, a record harvest of 2,320 fish occurred, but by
1983 this number had decreased to only 159 fish. Interactions with lake
trout and overharvest have nearly extirpated the Priest Lake bull trout
population (Esch and Hallock, citing others). Bull trout are still
found in Upper Priest Lake and are considered to be healthy and a
possible source of bull trout for the lower lake. Evidence also exists
for the decline in redd counts in tributaries of both lakes (Esch and
Hallock, citing others). Overall, Priest Lake is considered to be at a
high risk of extinction, while Upper Priest Lake is thought to be at a
moderate risk.
Little information is available in the 1994 administrative record
regarding bull trout status in the lower Pend Oreille River. Below Lake
Pend Oreille and Albeni Falls Dam, mainstem impoundments have
fragmented fluvial bull trout habitat. Historic records and accounts
indicate that fluvial bull trout were numerous (C. Vail, WDW, undated
USFS survey). The current bull trout population is considered remnant
and at a high risk of extinction (WDW 1992).
Spokane River Basin
Little information is available in the 1994 record concerning bull
trout status
[[Page 32274]]
in the Spokane River basin. It is assumed, however, that adfluvial,
fluvial, and resident bull trout were distributed throughout the system
including the Coeur d'Alene River, Lake Coeur d'Alene, and the St. Joe
River drainage (Draft Conservation Plan, Idaho Department of Fish and
Game (IDFG), Draft Bull Trout Conservation Plan for the Upper Spokane
River Basin, no date). Restricted to Lake Coeur d'Alene and the St. Joe
River, spawning appears to occur in only ten tributaries in headwater
reaches of the system. The Coeur d'Alene subbasin is currently
considered of special concern and at high risk of extinction (D. Cross,
USFS, in litt. 1992). The St. Joe system is considered of special
concern and at moderate risk of extinction.
In the Spokane River subbasin of the Columbia, stream surveys in
1935 and 1940 documented the presence of bull trout throughout the St.
Joe River (USFS 1935; Maclay 1940). By 1992, the occupied range in the
upper one-third of this river was reduced by 76 percent (Cross, pers.
comm. 1993). Similar reductions have occurred in the Coeur d'Alene
River drainage, where bull trout range may have been reduced 90 percent
since surveys in 1940; presently bull trout may persist in only one
isolated tributary in the entire drainage (Maclay 1940; Lider, USFS,
pers. comm. 1994). Due to low numbers of fluvial spawners, bull trout
in the Spokane River subbasin were estimated to have a moderate risk of
extinction (Hoelscher, IDFG, in litt. 1992).
Washington State Tributaries
Historically, bull trout probably inhabited a majority of the
tributaries to the upper Columbia River in Washington. In these
tributaries, bull trout distribution has been significantly restricted
and several populations, including the Okanogan River, Lake Chelan, and
lower Yakima River, are extirpated (WDW 1992). Currently, 17
populations of bull trout occur in Washington above the Snake River
confluence (WDW 1992). These populations include adfluvial, fluvial and
resident components. Subbasins within the upper Columbia River still
supporting bull trout are the Entiat, Methow, Naches, Wenatchee, and
Upper Yakima drainages (WDW 1992). Of these populations, three are
declining, seven are stable, and one population is considered secure.
The status of the six remaining bull trout populations is unknown.
Within the upper Columbia River, risk of extinction was calculated
for bull trout populations where the status was known (WDW 1992).
Populations with unknown status were not classified by risk of
extinction, but were given a priority ranking for information needs.
Bull trout populations in Kachess and Keechelus Lakes (Upper Yakima
River drainage), Roosevelt Lake, and the Pend Oreille River were
considered to be at high risk of extinction (WDW 1992). Four bull trout
populations in the Entiat, Methow, and Wenatchee River basins were
classified as being at moderate risk of extinction (WDW 1992).
Similarly, four other tributary populations in the Wenatchee, Methow,
and Naches River basins were considered to be at low risk of extinction
(WDW 1992). One tributary of the Methow River was considered to be at
no immediate risk (WDW 1992). The remaining four bull trout populations
in the upper Columbia River (Naches and Upper Yakima rivers) had an
unknown status and were not classified.
Bull trout populations in the Entiat, Upper Yakima, Wenatchee,
Methow and Naches occur in isolated segments and appear to be sparse in
abundance (Brown 1992, WDW 1992). However, certain populations
including the Chiwawa River and Rimrock Lake appear to be stable. In
Rimrock Lake and Indian Creek (spawning tributary) redd counts
increased from 29 in 1986, to 140 in 1993 (Yakima County Bull Trout
Status 1994; E. Anderson, WDW, in litt. 1994). The Chiwawa River is
recognized as having one of the stronger populations in the mid-
Columbia River (Brown 1992). While long-term trend data on the Chiwawa
River and tributaries were not available during 1991, 348 bull trout
redds were counted in this system.
Snake River and Tributaries
Historically, bull trout were likely widely dispersed throughout
the Snake River drainage, limited only by natural passage and thermal
barriers (Esch and Hallock, citing others). Current distribution is
primarily relegated to tributaries to the mainstem Snake River upstream
to and including the Boise River (Esch and Hallock, citing others).
Major tributaries of the Snake River in Oregon currently supporting
bull trout populations include the Tucannon, Grande Ronde, Imnaha, and
the Malheur. In Idaho, bull trout can be found in the Clearwater,
Salmon, Weiser and Boise river drainages.
Ratliff and Howell (1992) compiled a status assessment of Oregon
bull trout populations. Status was determined subjectively based on
relative abundance, suppressing factors, and recovery potential of
identified populations. In the 29 Oregon tributaries of the Snake River
where bull trout are found, 7 percent are considered to be at high risk
of extinction, while 14 percent are thought to be at low risk (Ratliff
and Howell 1992). The majority of bull trout populations are either at
moderate risk (38 percent) or are of special concern (34 percent).
Seven percent of the examined populations are considered to be extinct.
Of the 29 populations, 62 percent are classified as remnant, while 76
percent of the populations have a current status of unknown. Based on
limited information, a few tributaries, including portions of the
Grande Ronde, Minam River, and the North Fork of the Malheur, appear to
have viable bull trout populations (Ratliff and Howell 1992, Bowers et
al. 1993). Of the 10 identified Snake River bull trout populations
occurring in Washington, the status of 40 percent are declining, 30
percent stable, and 30 percent unknown (WDW 1992).
The quality and quantity of bull trout information for Snake River
tributaries in Idaho is poor. Limited spot surveys indicate that bull
trout may be widespread throughout the Clearwater and Snake River
drainages. However, the lack of identified populations and associated
trend information complicates status evaluation. The Rapid River is one
of the largest remaining bull trout populations for which long-term
trend information is available. Bull trout counts from a fish weir on
this Salmon River tributary averaged 206 fish between 1973-91 (Rieman
and McIntyre 1993).
Analysis by Rieman and McIntyre (1993) calculated a probability of
100-year persistence for Rapid River bull trout. Using weir counts
taken over a period of 19 years, the authors assumed a 1:1 sex ratio
and one female per redd to approximate the mean number of redds per
year in the spawning escapement. Based on this information, an
extinction threshold of 10 redds, alternate year spawning, and an
instantaneous growth rate of zero, the Rapid River population had a 58
percent probability of persistence. When the actual estimate for
instantaneous growth rate was used, the probability for persistence
increased to 74 percent.
Population trend data is also lacking for bull trout in the Weiser,
Payette, and Boise rivers. IDFG (1993) suggested that bull trout were
widely distributed in the Payette and Boise rivers, but restricted to
only two tributaries in the Weiser River. Density estimates for Sheep
and Anderson creeks of the Weiser drainage ranged from 2.8 to 5.2 bull
trout/100 square meters in 1992 (IDFG 1993), but no earlier data was
reported to establish
[[Page 32275]]
a trend. Neither historical nor current abundance data is available for
the Payette or Boise rivers, but Renstrom (no affiliation, in litt.
