Endangered and Threatened Wildlife and Plants; Proposed Rule To Reclassify the Oregon Chub (Oregonichthys crameri) From Endangered to Threatened, 22870-22880 [E9-11322]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 93 (Friday, May 15, 2009)]
[Proposed Rules]
[Pages 22870-22880]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-11322]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R1-ES-2009-0005; 92220-1113-0000-C6]
RIN 1018-AW42


Endangered and Threatened Wildlife and Plants; Proposed Rule To 
Reclassify the Oregon Chub (Oregonichthys crameri) From Endangered to 
Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: Under the authority of the Endangered Species Act of 1973, as 
amended (Act), we, the U.S. Fish and Wildlife Service (Service), 
propose to reclassify the Oregon chub (Oregonichthys crameri) from 
endangered to threatened. This proposal is based on a thorough review 
of the best available scientific data, which indicate that the species' 
status has improved such that it is not currently in danger of 
extinction throughout all or a significant portion of its range. We 
seek information, data, and comments from the public regarding the 
Oregon chub and this proposal.

DATES: We will accept comments received on or before July 14, 2009. 
Public hearing requests must be received by June 29, 2009.

[[Page 22871]]


ADDRESSES: You may submit comments by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov. 
Follow the instructions for submitting comments.
     U.S. mail or hand-delivery: Public Comments Processing, 
Attn: RIN 1018-AW42; Division of Policy and Directives Management; U.S. 
Fish and Wildlife Service; 4401 N. Fairfax Drive, Suite 222; Arlington, 
VA 22203.
    We will not accept e-mail or faxes. We will post all comments on 
https://www.regulations.gov. This generally means that we will post any 
personal information you provide us (see the Public Comments section 
below for more information).
    Public Hearing Requests: To request a public hearing, contact the 
person listed under FOR FURTHER INFORMATION CONTACT.

FOR FURTHER INFORMATION CONTACT: Paul Henson, State Supervisor, U.S. 
Fish and Wildlife Service, Oregon Fish and Wildlife Office, 2600 SE. 
98th Avenue, Suite 100, Portland, Oregon 97266; (telephone 503/231-
6179). Persons who use a telecommunications device for the deaf (TDD) 
may call the Federal Information Relay Service (FIRS) at 800/877-8339, 
24 hours a day, 7 days a week.

SUPPLEMENTARY INFORMATION:

Public Comments Solicited

    Our intent is to use the best available commercial and scientific 
data as the foundation for all endangered and threatened species 
classification decisions. Comments or suggestions from the public, 
other concerned governmental agencies, the scientific community, 
industry, or any other interested party concerning this proposed rule 
to downlist the Oregon chub are hereby solicited. Comments particularly 
are sought concerning:
    (1) Biological information concerning the Oregon chub, including 
competition from non-native species and the risks associated with loss 
of genetic diversity in isolated populations;
    (2) Relevant data concerning any current or likely future threats 
(or lack thereof) to the Oregon chub;
    (3) Additional information concerning the range, distribution, 
population size and population trends of the Oregon chub, including the 
locations of any additional populations; and
    (4) Information regarding management plans or other mechanisms that 
provide protection to Oregon chub or their habitats.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section. We will not 
accept comments sent by e-mail or fax or to an address not listed in 
the ADDRESSES section.
    We will post your entire comment on https://www.regulations.gov. 
Before including your address, phone number, or e-mail address, or 
other personal identifying information in your comment, you should be 
aware that your entire comment--including your personal identifying 
information--may be made publicly available at any time. While you can 
ask us in your comment to withhold your personal identifying 
information from public review, we cannot guarantee that we will be 
able to do so.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on https://www.regulations.gov, or by 
appointment during normal business hours at the Oregon Fish and 
Wildlife Office, 2600 SE. 98th Avenue, Suite 100, Portland, Oregon 
97266, (503/231-6179).

Public Hearing

    The Act provides for one or more public hearings on this proposal, 
if requested. Requests must be received by the date specified in DATES. 
Such requests must be made in writing and addressed to the Field 
Supervisor (see FOR FURTHER INFORMATION CONTACT section above).

Previous Federal Action

    In our December 30, 1982, Review of Vertebrate Wildlife for Listing 
as Endangered or Threatened Species Under the Act, we listed the Oregon 
chub as a Category 2 candidate species (47 FR 58454). Category 2 
candidates, a designation no longer used by the Service, were species 
for which information contained in Service files indicated that 
proposing to list was possibly appropriate but additional data were 
needed to support a listing proposal. The Oregon chub maintained its 
Category 2 status in both the September 18, 1985 (50 FR 37958) and 
January 6, 1989 (54 FR 554) Notices of Review.
    On April 10, 1990, the Service received a petition to list the 
Oregon chub as an endangered species and to designate critical habitat. 
The petition and supporting documentation were submitted by Dr. Douglas 
F. Markle and Mr. Todd N. Pearsons, both affiliated with Oregon State 
University. The petitioners submitted taxonomic, biological, 
distributional, and historical information and cited numerous 
scientific articles in support of the petition. The petition and 
accompanying data described the Oregon chub as endangered because it 
had experienced a 98 percent range reduction and remaining populations 
faced significant threats. On November 1, 1990, the Service published a 
90-day finding indicating that the petitioners had presented 
substantial information indicating that the requested action may be 
warranted and initiated a status review (55 FR 46080).
    On November 19, 1991, the Service published a 12-month finding on 
the petition concurrent with a proposal to list the species as 
endangered (56 FR 58348). A final rule listing the Oregon chub as 
endangered was published in the Federal Register on October 18, 1993 
(58 FR 53800). A 5-year review of the Oregon chub's status was 
completed in February 2008 (U.S. Fish and Wildlife Service 2008a, pp. 
1-34); this review concluded that the Oregon chub's status had 
substantially improved since listing, and that the Oregon chub no 
longer met the definition of an endangered species, but does meet the 
definition of a threatened species, under the Act. The review, 
therefore, recommended that the Oregon chub should be downlisted from 
endangered to threatened.
    On March 10, 2009, the Service published a proposed rule to 
designate critical habitat (74 FR 10412) for the Oregon chub. The 
public comment period on the proposed critical habitat rule closes on 
May 11, 2009.

