Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Oregon Chub (Oregonichthys crameri, 11010-11067 [2010-4654]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 75, Number 46 (Wednesday, March 10, 2010)]
[Rules and Regulations]
[Pages 11010-11067]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-4654]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R1-ES-2009-0010]
[MO 92210-0-0009-B4]
RIN 1018-AV87


Endangered and Threatened Wildlife and Plants; Designation of 
Critical Habitat for Oregon Chub (Oregonichthys crameri)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), designate 
critical habitat for the Oregon chub (Oregonichthys crameri) under the 
Endangered Species Act of 1973, as amended (Act). In total, 
approximately 53 hectares (ha) (132 acres (ac)) located in Benton, 
Lane, Linn, and Marion Counties, Oregon, fall within the boundaries of 
the critical habitat designation.

DATES: This rule becomes effective on April 9, 2010.

ADDRESSES: This final rule, the economic analysis, comments and 
materials received, as well as supporting documentation we used in 
preparing this final rule, are available for viewing at https://regulations.govat Docket No. FWS-R1-ES-2009-0010 and, by appointment, 
during normal business hours, at the U.S. Fish and Wildlife Service, 
Oregon Fish and Wildlife Office, 2600 SE 98\th\ Ave., Portland, OR 
97266; telephone 503-231-6179; facsimile 503-231-6195.

FOR FURTHER INFORMATION CONTACT: Paul Henson, State Supervisor, U.S. 
Fish and Wildlife Service, Oregon Fish and Wildlife Office (see 
ADDRESSES). If you use a telecommunications device for the deaf (TDD), 
call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    It is our intent to discuss only those topics directly relevant to 
the development and designation of critical habitat for the Oregon chub 
in this final rule. For a more complete discussion of the ecology and 
life history of this species, please see the Oregon Chub 5-year Review 
Summary and Evaluation completed February 11, 2008, which is available 
at: https://www.fws.gov/pacific/ecoservices/endangered/recovery/Documents/Oregonchub.pdf and the March 10, 2009, proposed rule (74 FR 
10412).

Description and Taxonomy

    The Oregon chub (Oregonichthys crameri) was first described in 
scientific literature in 1908 (Snyder 1908, pp. 181-182), but it wasn't 
until 1991 that it was identified as a unique species (Markle et al. 
1991, pp. 284-289). Oregon chub have an olive-colored back (dorsum) 
grading to silver on the sides and white on the belly. Scales are 
relatively large with fewer than 40 occurring along the lateral line; 
scales near the back are outlined with dark pigment (Markle et al. 
1991, pp. 286-288). While young of the year range in length from 7 to 
32 millimeters (mm) (0.3 to 1.3 inches (in)), adults can be up to 90 mm 
(3.5 in) in length (Pearsons 1989, p. 17). The species is distinguished 
from its closest relative, the Umpqua chub (Oregonichthys kalawatseti), 
by Oregon chub's longer caudal peduncle (the narrow part of a fish's 
body to which the tail is attached), mostly scaled breast, and more 
terminal mouth position (Markle et al. 1991, p. 290).

Distribution and Habitat

    Oregon chub are found in slack-water, off-channel habitats with 
little or no flow, silty and organic substrate, and considerable 
aquatic vegetative cover for hiding and spawning (Pearsons 1989, p.

[[Page 11011]]

10; Markle et al. 1991, p. 288; Scheerer and Jones 1997, p. 5; Scheerer 
et al. 2007, p. 3). The species' aquatic habitat is typically at depths 
of less than or equal to 2 meters (m) (6.6 feet (ft)), and has a C) 
(61Celsius (summer subsurface water temperature exceeding 15 F)) 
(Scheerer and Apke 1997, p. 45; Scheerer 2002, p. 1073; 
ScheererFahrenheit ( and McDonald 2003, p. 69). Optimal Oregon chub 
habitat provides 1 square meter (11 square feet) of aquatic surface 
area per adult, at depths between 0.5 m (1.6 ft) to 2 m (6.6 ft) 
(Scheerer 2008b). Oregon chub can be relatively long-lived with males 
living up to 7 years and females up to 9 years, although less than 10 
percent of fish in most Oregon chub populations are older than 3 years 
(Scheerer and McDonald 2003, p. 71). Outside of spawning season, the 
species is social and nonaggressive with fish of similar size classes 
schooling and feeding together (Pearsons 1989, pp. 16-17).
    The species is endemic to the Willamette River drainage of western 
Oregon (Markle et al. 1991, p. 288) and was formerly distributed 
throughout the Willamette River Valley in a dynamic network of off-
channel habitats such as beaver ponds, oxbows, side channels, backwater 
sloughs, low-gradient tributaries, and flooded marshes in the 
floodplain (Snyder 1908, p. 182). Records show Oregon chub were found 
as far downstream as Oregon City, as far upstream as Oakridge, and in 
various tributaries within the Willamette basin (Markle et al. 1991, p. 
288).
    Historically, Oregon chub would be dispersed and their habitat 
regularly altered, increased, or eliminated due to regular winter and 
spring flood events (Benner and Sedell 1997, pp. 27-28); this dispersal 
created opportunities for interbreeding between different populations. 
The installation of the flood control projects in the Willamette River 
basin altered the natural flow regime, and flooding no longer plays a 
positive role in creating Oregon chub habitat or providing 
opportunities for genetic mixing of populations. Flood events now 
threaten Oregon chub populations due to the dispersal of nonnative 
species that compete with or prey on Oregon chub. In the Santiam River 
basin, the two largest natural populations of Oregon chub declined 
substantially after nonnative fishes invaded these habitats during the 
1996 floods, and no new populations of Oregon chub were discovered in 
habitats located downstream of existing chub populations during 
thorough sampling in 1997-2000. This suggests that no successful 
colonization occurred as a result of the flooding event (Scheerer 2002, 
p. 1078).
    Currently, the largest populations of Oregon chub occur in 
locations with the highest diversity of native fish, amphibian, reptile 
and plant species (Scheerer and Apke 1998, p. 11). Beaver (Castor 
canadensis) appear to be especially important in creating and 
maintaining habitats that support these diverse native species 
assemblages (Scheerer and Apke 1998, p. 45). Conversely, the 
establishment and expansion of nonnative species in Oregon have 
contributed to the decline of the Oregon chub, limiting the species' 
ability to expand beyond its current range (Scheerer 2007, p. 92). Many 
sites formerly inhabited by the Oregon chub are now occupied by 
nonnative species (Scheerer et al. 2007, p. 9; Scheerer 2007a, p. 96). 
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 (e.g., Micropterus 
spp. (largemouth bass, smallmouth bass, bluegill) and Pomoxis spp. 
(crappies)), and bullhead catfishes (Ameiurus spp.) is probably 
preventing Oregon chub from recolonizing suitable habitats throughout 
the basin (Markle et al. 1991, p. 291).
    Although surveys conducted by the Oregon Department of Fish and 
Wildlife (ODFW) prior to the 1993 listing of Oregon chub as endangered 
under the Act indicated the presence of the species at 17 different 
locations, the impacts of floodplain alteration and nonnative predators 
and competitors were clearly represented in the relatively small 
numbers of Oregon chub found at these sites. At the time of listing, 
these surveys were the best evidence of the then-current distribution 
of the species. Of these 17 sites, only 9 supported populations of 10 
or more Oregon chub, and all but 1 of those populations were found 
within a 30-kilometer (km) (19-mile (mi)) reach of the Middle Fork 
Willamette River in the vicinity of Dexter and Lookout Point Reservoirs 
in Lane County, Oregon; this reach represented just 2 percent of the 
species' historical range (58 FR 53800). Very small numbers of the 
species, between 1 and 7 individuals, were found at the remaining 8 of 
the 17 sites at the time of listing. Currently, the distribution of 
Oregon chub is limited to 25 known naturally occurring populations and 
11 reintroduced populations scattered throughout the Willamette Valley 
(Scheerer et al. 2007, p. 2; 2008a, p. 2).