1993) indicated that bull trout are quite common in the upper reaches
of the North Fork Boise River and Johnson Creek; they often dominate
the sport catch in these systems.
Lower Columbia River
The lower Columbia River encompasses a large geographic area
including portions of Washington and Oregon. The lower Columbia River
includes the mainstem Columbia River and all tributaries below the
Snake River confluence. Major tributaries include the John Day,
Deschutes, and Willamette rivers.
The 1994 administrative record on bull trout status in the lower
Columbia River is largely incomplete. A significant portion of bull
trout status information for Washington and Oregon is unknown (USDA
1993, WDW 1992). Where sufficient data existed to determine status, 40
percent were declining, 5 percent stable, and 15 percent secure. The
status of the remaining 40 percent of lower Columbia River populations
in Oregon was unknown. Of the six lower Columbia River bull trout
populations identified in Washington all are considered remnant, with
17 percent classified as stable, and 83 percent as ``status unknown''
(WDW 1992).
Based on the 1994 administrative record, bull trout populations
within the lower Columbia River have declined from historic levels.
Remaining populations are generally considered to be isolated and
remnant (Ratliff and Howell 1992, USDA 1992). Historic bull trout
populations of the lower Columbia River consisted of adfluvial,
fluvial, and resident components. While each lifecycle is still
represented, the resident form is dominant, followed by the fluvial,
and adfluvial (USDA 1992).
Within the Oregon portion of the lower Columbia River, 23 percent
of bull trout populations are considered to be at a high risk of
extinction, while 15 percent are thought to be at a moderate risk, 12
percent of special concern, 19 percent at low risk, and 31 percent are
extinct (Ratliff and Howell 1992). In Washington, using a different
risk assessment method (WDW 1992), only the bull trout population in
Yale Reservoir was considered at risk (moderate). The remaining five
bull trout populations were not evaluated with respect to risk of
extinction due to a ``status unknown'' classification (WDW 1992).
The primary tributaries to the lower Columbia River still
containing bull trout are the Walla Walla, Umatilla, John Day,
Deschutes, Hood, Lewis, and Willamette rivers. With the exception of
the Deschutes River basin, remaining populations are dominated by
small, isolated, remnant populations. Long-term population trend
information contained in the 1994 administrative record is incomplete
or lacking for the remaining bull trout populations. Where information
was available, the low abundance, and fragmented nature of these
headwater populations is apparent.
An example of the variable and contradictory information found in
the 1994 administrative record is illustrated by the John Day River
basin. Based on bypass trap information from 1971-1992, bull trout
counts on the Upper John Day River have been as high as 345 in 1973 to
as low as 12 in 1988 (ODFW 1993). While the 1971-80 average of 152 was
larger than the 1981-92 average of 95, the mean counts were not
statistically different (p 0.05), and the 1992 bull trout
count (232) was the third highest on record. Ratliff and Howell (1992)
consider the Upper John Day River to be at moderate risk of extinction.
Similar trend information in the Middle Fork or the North Fork of the
John Day was not available. These populations are isolated and occur at
low numbers, and Ratliff and Howell (1992) considered Middle Fork to be
at high risk and North Fork of special concern.
The quality of bull trout population status information varies in
the Umatilla, Walla Walla, Hood, Willamette, and Lewis rivers.
Populations in the Umatilla, Walla Walla, and Hood rivers are
considered at low risk or of special concern (Ratliff and Howell 1992,
WDW 1992). Other populations in the Hood and Willamette systems are
considered to be at high risk of extinction. Based on direct counts and
professional judgement these populations are isolated via impoundments
or habitat degradation and are at low levels. Ratliff and Howell (1992)
considered these populations to be at moderate to high risk of
extinction.
The strongest remaining population of bull trout in the lower
Columbia River is the adfluvial population located in the Deschutes
River basin. Lake Billy Chinook and the Metolius River still support a
viable population bull trout as documented by increasing redd counts
from 1986-93 (Ratliff 1994). This population has benefitted from
restrictions in harvest regulations and is considered at low risk of
extinction (Ratliff and Howell 1992). Shitike Creek below lake Billy
Chinook still supports a relatively good population of fluvial bull
trout, which Ratliff and Howell (1992) considered to be at low risk of
extinction. The remaining bull trout populations in the Deschutes
system are not doing as well. Bull trout populations in the upper
Deschutes are either extinct or considered to be at high risk of
extinction in the future (Ratliff and Howell 1992).
Summary of Columbia River Population Segment
Based on the 1994 administrative record, bull trout populations
within the upper Columbia River have declined from historic levels
(Thomas 1992 and USDA 1993). Overall, remaining populations are
generally considered to be isolated and remnant (Rieman and McIntyre
1993, Thomas 1992, USDA 1993). Fluvial bull trout populations in the
upper Columbia River portion of the distinct population segment appear
to be nearly extirpated. Resident populations existing in headwater
tributary reaches are isolated and generally low in abundance (Thomas
1992). Based on information in the 1994 record, bull trout in Flathead
Lake and Lake Pend Oreille appear to be declining. The adfluvial
population in Swan Lake appears to be increasing and represents the
healthiest remaining population.
The 1994 administrative record on bull trout populations within the
Snake River and tributaries is largely incomplete. However, with the
lack of passage barriers, historic distribution throughout the system
was probable. Overall, the lack of specific trend information for the
Snake River made the analysis of population status difficult. Certain
populations appeared to be stable, while others were at a moderate to
high risk of extinction (Ratliff and Howell 1992).
Historic distribution of bull trout within the lower Columbia River
cannot be verified, but adfluvial, fluvial, and resident forms were
likely widely distributed throughout the area (Ratliff and Howell
1992). Current distribution is fragmented with dispersed remnant
populations of resident and fluvial bull trout inhabiting tributaries
(Ratliff and Howell 1992, USDS 1993, WDW 1992). Certain populations
appeared to be stable, while others were at high risk of extinction
(Ratliff and Howell 1992, WDW 1992).
The general trend of bull trout populations in the Columbia River
population segment where status is known is declining. An examination
of 386 bull trout populations in the Columbia River population segment
[[Page 32276]]
indicated that 33 percent are declining, 15 percent stable, 3 percent
secure, and 2 percent increasing (Ratliff and Howell 1992, USDA 1993,
and WDW 1992). The population status of the remaining 47 percent is
unknown. Of the 386 bull trout populations, 44 percent are considered
remnant, 30 percent not remnant, and 26 percent unknown (Ratliff and
Howell 1992, USDA 1993, WDW 1992).
Previous Federal Action
On September 18, 1985, the Service published an animal notice of
review in the Federal Register (50 FR 37958) designating the bull trout
a category 2 candidate for listing in the coterminous United States.
Category 2 taxa were those for which conclusive data on biological
vulnerability and threats were not currently available to support
proposed rules. The Service published updated notices of review for
animals on January 6, 1989 (54 FR 554), and November 21, 1991 (56 FR
58804), reconfirming the bull trout category 2 status. The Service
elevated bull trout in the coterminous United States to category 1 for
Federal listing on November 15, 1994 (59 FR 58982). Category 1 taxa
were those for which the Service had on file substantial information on
biological vulnerability and threats to support preparation of listing
proposals. Upon publication of the February 28, 1996, notice of review
(61 FR 7596), the Service ceased using category designations and
included the bull trout as a candidate species. Candidate species are
those for which the Service has on file sufficient information on
biological vulnerability and threats to support proposals to list the
species as threatened or endangered.