Species Information

    The Oregon chub is a small minnow (Family: Cyprinidae) endemic to 
the Willamette River Basin in western Oregon (Markle et al. 1991, p. 
288). The Oregon chub has an olive-colored back grading to silver on 
the sides and white on the belly (Markle et al. 1991, p. 286). Oregon 
chub are found in slack water off-channel habitats such as beaver 
ponds, oxbows, side channels, backwater sloughs, low-gradient 
tributaries, and flooded marshes. These habitats usually have little or 
no water flow, silty and organic substrate, and abundant aquatic 
vegetation for hiding and spawning cover (Pearsons 1989, p. 12; 
Scheerer and McDonald 2000, p. 9). Summer temperatures in shallow ponds 
inhabited by Oregon chub generally exceed 16 degrees Celsius (C) (61 
degrees Fahrenheit (F)) (Scheerer et al. 1998, p. 26). In the winter 
months, Oregon chub are found buried in detritus or concealed in 
aquatic vegetation (Pearsons 1989, p. 16).
    Oregon chub reach maturity at about 2 years of age (Scheerer and 
McDonald 2003, p. 78) and in wild populations can

[[Page 22872]]

live up to 9 years. Most individuals over 5 years old are females 
(Scheerer and McDonald 2003, p. 68). Oregon chub spawn in warm (16 to 
21 degrees C (61 to 70 degrees F)) shallow water from June through 
August (Scheerer and McDonald 2000, p. 10). The diet of Oregon chub 
collected in a May sample consisted primarily of copepods, cladocerans, 
and chironomid larvae (Markle et al. 1991, p. 288).
    In the early 1990s, Oregon chub populations were found 
predominantly in the Middle Fork Willamette River (Middle Fork), with a 
few, small populations found in the Mid-Willamette River, Santiam 
River, and Coast Fork Willamette River (Coast Fork). The species is now 
well distributed throughout the Willamette Basin (in Polk, Marion, 
Linn, Lane and Benton Counties, Oregon), with populations in the 
Santiam River (8 sites), Mid-Willamette River (6 sites), McKenzie River 
(4 sites), Middle Fork (14 sites), and Coast Fork (3 sites) (Scheerer 
et al. 2007, p. 2). There are currently 19 populations that contain 
more than 500 adults each; 16 of these have a stable or increasing 
trend (Scheerer 2008a, p. 6).

Review of the Recovery Plan

    The Service published a final recovery plan for the Oregon chub in 
1998 (U.S. Fish and Wildlife Service 1998). Recovery plans are intended 
to guide actions to recover listed species and to provide measurable 
objectives against which to measure progress towards recovery, however, 
precise attainment of the recovery criteria is not a prerequisite for 
downlisting or delisting. The Oregon chub recovery plan established the 
following criteria for downlisting the species from endangered to 
threatened:
    (1) Establish and manage 10 populations of at least 500 adults 
each;
    (2) All of these populations must exhibit a stable or increasing 
trend for 5 years; and
    (3) At least three populations must be located in each of the three 
sub-basins of the Willamette River identified in the plan (Mainstem 
Willamette River, Middle Fork, and Santiam River).
    The recovery plan established the following criteria for delisting 
(i.e., removing the species from the List of Endangered and Threatened 
Wildlife):
    (1) Establish and manage 20 populations of at least 500 adults 
each;
    (2) All of these populations must exhibit a stable or increasing 
trend for 7 years;
    (3) At least four populations must be located in each of the three 
sub-basins (Mainstem Willamette River, Middle Fork, and Santiam River); 
and
    (4) Management of these populations must be guaranteed in 
perpetuity.
    Recovery actions specified in the recovery plan to achieve the 
downlisting and delisting goals included managing existing sites, 
establishment of new populations, research into the ecology of the 
species, and public education and outreach to foster greater 
understanding of the Oregon chub and its place in the natural 
environment of the Willamette Basin (U.S. Fish and Wildlife Service 
1998, pp. 28-44).

Recovery Plan Implementation

    When the Oregon chub was listed as endangered in 1993, it was known 
to occur at only nine locations within a 30-kilometer (18.6-mile) reach 
of the Willamette River, representing just two percent of its 
historical range (58 FR 53800, p. 53801). Since 1992, the Service, 
Oregon Department of Fish and Wildlife (ODFW), U.S. Army Corps of 
Engineers (Corps), U.S. Forest Service, Oregon Parks and Recreation 
Department and Oregon Department of Transportation have funded ODFW 
staff to conduct surveys for Oregon chub throughout the Willamette 
Valley. ODFW has surveyed 650 off-channel habitats and small 
tributaries in the Willamette River Basin (Scheerer 2007, p. 92), 
greatly increasing our knowledge of the current and potential habitat 
available to the Oregon chub. Other research projects have resulted in 
new information on the species' habitat use, timing of spawning, and 
age and growth patterns (U.S. Fish and Wildlife Service 2008a, pp. 13-
15).
    The status of the Oregon chub has dramatically improved since it 
was listed as endangered. The improvement is due largely to the 
implementation of actions identified in the Oregon chub recovery plan. 
This includes the discovery of many new populations as a result of 
ODFW's exhaustive surveys of the basin, and the establishment of 
additional populations via successful reintroductions within the 
species' historical range (Scheerer 2007, p. 97). To date, Oregon chub 
populations have been introduced at 15 sites (7 in the Mainstem 
Willamette Sub-basin, 5 in the Middle Fork Sub-basin, and 3 in the 
Santiam Sub-basin) (Scheerer et al. 2007, p. 2; Scheerer 2008a, p. 6). 
Introduced populations have been established in suitable habitats with 
low connectivity to other suitable aquatic habitats to reduce the risk 
of invasion by nonnative fishes (see Factor C below for more 
information) (Scheerer 2007, p. 98). At present, 9 of these populations 
persist and exhibit stable or increasing trends; 1 population was 
reintroduced too recently to evaluate success (i.e., the population 
introduced in 2008 at St. Paul Ponds); and 5 introduced populations 
have been extirpated or are not likely to remain viable. Reasons for 
reintroduction failures include: pond desiccation, low dissolved 
oxygen, unauthorized introductions of nonnative predatory fishes, and 
high mortality of introduced fish (Scheerer et al. 2007, p. 2; Scheerer 
2008a, p. 6; Scheerer 2009a, p. 1).
    Currently, there are 36 Oregon chub populations, of which 19 have 
more than 500 adults (Scheerer et al. 2007, p. 2; Scheerer 2008a, p. 
6). Fifteen years have passed since listing, and the species is now 
relatively abundant and well distributed throughout much of its 
presumed historical range. The risk of extinction has been 
substantially reduced as threats have been managed, and as new 
populations have been discovered and re-established. The Oregon chub 
has exceeded or met nearly all of the criteria for downlisting to 
threatened described in the recovery plan. A review of the species' 
current status relative to the downlisting criteria follows.
    Downlisting Criterion 1: Establish and manage 10 populations of at 
least 500 adults each. This criterion has been exceeded. There are 19 
populations with more than 500 adult Oregon chub (table 1).
    Downlisting Criterion 2: All of these populations must exhibit a 
stable or increasing trend for 5 years. This criterion has been 
exceeded; there are 16 populations with at least 500 adults that are 
stable or increasing (table 1). Scheerer et al. (2007, p. 4) defined 
abundance trends as increasing, declining, stable, or not declining 
using linear regression of abundance estimates over time for each 
population with more than 500 adult fish over the last 5 years. When 
the slope of this regression was negative and significantly different 
from zero (P<0.10), the population was categorized as declining. When 
the slope was positive and significantly different from zero (P<0.10), 
the population was categorized as increasing. When the slope was not 
significantly different from zero (P>0.10), Scheerer et al. (2007, p. 
4) calculated the coefficient of variation of the abundance estimates 
to discriminate between populations that were stable (i.e., low 
variation in population abundance estimates) and those that were 
unstable but not declining (i.e., high variation in population 
abundance estimates). When the coefficient of variation was less than 
1.0, the