Previous Federal Actions

     On October 18, 1993, we listed the Oregon chub as endangered under 
the Endangered Species Act (Act) (58 FR 53800), and concluded that the 
designation of critical habitat was prudent but not determinable. A 
recovery plan for the Oregon chub (Recovery Plan) was completed in 1998 
(USFWS 1998). The Recovery Plan established certain criteria for 
downlisting the species from endangered to threatened, which included 
establishing and managing 10 populations of at least 500 adults each 
that exhibit a stable or increasing trend for 5 years. The Recovery 
Plan states that for purposes of downlisting the species, 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 Willamette, and Santiam River). The Recovery Plan also 
established criteria for delisting the Oregon chub (i.e., removing it 
from the List of Endangered and Threatened Wildlife). These criteria 
include establishing and managing 20 populations of at least 500 adults 
each, which demonstrate a stable or increasing trend for 7 years. In 
addition, at least four populations must be located in each of the 
three sub-basins (Mainstem Willamette River, Middle Fork Willamette, 
and Santiam River). The management of these populations must be assured 
in perpetuity.
    On June 17, 1999, we published a Safe Harbor Policy to encourage 
private and other non-Federal property owners to voluntarily undertake 
management activities on their property to enhance, restore, or 
maintain habitat to benefit federally listed species (62 FR 32717). 
Safe Harbor Agreements (SHAs) manage habitat for listed species, and 
provide assurances to landowners that additional land, water, and/or 
natural resource use restrictions will not be imposed as a result of 
their voluntary conservation actions to benefit covered species. In 
2001 and 2007, Safe Harbor Agreements (SHAs) for the Oregon chub were 
established in Lane County, Oregon (66 FR 30745, June 7, 2001; 72 FR 
50976, September 5, 2007). These two SHAs established new populations 
of Oregon chub in artificial ponds as refugia for natural populations, 
and contribute to the conservation of the species by reducing the risk 
of the complete loss of donor populations and any of their unique 
genetic material.
    On March 8, 2007, we issued a notice that we would begin a status 
review of the Oregon chub (72 FR 10547). On March 9, 2007, the 
Institute for Wildlife

[[Page 11012]]

Protection (IWP) filed suit in Federal district court, alleging that 
the Service and the Secretary of the Interior violated their statutory 
duties as mandated by the Act when they failed to designate critical 
habitat for the Oregon chub and failed to perform a 5-year status 
review (Institute for Wildlife Protection v. U.S. Fish and Wildlife 
Service). We completed the Oregon chub 5-Year Review on February 11, 
2008. In a settlement agreement with the Plaintiff, we agreed to submit 
a proposed critical habitat rule for Oregon chub to the Federal 
Register by March 1, 2009, and to submit a final critical habitat 
determination to the Federal Register by March 1, 2010.
     On March 10, 2009, we published a proposed rule in the Federal 
Register to designate critical habitat for the Oregon chub (74 FR 
10412), and accepted public comments for 60 days (March 10-May 10, 
2009). On September 22, 2009, we announced the reopening of the public 
comment period for 30 days (September 22-October 22, 2009); the 
availability of a draft economic analysis (DEA) and amended required 
determinations section of the proposal; and a public hearing to be held 
on October 5, 2009, in Corvallis, Oregon. The public was invited to 
review and comment on any of the above actions associated with the 
proposed critical habitat designation at the scheduled public hearing 
or in writing (74 FR 48211). For more information on previous Federal 
actions concerning the Oregon chub, refer to the Determination of 
Endangered Status for the Oregon Chub published in the Federal Register 
on October 18, 1993 (58 FR 53800), the Recovery Plan, or the May 15, 
2009, proposed rule to reclassify the Oregon chub from endangered to 
threatened status based on a thorough review of the best available 
scientific data, which indicated 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 (74 FR 22870).

Summary of Comments and Recommendations

    We requested written comments from the public on the proposed 
designation of critical habitat for the Oregon chub during the March 
10-May 10, 2009, comment period. We also contacted appropriate Federal, 
State, and local agencies, scientific organizations, and other 
interested parties and invited them to comment on the proposed rule and 
the draft economic analysis. During the March 10-May 10, 2009, comment 
period, we received a request for a public hearing from the IWP. 
Section 4(b)(5)(E) of the Act requires that one public hearing be held 
on a proposed regulation if any person files a request for such a 
hearing within 45-days after the date of publication of a proposed 
rule. We held a public hearing in Corvallis, Oregon on October 5, 2009; 
however, no one attended. During the September 22-October 22, 2009, 
comment period, the IWP resubmitted their earlier comments and 
requested another public hearing, however, since we held a public 
hearing on October 5, 2009, a second public hearing was not required. 
Furthermore, given the lack of attendance at the October 5, 2009, 
hearing, we determined that a second hearing was not necessary.
    We received six comments in response to the proposed rule. Four 
comment letters were received during the March 10-May 10, 2009, comment 
period from two peer reviewers, the Oregon Department of Fish and 
Wildlife (ODFW), and the IWP. Two comment letters were received during 
the September 22-October 22, 2009, comment period from one peer 
reviewer and the IWP. No comments were received regarding the DEA. All 
substantive comments have been either incorporated into the final 
determination or are addressed below.

Peer Review

    In accordance with our policy published in the Federal Register on 
July 1, 1994 (59 FR 34270), we solicited expert opinions from three 
knowledgeable individuals with scientific expertise that included 
familiarity with the species, the geographic region in which the 
species occurs, and conservation biology principles. We received 
responses from each of the peer reviewers that we contacted. The peer 
reviewers generally agreed we relied on the best scientific information 
available, accurately described the species and its habitat 
requirements (primary constituent elements (PCEs)), accurately 
characterized the reasons for the species' decline and the threats to 
its habitat, and concurred with our critical habitat selection criteria 
and the use of the Recovery Plan as a foundation for the proposed 
designation. The peer reviewers provided additional information, 
clarifications, and suggestions to improve the final critical habitat 
rule. Recommended editorial revisions and clarifications have been 
incorporated into the final rule as appropriate. We respond to all 
substantive comments below.

