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CFR Citation: 50 CFR Part 17

RIN ID: RIN 1018-AU47

FWS ID: [FWS-R1-ES-2008-0072] [92210-1117-0000-FY08-B4]

NOTICE: Part III

DOCUMENT ACTION: Final rule.

SUBJECT CATEGORY: Endangered and Threatened Wildlife and Plants; Critical Habitat Revised Designation for the Kootenai River Population of the White Sturgeon (Acipenser transmontanus)

DATES: This rule becomes effective August 8, 2008.

DOCUMENT SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are revising the designation of critical habitat for the Kootenai River population of the white sturgeon (Acipenser transmontanus) (Kootenai sturgeon) under the Endangered Species Act of 1973, as amended (Act). In total, 18.3 river miles (RM) (29.5 river kilometers (RKM)) of the Kootenai River are designated as critical habitat within Boundary County, Idaho.

SUMMARY: Interior Department, Fish and Wildlife Service,

SUPPLEMENTAL INFORMATION

Home Range

The Kootenai sturgeon, listed as endangered in 1994 (September 6, 1994; 59 FR 45989), is restricted to approximately 168 RM (270 RKM) of the Kootenai River in Idaho, Montana, and British Columbia, Canada. One of 18 landlocked populations of white sturgeon known to occur in western North America, the range of the Kootenai sturgeon extends from Kootenai Falls, Montana, located 31 RM (50 RKM) below Libby Dam, Montana, downstream through Kootenay Lake to Corra Linn Dam at the outflow from Kootenay Lake in British Columbia. The downstream waters of Kootenay Lake drain into the Columbia River system. For the purposes of this rule, this portion of the Kootenai River is divided into three geomorphic reaches: (1) The canyon reach, which extends from Kootenai Falls at RM 193.9 (RKM 312.0) in Montana to RM 159.7 (RKM 257.0) below the confluence with the Moyie River in Idaho; (2) the braided reach, which begins at the end of the canyon reach and extends downstream to RM 152.6 (RKM 246.0) at Bonners Ferry; and (3) the meander reach, which extends from the end of the braided reach at RM 152.6 (RKM 246.0) downstream to the confluence with Kootenay Lake in British Columbia at RM 74.6 (RKM 120.0). This reach includes an area described as the ``transition zone'' between RM 142.7 (RKM 245.9) and RM 151.8 (RKM 244.5) that joins the braided and meander reaches.

Critical habitat is currently designated in the braided reach from RM 159.7 (RKM 257.0), below the confluence with the Moyie River, downstream to RM 152.7 (RKM 245.9) at Bonners Ferry, and continues downstream into the meander reach to RM 141.4 (RKM 228), for a total of 18.3 RM (29.5 RKM) (71 FR 6383).

The canyon reach is characterized by rocky substrates and a relatively high water surface gradient. Downstream the valley broadens, and the river forms the lowgradient ``braided reach'' as it courses through multiple shallow channels over gravel and cobbles (Barton et al. 2005, p. 19; Berenbrock 2005a, p. 7). The meander reach is characterized by primarily sandy substrate, a low watersurface gradient, a series of deep holes, and low water velocities under present river operations. A deep hole (39 to 49 feet (ft) (12 to 19 meters (m)) deep) exists near Ambush Rock at approximately 151.7 RM (RKM 244.2) (Berenbrock 2005b, pp. 78) and is frequented by sturgeon in spawning condition. Both adult and juvenile sturgeon forage in and migrate freely throughout the lower Kootenai River, but apparently no longer commonly occur upstream of Bonners Ferry, Idaho (Partridge 1983, pp. 1, 23, 25; Apperson and Anders 1990, pp. 19, 22, 23, 25; Apperson and Anders 1991, pp. 3637, 3944, 4849), although there are no apparent physical barriers to sturgeon migration within these three geomorphic reaches of the Kootenai River. However, during recovery team discussions, shallow waters in the braided reach that have occurred since construction of Libby Dam have been suggested as a possible behavioral barrier to migration into the upstream canyon reach, where suitable spawning and incubation habitats appear to exist.

Population Status and Life History

Although information is not available specifically for Kootenai sturgeon, white sturgeon in general are very longlived, with females living from 34 to 70 years; some individuals may approach or exceed 100 years of age (NatureServe 2008; PSMFC 2008). It is believed that Kootenai sturgeon do not reach sexual maturity until 28 and 30 years, respectively, for males and females (Paragamian et al. 2005, p. 525). Thereafter, females spawn at 4to 6year intervals.

The number of Kootenai sturgeon has decreased from approximately 7,000 individuals in the 1970s to fewer than an estimated 500 adults by 2005, with fewer than 30 females projected to be spawning annually after the year 2015 (Paragamian et al. 2005, p. 526). Decreases in the abundance of Kootenai sturgeon were first noted beginning in the mid 1960s. These decreases were attributed primarily to the effects of diking and pollutants (Partridge 1983, p. 42). Almost no recruitment of juveniles has been detected since 1974, soon after Libby Dam began operating (Partridge 1983, p. 28; Apperson and Anders 1991, p. 45; Paragamian et al. 2005, p. 524). The current rate of population decline is estimated to be 9 percent per year, based on annual mortality rates in the absence of significant recruitment (Paragamian et al. 2005, p. 528). The final listing rule for the Kootenai sturgeon cites the hydropower and flood control operations of Libby Dam, a U.S. Army Corps of Engineers (Corps) facility upstream in Montana, as the primary threat to the Kootenai sturgeon because these operations adversely affect spawning and incubation habitat (September 6, 1994; 59 FR 45989).

Many Kootenai sturgeon spend part of their lives in Kootenay Lake in British Columbia and migrate upstream to spawn in the Kootenai River. The sturgeon have been described as having a unique twostep prespawning migration process, migrating first from the lower river and Kootenay Lake during autumn to staging reaches in the Kootenai River, then migrating in spring to the spawning reach near Bonners Ferry, Idaho (Paragamian et al. 2001, p. 22; Paragamian et al. 2002, p. 608). Successful reproduction is dependent upon Kootenai sturgeon spawning at
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sites where the eggs can settle in an area that supports their viability, and where the free embryos that emerge from the eggs have appropriate habitat for development and protection from predators (mobile or free embryos are embryos that have hatched and still have the yolk sac attached; larvae refers to young fish that have absorbed the yolk sac and are actively feeding). For the Kootenai sturgeon, these needs appear to be met by rocky substrates for spawning and attachment of eggs, and meeting inwater minimum flow, depth, and temperature requirements on at least an intermittent basis during the spawning period from May through the end of June.