[[Page 22873]]

population was defined as stable; otherwise, the population was 
considered unstable but not declining (table 1).
    Downlisting Criterion 3: At least three populations (which meet 
criteria 1 and 2 above) must be located in each of the three sub-basins 
of the Willamette River (Mainstem Willamette River, Middle Fork 
Willamette, and Santiam River). This criterion has been exceeded in two 
sub-basins, and is nearly accomplished in the third. In the Mainstem 
Willamette River sub-basin, there are 6 populations with 500 or more 
Oregon chub with stable or increasing trends; in the Middle Fork 
Willamette sub-basin, there are 8 populations with 500 or more Oregon 
chub with stable or increasing trends; and in the Santiam River sub-
basin, there are 3 populations with 500 or more Oregon chub, but only 2 
with stable or increasing trends over the last 5 years (Table 1). Five-
year trends were calculated for abundant populations (>500 individuals 
for the last 5 years) only. Table 1 shows the populations by sub-basin.

                              Table 1--Oregon Chub Population Estimates and Trends
                 [From Scheerer et al. 2007, p. 2; Scheerer, 2008a, p. 6, Scheerer 2008b, p. 1]
----------------------------------------------------------------------------------------------------------------
                                                                        Population
          Population site name                     Owner \1\           estimate \2\        5-Year trend \3\
----------------------------------------------------------------------------------------------------------------
                                             Santiam River Sub-Basin
----------------------------------------------------------------------------------------------------------------
Foster Pullout Pond.....................  Corps......................        2,640   stable.
Gray Slough.............................  Private....................          660   stable.
South Stayton Pond......................  ODFW.......................        1,710   ...........................
Geren Island North Channel..............  City of Salem..............          210   declining.
Pioneer Park Backwater..................  Private....................          320   ...........................
Stayton Public Works Pond...............  City of Stayton............           70   ...........................
Santiam I-5 Side Channels...............  ODOT.......................          (22)  ...........................
Green's Bridge Slough...................  Private....................           (8)  ...........................
----------------------------------------------------------------------------------------------------------------
                     Mainstem Willamette Sub-Basin (Includes McKenzie River and Coast Fork)
----------------------------------------------------------------------------------------------------------------
Ankeny Willow Marsh.....................  USFWS......................       36,450   increasing.
Dunn Wetland............................  Private....................       34,530   stable.
Finley Gray Creek Swamp.................  USFWS......................        2,140   increasing.
Finley Cheadle Pond.....................  USFWS......................        3,520   increasing.
Finley Display Pond.....................  USFWS......................          830   increasing.
Muddy Creek.............................  Private....................           (3)  ...........................
Russell Pond............................  Private....................          650   stable.
Shetzline Pond..........................  Private....................          200   ...........................
Big Island..............................  Private....................          130   ...........................
Green Island............................  Private....................          (12)  ...........................
Herman Pond.............................  USFS.......................          180   ...........................
Coast Fork Side Channels................  OPRD/ODOT..................           80   ...........................
Lynx Hollow Side Channels...............  OPRD.......................           (2)  ...........................
----------------------------------------------------------------------------------------------------------------
                                              Middle Fork Sub-Basin
----------------------------------------------------------------------------------------------------------------
Shady Dell Pond.........................  USFS.......................        7,250   increasing.
E. Bristow St. Park--Berry Slough.......  OPRD.......................        5,460   increasing.
Dexter Reservoir RV Alcove-- DEX3.......  Corps......................        4,020   increasing.
Wicopee Pond............................  USFS.......................        5,430   stable.
Fall Creek Spillway Ponds...............  Corps......................        3,050   declining.
Buckhead Creek..........................  USFS.......................        1,260   declining.
East Fork Minnow Creek Pond.............  ODOT.......................        2,160   stable.
Elijah Bristow Island Pond..............  OPRD.......................        1,620   stable.
Hospital Pond...........................  Corps......................        3,680   stable.
Dexter Reservoir Alcove--PIT1...........  Corps......................          680   stable.
Haws Pond...............................  Private....................          280   ...........................
E. Bristow St. Park--NE Slough..........  OPRD.......................          230   ...........................
Jasper Park Slough......................  OPRD.......................           (1)  ...........................
St. Paul Ponds..........................  ODFW.......................          (21)  ...........................
----------------------------------------------------------------------------------------------------------------
\1\ Owner abbreviations: Corps = U.S. Army Corps of Engineers, USFWS = U.S. Fish and Wildlife Service, ODOT =
  Oregon Department of Transportation, OPRD = Oregon Parks and Recreation Department, ODFW = Oregon Department
  of Fish and Wildlife.
\2\ Population estimate is the most recent available (Fall 2007 or Spring 2008). Abundances are mark--recapture
  estimates except those shown in parentheses, which are the number of fish collected.
\3\ 5-year trends were calculated for abundant populations (>500 individuals for the last 5 years) only.

Additional Conservation Measures

    The Oregon Chub Working Group (Working Group) was formed in 1991. 
This group of Federal and State agency biologists, academics, land 
managers and others meet each year to share information on the status 
of the Oregon chub, results of new research, and ongoing threats to the 
species. The Working Group has been an important force in improving the 
conservation status of the Oregon chub.
    An interagency conservation agreement was established for the 
Oregon chub in 1992, prior to listing (U.S. Fish and Wildlife Service 
1998, p. 59). ODFW, Oregon Department of Parks and Recreation, Corps, 
U.S. Bureau of

[[Page 22874]]

Land Management, U.S. Fish and Wildlife Service, and U.S. Forest 
Service are the parties to the agreement. The objectives of the 
conservation agreement are to: (1) Establish a task force drawn from 
participating agencies to oversee and coordinate Oregon chub 
conservation and management actions, (2) protect existing populations, 
(3) establish new populations, and (4) foster greater public 
understanding of the species, its status, and the factors that 
influence it (U.S. Fish and Wildlife Service 1998, pp. 65-66).
    The Oregon chub is designated as ``Sensitive-Critical'' by ODFW. 
The ``Sensitive'' species classification was created under Oregon's 
Sensitive Species Rule (OAR 635-100-040) to address the need for a 
proactive species conservation approach. The Sensitive Species List is 
a nonregulatory tool that helps focus wildlife management and research 
activities, with the goal of preventing species from declining to the 
point of qualifying as ``threatened'' or ``endangered'' under the 
Oregon Endangered Species Act (ORS 496.171, 496.172, 496.176, 496.182 
and 496.192). Species designated as Sensitive-Critical are those for 
which listing as threatened or endangered would be appropriate if 
immediate conservation actions were not taken. This designation 
encourages but does not require the implementation of any conservation 
actions for the species.

