Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Oregon Chub (Oregonichthys crameri), 10412-10453 [E9-4528]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 45 (Tuesday, March 10, 2009)]
[Proposed Rules]
[Pages 10412-10453]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-4528]



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Part III





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



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

Federal Register / Vol. 74, No. 45 / Tuesday, March 10, 2009 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R1-ES-2009-0010; 92210-1117-000-B4]
RIN 1018-AV87


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

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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

DATES: We will accept comments received on or before May 11, 2009. We 
must receive requests for public hearings, in writing, at the address 
shown in the FOR FURTHER INFORMATION CONTACT section by April 24, 2009.

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: U.S. mail or hand-delivery: 
Public Comments Processing, Attn: RIN 1018-AV87; 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 ``Public Comments'' section 
below for more information).

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, OR 97266 (telephone 503-231-6179; 
facsimile 503-231-6195). If you use a telecommunications device for the 
deaf (TDD) call the Federal Information Relay Service (FIRS) at 800-
877-8339.

SUPPLEMENTARY INFORMATION:

Public Comments

    We intend that any final action resulting from this proposal will 
be as accurate and as effective as possible. Therefore, we request 
comments or suggestions on this proposed rule. We particularly seek 
comments concerning:
    1. The reasons why we should or should not designate habitat as 
``critical habitat'' under section 4 of the Act (16 U.S.C. 1531 et 
seq.), including whether there are threats to the species from human 
activity, the degree of which can be expected to increase due to the 
designation, and whether the benefit of designation would outweigh 
threats to the species caused by the designation, such that the 
designation of critical habitat is prudent.
    2. Specific information on:
     The amount and distribution of habitat for the species 
included in this proposed rule;
     What areas occupied at the time of listing, and that 
contain features essential for the conservation of the species, we 
should include and why; and
     What areas not occupied at the time of listing are 
essential to the conservation of the species and why.
    3. Land use designations and current or planned activities in areas 
occupied by the species, and their possible impacts on the species and 
the proposed critical habitat.
    4. Any foreseeable economic, national security, or other potential 
impacts resulting from the proposed designation and, in particular, any 
impacts on small entities and the benefits of including or excluding 
areas that exhibit these impacts.
    5. Whether the benefits of excluding any particular area from 
critical habitat outweigh the benefits of including that area as 
critical habitat under section 4(b)(2) of the Act, after considering 
the potential impacts and benefits of the proposed critical habitat 
designation.
    6. Special management considerations or protections that the 
proposed critical habitat may require.
    7. Whether we could improve or modify our approach to designating 
critical habitat in any way to provide for greater public participation 
and understanding, or to better accommodate concerns and comments.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section. We will not 
consider comments sent by e-mail or fax or to an address not listed in 
the ADDRESSES section.
    If you submit a comment via https://www.regulations.gov, your entire 
comment--including any personal identifying information--will be posted 
on the Web site. If you submit a hardcopy comment that includes 
personal identifying information, you may request at the top of your 
document that we withhold this information from public review. However, 
we cannot guarantee that we will be able to do so. We will post all 
hardcopy comments on https://www.regulations.gov.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection at https://www.regulations.gov, or by 
appointment, during normal business hours, at the U.S. Fish and 
Wildlife Service, Oregon Fish and Wildlife Office (see FOR FURTHER 
INFORMATION CONTACT).
    You may obtain copies of the proposed rule by mail from the Oregon 
Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT) or by 
visiting the Federal eRulemaking Portal at https://www.regulations.gov.

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of critical habitat in this proposed 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 (https://www.fws.gov/pacific/ecoservices/
endangered/recovery/Documents/Oregonchub.pdf ).

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).