Although rocky substrates do not seem to be a cue for spawning site selection, they appear to be essential to the viability of eggs and the survival of free embryos. White sturgeon are broadcast spawners and release demersal eggs (eggs that quickly sink to the bottom) that are initially adhesive upon exposure to water (Paragamian et al. 2001, pp. 24, 27, and references therein; Anders et al. 2002, p. 73). Rocky substrates provide fixed surfaces for the attachment of the adhesive eggs during incubation and also provide shelter for the ``hiding phase,'' the period following hatching in which free embryos seek cover from predators in the intergravel spaces (Brannon et al. 1985, p. 58; Parsley et al. 2002, pp. 5859). Although we have little information specific to spawning substrates for Kootenai sturgeon, in other areas where white sturgeon are reliably reproducing and recruiting, the river bed at spawning sites typically consists of several miles of gravel, cobble, and boulder substrates that provide shelter and cover during this free embryo hiding phase. Successful spawning and incubation sites, such as the tailraces at Bonneville and Ice Harbor Dams on the Columbia River, have at least 5 RM (8 RKM) of suitable rocky substrate before transitioning into sandy substrate (Parsley et al. 1993, Table 2, p. 220 and p. 224).

White sturgeon spawn in fastflowing water, and water velocity appears to act as a cue for spawning. In the reach of the lower Columbia River immediately below Bonneville Dam, water velocity at spawning sites ranged from 2.6 to 9.2 ft per second (ft/s) (0.8 to 2.8 m per second (m/s)) (Parsley et al. 1993, Table 2, p. 220). Parsley and Beckman (1994, Figure 2, p. 815) suggest that optimal spawning conditions may occur when the mean water column velocity is 4.9 ft/s (1.8 m/s) or greater. In the Sacramento River, observed white sturgeon spawning sites had water velocities exceeding 3.3 ft/s (1.0 m/s) (Schaffter 1997, pp. 1, 113). White sturgeon spawning in fastflowing water greater than or equal to 3.3 ft/s (1.0 m/s) may experience reduced predation on eggs by limiting access of some predators to spawning and incubation areas (Brannon et al. 1985, p. 13; Miller and Beckman 1996, pp. 338339; Anders et al. 2002, p. 73 and Table 1, p. 75; Parsley et al. 2002, p. 60). Fastflowing waters also serve to maintain the exposed rocky substrate essential for successful egg incubation and the free embryo hiding phase of the Kootenai sturgeon's reproduction cycle.

Water depth also appears to be an important factor in spawning site selection for the Kootenai sturgeon. In the Columbia River, sturgeon eggs collected on mats ranged in depth from 13 to 89 ft (4 to 27 m), with median spawning depths of 19.7 to 36.1 ft (6 m to 11 m) (Parsley et al. 1993, Table 2, p. 220). In the Kootenai River, the mean depth of radiotagged white sturgeon during the spawning period was 21.3 ft (6.5 m) (Paragamian and Duehr 2005, p. 265). The mean water depth of the river during the spawning period was 30.8 15.1 ft (9.4 4.6 m) (Paragamian and Duehr 2005, p. 263). In a study based on sturgeon egg collections in the Kootenai River, Paragamian et al. 2001 (Table 2, p. 26) report average river depths at egg sites ranging from 27.9 to 42.7 ft (8.5 to 13.3 m), and eggs were found at depths ranging from 16.4 to 59 ft (5 to 18 m). Egg collection sites are likely more shallow than actual spawning sites, because high water velocity and turbulence in spawning areas may transport eggs to more shallow water (Parsley 2005, p. 1; Parsley 2006a, p. 1; Parsley 2006b, p. 1); thus, the depth at which spawning occurs is most likely greater than the depth at which eggs are found.

Although data collected on white sturgeon spawning in other areas may be considered as additional support for identifying the water depths associated with Kootenai sturgeon for spawning, we consider data specific to the environmental conditions in the Kootenai River to represent the best available scientific information for the Kootenai sturgeon. Our synthesis of the best available data specific to the Kootenai sturgeon, as described, indicates that a minimum water depth of 23 ft (7 m) is requisite for successful spawning at a level sufficient to achieve recovery.

Kootenai sturgeon spawn within a fairly narrow range of water temperatures, from 47.3 to 53.6 degrees Fahrenheit ([deg]F) (8.5 to 12 degrees Celsius ([deg]C)) (Paragamian et al. 2002, p. 27). Paragamian and Wakkinen (2002, p. 547) identify temperatures between 49.1 and 49.9[deg]F (9.5 and 9.9[deg]C), or roughly 50[deg]F (10[deg]C), as those at which spawning has the highest probability of occurring in the Kootenai River. Sudden drops of water temperature greater than 3.6[deg]F (2.0[deg]C) cause males to become reproductively inactive, thereby negatively affecting egg fertilization (Lewandowski 2004, p. 6).

Successful spawning of Kootenai sturgeon thus appears to require several synchronous environmental factors during the spawning period: the presence of sufficient rocky substrates to provide shelter for egg attachment and for normal free embryo behavior, and fastflowing (in excess of 3.3 ft/s (1.0 m/s), deep (equal to or greater than 23 ft (7.0 m)) water at a relatively stable temperature of approximately 50 [deg]F (10 [deg]C).

Although Kootenai sturgeon continue to spawn annually in the Kootenai River, this spawning has not resulted in significant levels of recruitment for over 30 years. A Kootenai sturgeon female is capable of releasing at least 100,000 eggs per spawning year, and field monitoring has shown most eggs are being fertilized (Paragamian et al. 2001, p. 26). However, based on data from 1992 through 2001, it is estimated that on average, a total of only about 10 juvenile sturgeon currently may be naturally produced in the Kootenai River annually (Paragamian et al. 2005, p. 524). The last significant sturgeon recruitment in the Kootenai River occurred in 1974, the last season prior to Libby Dam becoming fully operational in 1975 (Partridge 1983, p. 28). This recruitment failure is attributed largely to the spawning of Kootenai sturgeon over unsuitable sandy substrates (Paragamian et al. 2001, p. 29).