Summary of Factors Affecting the Species

    Section 4 of the Act and its implementing regulations (50 CFR part 
424) set forth the procedures for listing species, reclassifying 
species, or removing species from listed status. ``Species'' is defined 
by the Act as including any species or subspecies of fish or wildlife 
or plants, and any distinct vertebrate population segment of fish or 
wildlife that interbreeds when mature (16 U.S.C. 1532(16)). Once the 
``species'' is determined, we then evaluate whether that species may be 
endangered or threatened because of one or more of the five factors 
described in section 4(a)(1) of the Act. We must consider these same 
five factors in reclassifying or delisting a species. For species that 
are already listed as threatened or endangered, this analysis of 
threats is an evaluation of both the threats currently facing the 
species and the threats that are reasonably likely to affect the 
species in the foreseeable future following the delisting or 
downlisting and the removal or reduction of the Act's protections.
    A species is ``endangered'' for purposes of the Act if it is in 
danger of extinction throughout all or a significant portion of its 
range, and is ``threatened'' if it is likely to become endangered 
within the foreseeable future throughout all or a significant portion 
of its range. The word ``range'' is used here to refer to the range in 
which the species currently exists, and the word ``significant'' refers 
to the value of that portion of the range being considered to the 
conservation of the species. The ``foreseeable future'' is the period 
of time over which events or effects reasonably can or should be 
anticipated, or trends reasonably extrapolated; see discussion 
following Factor E, below.
    Following a rangewide threats analysis we evaluate whether the 
Oregon chub is threatened or endangered in any significant portion(s) 
of its range.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of Its Habitat or Range

    Historical records indicate that the Oregon chub was distributed 
throughout the Willamette Basin, from the Clackamas River in the north, 
to the Coast Fork and Middle Fork in the south (Markle 1991, p. 288). 
When the Oregon chub was listed as endangered in 1993, the species was 
known to exist at only nine locations, representing only 2 percent of 
the species' historical range (Markle 1991, pp. 288-289; Scheerer et 
al. 2007, p. 2). Four of these locations had fewer than 10 individuals 
(Scheerer et al. 2007, p. 2). This precipitous decline in the species' 
abundance and distribution was attributed to the extensive 
channelization, dam construction, and chemical contamination that 
occurred in the Willamette Basin, particularly from the 1940s through 
the late 20th century (Pearsons 1989, pp. 29-30).
    There are at least 371 dams in the Willamette River Basin, most of 
which were constructed during the period 1950 to 1980 (Hulse et al. 
2002, p. 30). These dams reduced the magnitude, extent, and frequency 
of flooding in the basin, which dramatically reduced the amount of 
slough and side channel habitats used by the Oregon chub (Hulse et al. 
2002, pp. 28-30). Other structural changes, such as revetment and 
channelization, diking and drainage, and the removal of floodplain 
vegetation, eliminated or altered the side channels and sloughs used by 
the Oregon chub, and destroyed the natural processes that replenish 
these slack water habitats (Hjort et al. 1984, p. 73; Sedell and 
Frogatt 1984, p. 1833; Hulse et al. 2002, p. 27). Analysis of 
historical records shows that over one-half of the Willamette's sloughs 
and alcoves had been lost by 1995 (Hulse et al. 2002, p. 18). Although 
the Oregon chub evolved in a dynamic environment in which flooding 
periodically created and reconnected habitat for the species, currently 
most populations of Oregon chub are isolated from other chub 
populations due to the reduced frequency and magnitude of flood events 
and the presence of migration barriers such as impassable culverts and 
beaver dams (Scheerer et al. 2007, p. 9).
    In the 15 years since the Oregon chub was listed as endangered, 
concerted efforts by Federal, State, and local governments and private 
landowners have increased the number of Oregon chub populations from 9 
to 36 (Scheerer et al. 2007, p. 2; Scheerer 2008a, p. 6). This dramatic 
increase in the number of populations is a result of the discovery of 
new populations through extensive surveys of suitable habitats 
throughout the Willamette Basin and the establishment of new 
populations through successful reintroductions within their historical 
range (Scheerer 2007, p. 97). Since 1992, Oregon chub have been 
reintroduced to 15 locations, resulting in the successful establishment 
of 9 populations (Scheerer et al. 2007, p. 2; Scheerer 2008a, p. 6).
    The analysis of threats in the final rule to list the Oregon chub 
as an endangered species and the recovery plan for the species 
discussed numerous potential threats to water quality in Oregon chub 
habitats. Many Oregon chub populations occur near rail, highway, and 
power transmission corridors, agricultural fields, and within public 
park and campground facilities, and there was concern that these 
populations could be threatened by chemical spills, runoff, or changes 
in water level or flow conditions caused by construction, diversions, 
or natural desiccation (58 FR 53800, October 18, 1993; U.S. Fish and 
Wildlife Service 1998, p. 14, Scheerer 2008c, p. 1). In the 15 years 
since listing, a few of these concerns have been realized, and are 
discussed in the paragraphs below.
    Excessive siltation from ground disturbing activities in the 
watershed, such as logging upstream of Oregon chub habitat, can degrade 
or destroy Oregon chub habitat. The threat of siltation due to logging 
in the watershed has been identified at five sites: Green Island North 
Channel, Finley Gray Creek Swamp, East Fork Minnow Creek Pond, Buckhead 
Creek, and Wicopee Pond (Scheerer 2008c, p. 1). In the 1990s, a large 
part of the Minnow Creek Watershed in the Middle Fork Willamette Sub-
basin was logged; flood events in the watershed in 1996, 1997, and 1998 
caused accelerated