[[Page 10413]]

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. 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 summer 
subsurface water temperature exceeding 15 [deg]Celsius ([deg]C) (61 
[deg]Fahrenheit ([deg]F)) (Scheerer and Apke 1997, p. 45; Scheerer 
2002, p. 1073; Scheerer and McDonald 2003, p. 69). Optimal Oregon chub 
habitat provides 1 square meter (m\2\) (11 square feet (ft\2\)) 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 non-aggressive 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. Whereas natural 
perturbations like floods often favor native species over nonnative 
species, human perturbations typically favor the nonnative species. In 
the Santiam River basin, the two largest natural populations of Oregon 
chub declined substantially after nonnative fishes invaded these 
habitat 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 
sp. (largemouth bass, smallmouth bass, bluegill) and Pomoxis sp. 
(crappies)), and bullhead catfishes (Ameiurus sp.) 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)) stretch of the Middle Fork 
Willamette River in the vicinity of Dexter and Lookout Point Reservoirs 
in Lane County, Oregon; this stretch represented just 2 percent of the 
species' historical range (58 FR 53800; October 18, 1993). Very small 
numbers of the species, between 1 and 7 individuals, were found at the 
remaining eight 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

     In 1993, we listed Oregon chub as endangered, in accordance with 
the Endangered Species Act (Act) (58 FR 53800; October 18, 1993). In 
that listing, we concluded that critical habitat was prudent but not 
determinable. A recovery plan for the Oregon chub was completed in 1998 
(USFWS 1998). The Oregon chub 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 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 
guaranteed in perpetuity.
    On March 9, 2007, the Institute for Wildlife Protection 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). On March 8, 2007, we 
issued a notice that we would begin a status review of the Oregon chub 
(72 FR 10547). 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.

[[Page 10414]]

    We have established two Safe Harbor Agreements (SHAs) for the 
Oregon chub; both in Lane County, Oregon, in 2001 (66 FR 30745; June 7, 
2001) and 2007 (72 FR 50976; September 5, 2007). These SHAs established 
new populations of Oregon chub in artificial ponds as refugia for 
natural populations, which contributes to the conservation of the 
species by reducing the risk of the complete loss of donor populations 
and any of their unique genetic material. The SHA policy was developed 
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. SHAs provide assurances to property owners allowing 
alterations or modifications to enrolled property, even if such actions 
result in the incidental take of a listed species. 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) or the 1998 Recovery 
Plan for Oregon Chub (USFWS 1998).

Critical Habitat

    Critical habitat is defined in section 3 of the Act as:
    1. The specific areas within the geographical area occupied by a 
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 a 
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.
    Critical habitat receives protection under section 7 of the Act 
through the prohibition against Federal agencies carrying out, funding, 
or authorizing activities that result in the destruction or adverse 
modification of critical habitat. Section 7 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 government or public 
access to private lands. Such designation does not require 
implementation of restoration, recovery, or enhancement measures by the 
landowner. Where the landowner seeks or requests Federal agency funding 
or authorization of an activity that may affect a listed species or 
critical habitat, the consultation requirements of section 7 would 
apply. However, even if a destruction or adverse modification finding 
were to be made, a landowner's obligation would not be to restore or 
recover the species, but rather, to implement reasonable and prudent 
alternatives to avoid destruction or adverse modification of critical 
habitat in order to receive the federal agency funding or 
authorization.
    For inclusion in a critical habitat designation, habitat within the 
geographic area occupied by the species at the time it was listed must 
contain the physical and biological features that are essential to the 
conservation of the species. Critical habitat designations identify, to 
the extent known using the best scientific data available, habitat 
areas that provide essential life cycle needs of the species (areas on 
which are found the primary constituent elements, as defined at 50 CFR 
424.12(b)). Occupied habitat that contains features essential to the 
conservation of the species meets the definition of critical habitat 
only if those features may require special management considerations or 
protection. Under the Act, we can designate areas that were unoccupied 
at the time of listing as critical habitat only when we determine that 
the best available scientific data demonstrate that the designation of 
that area is essential to 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 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), and Section 515 of 
the Treasury and General Government Appropriations Act for Fiscal Year 
2001 (Pub. L. 106-554; H.R. 5658) and the associated Information 
Quality Guidelines issued by the Service, provide criteria, and 
establish procedures and guidelines to ensure that decisions made by 
the Service represent the best scientific data available. They require 
Service 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 proposed 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.
    Habitat is often dynamic, and species may move from one area to 
another over time. Furthermore, we recognize that designation of 
critical habitat may not include all of the habitat areas that we may 
eventually determine are necessary for the recovery of the species, 
based on scientific data not now available to the Service. 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. They are also subject to 
the regulatory protections afforded by the Section 7(a)(2) jeopardy 
standard, as determined on the basis of the best 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 to these planning efforts calls for a different 
outcome.