Since the construction of Libby Dam, most Kootenai sturgeon spawn over sandy substrates in the meander reach below Bonners Ferry. The meander reach has a low stream gradient, and substrates are composed primarily of sand and other fine materials overlying lacustrine clay (Barton 2003, p. 45; Barton et al. 2004, pp. 1, 1821). Many of the eggs that are located in this reach are found drifting along the river bottom, covered with fine sand particles in sites without rocky substrate (Paragamian et al. 2001, p. 26), and where mean water column velocities seldom exceeded 3.3 ft/s (1.0 m/s) (Paragamian et al. 2001, Table 2, p. 26; Barton et al. 2005, Table 3). The sandy substrate in the current spawning sites in the Kootenai River differs from the rocky substrate that occurs in successful
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white sturgeon spawning sites elsewhere in the Columbia River Basin (Paragamian et al. 2001, pp. 2829; Parsley et al. 1993, Table 2, p. 220 and Figure 6, p. 222; Parsley and Beckman 1994, pp. 812827; Kock et al. 2006, pp. 134135, 139 and references therein).

Laboratory experiments suggest that high embryo or larval mortality results from smothering by finesediment substrates, such as the sand that dominates the Kootenai River at the present spawning sites (Kock et al. 2006, pp. 134141). Larval white sturgeon kept in an aquarium were observed to burrow into fine sediments with lethal results (Brannon 2002, as cited in Anders et al. 2002, p. 76). Due to the predominately sandy substrate in the meander reach and its unsuitability for egg attachment, incubation, and larval survival, it is unlikely that this area was the historical spawning site for Kootenai sturgeon. However, white sturgeon hatchery releases of age 2 plus years in this area have shown high survival (Ireland et al. 2002, p. 647), indicating that the meander reach can successfully support age 2plus yearold juvenile sturgeon.

The altered hydrograph of the Kootenai River below Libby Dam has resulted in decreased water velocities and depths, with negative effects on Kootenai sturgeon reproduction. In the current sturgeon spawning sites in the meander reach, the Kootenai River is characterized by mean water column velocities less than 3.3 ft/s (1.0 m/s), as well as shifting sand substrates (Barton et al. 2004, pp. 18 21; Anders et al. 2002, Table 1, p. 75). Low water velocity is believed to be a factor facilitating predation of sturgeon eggs and free embryos in the Columbia River (Golder Associates 2005, pp. 12, 2930; Miller and Beckman 1996, pp. 338339). Free embryos emerging in low water velocities (0.8 in/s (2.0 cm/s)), such as those that presently dominate in the meander reach, remained mobile in the water column 2 days longer than did those emerging in higher water velocity (3.1 in/s (7.9 cm/s)) (Brannon et al. 1985, pp. 14, 16). This delay in initiating the free embryo hiding phase may increase the risk of mortality of embryos emerging in these waters (Brannon et al. 1985, pp. 1315).

Since Libby Dam became operational, the peak flow events in the Kootenai River at Bonners Ferry during the sturgeon spawning and incubation period have been significantly reduced (Partridge 1983, p. 3; Corps 2005, p. 9). Mean spring flows that reached 80,000 cubic feet per second (cfs) (2,265.3 cubic meters per second (cms)) prior to the construction of the dam were reduced to flows of less than 10,000 cfs (283.2 cms) through the early 1990s (Berenbrock 2005a, p. 2). The median river stage at Bonners Ferry during peak flow events in the Kootenai River during the sturgeon spawning and incubation period has been reduced by 14 ft (4.27 m) (U.S. Army Corps of Engineers 2004, Figure 25, p. 10). This is a substantial change, since the braided reach beginning at Bonners Ferry is now usually less than 7 ft (2.2 m) deep (Berenbrock 2005, p. 7). There is recent evidence that portions of the Kootenai River channel within the braided reach have become wider, shallower, and more unstable since Libby Dam became operational (Barton 2005a, p. 3, and unpublished data). Peak flows of 40,000 cfs (1,200 cms) that typically occurred during the spawning and incubation period in the Kootenai River over an average of 30 days prior to dam construction have not been reached for a period of more than 2 days since the dam was completed, with only two exceptions (Hoffman 2005a, p. 8).

In summary, natural spawning in the Kootenai River has not resulted in sufficient levels of recruitment into the aging population of the Kootenai sturgeon to reverse the strong negative population trend that has been observed over the last 30 years. This recruitment failure appears to be related to changes in riverbed substrate and reduced river flows, reduced water velocities, lowered water depths, and downstream movement of the velocity transition points with reduced flows since Libby Dam became operational. While water depth appears to be a significant factor, it is unclear how other altered parameters may be involved in causing the sturgeon to spawn primarily at sites below Bonners Ferry in the meander reach. These sites have unsuitable sandy riverbed substrates, insufficient rocky substrate (Barton 2003, pp. 1 48; Barton 2004, pp. 1821; Anders et al. 2002, pp. 73, 76), and water velocities insufficient to provide protection from predation for eggs and free embryos and to assure normal dispersal behavior among free embryos (Parsley et al. 1993, pp. 220222, 224225; Miller and Beckman 1996, pp. 338339). The braided reach provides suitable rocky substrates, but a large portion of the braided reach has become wider and shallower due to loss of energy from reduced flows, reduced backwater effects, and bed load accumulation (the accumulation of large stream particles, such as gravel and cobble carried along the bottom of the stream) (Barton et al. 2004, p. 17; Hoffman 2005, p. 9; Barton 2005a and unpublished data). The increase in bed load is a result of the broadening of the braids and water velocity reductions.

Further details on the ecology and life history requirements of the Kootenai sturgeon can be found in our final listing rule (September 6, 1994; 59 FR 45989), the recovery plan for the Kootenai sturgeon (U.S. Fish and Wildlife Service 1999), our previous final rule designating critical habitat for the Kootenai sturgeon (September 6, 2001; 66 FR 46548), and our interim rule designating critical habitat for the Kootenai sturgeon (February 8, 2006; 71 FR 6383).

Previous Federal Actions

A description of Federal actions concerning the Kootenai sturgeon that occurred prior to our September 6, 2001, final rule designating critical habitat can be found in that final rule (September 6, 2001; 66 FR 46548). That final rule designated 11.2 RM (18 RKM) of the Kootenai River in the meander reach as critical habitat, from RM 141.4 (RKM 228) to RM 152.6 (RKM 246).

On February 21, 2003, the Center for Biological Diversity filed a complaint against the Corps and the Service (CV 0329MDWM) in Federal Court in the District of Montana, stating, among other issues, that designated critical habitat for the Kootenai sturgeon was inadequate, as it failed to include areas of rocky substrate.