[[Page 22875]]

sedimentation in the beaver pond at East Fork Minnow Creek Pond, and 
over half of the open water wetted area of the Oregon chub habitat 
there was lost as sediment filled the pond (Scheerer 2009b, p. 1). The 
Oregon chub population in East Fork Minnow Creek Pond declined 
dramatically following these floods and the resulting sedimentation 
(Scheerer 2009b, p. 1).
    Water quality investigations at sites in the Middle Fork and 
Mainstem Willamette sub-basins have found some adverse effects to 
Oregon chub habitats. Nutrient enrichment may have caused the crash of 
the Oregon chub population at Oakridge Slough on the Middle Fork. The 
slough is downstream from the Oakridge Sewage Treatment Plant and has a 
thick layer of decaying organic matter, which may limit the amount of 
useable habitat available to the chub (Buck 2003, p. 2). In the late 
1990s, the Oregon chub population in Oakridge Slough peaked at nearly 
500 individuals; since then, the population has apparently declined to 
zero (Scheerer et al. 2007, p. 2). Increased nitrogen and phosphorus 
concentrations have been detected in the slough; while the nutrient 
concentrations are not believed to be directly harmful to Oregon chub, 
the elevated nutrient levels may have resulted in eutrophication of the 
pond, with associated anoxic conditions unsuitable for chub, or 
increased plant and algal growth that severely reduced habitat 
availability (Buck 2003, p. 12).
    Studies at William L. Finley National Wildlife Refuge have found 
evidence of elevated levels of nutrients and pesticides in Oregon chub 
habitats (Materna and Buck 2007, p. 67). Water samples were collected 
in 1998 from Gray Creek Swamp, which is home to a large population of 
Oregon chub. Analyses detected three herbicides, although all were 
below criteria levels recommended for protection of aquatic life; 
however, one form of nitrogen (total Kjeldahl N) exceeded Environmental 
Protection Agency criteria levels recommended for protection of aquatic 
life in the Willamette Valley (Materna and Buck 2007, p. 67). The 
source of the contamination is likely agricultural runoff from farm 
fields adjacent to the refuge (Materna and Buck 2007, p. 68). We note 
that EPA's recommended criteria for protection of aquatic life are not 
intended to be protective of all aquatic life, and may not be fully 
protective of the Oregon Chub. EPA and the Service are working together 
to assess the effects of pollutants on the Oregon chub through section 
7 consultation on Oregon water quality standards.
    Fluctuating water levels in Lookout Point Reservoir on the Middle 
Fork Willamette River were limiting the breeding success of the Oregon 
chub population in Hospital Pond, which provides habitat for the 
species in a pool connected to the reservoir by a culvert. In 2001, 
2002, and 2003, the Corps, which manages Lookout Point Reservoir, 
implemented a series of projects to protect the population of Oregon 
chub in Hospital Pond. The goal was to allow the Corps to manage the 
water level in Lookout Point Reservoir independently of the water 
elevation in Hospital Pond. The Corps installed a gate on Hospital 
Pond's outlet culvert and lined the porous berm between the pond and 
reservoir; these modifications allow the Corps to maintain the water 
level needed to support Oregon chub spawning in Hospital Pond 
independent of the water level in the reservoir (U.S. Fish and Wildlife 
Service 2002, pp. 1-11). The Corps also excavated additional area to 
create more suitable spawning habitat in the pond (U.S. Fish and 
Wildlife Service 2003, pp. 1-3). The result of these management actions 
has been a large stable population of Oregon chub in Hospital Pond 
(Scheerer 2008a, p. 6).
    Most of the known Oregon chub populations occur on lands with some 
level of protective status and management (see Table 1). The Service 
manages several Oregon chub populations on the Finley and Ankeny units 
of the Willamette Valley National Wildlife Refuge Complex (Refuge). 
Recovery of the Oregon chub is a high priority for the Refuge. The 
Refuge actively monitors the status of the populations, habitat 
quality, and nonnative fish presence; when threats are detected, the 
Refuge implements management actions to reverse the threats (Smith 
2008, p. 1).
    Five populations of Oregon chub occur on lands managed by the 
Corps; the Corps manages Oregon chub in accordance with the Service's 
biological opinion on the Willamette Project. In July 2008, the Corps, 
Bonneville Power Administration (BPA), and Bureau of Reclamation (BOR) 
completed formal consultation with the Service under section 7(a)(2) of 
the Endangered Species Act on the operation and maintenance of the 
Willamette Project, the system of 13 dams and associated impoundments 
that provide flood control, irrigation, municipal and industrial water 
supply, navigation, fish and wildlife conservation, flow augmentation, 
hydroelectric power generation, and recreation to the Willamette 
Valley. The Service concluded that the project would not jeopardize the 
continued existence of the Oregon chub (U.S. Fish and Wildlife Service 
2008b, pp. 1-204). The Service's biological opinion describes the 
measures that will be implemented by the Corps, BPA, and BOR to 
maintain and improve habitat for the Oregon chub. These measures 
include:
    (1) Monitoring the status of Oregon chub populations affected by 
operation and maintenance of the dams to gain a better understanding of 
the influence of the Willamette Project on species;
    (2) Managing water levels in Oregon chub habitats directly affected 
by reservoir operations;
    (3) Relocating Oregon chub from ponds adversely affected by 
reservoir operations to new locations with better prospects for long-
term protection;
    (4) Studies to identify the effects of flow management on Oregon 
chub habitats; and
    (5) Funding a pilot study to investigate the impact of floodplain 
restoration and reconnection on fish communities in river reaches below 
Willamette Project dams.
    Operation and maintenance of the Willamette Project under the new 
biological opinion will result in improved protections for the Oregon 
chub and new information that will benefit the species throughout the 
Willamette Basin.
    The Oregon Department of Transportation has developed and is 
implementing a plan to protect and enhance Oregon chub populations on 
the agency's properties or those which may be affected by highway 
maintenance on the Santiam River, Coast Fork Willamette River, and 
Middle Fork Willamette River (Scheerer 2005, pp. 1-21).
    The Oregon chub populations at Elijah Bristow State Park and Jasper 
Park on the Middle Fork are managed by the Oregon Parks and Recreation 
Department, which uses the Service's recovery plan as guidance to 
ensure conservation of the chub populations within the parks (Schleier 
2008).
    The U.S. Forest Service monitors and manages several Oregon chub 
populations on the Middle Fork (Scheerer 2008b, p. 1).
    In addition to the management and protection provided to the Oregon 
chub on Federal and State lands, two Safe Harbor Agreements have been 
completed to guide management of Oregon chub populations on private 
lands. Safe Harbor Agreements are voluntary arrangements between the 
Service and cooperating non-Federal landowners to promote management 
for listed species on non-Federal property while giving assurances to 
participating

[[Page 22876]]

landowners that no additional future regulatory restrictions will be 
imposed. The Service's Oregon Fish and Wildlife Office is preparing a 
programmatic Safe Harbor Agreement to allow more landowners to enroll 
in the program, which, based on past experience, is likely to result in 
the reintroduction of Oregon chub populations on more private lands 
throughout the species' historical range.
    Summary of Factor A: The Oregon chub has experienced extensive loss 
of slough and side-channel habitat due to hydrological changes 
resulting from dam construction and channelization in the Willamette 
Valley. However, many new habitats have been artificially created and 
are being managed to maintain populations of Oregon chub. Habitat 
quality is threatened by water quality degradation, though this has 
been documented at only a few sites. Habitat conditions have improved 
to the point where the species is not presently in danger of 
extinction. However, without continued protections provided by the Act, 
or long-term management agreements, the Oregon chub would likely become 
endangered in the foreseeable future due, in part, to the destruction, 
modification or curtailment of its habitat.