On October 30, 1992, the Service received a petition to list the
bull trout as an endangered species throughout its range from the
following conservation organizations in Montana: Alliance for the Wild
Rockies, Inc., Friends of the Wild Swan, and Swan View Coalition
(petitioners). The petitioners also requested an emergency listing and
concurrent critical habitat designation for bull trout populations in
select aquatic ecosystems where the biological information indicates
that the species is in imminent threat of extinction. A 90-day finding,
published on May 17, 1993 (58 FR 28849), determined that the
petitioners had provided substantial information indicating that
listing of the species may be warranted. The Service initiated a
rangewide status review of the species concurrent with publication of
the 90-day finding.
On June 6, 1994, the Service concluded in the original 12-month
finding that listing of bull trout throughout its range was not
warranted due to unavailable or insufficient data regarding threats to,
and status and population trends of, the species within Canada and
Alaska. However, the Service determined that sufficient information on
the biological vulnerability and threats to the species was available
to support a warranted finding to list bull trout within the
coterminous United States. Because the Service concluded that the
threats were imminent and moderate to this population segment, the
Service gave the bull trout within the coterminous United States a
listing priority number of 9. As a result, the Service found that
listing a distinct vertebrate population segment of bull trout residing
in the coterminous United States was warranted, but precluded due to
higher priority listing actions.
On November 1, 1994, Friends of the Wild Swan, Inc. and Alliance
for the Wild Rockies, Inc. (plaintiffs) filed suit in the Federal
District Court of Oregon arguing that the warranted but precluded
finding was arbitrary and capricious. After the Service issued a
``recycled'' 12-month finding for the coterminous population of bull
trout on June 12, 1995, the district court issued an order declaring
the plaintiffs' challenge to the original finding moot. The plaintiffs
declined to amend their complaint and appealed to the Ninth Circuit
Court of Appeals, which found that the plaintiffs' challenge fell
``within the exception to the mootness doctrine for claims that are
capable of repetition yet evading review.'' On April 2, 1996, the
circuit court remanded the case back to the district court. On November
13, 1996, the district court (Court) issued an order and opinion
remanding the original finding to the Service for further
consideration. Included in the instructions from the Court were
requirements that the Service limit its review to the 1994
administrative record, and incorporate any emergency listings or high
magnitude threat determinations into current listing priorities. In
addition, reliance on other Federal agency plans and actions was
precluded. The reconsidered 12-month finding was delivered to the Court
on March 13, 1997. This finding determined that the Klamath River and
Columbia River population segments warranted listing based on the 1994
administrative record.
On March 24, 1997, the plaintiffs filed a motion for mandatory
injunction to compel the Service to issue a proposed rule to list the
Klamath and Columbia bull trout populations within 30 days based solely
on the 1994 administrative record. In response to this motion, the
Service ``concluded that the law of this case requires the publication
of a proposed rule'' to list the two warranted populations. On April 4,
1997, the Service requested 60 days to prepare and review the proposed
rule. In a stipulation between the Service and plaintiffs filed with
the Court on April 11, 1997, the Service agreed to issue a proposed
rule in 60 days to list the Klamath River population of bull trout as
endangered and the Columbia River population of bull trout as
threatened based solely on the 1994 record. As a result, the Service
did not consider any information received since the close of the 1994
record in the development of this proposal.
The processing of this proposed rule conforms with the Service's
final listing priority guidance published in the Federal Register on
December 6, 1996 (61 FR 64475). The guidance clarifies the order in
which the Service will process rulemakings during fiscal year 1997. The
guidance calls for giving highest priority to handling emergency
situations (Tier 1), second highest priority (Tier 2) to resolving the
listing status of the outstanding proposed listings, and third priority
(Tier 3) to new proposals to add species to the list of threatened and
endangered plants and animals. This proposed rule constitutes a Tier 3
action.
Summary of Factors Affecting These Species
Procedures found in section 4 of the Endangered Species Act (16
U.S.C. 1533) and regulations (50 CFR part 424) promulgated to implement
the Act set forth the procedures for adding species to the Federal
lists. A species may be determined to be an endangered or threatened
species due to one or more of the five factors described in section
4(a)(1). These factors and their application to the Klamath River
population segment and Columbia River population segment of bull trout
(Salvelinus confluentus) are as follows:
A. The present or threatened destruction, modification, or
curtailment of its habitat or range. According to the 1994
administrative record, many instream habitat features have been
significantly impaired as a result of land management activities,
including forest management and road building, hydropower and
irrigation diversions, mining, and grazing (Chamberlain et al. 1991,
Craig and Wissmar 1993, Frissell 1993, Furniss et al. 1991, Isaacson
1994, Meehan 1991, Nehlsen et al. 1991, Salo and Cundy 1987, Sedell and
Everest 1991). Based on a survey of biologists, only 18
[[Page 32277]]
percent of all bull trout populations and stream segments rangewide are
not threatened by degraded habitat conditions (USDA 1993). Adverse
impacts to bull trout habitat and populations due to land management
practices have been documented throughout the species' range in the
conterminous United States (Brown 1992, Fraley and Shepard 1989, Goetz
1989, Howell and Buchanan 1992, Isaacson 1994, Meehan and Bjorn 1991,
Platts et al. 1993, Pratt 1992, Pratt and Huston 1994, Rieman and
McIntyre 1993, Shepard et al. 1984a, 1984b, Thomas 1992, USDA 1993,
Weaver and Fraley 1991, WDW 1992). While some bull trout persist in
``managed'' drainages (Hicks, Plum Creek Timber Company, in litt.,
1993), it is likely that these populations are at risk of extinction
(Rieman and McIntyre 1993).
Forest management has degraded bull trout habitat throughout the
species' range. Logging and road building activities threaten bull
trout populations within and downstream of managed areas through
increased sediment production and delivery to streams, reduced
streamside canopy closure, increased stream temperatures, and reduced
woody debris recruitment (Chamberlain et al. 1991, Furniss et al. 1991,
Weaver and Fraley 1991, Thomas 1992, Isaacson 1994). Thousands of miles
of logging roads and vast acreage of recently logged watersheds will
continue to impact hydrologic functions and habitat quality throughout
the species' range for at least several decades (Isaacson 1994).
While forest management activity is cited as a contributor to bull
trout population decline, the precise impact of a specific activity or
accumulation of activities on the abundance, resilience or long-term
persistence of a population is unknown (USDA 1993). Haugen (1991)
estimated that salmonid habitat had been reduced in the Columbia Basin
by about 24 percent in the past century as a result of these land
management practices. On National Forests, most habitat alterations
occurred during the period 1940-1970 when forest management focused on
commodity resources.
Dam and reservoir construction and operation have significantly
altered major portions of the riverine habitats of bull trout
throughout the Columbia River Basin. Numerous dams without adequate
fish passage have created barriers to fluvial and adfluvial bull trout,
precluding access to former spawning, rearing, and migration habitats
(Craig and Wissmar 1993, WDW 1992b, ODFW 1993). Altered hydrographs and
water quality conditions may also degrade bull trout forage bases
(Marotz 1993). Many migratory bull trout populations associated with
mainstem river systems have been extirpated due to the construction of
dams, particularly in the Columbia Basin (Brown 1992, Goetz 1991, WDW
1992a, ODFW 1993). The completion of McCloud Dam in 1965 has been cited
as the primary cause of bull trout extirpation from California (Rode
1990).
Connectivity within and between watersheds is essential for
maintaining aquatic ecosystem functions and healthy bull trout
populations (Rieman and McIntyre 1993). Numerous hydroelectric and
water storage dams currently isolate a large number of bull trout
populations rangewide. The construction of hydropower dams on major
river tributaries has isolated upper basin populations, and eliminated
the downstream fluvial or adfluvial life history forms dependent on
upstream spawning habitat. Irrigation and hydroelectric dams, large and
small, have blocked bull trout migration in almost all drainages in the
Pacific Northwest and converted riverine habitats into reservoir
habitats (Platts et al. 1993). In many instances, natural
recolonization of historically occupied bull trout sites has become
impossible. But, movement of introduced species or undesirable species
may also be controlled by a dam, thus, enabling bull trout to utilize
historic habitats without competition from non-indigenous species.