Peer Reviewer Comments

    Comment 1: One peer reviewer commented that there was no discussion 
in the Primary Constituent Elements section of connectivity corridors 
for the maintenance of gene flow between populations, or to allow 
natural recolonization of additional habitat.
    Our Response: Connectivity corridors and periodic or seasonal 
connections were historically part of the Oregon chub's life history 
and were certainly the mechanism to provide for gene flow and natural 
colonization of new habitats. Now that most of the tributaries in the 
Willamette River basin have been impacted by dams and diversions, the 
Oregon chub's naturally connected habitat has been altered. Given the 
very serious risk of predation and competition from nonnative fish, 
connectivity now represents a threat to the Oregon chub in many 
locations. The Recovery Plan opts for a combination of approaches to 
recover the Oregon chub--from isolated, intensively managed ponds to 
more natural restored floodplain habitats. It is likely that 
populations will fall along this spectrum, and that Oregon chub 
recovery will be achieved through a variety of strategies (USFWS 1998, 
pp. 86-87). Establishing connectivity corridors may not be an optimal 
recovery strategy for many populations, given the nonnative species 
predation and competition threat. The species currently thrives in 
locations that are isolated and protected from that threat.
    Endangered Species Permit TE-818627-9 authorizes the ODFW to 
conduct Oregon chub population estimates, distribution surveys, collect 
life-history data, and conduct translocations or reintroductions 
following the guidelines presented in the Recovery Plan. Recovery Task 
2.3 in the Recovery Plan states that reintroduction stock should be 
taken from within the sub-basin that contains the new site, and that 
successive introductions within a sub-basin should come from a variety 
of source populations to ensure a diverse genetic makeup to the 
metapopulation within a sub-basin (USFWS 1998, p. 41). ODFW's 
authorized activities under the translocation and reintroduction 
guidelines are intended to address some of the concerns related to gene 
flow maintenance. The Recovery Plan acknowledges the need for a 
combination of approaches to recover Oregon chub, from isolated, 
intensively managed ponds to more natural restored floodplain habitats 
(USFWS 1998, pp. 85-86).

[[Page 11013]]

    Comment 2: One peer reviewer commented that PCE 3 (late spring and 
summer subsurface water temperatures between 15 and 25 C) is 
incomplete, stating that they would have included other water quality 
factors such as the absence or low level of contaminants.
    Our Response: In determining the PCEs for Oregon chub, we relied on 
the best scientific data available. Research has identified definitive 
temperature thresholds for the species for reproductive activity and 
other life-history needs, but has not explicitly defined 
characteristics of good water quality for the species beyond that 
attribute. We address several water quality characteristics in the 
Special Management Considerations or Protections section below, 
including protecting Oregon chub critical habitat areas from 
agricultural and forestry chemical runoff. Habitats that express the 
presence of PCE 2 (appropriate levels of aquatic vegetation that hosts 
abundant food for chub) would presumably be representative of habitats 
having good water quality characteristics.
    Comment 3: One peer reviewer suggested that PCE 4 (no or negligible 
levels of nonnative aquatic predatory or competitive species) is rather 
unspecific and that the term `negligible' may be difficult to 
characterize in practice.
    Our Response: We are unaware of any scientific data that presents a 
definitive numerical threshold of competitive and predatory nonnative 
fish species that would be detrimental to a population of Oregon chub. 
We use the term `negligible' to acknowledge the possibility that a 
population of Oregon chub may be able to persist in the presence of 
some level of nonnative competing species, which may depend on 
population ratios, the biology of the nonnative species involved, or 
other physical, biological, or hydrological factors. However, currently 
available scientific information indicates that Oregon chub and 
nonnative predators are not able to coexist at most sites, and where 
they do the Oregon chub populations remain at low levels.

Comments from States

    We received several recommendations for minor corrections to the 
critical habitat unit descriptions from the ODFW, which have been 
incorporated into this final rule. Other substantive comments received 
from the ODFW are addressed below.
    Comment 4: The context and importance of the population threshold 
of 500 adults was not explained in the Physical and Biological 
Features-Flow Velocities and Depth section of the proposed rule. The 
ODFW recommended that the final rule explain that this population 
threshold was based on delisting criteria identified in the Recovery 
Plan.
    Our Response: We have revised the section accordingly.
    Comment 5: Several sites with abundance levels of fewer than 500 
fish are capable of supporting large populations and are essential to 
the recovery of the species. The ODFW identified three sites that they 
believe contain all of the PCEs, and recommended that they be 
designated as critical habitat: (1) Pioneer Park backwater, Santiam 
sub-basin; (2) Sprick Pond, Coast Fork Willamette sub-basin; and (3) 
Haws Pond, Elijah Bristow South Slough and sites RM198.6 and RM199.5, 
Middle Fork Willamette sub-basin. The ODFW commented that several areas 
proposed as critical habitat for Oregon chub were at very low 
population levels for many years before increasing rapidly in 
abundance, including Unit 3J Buckhead Creek and Unit 3K Wicopee Pond.
    Our Response: In the critical habitat selection criteria of the 
proposed rule, we described the rule set used to identify proposed 
critical habitat areas. This critical habitat designation focuses on 
sites where we have the most confidence that the Oregon chub 
populations can achieve recovery criteria, based on the best available 
scientific information. The 2007 survey results for the Pioneer Park 
backwater site documented 420 fish; Sprick Pond is a new site that had 
19 Oregon chub introduced in 2008; and Oregon chub surveys in Hawes 
Pond documented 382 fish in 2007 and 277 in 2008. Each of the sites 
being designated as critical habitat in this final rule has been 
surveyed annually over several years, with the initial survey data for 
some critical habitat units conducted in the early 1990s (e.g., Shady 
Dell Pond (Unit 3I), Elijah Bristow State Park, Berry Slough (Unit 3B)) 
(Sheerer 2007a, p. 2). However, there is insufficient annual survey 
data to demonstrate whether the population trend is stable or 
increasing in any of the additional locations suggested by the ODFW. We 
have no survey data from the Elijah Bristow South Slough and RM 196.8 
and 199.5 sites, and are uncertain as to their specific location. 
However, based on the Recovery Plan, we have determined that 
designating critical habitat in 25 sites will be sufficient to meet 
recovery goals (see below discussion). Although the additional sites 
suggested by the ODFW may have an important role in Oregon chub 
conservation, they are not essential to the conservation of the 
species. Each of the sites designated in this final rule meet the 
definition of critical habitat under section 3(5)(a) of the Act, and is 
consistent with the criteria described in the Criteria Used to Identify 
Critical Habitat section below. Although the Recovery Plan calls for 
establishing and maintaining a minimum of 20 populations, we are 
designating critical habitat for 25 populations, to mitigate the 
potential that some units may become unable to support the species or 
primary constituent elements over time because of predation issues or 
other factors. Importantly, the designation of critical habitat does 
not imply that lands outside of critical habitat do not play an 
important role in the conservation of the Oregon chub. Federal 
activities undertaken in areas outside of critical habitat are subject 
to review under section 7 of the Act to ensure that they are not likely 
to jeopardize the continued existence of the Oregon chub. The 
prohibitions of section 9 against the take of listed species also 
apply, regardless of critical habitat designation.
    Comment 6: The ODFW suggested more unoccupied off-channel habitat 
in the Jasper to Dexter reach of the Middle Fork Willamette sub-basin 
should be designated as critical habitat. The ODFW commented that these 
habitats are essential for the conservation of the species and present 
the best opportunities to establish additional Oregon chub populations 
in connected habitats. They advised that habitats in this reach 
currently support several stable and abundant Oregon chub populations 
with minimal numbers of nonnative fishes, and that these habitats are 
necessary to recover the species.
    Our Response: The critical habitat selection criteria in the 
proposed rule identified sites that currently support at least 500 
adult Oregon chub, or those that currently express sufficient PCEs to 
support at least 500 adult Oregon chub and have done so in the past. We 
were not aware of the unoccupied off-channel habitat areas being 
suggested by ODFW when we developed the proposed rule, and did not have 
survey data for those locations. The ODFW has since clarified that the 
RM 196.8 and 199.5 sites and the Elijah Bristow South Slough sites 
referenced in their comments are within the Jasper to Dexter reach of 
the Middle Fork Willamette sub-basin. Although initially thought to be 
unoccupied, ODFW surveys conducted in 2008 documented one Oregon chub 
each in the RM 196.8 and RM 199.5 localities. Since the sites suggested 
are either unoccupied or currently support few Oregon chub, they would 
not satisfy the 500 adult fish or 5-year stability