Methods

    As required by section 4(b)(2) of the Act, we use the best 
scientific data

[[Page 10415]]

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) and the Recovery Plan for the Oregon chub 
(USFWS 1998); and annual surveys conducted by the ODFW (1992 through 
2008, as summarized in Scheerer et al. 2007 and Scheerer 2008a). 
Additionally we utilized regional Geographic Information System (GIS) 
shape files for area calculations and mapping.

Primary Constituent Elements

    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 consider 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 for 
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 derive the specific PCEs required for the Oregon chub from the 
biological needs of the species as described in the Background section 
of this proposed rule and the following information.

Space for Individual and Population Growth and Normal Behavior

Flow Velocities and Depth
    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, p. 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 fish (Pearsons 1989, p. 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 (m\2\ ) (0.12 ac) 
or more of aquatic surface area between 0.5-2.0 m (1.6-6.6 ft) deep. 
(Scheerer 2008b).

Cover

    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). A minimum of 250 m\2\ (0.06 ac) (or between approximately 25 and 
100 percent of the total surface area of the habitat) to be covered 
with aquatic vegetation is needed to provide 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. (pond-
lily); and Potamogeton spp. (pondweed) (Scheerer 2008c).
    Oregon chub in similar size classes school and feed together. 
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).

Substrates

    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). Females prefer a highly organic, vegetative 
substrate for spawning and will lay their adhesive eggs directly on the 
submerged vegetation (Pearsons 1989, p. 17, 23; Markle et al. 1991. p. 
290; Scheerer 2007b, p. 494).

Food

    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, p. 41-42).

Water Quality

    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 subsurface water temperatures exceed 15 [deg]C (59 [deg]F) 
or 16 [deg]C (61 [deg]F) (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 temperatures between 
approximately 15 and 25 [deg]C (59 and 77 [deg]F). The upper lethal 
temperature for the fish was determined to be 31 [deg]C (88 [deg]F) in 
laboratory studies (Scheerer and Apke 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 productivity and frequent algal 
blooms that might cause natural variability in water quality, 
especially dissolved oxygen levels (Scheerer and Apke 1997,

[[Page 10416]]

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 extant Oregon chub 
populations is threatened due to their proximity to areas of human 
activity. Many of the known extant populations of Oregon chub 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 vegetation control chemicals; 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).

Reproduction and Rearing 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 chub 
spawn from April through September, when temperatures exceed 15 [deg]C 
(59 [deg]F), with peak activity in July. Approximately 150 to 650 eggs 
will be released per spawning event, hatching within 10 to 14 days. As 
described above, females prefer a highly organic, vegetative substrate 
for spawning and will lay their adhesive eggs directly on the submerged 
vegetation (Pearsons 1989, p. 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 Protected From Disturbance

Nonnative Fish
    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 habitats 
surveyed 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; 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 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 for the Oregon Chub

    Pursuant to our regulations, we are required to identify the known 
physical and biological features, called primary constituent elements 
(PCEs), essential to the conservation of the Oregon chub and which may 
require special management considerations or protections. All areas 
proposed as critical habitat for Oregon chub are either occupied or 
within the species' historical geographic range.