On May 25, 2005, the District Court of Montana ruled in favor of the plaintiffs, and remanded the critical habitat designation to the Service for reconsideration with a due date of December 1, 2005. We filed a motion to alter or amend the judgment, and the Court extended the deadline for releasing a revised critical habitat designation to February 1, 2006. In the interim, the Court ruled that the 2001 designation of critical habitat remained in effect. In response to the District Court ruling and to meet the Court's deadline, we published an interim rule designating an additional reach of the Kootenai River, the braided reach, as critical habitat for the Kootenai River sturgeon on February 8, 2006 (71 FR 6383), resulting in a total of 18.3 RM (29.5 RKM) designated; we also completed a Draft Economic Analysis of Critical Habitat Designation for the Kootenai River White Sturgeon (Northwest Economic Associates 2006) and the Final Economic Analysis of Critical Habitat Designation for the Kootenai River White Sturgeon (ENTRIX, Inc. 2008; ENTRIX was formerly Northwest Economic Associates). Although the interim rule designating critical habitat for the Kootenai sturgeon constituted a final
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rule with regulatory effect, it also opened a comment period on the substance of the rule. This revised final rule considers and incorporates, where appropriate, the comments received on the interim rule.

We solicited comments from species experts and the public on the interim rule and the draft economic analysis. A summary of these comments and our responses follow.

Summary of Comments and Recommendations

We requested comments from the public on the interim rule's designation of critical habitat for the Kootenai sturgeon and the associated draft economic analysis during a comment period that opened concurrent with the publication of the interim rule on February 8, 2006 (71 FR 6383), and closed on April 10, 2006. In addition, we held an information meeting and public hearing in Bonners Ferry, Idaho, on March 16, 2006. We contacted appropriate Federal, State, and local agencies and Tribes; scientific organizations; and other interested parties and invited them to comment on the interim rule and draft economic analysis during this open comment period.

We received six comments during the comment period and public hearing, all from organizations or individuals. We did not receive any comments from State or Federal agencies or Tribes. In addition, in accordance with our peer review policy published on July 1, 1994 (59 FR 34270), we solicited expert opinions from five knowledgeable individuals with scientific expertise that included familiarity with the Kootenai sturgeon, the geographic region where the species occurs, and conservation biology principles. All five of the individuals we contacted responded.

We reviewed all comments received from the public and the peer reviewers for substantive issues and new information regarding the designation of critical habitat for the Kootenai sturgeon. All substantive information provided from the public and the peer reviewers has been either incorporated directly into this final rule or addressed in the following summary.

Peer Reviewer Comments

1. Comment: Both the braided channel and the canyon reach are essential to the conservation of the Kootenai sturgeon. Without these areas, it is difficult to understand how natural recruitment of the magnitude and frequency required to recover the sturgeon can occur.

Our Response: We have included the braided channel in this revised final critical habitat designation because it is essential to successful spawning and egg attachment and incubation, which are currently the life stages we believe are limiting natural recruitment of Kootenai sturgeon. There is limited information on whether, or how, Kootenai sturgeon use the canyon reach. Information available at this time indicates the canyon reach has the elements necessary to support Kootenai sturgeon spawning, but the fish do not currently appear to use the area for this purpose. We are willing to consider any additional information demonstrating that the canyon reach is essential to the conservation of the Kootenai sturgeon.

2. Comment: The background information regarding the need for a sustained increase in river discharge from Libby Dam to restore natural spawning habitat conditions is compelling.

Our Response: We identified the primary constituent elements (PCEs) of Kootenai sturgeon critical habitat based on the best available scientific information, including a flow regime during the spawning season that approximates natural variable conditions.

3. Comment: The rule indicates that Kootenai sturgeon spawning and the initial three weeks of life are the most important stage to protect, but does not elaborate on why this period was selected. The commenter offered that while critical data are lacking, their experience and that of many other sturgeon researchers suggest that yearclass strength and recruitment is established by the end of the larval life interval, which for white sturgeon occurs at about day 55 65, not day 21.

Our Response: In designating critical habitat, we consider those physical and biological features that are essential to the conservation of the species, and within areas occupied by the species at the time of listing, that may require special management considerations or protections. Current data indicate that the population bottleneck that is limiting Kootenai sturgeon recovery is at the egg attachment and incubation life phase (Paragamian et al. 2001, pp. 2233; Paragamian et al. 2002, pp. 608, 615); thus we have concentrated on this stage as the most important life phase to protect. We are not aware of data indicating that the larval period between day 21 and day 65 is currently limiting Kootenai sturgeon recovery and is in need of special management. We are willing to consider additional information in this regard.

4. Comment: The background information states that fertilized eggs will be deposited just downstream of the spawning site; yet, no data are given to support this conclusion. The information on spawning of adults in deep pools with high water velocities suggest most eggs will not be at the spawning site and that eggs could be distributed downstream for several kilometers, as happens during white sturgeon spawning in the Columbia River.

Our Response: We agree with the peer reviewer that fertilized eggs can drift downstream and may not remain immediately below the spawning site. In the interim rule published in the Federal Register on February 8, 2006 (71 FR 6383), we state, ``The linear downstream extent of rocky substrate from spawning sites is also important because eggs and free embryos are dispersed downstream by the current.''

5. Comment: The rule shows designated critical habitat ending at RM 141.4, which does not include all of the prespawning staging reach of adults (RM 125152). Furthermore, no estimate of the length of river reach needed downstream of existing spawning areas for rearing of egg larvaejuvenile life intervals is provided. Given recently documented dispersal behavior of Kootenai sturgeon during early life intervals, there is not one discrete rearing reach but, instead, a long reach downstream from egg deposition used for rearing of free embryos and larvae. Dispersal likely places early juveniles many miles (kilometers) downstream from the spawning site.

Our Response: We agree with the peer reviewer that areas downstream from the critical habitat designation are important for the pre spawning staging of adult Kootenai sturgeon and rearing of free embryos, larvae, and juveniles. However, the best available scientific information indicates that spawning and egg attachment and incubation are the limiting life stages of Kootenai sturgeon population growth (Paragamian et al. 2001, pp. 2233; Paragamian et al. 2002, pp. 608, 615). Therefore, this final rule focuses solely on these life stages and the physical and biological features essential to support these life stages that may require special management.

6. Comment: Research data specific to the Kootenai River supports increasing the primary constituent element for water depth to a minimum of 23 ft.