[[Page 11014]]

thresholds identified in the critical habitat selection criteria. 
However, although these sites are inconsistent with the selection 
criteria, they may represent habitat that has potential conservation 
value. The fact that a particular area is not designated as critical 
habitat does not imply that it does not have an important role in the 
conservation of the Oregon chub.
    Comment 7: Runoff of forestry chemicals is a threat to several 
sites, which should be acknowledged in the Special Management 
Considerations or Protections section discussion.
    Our Response: The Special Management Considerations or Protections 
section has been revised accordingly.
    Comment 8: The ODFW identified additional Special Management 
Considerations or Protections needs for several of the units, 
including: (1) Units 3G East Fork Minnow Creek Pond and 3K Wicopee 
Pond, which require special management to prevent the introduction or 
further introduction of nonnative fishes; (2) Unit 3A Fall Creek 
Spillway Ponds, which require special management to prevent or set back 
vegetative succession; and (3) Units 1A Santiam I-5 Side Channels, 
2B(5) Finley Gray Creek Swamp and 3G East Fork Minnow Creek Road, which 
require special management to maintain water quality and reduce the 
incursion of potentially hazardous agricultural and forestry chemicals 
into Oregon chub critical habitat areas.
    Our Response: We have revised the Special Management Considerations 
or Protections discussion accordingly.

Public Comments

    Comment 9: Relying on absolute population size rather than 
effective population size to establish the criteria for selecting 
critical habitat is inadequate; relying on the Recovery Plan to develop 
the critical habitat selection criteria is invalid for the same reason.
    Our Response: We agree that using effective population size would 
be an optimal approach for monitoring the status of Oregon chub 
populations in the designated critical habitat units. Effective 
population size (the average number of individuals in a population that 
are assumed to contribute genes equally to the next generation) is a 
genetic concept used in conservation planning, and is generally a 
smaller number than the total number of individuals in the population. 
The sampling protocol used to count and estimate Oregon chub population 
size employs an adult fish mark-recapture approach using seines, baited 
minnow traps, dip nets, or gill net panels depending on specific 
habitat conditions. Sampling is conducted over a percentage of the 
surface area at each site and within each of the habitat types present 
(Sheerer 2002, p. 1071). However, based on the best scientific and 
commercial data available, we are unable to determine the effective 
population size for any of the Oregon chub populations for which we are 
designating critical habitat in this final rule.
    Each area designated as critical habitat in this final rule:
    (1) Is based on the best scientific information available;
    (2) has been informed by more than 20 years of research (including 
population monitoring);
    (3) contains the essential physical and biological features 
essential to the conservation of the species;
    (4) is consistent with the Recovery Plan, which was peer reviewed 
and developed with help from knowledgeable individuals with scientific 
expertise and familiarity with the species; and
    (5) is consistent with the methodology used to identify critical 
habitat units. Using the Recovery Plan as the standard against which to 
measure Oregon chub recovery is appropriate and consistent with the 
best scientific data available standard we are required to apply under 
section 4(b)(2) of the Act.
    Comment 10: Global warming and climate change are certain to 
significantly degrade Oregon chub habitat in the future, but the 
proposal provided no analysis in this regard.
    Our Response: We agree that predicted global climate change appears 
likely to pose additional threats to the Oregon chub. In the proposed 
rule, we acknowledged that the designation of critical habitat may not 
include all areas that we may eventually determine are necessary for 
Oregon chub recovery. However, we currently do not have scientific data 
specific to the Oregon chub or its habitat that suggest what, if any, 
additional areas may be essential to the conservation of the species in 
light of climate change. The units being designated as critical habitat 
occur over a range of elevations and encompass large sites that provide 
for habitat heterogeneity and redundancy. We believe that this approach 
provides a buffer against environmental effects that may result from 
changing climate conditions in the Willamette Basin. Critical habitat 
designations are made on the basis of the best available information at 
the time of designation, and do not control the direction and substance 
of future recovery efforts if new information becomes available. If new 
scientific information related to climate change and its relation to 
sensitive habitats in the Willamette Valley becomes available in the 
future, we will fully consider that information in our recovery 
efforts. In addition, section 4(B)(2) of the Act provides for making 
revisions to critical habitat, based on the best scientific data 
available if a revision is appropriate.
    Comment 11: Several Clean Air Act nonattainment areas lie within or 
near the range of this species; the susceptibility of certain organisms 
such as lichens to acid precipitation is quite high; the susceptibility 
of oaks and ponderosa pine should be considered by the Service; use of 
herbicides, pesticides, and other chemical agents is known to have 
damaged animal populations, even though the phenomenon has been little 
studied; a variety of chemical herbicides have been used in habitat 
areas; pesticides have been used to kill various insects occurring in 
habitat areas; endocrine disrupters have been demonstrated in numerous 
species and are known to produce transgenerational effects.
    Our Response: Based on the general nature of the comment, we were 
unable to establish any particular relevance to the proposed 
designation of critical habitat for the Oregon chub. See the response 
to comment 2 for a discussion of water quality considerations.
    Comment 12: The critical habitat being designated is not adequate 
for recovery of the species.
    Our Response: We disagree. The proposed designation is consistent 
with the delisting criteria identified in the Recovery Plan, which was 
peer reviewed and developed with help from knowledgeable individuals 
with scientific expertise and familiarity with the species. Moreover, 
the commenter did not identify any additional areas that might be 
essential for the recovery of the species.
    Comment 13: The Federal Register notice failed to adequately inform 
the public by not providing information on: (1) occupied habitat that 
was not proposed as critical habitat; (2) unoccupied but suitable 
habitat that was not proposed as critical habitat; (3) previously 
occupied or likely to have been occupied habitat that is currently 
unoccupied and not proposed as critical habitat; (4) whether the amount 
or quality of occupied habitat is increased by the designation of 
critical habitat; and (5), whether occupied habitat that has been 
adversely affected was not proposed as critical habitat for that 
reason.