[[Page 10417]]

    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 (5,400 
square feet) 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 m\2\ (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 is 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 temperatures between 15 
and 25 [deg]C (59 and 78 [deg]F), with natural diurnal and seasonal 
variation.
    4. No or negligible levels of nonnative aquatic predatory or 
competitive species. Negligible is defined for the purpose of this 
proposed 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 is provided by PCE (4).
    This proposed 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 proposed 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 that are 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 use the best 
scientific data available in determining areas that contain the 
features that are essential to the conservation of the Oregon chub. 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 populations 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. Since, based on the recovery plan criteria described above, we 
found that areas occupied at time of listing were not sufficient to 
conserve the species, the next step was the identification of any 
additional sites that were not occupied at the time of listing, but 
that 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 
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 that met the above criteria.
    5. Our final step was to evaluate the 36 occupied sites within the 
context of the 1998 Oregon Chub 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 criteria:
     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 seven years 
(USFWS 1998, p. 28)), and also sites that are likely to meet the 
delisting criteria in the near future. Of the 18 sites meeting this 
selection criterion, 9 sites were occupied at the time of listing:
    [cir] Unit 2B(5), Finley Gray Creek Swamp
    [cir] Unit 3B, Elijah Bristow State Park--Berry Slough
    [cir] Unit 3E, Dexter Reservoir RV Alcove--DEX3
    [cir] Unit 3F, Dexter Reservoir Alcove--PIT1
    [cir] Unit 3G, East Fork Minnow Creek Pond
    [cir] Unit 3H, Hospital Pond
    [cir] Unit 3I, Shady Dell Pond
    [cir] Unit 3J, Buckhead Creek, and
    [cir] Unit 3K, Wicopee Pond.
    Three other sites supported naturally occurring populations but 
were not occupied at the time of listing:
    [cir] Unit 1B(1), Geren Island North Channel
    [cir] Unit 1B(4), Gray Slough, and
    [cir] Unit 3D, Elijah Bristow State Park Island Pond.
    In addition, six sites supported introduced populations:
    [cir] Unit 1C, Foster Pullout Pond
    [cir] Unit 2A(1), Russell Pond
    [cir] Unit 2B(1), Ankeny Willow Marsh
    [cir] Unit 2B(2), Dunn Wetland
    [cir] Unit 2B(4), Finley Cheadle Pond, and
    [cir] Unit 3A, Fall Creek Spillway Ponds.
     Sites that are capable of supporting large populations: 
Because the 1998 Recovery Plan for Oregon chub calls for establishing 
and maintaining a minimum of 20 populations that meet the recovery 
criteria, we identified seven currently occupied sites not already 
selected under the first criterion (above) that have the greatest 
potential to contribute to the long-term conservation and recovery of 
the species. Sites meeting this selection criterion include five sites 
that support naturally occurring populations: Unit 1A, Santiam I-5 Side 
Channels; Unit 1B(2), Stayton Public Works Pond; Unit 2A(2), Shetzline 
Pond; Unit 2A(3), Big Island; and Unit 3C, Elijah Bristow State Park 
Northeast Slough. In addition two sites that support introduced 
populations met this criterion: Unit 1B(3), South Stayton Pond; and 
Unit 2B(3), Finley Display Pond. Each of these sites either currently, 
or in the past, has supported populations of over 500 adults.

[[Page 10418]]