Our Response: We concur. The preponderance of applicable scientific information from the Kootenai River and elsewhere in the range of white sturgeon where reproduction is successfully occurring suggests a mean [[Page 39510]]
water depth of at least 23 ft (7 m) is necessary for a level of spawning that could potentially lead to recovery (Parsley et al. 1993, Table 2, p. 220; Parsley 1995, p. 1; Parsley and Kappenman 2000, Table 1, p. 199; Paragamian et al. 2001, pp. 28, 30; Golder and Associates 2005, Table 4.1, p. 59 and Table 4.4, p. 62; Barton et al. 2005 p. 37; Paragamian and Duehr 2005, Figure 2, pp. 264265; Parsley 2006a, p. 1; Parsley 2006b, p. 1). Based on public comments and other information received, a second round of peer review comments was sought specifically on the primary constituent elements for water depth and changes in water temperature associated with spawning behavior. We received five responses, all of which addressed a spawning site depth criterion of at least 23 ft (7 m). These reviewers acknowledged that this criterion is well supported by data on sites within the range of white sturgeon where reproduction is occurring. Based on the reconsideration of the data, along with public and peer review comments, we have changed the primary constituent element for water depth from a minimum of 16 ft (5 m) (February 8, 2006; 71 FR 6383) to 23 ft (7 m) in this final rule.

7. Comment: Regarding the depth Primary Constituent Element (PCE), there are examples of white sturgeon in other river systems utilizing shallow water habitat. For example, sturgeon were observed rolling in a shallow side channel and embryos and larvae were then collected in that side channel of the Fraser River, British Columbia, Canada (see Perrin et al. 1999).

Our Response: The lower Fraser River is an area where white sturgeon continue to reproduce regularly. Perrin et al. (1999, p. iv) noted that waters of the mainstem Fraser River in the vicinity of the Minto channel are approximately 33 ft (10 m) deep, and that they had no actual sturgeon spawning observations in their study. Two eggs were collected at one location in the adjacent Minto channel at a depth of 9.8 ft (3 m), and where water velocity was 4.3 ft/s (1.3 m/s). Based on observations by Parsley (2005, p. 1; 2006a, p. 1; 2006b, p. 1), when water velocity is high, some sturgeon eggs may be redistributed to shallower sites prior to attachment on substrate. A single female may release more than 100,000 eggs in a spawning event. Therefore, we believe that the presence of only two eggs found at a depth of 9.8 ft (3 m) in the Minto channel of the Fraser River may be anomalous and not useful in defining minimum spawning habitat water depth. Furthermore, the comment is based primarily on the capture sites of 20 free embryos; free embryos are mobile upon hatching (Perrin et al. 1999, p. iii), and are therefore an unreliable indicator of actual sturgeon spawning sites.

8. Comment: The derivation of the 5mile linear extent of the PCE involving rocky substrate is not cited.

Our Response: We have identified 5 miles (8 kilometers) as a minimum length of continuous rocky substrate based on observations of minimum habitat conditions at similar sites below Bonneville and Ice Harbor Dams where white sturgeon are known to reproduce annually. Although the authors do not explicitly state the linear extent of the rocky substrate utilized in these areas, this information is derived from the observations of spawning locations, water velocity, and substrate use provided in Parsley et al. 1993.

Comments from the Public

1. Comment: The February 8, 2006, critical habitat interim rule (71 FR 6383) was legally deficient because it failed to alert the public that a significant practical effect or goal of the critical habitat designation is increasing the level of Kootenay Lake in British Columbia.

Our Response: The February 8, 2006, interim critical habitat rule included a section on special management considerations documenting that ``threats to the braided reach include shallow water depths'' (71 FR 6388). The public was advised that appropriate special management would include measures to provide for water depths during the sturgeon spawning season that would provide for the conservation needs of the species. The operation of Kootenay Lake is outside the control of Federal agencies and the Service; nothing in the critical habitat designation has the legal effect of requiring Canadian authorities to raise the level of the lake.

2. Comment: The Service should have prepared an environmental document under the National Environmental Policy Act (NEPA) analyzing the effect of the critical habitat designation. The court opinion that held that NEPA is not applicable to critical habitat designations is limited to its facts and should not apply to the Kootenai sturgeon critical habitat.

Our Response: The Ninth Circuit, in Douglas County v. Babbitt, 48 F.3d 1495 (9th Cir. 1995) (Douglas County), held that NEPA is inapplicable to critical habitat designations. We contend that the court's opinion in Douglas County contained no intention to limit the holding to that specific situation. The opinion speaks in broad terms that apply to any critical habitat designation, explaining that requiring a NEPA analysis would be inconsistent with, or redundant to, Act requirements for designating critical habitat. The court explained: ``The purpose of the ESA [Act] is to prevent extinction of species, and Congress has allowed the Secretary to consider economic consequences of actions that further that purpose. But Congress has not given the Secretary the discretion to consider environmental factors, other than those related directly to the preservation of the species. The Secretary cannot engage in the very broad analysis NEPA requires when designating a critical habitat under the ESA [Act]'' (48 F.3d at 1507).

The court concluded that ``the legislative histories of NEPA and the ESA (Act) likewise indicate that Congress did not intend that the Secretary file an Environmental Impact Statement (EIS) before designating a critical habitat'' (48 F.3d at 1507).

3. Comment: The draft economic analysis is defective because it does not factor in the increased level of Kootenay Lake that may be necessary to achieve desired river depths for sturgeon, and the impacts of higher lake levels are likely to have enormous economic consequences. No information regarding any costs above the amount that might be expected as a result of higher Kootenay Lake levels was provided.

Our Response: The level of Kootenay Lake is controlled by Canadian authorities; critical habitat designation has no legal effect on the actions of a foreign government. The draft economic analysis included an estimate of the cost of crop damage that might be expected as a result of flows required for Kootenai sturgeon recovery.

4. Comment: The critical habitat designation would result in higher water tables and an increased risk of flooding, which would be a compensable taking of private property under the Fifth Amendment. In addition, a potential ``relative benefits'' defense by the Service, where the landowner incurs both harm and benefits that must be weighed against each other, would not apply because no relative benefits would be imparted by critical habitat designation.