Impacts associated with agriculture, including irrigation and water
storage activities, have adversely impacted bull trout habitat.
Agricultural activities reduce streamside cover, increase
sedimentation, and introduce point and non-point source pollution.
Unscreened irrigation diversions likely trap juvenile bull trout
migrating downstream (Ratliff and Howell 1992).
Grazing impacts to salmonid habitat have been described by many
authors (Platts 1991, Elmore and Beschta 1987, Meehan and Platts 1978).
Improper livestock grazing negatively affects bull trout by reducing
riparian vegetation, changing stream morphology and increasing soil
erosion. These alterations degrade thermal and structural habitat
conditions and water quality for bull trout, and compound the negative
impacts of human activities.
Mining has adversely affected bull trout and their habitats in
Idaho, Montana, Oregon, and Washington (Coeur d'Alene Tribe of Idaho et
al. 1991, Johnson and Schmidt 1988, Martin and Platts 1981, Platts et
al. 1993, USDA 1992, USDA 1993, WDW 1992b). Mining can degrade aquatic
systems by producing sediment and toxic heavy metals, altering water
acidity levels, and changing stream channels and flow (Esch and
Hallock, citing others).
Klamath River Population Segment
The migratory life history forms (fluvial and adfluvial) of bull
trout in the Klamath Basin have been lost because the habitat and
migratory corridors that once supported these fish have been degraded
to an unsuitable condition. This degradation appears to have been
caused primarily by the loss of riparian vegetation and water
withdrawals, but channelization of Sun Creek and a few other streams
near Crater Lake has also been blamed for the loss of migratory fish.
Land ownership and agricultural practices in the basin suggest that the
loss of riparian vegetation is due to livestock grazing, timber
harvest, and road construction. Ziller (in litt. 1992) noted that the
removal of the riparian canopy increased stream temperatures. Water
withdrawals at irrigation diversions are common in the basin, and occur
on most streams where bull trout reside (OCAFS 1993). Because these
diversions are unscreened and unregulated in regard to minimum flow
and/or maximum withdrawal, direct loss of fish has been suggested and
downstream areas have become entirely dewatered or unsuitable for bull
trout due to low water flows and associated increasing temperatures
(OCAFS 1993). These factors have rendered much of the basin unsuitable
habitat for bull trout, and have isolated small resident populations in
extreme headwater areas where suitable habitat still exists (Ziller
1992, Ratliff and Howell 1992). Irrigation, livestock grazing, timber
harvest, and road construction is expected to continue in the basin
along with the associated impacts to aquatic habitat. Based on the 1994
record, the present or threatened destruction, modification, or
curtailment of bull trout habitat or range threatens the Klamath River
distinct population segment of bull trout.
Columbia River Population Segment
Bull trout populations in the Columbia River population segment
face a number of threats from habitat degradation and passage problems.
Isaacson (1994) documented extensive habitat degradation of watersheds
in Idaho and Montana. Suitable bull trout habitat on National Forest
lands west of the Continental Divide have been impacted by land
management practices including logging, road building, and grazing.
Based on a survey of National
[[Page 32278]]
Forests reported by Isaacson (1994), a significant portion of
watersheds on the Clearwater (71 percent), Nez Perce (67 percent),
Kootenai (42 percent), Lolo (65 percent), Bitterroot (66 percent),
Flathead (44 percent), and Idaho Panhandle National Forests (64
percent) have been moderately to severely degraded. Moreover, a large
number of National Forests in Idaho and Montana do not meet existing
Forest Plan standards for woody debris, pool/riffle ratios and other
stream habitat parameters correlated with bull trout persistence
(Isaacson 1994). Only 31 percent of streams in the Lake Pend Oreille
basin meet Forest Plan standards for stream habitat attributes, and
most of these streams (52 percent) are in the most degraded category.
Such land management practices have deleterious effects on bull trout
populations. In the Flathead River drainage, decreased survival of
early life history stages was associated with increases in deposition
of fine sediments in spawning gravel (Shepard 1984a, Weaver and Fraley
1991).
High water temperature is considered to be a factor limiting bull
trout in certain Washington systems (Craig and Wissmer 1993). The
negative impacts of grazing appear to be major factors in habitat
degradation in Oregon and Idaho (USDA 1993). Grazing is identified as a
major cause of habitat degradation in 15 of 34 streams/stream reaches
supporting bull trout populations in the Clearwater River basin (USFS,
in litt., 1993). In Washington, for instance, agriculture was
identified as being one of the greatest sources of non-point source
pollution to rivers and streams (Edwards et al. 1992 in USDA 1994).
Water quality in the Yakima River system has been degraded due to
agricultural activities (WDE 1992).
Based on re-surveys of five rivers in the Lower Columbia, Sedell
and Everest (1991) documented a loss of large pools during the past 50
years due to grazing, road construction, dredge mining, agricultural
practices, and forest management. On the Middle Fork Salmon River in
Idaho, large pool density has decreased 52 percent in some tributaries.
On the Grande Ronde, Willamette, and Lewis and Clark rivers in Oregon
the concentration of large pools has decreased by 67, 41, and 60
percent, respectively. Only tributaries in the Yakima River basin in
Washington exhibited an increase (27 percent) in pool density.
Habitat degradation as the result of mining related activities in
Montana has resulted in the extinction of some populations and the
reduction of others (Thomas 1992). The upper Clark Fork above Milltown
Dam in Montana has been contaminated by high levels of arsenic,
cadmium, copper, lead, and zinc from large-scale copper mining and
mineral processing. As a result, four Superfund sites have been
designated in this area, and tests indicate that contamination has
caused substantial reductions in the number, growth, and diversity of
trout (RCG/Hagler, Bailly, Inc. 1993). Bull trout have likely been
among the fish impacted, as only a few scattered headwater populations
of bull trout currently exist. Entire drainages within the Clearwater
and Salmon River basins have been severely degraded by past gold dredge
mining practices (Esch and Hallock, no date). Mining continues in two
streams with bull trout in the North Fork Clearwater River (C.
Huntington, Clearwater Biostudies, pers. comm. 1993).
Irrigation practices restrict bull trout migrations and isolate
populations from historical mainstem habitats in the Snake, Yakima,
Walla Walla, Powder, Malheur, Grande Ronde, Umatilla, John Day, Clark
Fork, and Bitterroot rivers (ODFW 1993, Thomas 1992, WDW 1992b).
Dorratcaque (1986) documented chronic flow and passage problems on the
Lemhi River of Idaho, where a complete lack of flow has occurred during
the migration period. Over 80 percent of the annual stream flow in the
Yakima subbasin is diverted for irrigation purposes and return flows
account for 90 percent of the lower-river flow during the irrigation
season (WDE 1992). Bull trout in this subbasin are now isolated in
upper tributaries and are at high risk of extinction (WDW 1992b).
In addition to the negative effects associated with improper land
management practices, habitat fragmentation due to hydroelectric
impoundments have significantly impacted bull trout populations.