     Sites representative of the geographic distribution of 
Oregon chub: The delisting criteria outlined in the 1998 Recovery Plan 
require that at least four populations be located in each of three sub-
basins. We determined that the 25 sites selected under the preceding 
critical habitat criteria also met this objective (USFWS 1998, p. 28). 
Six units are being proposed as critical habitat in the Santiam River 
watershed, 8 sites are being proposed as critical habitat in the 
Mainstem Willamette River watershed, and 11 sites are being proposed as 
critical habitat in the Middle Fork Willamette River watershed. By 
protecting a variety of habitats throughout the species' historical 
range, we increase the probability that the species can adjust in the 
future to various limiting factors that may affect the population, such 
as predators, disease, and flood events exceeding annual high water 
levels.
    Based on this analysis, we are proposing to designate 25 units as 
critical habitat. Although the 1998 recovery plan calls for 
establishing and maintaining a minimum of 20 populations, we believe 
that establishing additional populations will allow the Service 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.
    After applying the above criteria, we mapped the critical habitat 
unit boundaries at each of these 25 sites. Mapping was completed using 
a Geographic Information System (GIS), and involved several steps. 
Critical habitat unit boundaries were delineated to encompass the 
extent of habitat containing the physical and biological features 
essential to the conservation of the species that may require special 
management considerations or protection. Polygon vertices (points where 
two lines meet) were collected along the annual high water mark at 
least every 30 meters (98 ft) around the perimeter of the site, and at 
a greater frequency in areas of complexity or where higher resolution 
was necessary. The full extent of each pond or slough was mapped; 
islands were mapped with the same method as the perimeter of the site. 
At sites where tributaries or channels entered or exited a site, only 
the extent of suitable Oregon chub habitat was mapped. The extent of 
chub use in open systems was defined by habitat features and by 
previous experience sampling in those areas. Habitat features that 
defined the limit of Oregon chub use in a channel included increased 
gradient, the absence of aquatic vegetation, and areas where gravel, 
cobble, or other large substrate was present. We combined the polygon 
data with information from aerial photos to determine the proposed 
critical habitat unit boundaries of each site.

Special Management Considerations or Protections

    The term critical habitat is defined in section 3(5)(A) of the Act, 
in part, as geographic areas on which are found those physical or 
biological features essential to the conservation of the species and 
``which may require special management considerations or protections.'' 
Accordingly, in identifying critical habitat in occupied areas, we 
assess whether the primary constituent elements within the areas 
determined to be occupied at the time of listing may require any 
special management considerations or protections. Although the 
determination that special management may be required is not a 
prerequisite to designating critical habitat in areas essential to the 
conservation of the species that were unoccupied at the time of 
listing, all areas being proposed as critical habitat require some 
level of management to address current and future threats to the Oregon 
chub, to maintain or enhance the physical and biological features 
essential to its conservation, and to ensure the recovery and survival 
of the species.
    The primary threats impacting the physical and biological features 
essential to the conservation of the Oregon chub that may require 
special management considerations within the proposed critical habitat 
units include: Competition and predation by nonnative fish; the 
potential for initial or further introduction of nonnative fish; 
vegetative succession of shallow aquatic habitats; possible 
agricultural chemical runoff; possible excessive siltation from logging 
in the watershed; other threats to water quality (including threat of 
toxic spills, low dissolved oxygen); and fluctuations in water levels 
due to regulated flow management at flood control dams, as well as low 
summer water levels.
    Some additional threats to the continued survival and recovery of 
the Oregon chub, such as the potential for reduced genetic diversity 
due to the low level of mixing between populations, will likely be 
addressed by direct management of populations (e.g., translocation of 
individuals) rather than by management of the physical and biological 
features of the habitat. Such threats, therefore, are not addressed in 
this section specific to the special management required of the 
physical and biological features of the proposed critical habitat 
areas.
    Special management considerations or protections are needed in most 
of the units to address the impacts of competition and predation by 
nonnative fishes in Oregon chub habitat or to avoid the potential 
introduction of nonnative fishes into areas occupied by Oregon chub. 
Predatory nonnative fishes are considered the greatest current threat 
to the recovery of the Oregon chub. Management for the Oregon chub has 
focused on establishing secure, isolated habitats free of nonnative 
fishes. Nonnative fishes are abundant and ubiquitous in the Willamette 
River Basin, and monitoring and management are required to remove 
nonnative fishes from Oregon chub habitat when possible, and to protect 
Oregon chub populations that have not yet been affected by nonnative 
fishes from invasion.
    Special management is needed to reduce or eradicate the threat 
posed by nonnative fishes already present in the following proposed 
units:
     Unit 1A Santiam I-5 Side Channels
     Unit 1B(1) Geren Island North Channel
     Unit 1B(2) Stayton Public Works Pond
     Unit 1B(4) Gray Slough, Unit 2B(5) Finley Gray Creek Swamp
     Unit 3C Elijah Bristow State Park--NE Slough
     Unit 3D Elijah Bristow State Park Island Pond, and
     Unit 3F Dexter Reservoir Alcove--PIT1.
    Special management or protections are needed to prevent the 
introduction or further introduction of nonnative fishes into the 
following proposed units:
     Unit 1A Santiam I-5 Side channels
     Unit 1B(2) Stayton Public Works Pond
     Unit 1B(3) South Stayton Pond
     Unit 1B(4) Gray Slough
     Unit 1C Foster Pullout Pond
     Unit 2A(2) Shetzline Pond
     Unit 2A(3) Big Island
     Unit 2B(1) Ankeny Willow Marsh
     Unit 2B(3) Finley Display Pond
     Unit 2B(4) Finley Cheadle Pond
     Unit 2B(5) Finley Gray Creek Swamp
     Unit 3A Fall Creek Spillway Ponds
     Unit 3B Elijah Bristow State Park--Berry Slough
     Unit 3C Elijah Bristow State Park--Northeast Slough
     Unit 3D Elijah Bristow State Park Island Pond
     Unit 3E Dexter Reservoir RV Alcove--DEX3
     Unit 3F Dexter Reservoir Alcove--PIT1, Unit 3H Hospital 
Pond