Our Response: Designation of critical habitat imposes no direct regulatory burden on private parties; it requires Federal agencies to insure that actions that they authorize, fund, or carry out, do not adversely modify designated habitat (16 U.S.C. 1536(a)(2)). A private party with a Federal grant or permit that constitutes a ``nexus'' for purposes of the Act's section 7 might bear an
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indirect regulatory burden as a result of a critical habitat designation. Courts assess takings claims based on the degree of impairment of the property interest, the owner's reasonable expectations, and the importance of the government interest being advanced. In light of these factors, we believe that no compensable taking will occur as a result of designation of critical habitat.

5. Comment: The Service violated the Act by promulgating the interim rule without the requisite 90day notice as is indicated under section 4(b)(5) of the Act.

Our Response: We were under a court order to issue a critical habitat rule for Kootenai sturgeon by a specific date, and the schedule imposed by the court made it impracticable to issue a proposed rule prior to a final rule. We acknowledge that section 4(b)(5) of the Act requires a 90day advance notice before the effective date of a final rule. However, we believe that we remedied the situation as well as possible by seeking both public and peer review comments on the interim rule and reconsidering it in light of those comments, as we are doing here. In the declaration that accompanied our motion to amend the court's May 25, 2005, judgment, we explained that the timeline given by the court to issue a new final rule was insufficient to complete a legally proper and welljustified revision of critical habitat.

Under these circumstances, we have determined under 5 U.S.C. 553(b)(3)(B) that we had good cause to issue the interim rule without prior opportunity for public comment because prior notice and public procedure would have been impracticable. From the time required to research the interim rule, we did not have sufficient time to issue a proposed rule, open a reasonable comment period, and subsequently issue a final rule prior to the courtimposed deadline. Therefore, without issuance of an interim rule, we would have been in violation of the court order. Thus, in effect, the interim rule served as the proposed rule for this revised final rule, and the Service treated the interim rule as the proposed rule for the purpose of complying with ESA Sec. 4(b)(5).

6. Comment: The Service has failed to acknowledge the need for special management to address PCEs that may not be fully available at all times or places within designated critical habitat.

Our Response: This final rule designates critical habitat within the braided and meander reaches of the Kootenai River that will require special management to restore functional water depth, flow timing, and water temperature. At this time, these PCEs are intermittently present within these reaches of the Kootenai River.

7. Comment: The Service used flawed reasoning in stating that Libby Dam is part of the environmental baseline, and thus that its continued operation will not result in adverse modification of critical habitat. The commenter further stated that the operations of Libby Dam are widely acknowledged as being the primary reason the sturgeon is headed toward extinction, and the reason why the sturgeon fails to spawn in the braided reach.

Our Response: The Service's use of the term ``environmental baseline'' is restricted to the section 7 compliance process under the Act. In that context, the future effects of Libby Dam operations on the Kootenai sturgeon and its critical habitat are not part of the environmental baseline. The Service defines the term ``environmental baseline'' as ``* * * the past and present impacts of all Federal, State, or private actions and other human activities in the action area, the anticipated impacts of all proposed Federal projects in the action area that have already undergone formal or early section 7 consultation, and the impact of State or private actions which are contemporaneous with the consultation in process.'' On that basis, the effects of Libby Dam construction and past operations on the Kootenai sturgeon and its critical habitat are part of the environmental baseline.

At the time the sturgeon was listed and critical habitat was designated, all future operations of Libby Dam were subject to the jeopardy and adverse modification of critical habitat standards under section 7(a)(2) of the Act. Because the action of constructing the dam was completed in 1973, the continued presence of the dam is not an action subject to the requirements of section 7 of the Act. However, the effects of future operations on listed species and critical habitat are subject to the requirements of section 7 of the Act. Subsequently, we completed formal consultations with the Corps, Bureau of Reclamation (BOR), and the Bonneville Power Administration (BPA) on the effects of Libby Dam operations on the sturgeon in 1995, 2000, and 2006; our 2006 Biological Opinion (BO) on the effects of Libby Dam operations on the Kootenai sturgeon also addressed the effects of dam operations on designated critical habitat (USFWS 2006b). The latter two consultations resulted in BOs in which we concluded that future operations of Libby Dam, as proposed by the Federal action agencies, were likely to jeopardize the continued existence of the sturgeon and adversely modify its critical habitat.

In accordance with our regulations, we included a Reasonable and Prudent Alternative (RPA) to the proposed operation of Libby Dam that would avoid jeopardy and adverse modification in our 2006 BO. The Corps, as operator of Libby Dam, and BPA, as marketer of the hydropower generated at Libby Dam, are currently implementing the RPA.

8. Comment: The current designation of critical habitat, which includes only the river to the high water mark, improperly excludes side channel habitats.

Our Response: The braided reach of the Kootenai River designated as critical habitat includes several side channels that, because of their structure and condition, function as both foraging and spawning habitat for the Kootenai sturgeon. These areas have not been excluded from the designation.

9. Comment: If in the future it is found that designation of this critical habitat is not necessary, what process is there for removing it from critical habitat?

Our Response: Section 4(a)(3)(A) of the Act and implementing regulations at 50 CFR 424.12 require that ``critical habitat shall be specified to the maximum extent prudent and determinable.'' Critical habitat is considered not prudent when the identification of critical habitat can be expected to increase the degree of threat from taking or other human activity, or if the designation of critical habitat would not be beneficial to the species. In the absence of a ``not prudent'' finding, the Act requires that we designate critical habitat for listed species. The Act does provide that critical habitat designations may be revised, as appropriate. Any revisions would occur through the rulemaking process.

10. Comment: Hopefully, this designation will not affect the private gravel operations that take place upstream of the designated area.

Our Response: The effect of a critical habitat designation is that activities authorized, funded, or carried out by a Federal agency require consultation under section 7 of the Act to ensure that they are not likely to destroy or adversely modify critical habitat. For example, activities on private or State lands requiring a permit from a Federal agency, such as a permit from the Corps under section 404 of the Clean Water Act, a section 10(a)(1)(B) permit from us, or some other Federal action, including funding (for example, Federal Highway Administration or Federal Emergency Management Agency funding), would be subject to the
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section 7 consultation process. Activities on State, Tribal, local, or private lands that are not carried out, funded, or authorized by a Federal agency are not subject to any regulatory requirements as a result of critical habitat designation. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area, and the designation of critical habitat does not allow government or public access to private lands.