[[Page 11015]]

    Our Response: We disagree that the above information was required 
to be included in the proposed rule. However, in the proposed rule we 
identified a point of contact for additional information in the FOR 
FURTHER INFORMATION CONTACT section. We also provided an opportunity 
for interested parties to obtain additional information during the 
informal session before the public hearing that was held in Corvallis, 
Oregon on October 5, 2009. In the Criteria Used to Identify Critical 
Habitat section of the proposed rule, we described the rule set we used 
to identify proposed critical habitat areas. Each of the sites 
designated in this final rule meets the definition of critical habitat 
under section 3(5)(a) of the Act, after applying the criterion 
described in the Criteria used to Identify Critical Habitat section 
below. The final designation does not increase the quantity or quality 
of any occupied habitat, but does specify those areas that are 
essential for the conservation of the species.

Summary of Changes from the Proposed Rule

    1. In response to a comment from the ODFW, we clarified the context 
and importance of the population threshold of 500 adults as discussed 
in the Recovery Plan in the Physical and Biological Features-Space for 
Individual and Population Growth and Normal Behavior, and in the 
Criteria Used to Identify Critical Habitat sections of the final rule.
    2. In response to a comment from the ODFW, we added forestry 
chemicals to the discussion of the threat of agricultural chemical 
runoff in the Special Management Considerations or Protections section 
of the final rule.
    3. In response to a comment from the ODFW, we revised the Special 
Management Considerations or Protections section of the final rule by 
adding the following information:
 Units 3G East Fork Minnow Creek Pond and 3K Wicopee Pond 
require special management to prevent the introduction or further 
introduction of nonnative fishes.
 Unit 3A Fall Creek Spillway Ponds requires special management 
to prevent or set back vegetative succession.
 Units 1A Santiam I-5 Side Channels, 2B(5) Finley Gray Creek 
Swamp, and 3G East Fork Minnow Creek Road require special management to 
reduce the incursion of potentially hazardous agricultural and forestry 
chemicals into Oregon chub habitats and to maintain water quality.
     4. We made the following revisions to the Critical Habitat 
Designation section:
 In Unit 3E Dexter Reservoir RV Alcove (DEX 3) we clarified 
that the connection to Dexter Reservoir is through a culvert.
 In Unit 3H Hospital Pond we clarified that the site is spring 
fed, rather than fed by Hospital Creek.
 In Unit 3K Wicopee Pond we clarified that although the site 
currently has no nonnative predatory or competitive species, a 
potential threat from the introduction of nonnative species exists.

Critical Habitat

Background

    Critical habitat is defined in section 3 of the Act as:
    1. The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    a. Essential to the conservation of the species, and
    b. Which may require special management considerations or 
protection; and
    2. Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Conservation, as defined under section 3 of the Act, means the use 
of all methods and procedures that are necessary to bring any 
endangered species or threatened species to the point at which the 
measures provided under the Act are no longer necessary. Such methods 
and procedures include, but are not limited to, all activities 
associated with scientific resources management such as research, 
census, law enforcement, habitat acquisition and maintenance, 
propagation, live trapping, and transplantation, and, in the 
extraordinary case where population pressures within a given ecosystem 
cannot be otherwise relieved, may include regulated taking.
     Critical habitat receives protection under section 7 of the Act 
through the prohibition against Federal agencies carrying out, funding, 
or authorizing the destruction or adverse modification of critical 
habitat. Section 7(a)(2) of the Act requires consultation on Federal 
actions that may affect critical habitat. The designation of critical 
habitat does not affect land ownership or establish a refuge, 
wilderness, reserve, preserve, or other conservation area. Such 
designation does not allow the government or public to access private 
lands. Such designation does not require implementation of restoration, 
recovery, or enhancement measures by non-Federal landowners. Where a 
landowner seeks or requests Federal agency funding or authorization for 
an action that may affect a listed species or critical habitat, the 
consultation requirements of section 7(a)(2) of the Act would apply, 
but even in the event of a destruction or adverse modification finding, 
Federal action agency's and the applicant's obligation is not to 
restore or recover the species, but to implement reasonable and prudent 
alternatives to avoid destruction or adverse modification of critical 
habitat.
     For inclusion in a critical habitat designation, the habitat 
within the geographical area occupied by the species at the time it was 
listed must contain the physical and biological features essential to 
the conservation of the species, and may be included only if those 
features may require special management considerations or protection. 
Critical habitat designations identify, to the extent known using the 
best scientific and commercial data available, habitat areas that 
provide essential life-cycle needs of the species (areas on which are 
found the physical and biological features laid out in the appropriate 
quantity and spatial arrangement for the conservation of the species). 
Under the Act and regulations at 50 CFR 424.12, we can designate 
critical habitat in areas outside the geographical area occupied by the 
species at the time it is listed only when we determine that those 
areas are essential for the conservation of the species and that 
designation limited to those areas occupied at the time of listing 
would be inadequate to ensure the conservation of the species. When the 
best available scientific data do not demonstrate that the conservation 
needs of the species require such additional areas, we will not 
designate critical habitat in areas outside the geographical area 
occupied by the species at the time of listing. An area currently 
occupied by the species but that was not occupied at the time of 
listing may, however, be essential to the conservation of the species 
and may be included in the critical habitat designation.
     Section 4 of the Act requires that we designate critical habitat 
on the basis of the best scientific and commercial data available. 
Further, our Policy on Information Standards Under the Endangered 
Species Act (published in the Federal Register on July 1, 1994 (59 FR 
34271)), the Information Quality Act (section 515 of the Treasury and 
General Government Appropriations Act for

[[Page 11016]]

Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), and our associated 
Information Quality Guidelines provide criteria, establish procedures, 
and provide guidance to ensure that our decisions are based on the best 
scientific data available. They require our biologists, to the extent 
consistent with the Act and with the use of the best scientific data 
available, to use primary and original sources of information as the 
basis for recommendations to designate critical habitat.
     When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information developed during the listing process for the species. 
Additional information sources may include the recovery plan for the 
species, articles in peer-reviewed journals, conservation plans 
developed by States and counties, scientific status surveys and 
studies, biological assessments, or other unpublished materials and 
expert opinion or personal knowledge. Substantive comments received in 
response to proposed critical habitat designations are also considered.
     Habitat is often dynamic, and species may move from one area to 
another over time. Furthermore, we recognize that critical habitat 
designated at a particular point in time may not include all of the 
habitat areas that we may later determine are necessary for the 
recovery of the species. For these reasons, a critical habitat 
designation does not signal that habitat outside the designated area is 
unimportant or may not be required for recovery of the species.
     Areas that support populations, but are outside the critical 
habitat designation, may continue to be subject to conservation actions 
we implement under section 7(a)(1) of the Act. Areas that support 
populations are also subject to the regulatory protections afforded by 
the section 7(a)(2) jeopardy standard, as determined on the basis of 
the best available scientific information at the time of the agency 
action. Federally funded or permitted projects affecting listed species 
outside their designated critical habitat areas may still result in 
jeopardy findings in some cases. Similarly, critical habitat 
designations made on the basis of the best available information at the 
time of designation will not control the direction and substance of 
future recovery plans, habitat conservation plans (HCPs), or other 
species conservation planning efforts if new information available at 
the time of these planning efforts calls for a different outcome.