Numerous impoundments throughout the Columbia Basin have isolated
populations and altered mainstem habitat. Hydroelectric facilities such
as Albeni Falls (1952), Noxon Rapids (1958), Cabinet Gorge (1951), and
Milltown (1906) in the Clark Fork/Pend Oreille system have eliminated
or reduced adfluvial and fluvial populations (Paragamian and Ellis
1993, Pratt and Houston 1993, and Thomas 1992). Similar consequences
have occurred on the Flathead River where Kerr, Big Fork, and Hungry
Horse Dams curtail population interchange (Fraley et al. 1989). Bull
trout populations in Montana and northern Idaho are functionally
isolated from lower Columbia River populations by a number of mainstem
River impoundments including Chief Joseph and Grand Coulee Dams. The
mainstem Columbia and Snake rivers are fragmented by 11 hydroelectric
facilities. In addition, smaller impoundments are numerous throughout
the system and have isolated bull trout populations in Montana, Idaho,
Washington, and Oregon (USDA 1993). New hydropower development
continues to occur, primarily for small hydropower facilities. For
example, the Horseshoe Bend Project on the Payette River in Idaho,
would involve a diversion dam and powerhouse that could cause bull
trout migration problems and habitat losses from dewatering. Other
examples of segregation due to hydropower include three dams along the
Lewis River in southwest Washington, all built without passage
facilities.
Although bull trout are widely distributed throughout the Columbia
River population segment, individual populations are highly fragmented,
and most populations are isolated and remnant. Of those populations
where status is known and population data exist, the general trend in
this distinct population segment is declining. A few populations,
however, are considered stable or increasing, and are represented in
parts of the Swan, Deschutes, Grande Ronde, Tucannon, and Malheur River
basins. Documented habitat losses from timber harvest, grazing, mining,
and hydropower are widespread and expected to continue throughout the
distinct population segment. Based on the 1994 record, the present or
threatened destruction, modification, or curtailment of bull trout
habitat or range threatens the Columbia River distinct population
segment of bull trout.
B. Overutilization for commercial, recreational, scientific, or
educational purposes. According to the 1994 administrative record, bull
trout historically have been targeted by anglers and government
agencies who viewed the species as undesirable because of its
piscivorous habits (Bond 1992). As recently as 1990, programs were
conducted to remove bull trout through outright killing of fish,
bounties, and poisoning of waterways (Simpson and Wallace 1978, Ratliff
and Howell 1992, ODFW 1993, Newton and Pribyl 1994).
Many bull trout populations were intensely harvested prior to the
implementation of restrictive angling regulations (Brown 1992, ODFW
1993, WDW 1992b). Overharvest (both legal and illegal) can seriously
threaten populations already reduced by factors such as competition,
degraded habitat, and isolation (Fraley et al. 1989, Brown
[[Page 32279]]
1992a, Craig and Wissmar 1993). Forty-two percent of all populations
across the range were considered suppressed due to accessibility and
overharvest (USDA 1993).
In recognition of the decline of bull trout populations rangewide,
harvest regulations have become significantly restrictive in recent
years. While certain introduced fish, such as small rainbow trout, may
provide supplemental forage for large adult bull trout (Faler 1991,
Pratt 1992, ODFW 1993), introductions have been shown to increase the
risk of incidental and illegal harvest (Rode 1990, Bond 1992, WDW
1992b). Unfortunately, illegal poaching of bull trout continues and
especially threatens small populations (WDW 1992b; Pratt and Huston
1993; USDA 1993; Goetz, pers. comm. 1994, Perkinson, Kootenai National
Forest, in litt., 1994).
Electrofishing-induced injury may pose a new threat to bull trout
because of the dramatic rise in bull trout inventories using
electrofishing techniques (Horton, pers. comm. 1993). If electrofishing
is not conducted properly, bull trout may suffer mortality or injury
(Fredenberg 1992; McMichael 1993; Sharber and Carothers 1988;
Fredenberg, Fish and Wildlife Service, pers. comm. 1993).
Klamath River Population Segment
Though recreational harvest of adult bull trout likely contributed
to the historical decline of the species, harvest has been curtailed
since a regulatory ban was imposed in 1992. Because angling for other
trout species continues, OCAFS (1993) suggested that incidental
mortality may occur on bull trout in spite of their no-harvest
regulation. This claim is speculative, however, and it is not supported
in the 1994 record. As a result, the overutilization of bull trout for
commercial, recreational, scientific, or educational purposes does not
threaten the Klamath Basin population segment based on the 1994 record.
Columbia River Population Segment
Historic harvest in the range of the Columbia River population
segment likely contributed to the observed decline of bull trout. In
the past, harvest included legal recreational angling, poaching, and
directed eradication programs (Thomas 1992). Statewide angling
regulations have recently become more restrictive in an attempt to
protect bull trout throughout Montana, Idaho, Oregon and Washington.
Oregon, Idaho, and Montana have adopted much more restrictive statewide
angling regulations for harvest fisheries associated with Lake Billy
Chinook, Lake Pend Oreille, and Flathead Lake. Those areas of Oregon
where bull trout are in the most precarious situations (including the
Willamette, Hood, Malheur, Powder, and Pine rivers) are now closed to
fishing (Ratliff and Howell 1992). In an effort to protect bull trout
from recreational harvest, the Washington Department of Fish and
Wildlife has prohibited take of bull trout in eastern Washington and in
the lower Columbia River (Brown 1992). While undocumented, poaching may
still be a problem in certain areas of the Columbia River population
segment, especially for large adfluvial and fluvial adults. However,
because angling restrictions are in place and legal harvest is limited
to only a few large populations, the overutilization of bull trout for
commercial, recreational, scientific, or educational purposes in the
Columbia River population segment is not substantiated in the 1994
record.
C. Disease and predation. Disease is not believed to be a critical
factor in the long-term health and survival of bull trout populations.
Predation on juvenile bull trout by non-native fish species, such as
lake, brown, and brook trout, is a recent and potentially serious
threat to some populations (Pratt and Huston 1993, Rieman and McIntyre
1993).
Klamath River Population Segment
Exotic fish species have been introduced into Klamath Basin
streams, and either brown or brook trout reside in conjunction with
bull trout in all but one of the seven remaining populations (Ziller
1992, Ratliff and Howell 1992). The most significant threat by
introduced species to bull trout is hybridization (see section E. Other
natural or manmade factors affecting its continued existence). Although
the potential for predation prevails, no evidence in the 1994 record
suggests that predation occurs in this population segment. Neither
Ratliff and Howell (1992) or OCAFS (1993) considered predation to be a
threat to bull trout in the Klamath Basin. Based on the administrative
1994 record, disease or predation do not threaten the Klamath Basin
population segment.
Columbia River Population Segment
Little information exists for the Columbia River population segment
that implicates predation or disease as a significant factor for bull
trout decline. Introductions of non-native fish present the most
serious threat through hybridization (see section E. Other natural or
manmade factors affecting its continued existence). However, lake trout
populations have increased in Flathead Lake and resulted in the
expansion of lake trout into the Flathead River system (Vashro et al.
1992), where they may prey on emigrating juvenile bull trout (Thomas
1992; Fredenberg, pers. comm. 1994). Similarly, bull trout population
declines in Priest Lake, Idaho, appear to be correlated with the
abundance of lake trout (Mauser 1985, Pratt and Houston 1993) and may
be due to either competition or predation. Nonetheless, based on
administrative 1994 record, disease does not threaten the Columbia
River population segment and the threat posed by predation is limited
and not substantiated for the entire population segment.
D. The inadequacy of existing regulatory mechanisms. Implementation
of Federal and State laws designed to conserve fish resources or
maintain water quality has been inadequate to prevent past and ongoing
habitat degradation and population fragmentation. Deficient agency
funding, competing implementation priorities and the large multi-state/
international geographic area have contributed to this inadequacy. In
addition, conservation measures provided for in many additional
regulations are merely advisory to action agencies. Federal laws
include the Fish and Wildlife Coordination Act; National Forest
Management Act; Federal Land Policy and Management Act; Oregon and
California Act; Clean Water Act; Rivers and Harbors Act; Federal Power
Act; Pacific Northwest Electric Power Planning and Conservation Act;
and Comprehensive Environmental Response, Compensation, and Liability
Act. State laws include the Montana Stream Protection Act, Montana
Natural Streambed and Land Preservation Act, and the Washington Forest
Practices Act. In response to population declines, State fisheries
agencies throughout the range have imposed increasingly restrictive
harvest regulations for bull trout.