Summary of Changes from the Interim Rule

In developing this revised final critical habitat rule for the Kootenai sturgeon, we reviewed peer review and public comments received on the interim rule and draft economic analysis published in the Federal Register on February 8, 2006 (71 FR 6383), as well as a second round of peer review comments received specifically on the PCEs. Based on comments received, including peer review comments, this final rule modifies the interim rule in the following ways:
(1) We have made the PCEs more explicit to more clearly communicate the best available scientific information regarding the conservation needs of the species.
(2) We have modified the depth PCE (PCE 1) from a minimum of 16 ft (5 m) to a minimum of 23 ft (7 m) to more accurately reflect the best available science, indicating that mean water depth of at least 23 ft (7 m) is necessary for spawning site selection by white sturgeon in the Kootenai River (for example, Paragamian et al. 2001, Table 2, p. 27, p. 29, and Figure 4, p. 29; Paragamian and Duehr 2005, p. 263, 265; Parsley 2006a, p. 1; Parsley 2006b, p. 1).
(3) In the interim rule, we stated that we added 6.9 RM (11.1 RKM) to the critical habitat designation, but later stated that this additional reach extends from ``RM 159.7 (RKM 257) to RM 152.6 (RKM 245.9),'' which is actually 7.1 RM. The area designated as critical habitat in the interim rule remains unchanged in this revised final rule. This final rule simply corrects the RM totals to indicate that we added 7.1 RM to our 2001 designation of 11.2 RM, for a total of 18.3 RM.
(4) We have combined the two former units, the braided reach and the meander reach, into a single designation because the two units are contiguous, and clarified the location of the river reaches within the designation:
(i) The braided reach begins at RM 159.7 (RKM 257.0), below the confluence with the Moyie River, and extends downstream within the Kootenai River to RM 152.6 (RKM 246.0) below Bonners Ferry. (ii) The meander reach begins at RM 152.6 (RKM 246.0) below Bonners Ferry, and extends downstream to RM 141.4 (RKM 228.0) below Shorty's Island.
(iii) This designation includes the 0.9 mi (1.5 km) ``transition zone,'' described in the February 2006 interim rule (71 FR 6383) that joins the meander and braided reaches at Bonners Ferry.

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 an endangered 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 resource 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 private landowners. Where a landowner 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) would apply, but even in the event of a destruction or adverse modification finding, the landowner'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 of listing must contain the physical and biological features essential to the conservation of the species, and 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 data available, habitat areas that provide essential life cycle needs of the species. Under the Act, 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.

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 Fiscal Year 2001 (Pub. L. 106554; 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 proposed as critical habitat, our primary source of information is generally the information developed during the listing process for the species. Additional information sources include the recovery plan for the species, if available; articles in peerreviewed 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.

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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 to be 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 promote the recovery of the species.

Areas that support populations, but are outside the critical habitat designation, will continue to be subject to conservation actions. 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 available information at the time of the action. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may require consultation under section 7 of the Act and 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, or other species conservation planning efforts if information available at the time of these planning efforts calls for a different outcome.

Primary Constituent Elements

In accordance with section 3(5)(A)(i) of the Act and the regulations at 50 CFR 424.12, in determining which areas occupied at the time of listing to propose as critical habitat within areas occupied by the species at the time of listing, we consider the physical and biological features that are essential to the conservation of the species to be the primary constituent elements 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, or other nutritional or physiological requirements;
(3) Cover or shelter;
(4) Sites for breeding, reproduction, rearing of offspring, germination, or seed dispersal;
(5) Habitats that are protected from disturbance or are representative of the historical geographical and ecological distributions of a species.

As required by 50 CFR 424.12(b)(5), we are to list the known PCEs with our description of critical habitat. The PCEs provided by the physical and biological features upon which the designation is based may include, but are not limited to, the following: roost sites, nesting grounds, spawning sites, feeding sites, seasonal wetland or dryland, water quality or quantity, host species or plant pollinator, geological formation, vegetation type, tide, and specific soil types. Primary Constituent Elements for the Kootenai Sturgeon

We identified the PCEs for Kootenai sturgeon critical habitat based on our knowledge of the life history, biology, and ecology of the species, and the physical and biological features of the habitat necessary to sustain its essential life history functions, as described in the Background section of this rule. We are changing the PCEs from those identified in our critical habitat interim rule (February 8, 2006; 71 FR 6383) to better fit our current understanding of the features needed to support the sturgeon's life history functions, and to reflect the information received from peer review and public comment.

This designation focuses solely on spawning and rearing habitats, the factors that we understand to be currently limiting to sturgeon conservation (Paragamian et al. 2001, pp. 2233; Paragamian et al. 2002, pp. 608, 615). All of the following PCEs must be present during the spawning and incubation period for successful spawning, incubation, and embryo survival to occur. However, although the PCEs to support successful spawning must occur simultaneously in time and space, it is not necessary for them to be present through the entire spawning period, nor must they be present throughout the entire designated area. The PCEs are:
(1) A flow regime, during the spawning season of May through June, that approximates natural variable conditions and is capable of producing depths of 23 ft (7 m) or greater when natural conditions (for example, weather patterns, water year) allow. The depths must occur at multiple sites throughout, but not uniformly within, the Kootenai River designated critical habitat.
(2) A flow regime, during the spawning season of May through June, that approximates natural variable conditions and is capable of producing mean water column velocities of 3.3 ft/s (1.0 m/s) or greater when natural conditions (for example, weather patterns, water year) allow. The velocities must occur at multiple sites throughout, but not uniformly within, the Kootenai River designated critical habitat. (3) During the spawning season of May through June, water temperatures between 47.3 and 53.6 [deg]F (8.5 and 12 [deg]C), with no more than a 3.6 [deg]F (2.1 [deg]C) fluctuation in temperature within a 24hour period, as measured at Bonners Ferry.
(4) Submerged rocky substrates in approximately 5 continuous river miles (8 river kilometers) to provide for natural free embryo redistribution behavior and downstream movement.
(5) A flow regime that limits sediment deposition and maintains appropriate rocky substrate and intergravel spaces for sturgeon egg adhesion, incubation, escape cover, and free embryo development. Note: the flow regime described above under PCEs 1 and 2 should be sufficient to achieve these conditions.