Methods

    As required by section 4(b)(2) of the Act, we used the best 
scientific data available in determining areas that contain the 
features that are essential to the conservation of the Oregon chub. 
Data sources include research published in peer-reviewed articles; 
previous Service documents on the species, including the final listing 
determination (58 FR 53800; October 18, 1993), the Recovery Plan (USFWS 
1998), and annual surveys conducted by the ODFW from 1992 through 2008 
(summarized in Scheerer et al. 2007 and Scheerer 2008a). Additionally 
we utilized regional Geographic Information System (GIS) shape files 
for area calculations and mapping.

Physical and Biological Features

     In accordance with section 3(5)(A)(i) of the Act and regulations 
at 50 CFR 424.12(b), in determining which areas occupied at the time of 
listing to propose as critical habitat, we considered the physical and 
biological features that are essential to the conservation of the 
species and that may require special management considerations or 
protection. These features are the primary constituent elements (PCEs) 
laid out in the appropriate quantity and spatial arrangement essential 
for the conservation of the species. These include, but are not limited 
to:
    1. Space for individual and population growth and for normal 
behavior;
    2. Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    3. Cover or shelter;
    4. Sites for breeding, reproduction, and rearing (or development) 
of offspring; and
    5. Habitats that are protected from disturbance or are 
representative of the historical geographical and ecological 
distributions of a species.
    We derived the specific PCEs required for the Oregon chub from the 
biological needs of the species as described in the Background section 
of this rule and the following information:
Space for Individual and Population Growth and Normal Behavior
    Oregon chub habitats are typically slack-water off-channel water 
bodies with little or no flow, such as beaver ponds, oxbows, side 
channels, backwater sloughs, low-gradient tributaries (less than 2.5 
percent gradient) and flooded marshes (Pearsons 1989, pp. 30-31; Markle 
et al. 1991, pp. 288-289; Scheerer et al. 2007, p. 3; Scheerer 2008e). 
The species' swimming ability has been described as poor, and it is 
believed that no- or low-flow velocity water optimizes the energy 
expenditure of these slow-moving fish (Pearsons 1989, pp. 30-31). 
Although Oregon chub habitat may contain water of somewhat greater 
depth, the species mainly occupies water depths between approximately 
0.5-2.0 m (1.6-6.6 ft). In order for a habitat to provide enough space 
to allow normal behavior for a population of 500 or more individuals, 
the water body needs to include approximately 500 square meters (0.12 
ac) or more of aquatic surface area between 0.5-2.0 m (1.6-6.6 ft) deep 
(Scheerer 2008b). Adequate aquatic surface area for 500 or more 
individuals is significant because the Recovery Plan identifies 
populations at or above the 500 adult threshold as one of the delisting 
criteria for the species (USFWS 1998, p. 28).
Food, Water, Air, Light, Minerals, or Other Requirements
    Known as obligatory sight feeders (Davis and Miller 1967, p. 32), 
Oregon chub feed throughout the day and stop feeding after dusk 
(Pearsons 1989, p. 23). The fish feed mostly on water column fauna, 
especially invertebrates that live in dense aquatic vegetation. Markle 
et al. (1991, p. 288) found that the diet of Oregon chub adults 
consisted primarily of minute crustaceans including copepods, 
cladocerans, and chironomid larvae. The diet of juveniles also consists 
of minute organisms such as rotifers, copepods, and cladocerans 
(Pearsons 1989, pp. 41-42).
    With respect to water quality, the temperature regime at a site may 
determine the productivity of Oregon chub at that location. Spawning 
activity for the species has been observed from May through early 
August when F)C (61 F) or 16 C (59 subsurface water temperatures exceed 
15 (Scheerer and Apke 1997, p. 22; Markle et al. 1991, p. 288; Scheerer 
and MacDonald 2003, p. 78). The species will display normal life-
history behavior at F).C (59 and 77 temperatures between approximately 
15 and 25 The upper lethal temperature for the fish F) in laboratory 
studies (Scheerer and ApkeC (88 was determined to be 31 1997, p. 22).
    Optimal Oregon chub habitat contains water with dissolved oxygen 
levels greater than 3 parts per million (ppm) and an absence of 
contaminants such as copper, arsenic, mercury, and cadmium; human and 
animal waste products; pesticides; nitrogen and phosphorous 
fertilizers; and gasoline or diesel fuels. However, the species habitat 
is also characterized by high primary

[[Page 11017]]