Klamath River Population Segment
Though historic harvest in the Klamath River basin likely
contributed to the decline of bull trout, no information is provided in
1994 record to suggest that harvest, or the inadequacy of environmental
rules and regulations now threaten bull trout. Given that legal harvest
has been stopped since 1992, the 1994 record does not document
inadequate existing regulatory mechanisms for the Klamath River
population segment.
Columbia River Population Segment
Historic harvest in the Columbia River Basin likely contributed to
the decline
[[Page 32280]]
of bull trout (Ratliff and Howell 1992, Thomas 1992). Harvest included
legal recreational angling, poaching, and directed eradication programs
(Thomas 1992). Idaho, Montana, and Oregon have since adopted much more
restrictive harvest regulations for the stronghold fisheries of Lake
Pend Oreille, Flathead Lake, and Lake Billy Chinook. Fishing seasons
are closed to the harvest of bull trout in virtually all other waters
of this distinct population segment outside of Canada. However,
implementation of Federal and State laws designed to conserve fish
resources or maintain water quality has been inadequate to prevent past
and ongoing habitat degradation and population fragmentation. Deficient
agency funding, competing implementation priorities and the large
multi-state/international geographic area have contributed to this
inadequacy. Thus, given the above and that the general trend of bull
trout populations in this distinct population segment is declining, the
1994 record suggests that existing regulatory mechanisms for the
Columbia River distinct population segment are inadequate.
E. Other natural or manmade factors affecting its continued
existence. Isolation, competition, and hybridization with introduced
species adversely impact the persistence and viability of bull trout
populations. Widespread introduction of non-native species across the
range of bull trout has frequently resulted in serious population
declines and extirpations (Bond 1992, Donald and Alger 1993, Howell and
Buchanan 1992, Leary et al. 1993, Markle 1992, Platts et al. 1993,
Pratt and Huston 1993, Rieman and McIntyre 1993, Isaacson 1994). Fish
introductions significantly affect the persistence of populations,
particularly when occurring in concert with habitat degradation and
extirpated migratory life history forms (Rieman and McIntyre 1993).
Introduced brook trout have become established throughout much of
the range of bull trout and hybridization seriously threatens the
persistence of bull trout populations (Leary et al. 1993; Markle 1992;
Rieman and McIntyre 1993; Thomas 1992, WDW 1992a and 1992b).
Hybridization results in offspring that are nearly always sterile,
eventually eliminating bull trout from a system (Leary et al. 1993).
Life history differences between the two species (brook trout mature
faster and have a higher reproductive rate) favor brook trout where
ranges overlap (Thomas 1992). This threat is exacerbated when larger,
migratory forms of bull trout have been eliminated and gene flow is
prevented by the isolation of remnant bull trout populations.
Non-native lake trout are dominant and are able to displace bull
trout where niche overlap and potential competition between the two
species is substantial (Donald and Alger 1993). In two cases,
introduced lake trout have replaced bull trout in less than 30 years
(Donald and Alger 1993). In another case, lake trout appear to be in
the process of replacing bull trout in Flathead Lake, which was
considered a stronghold for bull trout (Thomas 1992, Weaver 1993).
Non-native brown trout and bull trout are likely to be in direct
competition in numerous drainages (Platts et al. 1993, Pratt and Huston
1993, Ratliff and Howell 1992). Pratt and Huston (1993) note that brown
trout and bull trout achieve similar sizes and have overlapping
spawning seasons, which may result in disruption of bull trout redds
and competition for resources.
A variety of mechanisms are responsible for isolating bull trout
populations across their range. Isolation may occur directly, resulting
from barrier structures (e.g., dams, weirs, culverts, stream
diversions), or indirectly as a result of degraded habitat conditions
(e.g., altered thermal regimes, dewatered stream reaches,
channelization). Once isolated, bull trout populations face relatively
high probabilities of extinction due to loss of gene flow and
relatively low population size (Rieman and McIntyre 1993).
Klamath River Population Segment
Perhaps the most significant threat to the remaining bull trout
populations in the Klamath Basin is hybridization with introduced brook
trout. Where the two species reside together, bull trout abundance is
alarmingly low, and hybrids are common; only four populations exist in
the absence of brook trout and these populations are the most abundant
populations in the basin (Ratliff and Howell 1992, Ziller, 1992). Bull
trout have recently gone extinct in the Upper Sycan River and Sevenmile
Creek, which now contain only brook trout and hybrids (Ratliff and
Howell 1992). Because bull trout brook trout hybrids are
almost always sterile, the loss of the less numerous parental species
(typically bull trout) inevitably occurs (Leary et al, 1992).
Differences in life history and habitat tolerances between the species
also tend to favor brook trout.
Competition with introduced brook and brown trout particularly may
threaten bull trout in the Klamath Basin because only one of the seven
remaining populations exist in the absence of these species (Ratliff
and Howell 1992, Ziller 1992). Population declines, however, have not
been attributed to competition in the basin like they have been to
hybridization and habitat loss.
The seven remaining populations of bull trout in the Klamath Basin
are isolated from one another by degraded, unsuitable habitat. In
addition, four of these populations have a total population size of
fewer than 500 individuals (all age classes represented) (B. Hooton,
ODFW, in litt. 1993). Extinction risks increase dramatically when
isolated populations decrease in size and/or metapopulations become
further fragmented (Rieman and McIntyre 1993). In addition, the
restriction of gene flow among isolated populations compounds these
threats and reduces genetic diversity and the associated plasticity of
populations to withstand extreme environmental conditions (Rieman and
McIntyre 1993). These situations are prominent within the Klamath River
population segment. Based on the documented hybridization and human-
induced isolation described in the 1994 record, other natural or
manmade factors pose a threat to the continued existence of the Klamath
River population segment.
Columbia River Population Segment
In parts of the Columbia River Basin, non-native introductions
seriously threaten bull trout populations. Where bull trout occur with
brook trout, the threat of hybridization, loss of genetic integrity,
and production of sterile offspring is a major concern (Ratliff and
Howell 1992; Thomas 1992; Esch and Hallock, no date; USDA 1992). Forty-
five percent of the bull trout populations in Oregon evaluated by
Ratliff and Howell (1992) were considered at risk from brook trout.
Populations that are at greatest risk are resident forms occurring
predominantly in the headwater tributary reaches. Adfluvial and fluvial
bull trout appear to be at less risk (Ratliff and Howell 1992).
However, adfluvial and fluvial bull trout are in direct competition
with non-native lake trout in certain areas such as Priest Lake, Idaho
(Pratt and Houston 1993). Bull trout displacement by lake trout is of
special concern in Flathead Lake, Montana and Lake Pend Oreille, Idaho,
which have been considered strongholds for bull trout (Thomas 1992,
Weaver 1993). Based on the documented hybridization and competition
from introduced brook and lake trout described in the 1994 record,
other natural and manmade factors pose a threat to the continued
existence of the Columbia River population segment.
The Service has carefully assessed the best scientific and
commercial
[[Page 32281]]
information available in the 1994 administrative record regarding the
present and future threats facing the two distinct population segments
of bull trout. Determinations by distinct population segment follow.
Klamath River Population Segment
The trend for this distinct population segment is declining based
on the 1994 record. Only seven bull trout populations remain, which are
isolated and remnant, and occupy only a fraction of the historically
available habitat. Larger, more fecund migratory forms have essentially
been lost from the entire distinct population segment, with only small,
resident fish still existing. Imminent threats from habitat
degradation, irrigation diversions, and the presence of non-native
brook trout place this distinct population segment at a moderate to
high risk of extinction.