[[Page 10419]]

     Unit 3I Shady Dell Pond, and
     Unit 3J Buckhead Creek.
    Although Oregon chub require some aquatic vegetation for cover and 
spawning, some areas of Oregon chub habitat are threatened by 
succession to wet meadow systems due to a lack of natural disturbance 
(such as floods) or excessive siltation. If vegetation completely fills 
in the open water areas of Oregon chub habitat, these areas are no 
longer suitable for the Oregon chub. Special management is required to 
prevent or set back vegetative succession in Unit 3G, East Fork Minnow 
Creek Pond, to alleviate this threat to the Oregon chub's aquatic 
habitat.
    Some units require special management to avoid the degradation of 
water quality in Oregon chub habitats due to agricultural chemical 
runoff. Elevated levels of nutrients and pesticides have been found in 
some Oregon chub habitats (Materna and Buck 2007, p. 67). The source of 
the contamination is likely agricultural runoff from adjacent farm 
fields (Materna and Buck 2007, p. 68). Special management will be 
needed to reduce the incursion of potentially hazardous agricultural 
chemicals into Oregon chub habitats and maintain water quality in Units 
1B(4) Gray Slough, Unit 2B(2) Dunn Wetland, and Unit 2B(4) Finley 
Cheadle Pond.
    Although Oregon chub utilize fine silty substrates, an 
overabundance of siltation resulting from activities such as logging 
poses a threat to Oregon chub habitat by filling in the shallow aquatic 
areas utilized by the species. Excess sedimentation can also lead to 
the succession of open water habitats to wet meadow, as discussed 
above. Special management to alleviate the threat posed by excess 
watershed siltation due to logging and other activities is needed in 
Unit 1B(1) Geren Island North Channel, Unit 2A(1) Russell Pond, Unit 
2B(5) Finley Gray Creek Swamp, Unit 3G East Fork Minnow Creek Pond, 
Unit 3J Buckhead Creek, and Unit 3K Wicopee Pond.
    Special management is required in several of the proposed critical 
habitat units to maintain the water quality required by Oregon chub and 
protect against the impacts of several potential threats to water 
quality. Many Oregon chub populations occur near rail, highway, and 
power transmission corridors, agricultural fields, and within public 
park and campground facilities, and there is 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, U.S. Fish and Wildlife Service 
1998, p. 14). Water quality investigations at sites in the Middle Fork 
and Mainstem Willamette subbasins have found some adverse effects to 
Oregon chub habitats caused by changes in nutrient levels. Elevated 
nutrient levels at some Oregon chub locations, particularly increased 
nitrogen and phosphorus, may result in eutrophication and associated 
anoxic conditions unsuitable for chub, or increased plant and algal 
growth that severely reduce habitat availability (Buck 2003, p. 12). 
Monitoring and special management are needed to ameliorate the effects 
of excessive nutrient levels in Oregon chub habitats, as well as 
provide protection against accidental sources of contamination to the 
extent possible, in the following units:
     Unit 1A Santiam I-5 Side Channels
     Unit 2B(5) Finley Gray Creek Swamp
     Unit 3E Dexter Reservoir RV Alcove--DEX3
     Unit 3F Dexter Reservoir Alcove--PIT1
     Unit 3G East Fork Minnow Creek Pond
     Unit 3H Hospital Pond
     Unit 3I Shady Dell Pond, and