This critical habitat designation is focused on Kootenai sturgeon spawning habitats and egg attachment and egg incubation habitats, as these areas are currently the limiting habitat components essential to Kootenai sturgeon conservation (Paragamian et al. 2001, pp. 2233; Paragamian et al. 2002, pp. 608, 615). Maintaining the PCEs in this designated area is consistent with our recovery objective to re establish successful natural recruitment of Kootenai sturgeon (U.S. Fish and Wildlife Service 1999, p. iv). However, the presence of PCE components related to flow, temperature, and depth are dependent in large part on the amount and timing of precipitation in any given year. These parameters vary during and between years, and at times some or all of the parameters are not present in the area designated as critical habitat. Within the critical habitat reaches, the specific conditions are variable due to a number of factors such as snowmelt, runoff, and precipitation. This designation recognizes the natural variability of these factors, and does not require that the PCEs be available yearround, or even every year during the spawning period. At present, the PCEs are achieved only infrequently, such as in 2006 during the ``stacked flow'' operations when the Kootenai River reached river stage 1,763.61 MSL (feet above mean sea level; 537.5 m) at Bonners Ferry (Corps 2007, p. 6), resulting in the first documented movement of tagged female Kootenai sturgeon into the braided reach above Bonners Ferry (Kootenai Sturgeon Recovery Team 2006, pp. 12). The designation means that sufficient PCE components to support successful spawning must be present and protected during the spawning season of May through June at multiple sites throughout, but not uniformly within,
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the Kootenai River designated critical habitat in all years when natural conditions (for example, weather patterns, water year) make it possible.

Special Management Considerations or Protections

When designating critical habitat, we assess whether the areas occupied by the species at the time of listing contain the physical and biological features essential to the conservation of the species, and whether these features may require special management consideration or protections. In this case, the threats to the physical and biological features in the area designated as critical habitat that may require special management considerations or protections include shallow water depths (loss of deeper water habitat), low water velocities, and sudden drops in water temperature that adversely affect Kootenai sturgeon breeding behavior.

Both of the designated reaches provide the physical and biological features that are essential to the Kootenai sturgeon for spawning, egg attachment, incubation, and juvenile rearing, and both require special management to ensure that the appropriate water depths, velocities, and temperature are achieved during the spawning period in all years when natural conditions allow.

Libby Dam is operated by the Corps to meet a variety of needs, including power production, flood control, recreation, and special operations for the recovery of species listed under the Act, including Kootenai sturgeon, bull trout, and salmon in the lower Columbia River. The Corps currently operates the dam so as not to exceed 1,764 MSL at Bonners Ferry, Idaho (the flood stage designated by the National Weather Service for the purposes of flood protection). However, flood stage can be exceeded due to unexpected increased inflow to Libby Dam or due to tributary flows downstream of Libby Dam (U.S. Fish and Wildlife Service 2006b, p. 5). The Corps has noted that it considers 1,764 MSL to be the ``current target river stage for Libby Dam operations'' (Corps 2007, p.1).

The Corps conducted a stacked flow operation in spring 2006 to test different flow strategies for meeting the habitat attributes identified for the Kootenai sturgeon in the Service's 2006 BO on the effects of Libby Dam operations on the Kootenai sturgeon and its critical habitat (U.S. Fish and Wildlife Service 2006b). The stacked flow operation was developed to utilize Libby outflows at full powerhouse capacity (25,000 cfs) and temperature control at the dam (to the extent possible) such that releases were timed to ``stack'' on local tributary inflows to provide velocities, depth, and temperature conditions specified in the BO. The operation, initiated in May 2006, controlled releases from the dam as much as possible to provide the appropriate temperature for sturgeon migration and spawning (Corps 2006, p. 5). This stacked flow operation demonstrated that the Corps was able to achieve depth in the middle of the channel, continuously exceeding 23 ft (7m) as far upstream as RM 153.1, with some areas exceeding 39 ft (12 m) between RM 152 and 157, at flows below flood stage (Corps 2007, p. 6).

We recognize that, due to existing morphologic constraints and limitations at Libby Dam, the depth PCE described in this rule (23 ft; 7 m) is currently not achievable on an annual basis in the braided reach. Since the construction of Libby Dam and the subsequent altered hydrograph, the braided reach has become shallower and wider (Barton 2005a, unpublished data), thus limiting the ability to achieve the depth PCE in the braided reach in most years. To address this issue, the Kootenai Tribe of Idaho, in cooperation with regional partners and Federal managers, is pursuing the Kootenai River Ecosystem Restoration Project. This restoration project has as one of its goals to ``restore and maintain Kootenai River habitat conditions that support all life stages'' of Kootenai sturgeon. The objectives of the project include (but are not limited to): adjusting ``the dimension, pattern, and profile of the river * * * to match current flow, hydraulic, and sediment transport regimes resulting from the construction and operation of Libby Dam''; and addressing ``depth requirements'' of Kootenai sturgeon (Kootenai Tribe of Idaho 2008, p. 4). Until this project is implemented, we recognize that the ability to meet the depth PCE in the braided reach is limited. However, we also acknowledge that the depth PCE has been achieved intermittently under current operating conditions (stacked flows in 2006).

Criteria Used To Identify Critical Habitat

As required by section 4(b)(1)(A) of the Act, we used the best scientific and commercial information available in determining those areas that were occupied by the species at the time of listing and contain PCEs in the quantity and spatial arrangement to support life history functions essential for the conservation of the species in our designation of critical habitat. We relied on information in our prior rulemaking, our recovery plan, more recent information on the biological needs of the species summarized in our 2006 interim rule designating critical habitat for the Kootenai sturgeon (71 FR 6383), and new information gained through the peer review and public comment process on that interim rule.

We have also reviewed available information that pertains to habitat requirements of this species. The materials included data and analysis in section 7 consultations and gathered by biologists holding section 10(a)(1)(A) recovery permits; research published in peer reviewed articles and presented in academic theses and agency reports; original data sets and data analyses; and accounts of involved scientists and resource managers.

This designation focuses solely on those life stages that are, based on the best available scientific information, limiting productivity (that is, spawning and egg attachment and incubation), which is the limiting demographic parameter relative to Kootenai sturgeon population recovery. Using this framework, we selected those areas where sturgeon currently spawn in the meander reach; areas with appropriate rocky substrates in the braided reach where sturgeon may be expected to spawn successfully under the appropriate temperature, depth, and flow conditions; and those areas downstream of spawning sites that are essential for egg attachment and incubation. Final Revised Critical Habitat Designation

We are designating approximately 18.3 RM (29 RKM) of the Kootenai River as revised critical habitat within Boundary

FOR FURTHER INFORMATION CONTACT Susan Martin, Field Supervisor, Upper Columbia Fish and Wildlife Office (see ADDRESSES). If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 8008778339.