Documented evidence for a drastic decline in bull trout in the
Klamath River population segment was prominent in the 1994 record. None
of the seven remaining populations occupy any more than 2.5 miles of
available habitat, and no one population consists of more than 500
individuals (all year classes represented). Because the remaining
populations consist of small resident forms with low fecundity,
reproductive and natural recovery potential is extremely poor. As a
result, their likelihood of persistence in the foreseeable future is
uncertain in the absence of special protection and recovery efforts.
Based on an evaluation of the 1994 administrative record, the Klamath
River population segment is in danger of extinction throughout all or a
significant portion of its range, and, thus, this population segment
fits the definition of endangered as defined by the Act.
Columbia River Population Segment
Bull trout populations within the Columbia River population segment
have declined from historic levels and are generally considered to be
isolated and remnant (Rieman and McIntyre 1993, Thomas 1992, USDA 1993,
WDW 1992). An examination of 386 bull trout populations in this
population segment in the United States indicated that 33 percent were
declining, 15 percent stable, 3 percent secure, and 2 percent
increasing (Ratliff and Howell 1992, USDA 1993, WDW 1992). The
population status of the remaining 47 percent in the United States was
unknown, as were those populations in British Columbia in the 1994
record. Because the Service considered known documented trends within a
distinct population segment to be representative of the entire
population segment, an overall declining trend of bull trout
populations in the Columbia River basin was evident based on the 1994
administrative record.
Decrease in bull trout abundance throughout the Columbia River
population segment is evident with former stronghold populations in
Flathead Lake and Lake Pend Oreille declining. However, examples of
stable or increasing populations, such as Swan Lake and Lake Billy
Chinook, were also found in this distinct population segment. Because
of the species' wide range, scattered distribution, and diversity of
life histories in the Columbia River basin, threats from habitat
degradation, passage restriction, and non-native brook trout are
moderate for bull trout populations in this distinct population
segment. Based on the above evaluation of the 1994 administrative
record, the Columbia River population segment is likely to become
endangered within the foreseeable future throughout all or a
significant portion of its range, and, thus, this population segment
fits the definition of threatened as defined by the Act.
Critical habitat is not determinable for the two distinct
population segments of bull trout included in this proposed rule, for
reasons discussed in the ``Critical Habitat'' section of this rule.
Critical Habitat
Critical habitat is defined in section 3 of the Act as--(i) the
specific area within the geographical area occupied by a species, at
the time it is listed in accordance with the Act, on which are found
those biological features (I) essential to the conservation of the
species and (II) which may require special management considerations or
protection; and (ii) specific areas outside the geographical area
occupied by a species at the time it is listed, upon a determination
that such areas are essential for the conservation of the species.
``Conservation'' means the use of all methods and procedures needed to
bring the species to the point at which listing under the Act is no
longer necessary.
Section 4(a)(3) of the Act, as amended, and implementing
regulations (50 CFR 424.12) require that, to the maximum extent prudent
and determinable, the Secretary designate critical habitat at the time
the species is determined to be endangered or threatened. Service
regulations (50 CFR 424.12(a)) state that critical habitat is not
determinable if information sufficient to perform required analysis of
impacts of the designation is lacking or if the biological needs of the
species are not sufficiently well known to permit identification of an
area as critical habitat. Section 4(b)(2) of the Act requires the
Service to consider economic and other relevant impacts of designating
a particular area as critical habitat on the basis of the best
scientific data available. The Secretary may exclude any area from
critical habitat if he determines that the benefits of such exclusion
outweigh the conservation benefits, unless to do such would result in
the extinction of the species.
The Service finds that the determination of critical habitat is not
determinable for these distinct population segments based on the 1994
administrative record. When a ``not determinable'' finding is made, the
Service must, within 2 years of the publication date of the original
proposed rule, designate critical habitat, unless the designation is
found to be not prudent. The Service reached this conclusion because
the biological needs of the species in the two population segments are
not sufficiently well known to permit identification of areas as
critical habitat in the 1994 administrative record. Specifically, no
information was available in the 1994 record on the number of
individuals required for a viable population throughout the distinct
population segment. In addition, the extent of habitat required for
recovery of these fish had not been identified. This information is
considered essential for determining critical habitat for these
population segments. Therefore, the Service finds that designation of
critical habitat for these species is not determinable at this time.
Available Conservation Measures
Conservation measures provided to species listed as endangered or
threatened under the Endangered Species Act include recognition,
recovery actions, requirements for Federal protection, and prohibitions
against certain activities. Recognition through listing encourages and
results in conservation actions by Federal, State, and private
agencies, groups, and individuals. The Act provides for possible land
acquisition and cooperation with the State and requires that recovery
actions be carried out for all listed species. The protection required
of Federal agencies and the prohibitions against taking and harm are
discussed, in part, below.
Section 7(a) of the Act, as amended, requires Federal agencies to
evaluate their actions with respect to any species that is proposed or
listed as endangered or threatened and with respect to its critical
habitat, if any is being
[[Page 32282]]
designated. Regulations implementing this interagency cooperation
provision of the Act are codified at 50 CFR Part 402. Section 7(a)(4)
requires Federal agencies to confer with the Service on any action that
is likely to jeopardize the continued existence of a species proposed
for listing or result in destruction or adverse modification of
proposed critical habitat. If a species is listed subsequently, section
7(a)(2) requires Federal agencies to insure that activities they
authorize, fund, or carry out are not likely to jeopardize the
continued existence of a listed species or to destroy or adversely
modify its critical habitat. If a Federal action may affect a listed
species or its critical habitat, the responsible Federal agency must
enter into formal consultation with the Service.
The Klamath River and Columbia River bull trout population segments
occur on lands administered by the U.S. Forest Service and Bureau of
Land Management (BLM); various State-owned properties in Oregon,
Washington, Idaho and Montana; and private lands. Federal agency
actions that may require conference and/or consultation as described in
the preceding paragraph include Army Corps of Engineers (Corps)
involvement in projects such as the construction of roads and bridges,
and the permitting of wetland filling and dredging projects subject to
section 404 of the Clean Water Act (33 U.S.C. 1344 et seq.); Federal
Energy Regulatory Commission licensed hydropower projects authorized
under the Federal Power Act; Forest Service and BLM timber and grazing
management activities; Environmental Protection Agency authorized
discharges under the National Pollutant Discharge System of the Clean
Water Act; and U.S. Housing and Urban Development projects.
The Act and its implementing regulations found at 50 CFR 17.21 and
17.31 set forth a series of general trade prohibitions and exceptions
that apply to all endangered and threatened wildlife, respectively.
These prohibitions, in part, make it illegal for any person subject to
the jurisdiction of the United States to take (includes harass, harm,
pursue, hunt, shoot, wound, kill, trap, or collect; or attempt any of
these), import or export, ship in interstate commerce in the course of
commercial activity, or sell or offer for sale in interstate or foreign
commerce any listed species. It is also illegal to possess, sell,
deliver, carry, transport, or ship any such wildlife that has been
taken illegally. Certain exceptions apply to agents of the Service and
State conservation agencies.
Permits may be issued to carry out otherwise prohibited activities
involving endangered and threatened wildlife under certain
circumstances. Regulations governing permits are at 50 CFR 17.22, 17.23
and 17.32. Such permits are available for scientific purposes, to
enhance the propagation or survival of the species, and/or for
incidental take in connection with otherwise lawful activities. For
threatened species, permits are also available for zoological
exhibition, educational purposes, or special purposes consistent with
the purpose of the Act.
It is the policy of the Service published in the Federal Register
on July 1, 1994, (59 FR 34272) to identify to the maximum extent
practicable at the time a species is listed those activities that would
or would not constitute a violation of section 9 of the Act. The intent
of this policy is to increase public awareness of the effect of this
listing on proposed and ongoing activities within the species' range.