     Unit 3J Buckhead Creek.
    Although the Oregon chub evolved in a dynamic environment in which 
frequent flooding continually created and reconnected habitat for the 
species, currently most populations of Oregon chub are isolated from 
each other 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). Historically, regulated flow 
management of flood control dams eliminated many of the slough and side 
channel habitats utilized by Oregon chub by reducing the magnitude, 
extent, and frequency of flood events in the Willamette River Basin. 
Currently, flow management activities impact Oregon chub in many of 
their remaining habitats by inadvertently raising or lowering the depth 
of water bodies to levels above or below the optimum for the species. 
Water depths in the summer may be reduced to levels that threaten the 
survival of Oregon chub due to flow management in adjacent reservoirs 
or rivers, or from natural drought cycles. Special management is 
required to ameliorate the effects of fluctuating or reduced water 
levels for the Oregon chub in:
     Unit 1A Santiam I-5 Side Channels
     Unit 1B(1) Geren Island North Channel
     Unit 1B(2) Stayton Public Works Pond
     Unit 1B(4) Gray Slough
     Unit 2A(3) Big Island
     Unit 2B(5) Finley Gray Creek Swamp
     Unit 3A Fall Creek Spillway Ponds
     Unit 3C Elijah Bristow State Park--Northeast Slough
     Unit 3D Elijah Bristow State Park Island Pond
     Unit 3E Dexter Reservoir RV Alcove--DEX3
     Unit 3F Dexter Reservoir Alcove--PIT1, and
     Unit 3I Shady Dell Pond.
    In summary, we find that each of the areas we are proposing as 
critical habitat contains features essential to the conservation of the 
Oregon chub, and that these features may require special management 
considerations or protection. These special management considerations 
and protections are required to eliminate, or reduce to a negligible 
level, the threats affecting each unit and to preserve and maintain the 
essential features that the proposed critical habitat units provide to 
the Oregon chub. A more comprehensive discussion of threats facing 
individual sites is in the individual unit descriptions.
    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 that may affect 
those unprotected areas outside of critical habitat are still subject 
to review under section 7 of the Act if they may affect Oregon chub. 
The prohibitions of section 9 against the take of listed species also 
continue to apply both inside and outside of designated critical 
habitat. Take is broadly defined in the Act as to harass, harm, wound, 
kill, trap, capture, or collect a listed species, or to attempt to 
engage in any such conduct.

Proposed Critical Habitat Designation

    The areas we are proposing as critical habitat currently provide 
all habitat components necessary to meet the primary biological needs 
of the Oregon chub, as defined by the primary constituent elements. The 
areas proposed for designation are those areas most likely to 
substantially contribute to conservation of the Oregon chub, and when 
combined with future management of certain habitats suitable for 
restoration efforts, will contribute to the long-term survival and 
recovery of the species.
    Under the Act, we can designate critical habitat in areas outside 
of the geographical area occupied by the species at the time it is 
listed only when

[[Page 10420]]