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    Overutilization was not a factor in listing nor is it currently 
known to be a threat to the Oregon chub.

Factor C. Disease or Predation

    The proliferation of predatory nonnative fish is the largest 
current threat to Oregon chub populations (Scheerer et al. 2007, p. 
14). Nearly half of the fish species found in the Willamette Basin are 
introduced; the basin contains 31 native fish species and 29 nonnative 
species (Hulse et al. 2002, p. 44). The large-scale alteration of the 
Willamette Basin's hydrologic system (i.e., construction of dams and 
the resultant changes in flood frequency and intensity) has created 
conditions that favor nonnative predatory fishes, and reservoirs 
throughout the basin have become sources of continual nonnative fish 
invasions in the downstream reaches (Li et al. 1987, p. 198).
    Oregon chub are most abundant at sites where nonnative fishes are 
absent (Scheerer 2007, p. 96). Predatory nonnative centrarchids (bass 
and sunfish) and Ameiurus spp. (bullhead catfish) are common in the 
off-channel habitats used by Oregon chub (Scheerer 2002, p. 1075). 
Sites with high connectivity to adjacent flowing water frequently 
contain nonnative predatory fishes and rarely contain Oregon chub 
(Scheerer 2007, p. 99). The presence of centrarchids and bullhead 
catfishes is probably preventing Oregon chub from recolonizing suitable 
habitats throughout the basin (Markle et al. 1991, p. 291).
    Management for Oregon chub has focused on establishing secure, 
isolated habitats free of nonnative fishes. However, natural flood 
events may breach barriers to connectivity allowing invasion by 
nonnative fishes. During the 1996 floods in the Willamette Basin, 
nonnative fishes invaded the habitats of the two largest Oregon chub 
populations in the Santiam River; in the next 2 years, these 
populations declined by more than 50 percent, and had not recovered to 
pre-1996 levels more than 5 years later (Scheerer 2002, p. 1078).
    Game fish have also been intentionally introduced into chub ponds. 
An illegal introduction of largemouth bass (Micropterus salmoides) at 
an Oregon chub population site on the Middle Fork apparently caused a 
significant decline in that population from over 7,000 fish to 
approximately 2,000 fish from 2000 to 2007 (Scheerer et al. 2007, p. 
14). The ubiquity of nonnative fishes in the Willamette Basin has 
created a substantial challenge to the recovery of the Oregon chub. 
Scheerer et al. (2007, pp. 10-14) conclude, ``The resulting paradox is 
that the frequent interaction of the river with the floodplain habitats 
* * *, conditions which historically created off-channel habitats and 
aided in the dispersal of chub and the interchange of individuals among 
populations, now poses a threat to Oregon chub by allowing dispersal of 
nonnative species.''
    Nonnative fishes may also serve as sources of parasites and 
diseases for the Oregon chub. However, disease and parasite problems 
have not been identified in this species, nor has the issue been 
studied.
    Summary of Factor C: Predatory nonnative fishes are the greatest 
current threat to the recovery of the Oregon chub. Nonnative fishes are 
abundant and ubiquitous in the Willamette River Basin, and continual 
monitoring and management are required to protect existing Oregon chub 
populations from invasion. Predation remains a concern, but as the 
status of the species has improved since listing (i.e., more 
populations have been established and are being managed to minimize 
threats), the relative effect of the threat of predatory nonnative 
fishes has declined. Nevertheless, predation continues to impact the 
Oregon chub such that it is likely to become endangered in the 
foreseeable future without continued protection under the Act.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    Before the Oregon chub was federally listed as endangered in 1993, 
the species had no regulatory protections. Upon its listing as 
endangered, the species benefited from the protections of the 
Endangered Species Act, which include the prohibition against take and 
the requirement for interagency consultation for Federal actions that 
may affect the species. Section 9 of the Act and Federal regulations 
pursuant to section 4(d) of the Act prohibit the take of endangered and 
threatened species without special exemption. ``Take'' is defined as to 
harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or 
collect, or to attempt to engage in any such conduct (50 CFR 17.3). 
``Harm'' is further defined to include significant habitat modification 
or degradation that results in death or injury to listed species by 
significantly impairing essential behavioral patterns, including 
breeding, feeding, or sheltering; ``harass'' is defined as intentional 
or negligent actions that create the likelihood of injury to listed 
species to such an extent as to significantly disrupt normal behavior 
patterns, which include, but are not limited to, breeding, feeding, or 
sheltering (50 CFR 17.3).
    Section 7(a)(1) of the Act requires all Federal agencies to utilize 
their authorities in furtherance of the purposes of the Act by carrying 
out programs for the conservation of endangered species and threatened 
species. Section 7(a)(2) of the Act requires Federal agencies to ensure 
that any action authorized, funded, or carried out by them is not 
likely to jeopardize the continued existence of listed species or 
adversely modify their critical habitat. Thus, listing the Oregon chub 
provided a variety of protections, including the prohibition against 
take and the conservation mandates of section 7 for all Federal 
agencies. Because the Service has regulations that prohibit take of all 
threatened species (50 CFR 17.31(a)), unless modified by a special rule 
issued pursuant to section 4(d) of the Act (50 CFR 17.31(c)), the 
regulatory protections of the Act are largely the same for species 
listed as endangered and as threatened; thus, the protections provided 
by the Act will remain in place if the Oregon chub is reclassified as a 
threatened species.
    The Oregon chub is designated as ``Sensitive-Critical'' by ODFW. 
This designation is a nonregulatory tool that

[[Page 22877]]

helps focus wildlife management and research activities, with the goal 
of preventing species from declining to the point of qualifying as 
``threatened'' or ``endangered'' under the Oregon Endangered Species 
Act (ORS 496.171, 496.172, 496.176, 496.182 and 496.192). Sensitive-
Critical designation encourages but does not require the implementation 
of any conservation actions for the species (see the discussion above 
under Additional Conservation Measures).
    The Oregon chub is not protected by any other regulatory 
mechanisms.
    Summary of Factor D: The regulatory mechanisms in effect under the 
Endangered Species Act provide a prohibition against take, the 
affirmative conservation mandate of section 7(a)(1), and the protection 
against jeopardy of section 7(a)(2); these regulatory mechanisms will 
remain in place if the Oregon chub is downlisted to threatened. A 
program of conservation actions will be implemented by the Corps, BPA, 
and BOR as a result of the Service's biological opinion on the 
Willamette Project. However, because there are no other regulatory 
mechanisms in place beyond the Act, the inadequacy of regulatory 
mechanisms still threatens the Oregon chub.