productivity and frequent algal blooms that might cause natural 
variability in water quality, especially dissolved oxygen levels 
(Scheerer and Apke 1997, p. 15). Optimal Oregon chub habitat includes 
water dominated by fine substrates, but protected from excessive 
sedimentation. When excessive sediment is deposited, surface area can 
be lost as the sediment begins to displace open water. The resulting 
succession of open water habitat to wet meadow is detrimental to Oregon 
chub populations (Scheerer 2008c).
    The water quality in the habitats of many known Oregon chub 
populations is threatened due to their proximity to areas of human 
activity. Many of the known populations occur near rail, highway, and 
power transmission corridors and within public park and campground 
facilities. These populations may be threatened by chemical spills from 
overturned truck or rail tankers; runoff or accidental spills of 
herbicides; overflow from chemical toilets in campgrounds; 
sedimentation of shallow habitats from construction activities; and 
changes in water level or flow conditions from construction, 
diversions, or natural desiccation. Oregon chub populations near 
agricultural areas are subject to poor water quality as a result of 
runoff laden with sediment, pesticides, and nutrients. Logging in the 
watershed can result in increased sedimentation and herbicide runoff 
(USFWS 1998, p. 14).
Cover or Shelter
    The species' habitat preference varies depending on lifestage and 
season, but all Oregon chub require considerable aquatic vegetation for 
hiding and spawning activities (Pearsons 1989, p. 22; Markle et al. 
1991, p. 290; Scheerer and Jones 1997, p. 5; Scheerer et al. 2007, p. 
3). Oregon chub in similar size classes school together. A minimum of 
250 square meters (0.06 ac) (or between approximately 25 and 100 
percent of the total surface area of the habitat) covered with aquatic 
vegetation is needed to provide for the life-history requirements for a 
population of 500 Oregon chub (Scheerer 2008e). Aquatic plant 
communities within Oregon chub habitat include, but are not limited to, 
both native and nonnative species, including:
    1. Emergent vegetation: Carex spp. (sedge), Eleocharis spp. 
(spikerush), Scirpus spp. (bulrush), Juncus spp. (rush), Alisma spp. 
(water plantain), Polygyonum spp. (knotweed), Ludwigia spp. (primrose-
willow), Salix spp. (willow), Sparganium spp. (bur-reed), and Typha 
spp. (cattail).
    2. Partly submerged/emergent vegetation: Ranunculus spp. 
(buttercup).
    3. Floating/submerged vegetation: Azolla spp. (mosquitofern), 
Callitriche sp. (water-starwort), Ceratophyllum sp. (hornwort), Elodea 
spp. (water weed), Fontinalis spp. (fontinalis moss), Lemna spp. 
(duckweed), Myriophyllum spp. (parrot feather), Nuphar spp. (pondlily), 
and Potamogeton spp. (pondweed) (Scheerer 2008c).
    Larval Oregon chub congregate in the upper layers of the water 
column, especially in shallow, near-shore areas. Juvenile Oregon chub 
venture farther from shore into deeper areas of the water column. Adult 
Oregon chub seek dense vegetation for cover and frequently travel in 
the mid-water column in beaver channels or along the margins of aquatic 
plant beds. In the early spring, Oregon chub are most active in the 
warmer, shallow areas of the ponds (Pearsons 1989, pp. 16-17; USFWS 
1998, p. 10). Because Oregon chub habitat is characterized by little or 
no water flow, resulting substrates are typically composed of silty and 
organic material. In winter months, Oregon chub of various life stages 
can be found buried in the detritus or concealed in aquatic vegetation 
(Pearsons 1989, p. 16).
Sites for Breeding, Reproduction, and Rearing (or Development) of 
Offspring
    Although most mature Oregon chub are found to be greater than or 
equal to 2 years old, maturity appears to be mainly size- rather than 
age-dependent (Scheerer and McDonald 2003, p. 78). Males over 35 mm 
(1.4 in) have been observed exhibiting spawning behavior. Oregon C 
(59chub spawn from April through September, when temperatures exceed 15 
F), with peak activity in July. Approximately 150 to 650 eggs will be 
released per spawning event, hatching within 10 to 14 days. Females 
prefer a highly organic, vegetative substrate for spawning and will lay 
their adhesive eggs directly on the submerged vegetation (Pearsons 
1989, pp. 17, 23; Markle et al. 1992, p. 290; Scheerer 2007b, p. 494). 
Larvae and juveniles seek dense cover in shallow, warmer regions of 
off-channel habitats (Pearsons 1989, p. 17; Scheerer 2007b, p. 494).
Habitats (Those protected from anthropogenic disturbance or that are 
representative of the historical and ecological distribution of a 
species.)
    Many species of nonnative fish that compete with or prey upon 
Oregon chub have been introduced and are common throughout the 
Willamette Valley, including largemouth bass (Micropterus salmoides), 
smallmouth bass (Micropterus dolomieui), crappie (Pomoxis sp.), 
bluegill (Lepomis macrochirus), and western mosquitofish (Gambusia 
affinis). Of the 747 Willamette Valley sites sampled for Oregon chub by 
ODFW since the beginning of annual survey efforts by the agency in 
1991, 42 percent contained nonnative fish. Most of the surveyed 
habitats that supported large populations of Oregon chub had no 
evidence of nonnative fish presence (Scheerer 2002, p. 1078; Scheerer 
2007a, p. 96; Scheerer et al. 2007, p. 14). The presence of nonnative 
fish in the Willamette Valley, especially centrarchids (e.g., basses 
and crappie) and ictalurids (catfishes) is suspected to be a major 
factor in the decline of Oregon chub and the biggest threat to the 
species' recovery (Markle et al. 1991, p. 291; Scheerer 2002, p. 1078; 
Scheerer et al. 2007, p. 18).
    Specific interactions responsible for the exclusion of Oregon chub 
from habitats dominated by nonnative fish are not clear in all cases. 
While information confirming the presence of Oregon chub in stomach 
contents of predatory fish is lacking, many nonnative fish, 
particularly adult centrarchids and ictalurids, are documented 
piscivores (fish eaters) (Moyle 2002, pp. 397, 399, 403; Wydoski and 
Whitney 2003, pp. 125, 128, 130; Li et al. 1987, pp. 198-201). These 
fish are frequently the dominant inhabitants of ponds and sloughs 
within the Willamette River drainage and may constitute a major 
obstacle to Oregon chub recolonization efforts. Nonnative fish may also 
serve as sources of parasites and diseases; however, disease and 
parasite problems have not been studied in the Oregon chub.
    Observed feeding strategies and diet of introduced fish, 
particularly juvenile centrarchids and adult mosquitofish (Li et al. 
1987, pp. 198-201), often overlap with diet and feeding strategies 
described for Oregon chub (Pearsons 1989, pp. 34-35). This suggests 
that direct competition for food between Oregon chub and introduced 
species may further impede species survival as well as recovery 
efforts. The rarity of finding Oregon chub in waters also inhabited by 
mosquitofish may reflect many negative interactions, including but not 
limited to food-based competition, aggressive spatial exclusion, and 
predation on eggs and larvae (Meffe 1983, pp. 316, 319; Meffe 1984, pp. 
1,530-1,531). Because many remaining population sites are easily 
accessible, there continues to be a potential for unauthorized 
introductions of nonnative fish, particularly

[[Page 11018]]

mosquitofish and game fish such as bass and walleye (Stizostedion 
vitreurn).
    The bullfrog (Rana catesbiana), a nonnative amphibian, also occurs 
in the valley and breeds in habitats preferred by the Oregon chub (Bury 
and Whelan 1984, pp. 2-3; Scheerer 1999, p. 7). Adult bullfrogs prefer 
habitat similar in characteristics (i.e., little to no water velocity, 
abundant aquatic and emergent vegetation) to the preferred habitat for 
Oregon chub, and are known to consume small fish as part of their diet 
(Cohen and Howard 1958, p. 225; Bury and Whelan 1984, p. 3), but it is 
unclear if they have a negative impact on Oregon chub populations, as 
several sites that have large numbers of bullfrogs also maintain robust 
Oregon chub populations (Scheerer 2008d).
Flood Control
    Major alteration of the Willamette River for flood control and 
navigation improvements has eliminated most of the river's historical 
floodplain, impairing or eliminating the environmental conditions in 
which the Oregon chub evolved. The decline of Oregon chub has been 
correlated with the construction of these projects based on the date of 
last capture at a site (58 FR 53801; October 18, 1993). Pearsons (1989, 
pp. 32-33) estimated that the most severe decline occurred during the 
1950s and 1960s when 8 of 11 flood control projects in the Willamette 
River drainage were completed (USACE 1970, pp. 219-237). Other 
structural changes along the Willamette River corridor such as 
revetment and channelization, dike construction and drainage, and the 
removal of floodplain vegetation have eliminated or altered the slack 
water habitats of the Oregon chub (Willamette Basin Task Force 1969, 
pp. I9, II22-II24; Hjort et al. 1984, pp. 67-68, 73; Sedell and 
Froggatt 1984, pp. 1,832-1,833; Li et al. 1987, p. 201). Management of 
water bodies (such as reservoirs) adjacent to occupied Oregon chub 
habitat continues to impact the species by causing fluctuations in the 
water levels of their habitat such that it may exceed or drop below 
optimal water depths.