(1) the inclusion of specific areas occupied at the time of listing 
defined by the essential physical and biological factors are not 
sufficient to conserve the species; and (2) we determine that those 
areas outside the geographical area occupied by the species are 
essential for the conservation of the species.
    We have determined that 25 units totaling approximately 53 ha (132 
acres) meet our definition of critical habitat for the Oregon chub, 
including land under State, Federal, other government, and private 
ownership. Nine of the critical habitat units described below 
constitute our best assessment of areas determined to be occupied at 
the time of listing that contain the primary constituent elements and 
require special management (units 2B(5), 3B, 3E, 3F, 3G, 3H, 3I, 3J, 
3K). Because the nine occupied units do not alone contain physical and 
biological features sufficient to conserve the species, we are 
proposing an additional 16 units. The other 16 proposed units 
constitute our best assessment of areas that were not occupied or not 
known to be occupied at the time of listing but were within the 
species' historical range, which were found to be essential to the 
conservation of the Oregon chub. These additional areas include natural 
and introduced populations. The Critical Habitat Selection Criteria and 
Special Management Considerations or Protections sections above address 
why the inclusion of specific areas occupied at the time of listing 
defined by the essential physical and biological factors are not 
sufficient to conserve the species; and, for the additional 16 proposed 
units, why we determine that those areas outside the geographical area 
occupied by the species are essential for the conservation of the 
species.
Area 1: Santiam River Basin--Linn and Marion Counties, Oregon
A. Mainstem
    Unit 1A, the Santiam I-5 Side Channels: This site consists of three 
ponds totaling 1.4 ha (3.3 ac), located on a 27-ha (66-ac) property on 
the south side of the Santiam River upstream of the Interstate Highway 
5 bridge crossing in Linn County, Oregon. The areas containing Oregon 
chub include a small backwater pool, a gravel pit, and a side channel 
pond. This unit is owned by the Oregon Department of Transportation 
(ODOT) and Oregon chub were first observed here in 1997. Although only 
22 Oregon chub were counted at the site in 2007, the habitat contains 3 
of the 4 PCEs and has exhibited capability of supporting a substantial 
population of the species based on past survey population estimates of 
over 500 individuals. The maximum water depth is approximately 3 m (9.8 
ft), averaging 1.5 m (4.9 ft), and the temperature was recorded at 
between 19.5 and 21 [deg]C (60 and 67 [deg]F) on July 30, 2008. The 
substrate is composed of 80 percent silt and organic material, and 
there is a variety of emergent and submergent vegetation covering 65 
percent of the surface area. Beaver have been observed at this 
location. This site is at risk of the vegetation expanding to levels 
detrimental to Oregon chub habitat. The site is periodically connected 
to the Santiam River, and its water levels can be affected by 
hydrologic changes in the river, particularly the low summer levels 
common in the drainage. Competing and predatory nonnative species have 
been observed; nonnative predators are suspected to be a major factor 
in the drop in Oregon chub population estimates at this site between 
the 2006 and 2007 surveys (Scheerer 2008d).
B. North
    Unit 1B(1), Geren Island North Channel: This site totals 
approximately 0.8 ha (1.9 ac) and is located on the grounds of a water 
treatment facility owned by the City of Salem in Marion County, Oregon. 
The species was first observed at this site in 1996. Although only 207 
Oregon chub were counted at the site in 2008, the habitat contains 3 of 
the 4 PCEs and has exhibited capability of supporting a substantial 
population of the species based on past survey population estimates of 
over 500 individuals. The maximum water depth is 2.2 m (7.2 ft), 
averaging 1.8 m (5.9 ft), and the temperature was recorded at 26 [deg]C 
(79 [deg]F) on July 10, 2008. The substrate is composed of 90 percent 
silt and organic material, and there is a variety of emergent and 
submergent vegetation covering 65 percent of the surface area. Beaver 
have been observed at this location. The site is screened and isolated 
from other water bodies, but water levels are influenced through water 
releases at Detroit and Big Cliff Dams. Competing and predatory 
nonnative species have been observed at the site. There is also a risk 
of excess se