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

    Almost half of all the fish species in the Willamette River are not 
native to the basin (Hulse et al. 2002, p. 44). Along with the direct 
threat of predation (see Factor C, above), nonnative fish compete with 
Oregon chub for food resources. Competition with nonnative fishes may 
contribute to the decline and exclusion of Oregon chub from suitable 
habitats. Observed feeding strategies and diet of nonnative fishes, 
particularly juvenile centrarchids and adult mosquitofish (Gambusia 
affinis) overlap with the diet and feeding strategies described for the 
Oregon chub (Li et al. 1987, pp. 197-198). Thus, direct competition for 
food between Oregon chub and nonnative species may limit the 
distribution and expansion of the species; however, no studies have 
focused on the topic of competitive exclusion to date.
    Historically, floods provided the mechanism of dispersal and 
genetic exchange for Oregon chub populations throughout the Willamette 
Basin (Scheerer 2002, p. 1078). The current management focus on 
protecting Oregon chub populations in isolation, which protects the 
species from the introduction of predatory nonnative fishes, may be 
having negative genetic implications (Scheerer 2002, p. 1078). This 
lack of connectivity means that movement of individuals among 
populations occurs rarely, if at all, which results in little or no 
genetic exchange among populations (Scheerer et al. 2007, p. 9). 
Research is under way to determine if Oregon chub populations have 
distinct genetic characteristics in the different sub-basins of the 
Willamette River (Ardren et al. 2008, p. 1). There is concern that an 
unintended effect of managing for isolated populations may be genetic 
drift and inbreeding. If this proves to be the case, managers may need 
to move fish among populations to fulfill the role that natural 
flooding once played (Scheerer et al. 2007, p. 15).
    Summary of Factor E: Competition from nonnative species and the 
loss of genetic diversity as a result of managing Oregon chub 
populations in isolated habitats are potential threats that could 
affect Oregon chub populations throughout the species' range. However, 
the magnitude of these threats is unknown.

Foreseeable Future

    The term ``threatened species'' means any species (or subspecies 
or, for vertebrates, distinct population segments) that is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. The Act does not define the 
term ``foreseeable future.'' For the purpose of this proposed rule, we 
defined the ``foreseeable future'' to be the extent to which, given the 
amount and substance of available data, we can anticipate events or 
effects, or reliably extrapolate threat trends, such that we reasonably 
believe that reliable predictions can be made concerning the future as 
it relates to the status of the species at issue.
    In considering the foreseeable future as it relates to the status 
of the Oregon chub, we considered the threats to the Oregon chub, 
historical declines, and ongoing conservation efforts.
    With respect to the Oregon chub, in the absence of the Act's 
regulatory protections, historical population declines, and range 
contraction, which were the result of habitat loss, predation by 
nonnative fishes, and the lack of sufficient regulatory mechanisms are 
expected to continue throughout the species' range. We have no 
information to suggest that the threats identified above are likely to 
be reduced in the foreseeable future, nor that regulatory mechanisms 
will materialize to address or ameliorate the ongoing threats to the 
species. Thus, future Oregon chub population declines and range 
contraction, similar to what has been observed in the past, is a 
reasonable expectation without continued protection under the Act.

Conclusion of 5-Factor Analysis

    We have carefully assessed the best scientific and commercial data 
available and have determined that the Oregon chub is not currently in 
danger of extinction. We believe that the species now meets the 
definition of a threatened species throughout all of its range. It has 
exceeded two of the downlisting criteria and is on the brink of meeting 
the third. Recovery plans are intended to guide and measure recovery. 
Recovery criteria for downlisting and delisting are developed in the 
recovery planning process to provide measurable goals on the path to 
recovery; however, precise attainment of all recovery criteria is not a 
prerequisite for downlisting or delisting. Rather, the decision to 
revise the status of a listed species is based solely on the analysis 
of the 5 listing factors identified in section 4 of the Act. The Act 
provides for downlisting from endangered to threatened when the best 
available data indicates that a species, subspecies, or distinct 
population segment is no longer in danger of extinction.
    At the time we completed the Recovery Plan for the Oregon Chub in 
1998, we attempted to describe what the range, abundance, and 
distribution of Oregon chub populations should be before downlisting 
and delisting. These estimates were manifested in the downlisting and 
delisting criteria discussed above, and these criteria effectively 
established the Service's position on what constitutes ``threatened,'' 
in the case of downlisting criteria, and ``recovered,'' in the case of 
the delisting criteria. Because the downlisting criteria have not been 
precisely met, the proposed finding in this rule represents a departure 
from the Service's previously articulated description of 
``threatened,'' and so must be further explained.
    We compared current Oregon chub population information with the 
downlisting criteria for each sub-basin and estimated the amount by 
which each population goal's had been exceeded. The result of this 
comparison is shown in table 2.

[[Page 22878]]



    Table 2--Comparison of Numerical Population Goals for Downlisting From the Oregon Chub Recovery Plan With
                                   Current Population Estimates, by Sub-Basin
----------------------------------------------------------------------------------------------------------------
                                                                                                 Percent of
                                                  Downlisting goal     Current population     downlisting goal
                   Sub-basin                      (number of fish/     estimate (number of   achieved (number of
                                                      number of          fish/number of        fish/number of
                                                    populations)          populations)          populations)
----------------------------------------------------------------------------------------------------------------
Santiam.......................................               1,500/3               5,640/8               376/267
Mainstem Willamette...........................               1,500/3             78,727/13             5,248/433
Middle Fork Willamette........................               1,500/3             35,142/14             2,343/467
----------------------------------------------------------------------------------------------------------------

    Although these totals do not incorporate the 5-year stable or 
increasing trend aspect of the downlisting criteria, the number of chub 
in these basins greatly exceeds the minimum required in the downlisting 
criteria for both the number of populations and the number of 
individual fish. Taken together, along with the 5-factor analyses 
discussed above, it is clear that the status of the chub is likely far 
more secure than it might be with 4,500 fish in 9 populations across 3 
sub-basins with 5-year stable or increasing trends.
    The number of populations has increased from 9 to 36 since the 
species was listed in 1993; there are 16 large (>500 individuals) 
populations with stable or increasing trends. The species is well 
distributed throughout the Willamette Basin, and most of these 
populations have some type of protective management and appear to be 
viable as long as they are monitored and adaptively managed. Although 
many of the threats have been reduced by recovery efforts, threatened 
status is appropriate because the species is likely to become 
endangered in the foreseeable future without the protections of the Act 
or long-term management agreements and adaptive management actions. In 
addition, concerns remain regarding the genetic implications of 
managing Oregon chub in isolated ponds, cut off from potential 
interactions with other populations in the basin.
    Threats to existing habitats remain, including manipulation of 
flows which can lead to desiccation, nutrient and pesticide runoff, and 
vegetative succession in shallow pond environments. The chief threat to 
existing Oregon chub populations is nonnative fish invasions, which may 
occur as a result of flood events, intentional introductions, or 
through connections between isolated chub habitats and adjacent 
watercourses. However, as the status of the species has improved since 
listing (i.e., more populations have been established and are being 
managed to minimize threats), the relative effect of the threat of 
predatory nonnative fishes has declined. Monitoring for nonnative fish 
invasions and adaptively managing in response to such invasions is 
necessary for the long-term viability of this species.