Primary Constituent Elements (PCEs) for the Oregon Chub

     Pursuant to our regulations, we are required to identify the known 
physical and biological features essential to the conservation of the 
Oregon chub and which may require special management considerations or 
protection. These features are the primary constituent elements (PCEs) 
laid out in the appropriate quantity and spatial arrangement essential 
for the conservation of the species. The PCEs are listed below. All 
areas designated as critical habitat for Oregon chub are either 
occupied or within the species' historical geographic range.
    Based on the above needs and our current knowledge of the life 
history, biology, and ecology of the species and the characteristics of 
the habitat necessary to sustain the essential life-history functions 
of the species, we have identified four PCEs for Oregon chub critical 
habitat:
    1. Off-channel water bodies such as beaver ponds, oxbows, side-
channels, stable backwater sloughs, low-gradient tributaries, and 
flooded marshes, including at least 500 continuous square meters (0.12 
ac) of aquatic surface area at depths between approximately 0.5 and 2.0 
m (1.6 and 6.6 ft).
    2. Aquatic vegetation covering a minimum of 250 square meters (0.06 
ac) (or between approximately 25 and 100 percent) of the total surface 
area of the habitat. This vegetation is primarily submergent for 
purposes of spawning, but also includes emergent and floating 
vegetation and algae, which are important for cover throughout the 
year. Areas with sufficient vegetation are likely to also have the 
following characteristics:
 Gradient less than 2.5 percent;
 No or very low water velocity in late spring and summer;
 Silty, organic substrate; and
 Abundant minute organisms such as rotifers, copepods, 
cladocerans, and chironomid larvae.
    3. Late spring and summer subsurface water F), with natural diurnal 
andC (59 and 78 temperatures between 15 and 25 seasonal variation.
    4. No or negligible levels of nonnative aquatic predatory or 
competitive species. Negligible is defined for the purpose of this rule 
as a minimal level of nonnative species that will still allow the 
Oregon chub to continue to survive and recover.
    The need for space for individual and population growth and normal 
behavior is met by PCE (1); areas for reproduction, shelter, food, and 
habitat for prey are provided by PCE (2); optimal physiological 
processes for spawning and survival are ensured by PCE (3); habitat 
free from disturbance and, therefore, sufficient reproduction and 
survival opportunities are provided by PCE (4).
    This final critical habitat designation is designed for the 
conservation of PCEs necessary to support the life-history functions 
that were the basis for the proposal. Each of the areas designated in 
this rule has been determined to contain sufficient PCEs to provide for 
one or more of the life-history functions of the Oregon chub. 
Specifically, these areas fall into two groups: areas occupied at time 
of listing containing PCEs sufficient for one or more life-history 
functions, and areas not occupied at time of listing but essential to 
the conservation of the species and that also contain PCEs for one or 
more life-history functions.

Criteria Used To Identify Critical Habitat

    As required by section 4(b)(1)(A) of the Act, we used the best 
scientific data available in determining areas that contain the 
features that are essential to the conservation of the Oregon chub. We 
only designated areas outside the geographical area occupied by the 
species when a designation limited to its present range would be 
inadequate to ensure the conservation of the species (50 CFR 
424.12(e)). The steps we followed in identifying critical habitat were:
    1. Our initial step in identifying critical habitat was to 
determine, in accordance with section 3(5)(A)(i) of the Act and 
regulations at 50 CFR 424.12, the physical and biological habitat 
features (PCEs) that are essential to the conservation of the species 
as explained in the previous section.
    2. We then identified areas occupied by the Oregon chub at the time 
of listing. Of the 5 occupied sites known at the time of the 1993 
listing (58 FR 53801), and the 12 additional sites confirmed by post-
listing survey data to be occupied with one or more Oregon chub at the 
time of listing, 10 still support Oregon chub (Scheerer et al. 2007, p. 
2; Scheerer 2008a, p. 2) and contain at least one PCE.
    3. Because we found that areas occupied at time of listing were not 
sufficient to conserve the species, we then identified any additional 
sites that were not occupied at the time of listing but are currently 
occupied and contain PCEs, and which may be essential for the 
conservation of the species. Surveys conducted in 2007 and 2008 
indicate that 15 additional sites are currently occupied with one or 
more Oregon chub (Scheerer et al. 2007, p. 2; Scheerer 2008a, p. 2).
    4. Next we identified sites that support introduced populations of 
Oregon chub that also contain the PCEs, and which may be essential for 
the conservation of the species, which resulted in 11 additional sites 
being identified (Scheerer et al. 2007, p. 2; Scheerer 2008a, p. 2). 
Collectively, the above efforts resulted in the identification of 36 
occupied sites.

[[Page 11019]]

    5. Our final step was to evaluate the 36 occupied sites within the 
context of the Recovery Plan, to determine which areas contained the 
physical and biological features in the amount and spatial 
configuration essential to the conservation of the species. This step 
involved the application of the following selection criteria:
    A. Sites that support large, stable populations.
    From the list of occupied sites that contain PCEs, we selected 
sites that support populations meeting the delisting population 
criteria outlined in the 1998 Recovery Plan (i.e., establishing 20 
populations of at least 500 adults with a stable or increasing trend 
over 7 years (USFWS 1998, p. 28)), and also sites that were likely to 
meet the delisting criteria in the near future. Eighteen sites had at 
least 500 adults and were likely to have a stable or increasing trend 
over 7 years in the near future. Of the 18 sites meeting this selection 
criterion, 9 sites were occupied at the time of listing:
 Unit 2B(5), Finley Gray Creek Swamp
 Unit 3B, Elijah Bristow State Park-- Berry Slough
 Unit 3E, Dexter Reservoir RV Alcove--DEX3
 Unit 3F, Dexter Reservoir Alcove PIT 1
 Unit 3G, East Fork Minnow Creek Pond Unit
 Unit 3H, Hospital Pond
 Unit 3I, Shady Dell Pond
 Unit 3J, Buckhead Creek, and
 Unit 3K, Wicopee Pond.
    Three other sites supported naturally occurring populations but 
were not occupied at the time of listing:
 Unit 1B(1), Geren Island North Channel
 Unit 1B(4), Gray Slough, and
 Unit 3D, Elijah Bristow State Park Island Pond.
    In addition, six sites supp