The Service believes the following actions would not be likely to
result in a violation of section 9:
(1) Actions that may affect bull trout in the Klamath and Columbia
River basins and are authorized, funded or carried out by a Federal
agency when the action is conducted in accordance with an incidental
take statement issued by the Service pursuant to section 7 of the Act;
(2) Possession of Columbia River basin bull trout caught legally in
accordance with state fishing regulations.
With respect to both the Klamath River and Columbia River bull
trout population segments, the following actions likely would be
considered a violation of section 9:
(1) Take of bull trout without a permit, which includes harassing,
harming, pursuing, hunting, shooting, wounding, killing, trapping,
capturing, or collecting, or attempting any of these actions, except in
accordance with applicable State fish and wildlife conservation laws
and regulations within the Columbia River bull trout population
segment;
(2) Possess, sell, deliver, carry, transport, or ship illegally
taken bull trout;
(3) Interstate and foreign commerce (commerce across state and
international boundaries) and import/export (as discussed earlier in
this section);
(4) Introduction of non-native fish species that compete or
hybridize with, or prey on bull trout;
(5) Destruction or alteration of bull trout habitat by dredging,
channelization, diversion, in-stream vehicle operation or rock removal,
or other activities that result in the destruction or significant
degradation of cover, channel stability, substrate composition,
temperature, and migratory corridors used by the species for foraging,
cover, migration, and spawning;
(6) Discharges or dumping of toxic chemicals, silt, or other
pollutants into waters supporting bull trout that result in death or
injury of the species; and
(7) Destruction or alteration of riparian or lakeshore habitat and
adjoining uplands of waters supporting bull trout by timber harvest,
grazing, mining, hydropower development, or other developmental
activities that result in destruction or significant degradation of
cover, channel stability, substrate composition, temperature, and
migratory corridors used by the species for foraging, cover, migration,
and spawning.
Questions regarding whether specific activities may constitute a
violation of section 9 should be directed to the Field Supervisor of
the Service's Snake River Basin Office (see ADDRESSES section).
Requests for copies of the regulations concerning listed animals and
inquiries regarding prohibitions and permits may be addressed to the
U.S. Fish and Wildlife Service, Endangered Species Permits, 911 NE.
11th Avenue, Portland, Oregon 97232-4181 (telephone 503/231-6241;
facsimile 503/231-6243).
Special Rule
Section 4(d) of the Act provides authority for the Service to
promulgate special rules for threatened species that would relax the
prohibition against taking. In this case, the Service proposes a
special rule for the Columbia River bull trout distinct population
segment (see Proposed Regulations Promulgation section). The Service
recognizes that, based on the 1994 administrative record, statewide
angling regulations have become more restrictive in an attempt to
protect bull trout throughout Montana, Idaho, Oregon, and Washington.
The Service intends to continue to work with the States in developing
management plans and agreements with the objective of recovery and
eventual delisting of the Columbia River bull trout distinct population
segment. The Service is consequently proposing a special rule under
section 4(d) that offers additional management flexibility for this
population segment. The special rule would allow for take of bull trout
within the Columbia River population segment
[[Page 32283]]
when it is in accordance with applicable State fish and wildlife
conservation laws and regulations. The Service believes that a special
rule of this nature will benefit the Columbia River distinct population
segment of bull trout, and that the rule would satisfy the requirement
under section 4(d) that regulation applied to threatened species embody
those measures deemed necessary and advisable to provide for the
conservation of the population segment in question.
Public Comments Solicited
The Service intends that any final action resulting from this
proposal will be as accurate and as effective as possible. Therefore,
comments or suggestions from the public, other concerned governmental
agencies, the scientific community, industry, or any other interested
party concerning this proposed rule are hereby solicited. Comments
particularly are sought concerning:
(1) Biological, commercial trade, or other relevant data concerning
threat (or lack thereof) to these two population segments;
(2) The location of any additional populations of the two segments
and the reasons why any habitat should or should not be determined to
be critical habitat as provided by section 4 of the Act;
(3) Additional and updated information concerning the range,
distribution, and population size of the two segments;
(4) Current or planned activities in the subject area and their
possible impacts on the two population segments; and
(5) Promulgation of the special rule.
The final decision on this proposal will take into consideration
the comments and any additional information received by the Service,
and such communications may lead to a final determination that differs
from this proposal. In addition, the Service will consider significant
new information on bull trout received since the close of the 1994
administrative record. A list of significant references concerning bull
trout that have become available since the close of the 1994 record may
be obtained upon request from the Snake River Basin Field Office (see
ADDRESSES above).
The Endangered Species Act provides for at least one public hearing
on this proposal, if requested. However, given the high likelihood of
several requests throughout the range of both population segments, the
Service has scheduled five hearings in advance of any request. The
hearings are scheduled for Portland, Oregon, on July 1, 1997; Spokane,
Washington, on July 8, 1997; Missoula, Montana, on July 10, 1997;
Klamath Falls, Oregon, on July 15, 1997; and Boise, Idaho, on July 17,
1997. For additional information on public hearings, see the DATES
section.
National Environmental Policy Act
The Fish and Wildlife Service has determined that Environmental
Assessments and Environmental Impact Statements, as defined under the
authority of the National Environmental Policy Act of 1969, need not be
prepared in connection with regulations adopted pursuant to section
4(a) of the Endangered Species Act of 1973, as amended. A notice
outlining the Service's reasons for this determination was published in
the Federal Register on October 25, 1983 (48 FR 49244).
Required Determinations
The Service has examined this regulation under the Paperwork
Reduction Act of 1995 and found it to contain no information collection
requirements.
References Cited
A complete list of all references cited herein is available upon
request from the Snake River Basin Field Office (see ADDRESSES above).
Author: The primary authors of this proposed rule are Don Sundeen
and Jim Bartel, Regional Office, Portland, Oregon.
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, and Transportation.
Proposed Regulations Promulgation
PART 17--[AMENDED]
Accordingly, part 17, subchapter B of Chapter I, Title 50 of the
Code of Federal Regulations, is proposed to be amended as set forth
below:
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.
2. Amend Sec. 17.11(h) by adding the following, in alphabetical
order under Fishes, to the List of Endangered and Threatened Wildlife:
Sec. 17.11 Endangered and threatened wildlife.
* * * * *
(h) * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Vertebrate
------------------------------------------------------ population where Critical
Historic range endangered or Status When listed habitat Special rules
Common name Scientific name threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * * * *
Fishes
* * * * * * *
Trout, bull..................... Salvelinus U.S.A. (OR)....... Klamath River..... E NA NA
confluentus.
Do.......................... ......do........... U.S.A. (ID, MT, Columbia River.... T NA 17.44(v)
OR, WA) Canada.
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
3. Amend Sec. 17.44 by adding paragraph (v) to read as follows:
Sec. 17.44 Special rule--fishes.
* * * * *
(v) Bull trout (Salvelinus confluentus), Columbia River population
(1) No person shall take this species, except in accordance with
applicable State fish and wildlife conservation laws and regulations.
(2) Any violation of applicable State fish and wildlife
conservation laws or regulations with respect to the taking of this
species is also a violation of the Endangered Species Act.
(3) No person shall possess, sell, deliver, carry, transport, ship,
import, or export, any means whatsoever, any such
[[Page 32284]]
species taken in violation of these regulations or in violation of
applicable State fish and game laws and regulations.
(4) It is unlawful for any person to attempt to commit, solicit
another to commit, or cause to be committed, any offense defined in
paragraphs (v) (1) through (3) of this section.
Dated: June 9, 1997.
William Leary,
Acting Deputy Assistant Secretary for Fish and Wildlife and Parks.
[FR Doc. 97-15584 Filed 6-12-97; 8:45 am]
BILLING CODE 4310-55-P