Significant Portion of the Range Analysis

    Having determined that the Oregon chub is threatened throughout its 
range, we next considered whether it is in danger of extinction in any 
significant portions of its range.
    The Act defines an endangered species as one ``in danger of 
extinction throughout all or a significant portion of its range,'' and 
a threatened species as one ``likely to become an endangered species 
within the foreseeable future throughout all or a significant portion 
of its range.'' The term ``significant portion of its range'' is not 
defined by statute. For purposes of this finding, a significant portion 
of a species' range is an area that is important to the conservation of 
the species because it contributes meaningfully to the representation, 
resiliency, or redundancy of the species. The contribution must be at a 
level such that its loss would result in a decrease in the ability to 
conserve the species.
    The first step in determining whether a species is threatened or 
endangered in a significant portion of its range is to identify any 
portions of the range of the species that warrant further 
consideration. The range of a species can theoretically be divided into 
portions in an infinite number of ways. However, there is no purpose to 
analyzing portions of the range that are not reasonably likely to be 
significant and endangered. To identify only those portions that 
warrant further consideration, we determine whether there is 
substantial information indicating that: (1) The portions may be 
significant, and (2) the species may be in danger of extinction there. 
In practice, a key part of this analysis is whether the threats are 
geographically concentrated in some way. If the threats to the species 
are essentially uniform throughout its range, no portion warrants 
further consideration. Moreover, if any concentration of threats 
applies only to portions of the range that are unimportant to the 
conservation of the species, such portions will not warrant further 
consideration.
    If we identify any portions of a species' range that warrant 
further consideration, we then determine whether in fact the species is 
threatened or endangered in any significant portion of its range. 
Depending on the biology of the species, its range, and the threats it 
faces, it may be more efficient in some cases for the Service to 
address the significance question first, and in others the status 
question first. Thus, if the Service determines that a portion of the 
range is not significant, the Service need not determine whether the 
species is threatened or endangered there. If the Service determines 
that the species is not threatened or endangered in a portion of its 
range, the Service need not determine if that portion is significant. 
If the Service determines that both a portion of the range of a species 
is significant and the species is threatened or endangered there, the 
Service will specify that portion of the range where the species is in 
danger of extinction pursuant to section 4(c)(1) of the Act.
    The terms ``resiliency,'' ``redundancy,'' and ``representation'' 
are intended to be indicators of the conservation value of portions of 
the species' range. Resiliency allows the species to recover from 
periodic disturbance. A species will likely be more resilient if large 
populations exist in high-quality habitat that is distributed 
throughout the range of the species in such a way as to capture the 
environmental variability within the range of the species. It is likely 
that the larger size of a population will help contribute to the 
viability of the species. Thus, a portion of the range of a species may 
make a meaningful contribution to the resiliency of the species if the 
area is relatively large and contains particularly high-quality habitat 
or if its location or characteristics make it less susceptible to 
certain threats than other

[[Page 22879]]

portions of the range. When evaluating whether or how a portion of the 
range contributes to resiliency of the species, it may help to evaluate 
the historical value of the portion and how frequently the portion is 
used by the species. In addition, the portion may contribute to 
resiliency for other reasons--for instance, it may contain an important 
concentration of certain types of habitat that are necessary for the 
species to carry out its life-history functions, such as breeding, 
feeding, migration, dispersal, or wintering.
    Redundancy of populations may be needed to provide a margin of 
safety for the species to withstand catastrophic events. This does not 
mean that any portion that provides redundancy is a significant portion 
of the range of a species. The idea is to conserve enough areas of the 
range such that random perturbations in the system act on only a few 
populations. Therefore, each area must be examined based on whether 
that area provides an increment of redundancy that is important to the 
conservation of the species.
    Adequate representation ensures that the species' adaptive 
capabilities are conserved. Specifically, the portion should be 
evaluated to see how it contributes to the genetic diversity of the 
species. The loss of genetic diversity may substantially reduce the 
ability of the species to respond and adapt to future environmental 
changes. A peripheral population may contribute meaningfully to 
representation if there is evidence that it provides genetic diversity 
due to its location on the margin of the species' habitat requirements.
    Applying the process described above, we evaluated the range of the 
Oregon chub to determine if any units could be considered a significant 
portion of its range. A case could be made that each of the three sub-
basins discussed in the recovery plan (Mainstem Willamette River, 
Middle Fork Willamette, and Santiam River) (U.S. Fish and Wildlife 
Service 1998, pp. 27-28) are significant portions of the range of the 
Oregon chub. As discussed above, a portion of a species' range is 
significant if it is part of the current range of the species and is 
important to the conservation of the species because it contributes 
meaningfully to the representation, resiliency, or redundancy of the 
species. The contribution must be at a level such that its loss would 
result in a decrease in the ability to conserve the species. Each of 
the three sub-basins clearly meets these criteria, as described in the 
recovery plan (U.S. Fish and Wildlife Service 1998, pp. 27-28).
    Next we must determine if the threats to the Oregon chub are 
nonuniformly distributed, such that populations in any of the sub-
basins experience a higher level of threat than populations in any 
other sub-basin. The primary remaining threats to the species are 
introduction of predatory nonnative fishes into chub ponds and water 
quality degradation. Extensive surveys of the Willamette Basin have 
found that predatory nonnative fishes are abundant and widespread in 
each of the sub-basins (Scheerer 2007, p. 97). Threats to water 
quality, including chemical spills, agricultural runoff, and drought, 
are not restricted to any portion of the Oregon chub's range, and are 
equally likely to occur in any of the three sub-basins. The threats 
associated with reduced genetic exchange among populations are not yet 
well understood; it seems likely, however, that the potential genetic 
consequences of management for isolated populations (e.g., inbreeding 
and genetic drift) could be experienced across the range of the 
species, since protection of isolated ponds is the management goal for 
populations in all three of the sub-basins.
    In summary, the primary threats to the Oregon chub are relatively 
uniform throughout the species' range. We have determined that none of 
the existing or potential threats, either alone or in combination with 
others,