Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for Santa Ana Sucker

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2009-0072; 92210-1117-0000-B4]

RIN 1018-AW23

Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for Santa Ana Sucker

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), designate critical habitat for Santa Ana sucker (

Catostomus santaanae

) under the Endangered Species Act of 1973, as amended. In total, approximately 9,331 acres (3,776 hectares) of habitat in the Santa Ana River in San Bernardino, Riverside, and Orange Counties and the San Gabriel River and Big Tujunga Creek in Los Angeles County in southern California fall within the boundaries of the critical habitat designation. This final revised designation constitutes an overall increase of approximately 1,026 acres (415 hectares) from the 2005 designation of critical habitat for Santa Ana sucker.

DATES:

This rule becomes effective on January 13, 2011.

ADDRESSES:

This final rule and the associated final economic analysis are available on the Internet at

http://www.regulations.gov

and

http://www.fws.gov/carlsbad/.

Comments and materials received, as well as supporting documentation used in preparing this final rule are available for public inspection, by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Carlsbad Fish and Wildlife Office, 6010 Hidden Valley Road, Suite 101, Carlsbad, CA 92011; telephone 760-431-9440; facsimile 760-431-5901.

FOR FURTHER INFORMATION CONTACT:

Jim Bartel, Field Supervisor, U.S. Fish and Wildlife Service, Carlsbad Fish and Wildlife Office, 6010 Hidden Valley Road, Suite 101, Carlsbad, CA 92011; telephone 760-431-9440; facsimile (760) 760- 431-5901. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

It is our intent to discuss only those topics directly relevant to the development and designation of revised critical habitat for Santa Ana sucker in this final rule. In the proposed rule (74 FR 65056; December 9, 2009) and the document that made available the draft economic analysis (DEA) (75 FR 38441; July 2, 2010), we stated that there was new information on the distribution of Santa Ana sucker and its habitat within the Santa Ana River that we did not discuss in the 2005 final critical habitat designation for this species (70 FR 425; January 4, 2005). As a result of public comments on this new information, we are providing clarification of this information in the Habitat and Geographic Range and Status sections of this final rule. Additionally, we incorporated information from recent surveys in the Santa Ana River (

see

Geographic Range and Status section) and new information on the hydrology and flow regime of the Santa Ana River (

see

Sites for Breeding, Reproduction, and Rearing (or Development) of Offspring section). No new information pertaining to the species' description, life history, or ecology was received following the 2009 proposed revised rule and the document that made available the DEA. For more information on Santa Ana sucker, refer to the final listing rule published in the

Federal Register

on April 12, 2000 (65 FR 19686); the designation and revision of critical habitat published in the

Federal Register

on February 26, 2004 (69 FR 8839), and on January 4, 2005 (70 FR 425), respectively; the proposed revised critical habitat published in the

Federal Register

on December 9, 2009 (74 FR 65056); and the document that made available the DEA published in the

Federal Register

on July 2, 2010 (75 FR 38441).

Habitat

As discussed in detail in the Habitat section of the proposed revised critical habitat rule (74 FR 65056; December 9, 2009), Santa Ana sucker requires various substrate types throughout different stages of its life. The presence of coarse substrates, including gravel, cobble, and a mixture of gravel or cobble with sand, and a combination of shallow riffle areas and deeper runs and pools provide optimal stream conditions (Haglund

et al.

2001, p. 60; Haglund and Baskin 2003, p. 55). Areas of shifting sandy substrates are less suitable for development of algae, an important food source for suckers (Saiki

et al.

2007, p. 98). Therefore, an integrated water system that contains and provides the appropriate quantity of coarse substrates such as gravel, larger cobbles, or boulders that provide the space for reproductive development and growth of algae as a primary food source is important for a viable population of Santa Ana suckers.

Saiki

et al.

(2007, p. 98) indicates that the San Gabriel River supports higher body condition Santa Ana suckers (as described by their higher length-weight relationship) and greater availability of various habitat types than the Santa Ana River. They state that the San Gabriel River generally contains a higher abundance of Santa Ana suckers and larger individuals, which may be attributed to more suitable habitat characters such as cooler water temperature, intermediate water velocities, and commonality of pools and riffles with coarser bottom substrates, all of which may contribute to a better functioning system and more suitable habitat for Santa Ana suckers (Saiki

et al.

2007, pp. 99-100).

In the San Gabriel River, there are some distinct differences between the three forks of the river (north, west, and east), which seem to correlate with both fish abundance and life stage occupancy (Tennant 2006, pp. 4-5, 9). Overall, the water condition (

i.e.,

lower temperature, lower specific conductance, and lower turbidity) and habitat available in the San Gabriel River system appear to be primary reasons that Santa Ana suckers are in higher abundance and better condition compared to those in the Santa Ana River, although other variables (

i.e.,

stream width or depth) may also influence the species' abundance and condition. For example, in the Santa Ana River, the predominate riparian vegetation is the nonnative species

Arundo donax

(giant reed). In Big Tujunga Creek,

A. donax

can be common in the lower reaches (Baskin and Haglund 1999, p. 11; Saiki 2000, pp. 62-80). In the San Gabriel River, this nonnative plant is rarely found, and the riparian vegetation consists of primarily native vegetation or may be bare due to the steeper, mountainous terrain (Saiki 2000, pp. 18-19; Saiki

et al.

2007, p. 90). Native riparian vegetation provides cover and shelter from predators, which is essential for juvenile and adult Santa Ana suckers (

see

Primary Constituent Elements—Cover and Shelter and Primary Constituent Elements for Santa Ana Sucker below).

Arundo donax

is an aquatic plant in the genus of perennial reed-like grasses (Poaceae) and is often found growing along lakes, streams, and other wetted areas. Compared to other riparian vegetation, it is known to use excessive amounts of water to supply its exceptionally high growth rates (Bell 1997, p. 104) and could crowd out native riparian vegetation or possibly lower the water table (Zembal and Hoffman 2000, p. 66). In areas where

A.

donax

is common, flows may become diminished and sandy pools may form. Slow-moving flows and formation of pools are preferred habitat for nonnative predators such as largemouth bass (

Micropterus salmoides

) and green sunfish (

Lepomis cyanellus

), which have been suggested to prey heavily on Santa Ana suckers. The effects of

A. donax

presence may negatively affect Santa Ana sucker by altering the instream habitat and, may also provide habitat for nonnative predators. However, these types of impacts would need to be evaluated within the context of potential threats to the Santa Ana sucker.

The unmodified and unpolluted habitat in the San Gabriel River supports what appears to be a healthier and more viable population of Santa Ana sucker. Habitat assessments conducted throughout the Big Tujunga Creek indicate that the habitat suitability is variable throughout the system; however, the river does contain areas that are suitable for all Santa Ana sucker life stages (LACDPW 2009, Google Earth kmz file). It is likely that because of the variability in habitat suitability, the density of Santa Ana suckers in the Big Tujunga Creek is patchy and often low (Ecorp Consulting 2010a, p. 5; Haglund and Baskin 2010, pp. 5-6).

Santa Ana sucker habitat may be impacted as a result of wildfires. Impacts associated with wildfires may occur immediately or may not become apparent until much later. Immediate impacts may include the loss of upland and riparian vegetation and creation of roads for fire-fighting, which may allow greater access to streambeds and facilitate increased Off Highway Vehicle (OHV) use, resulting in further habitat degradation (USGS 2009, p. 7). Excessive debris flows and changes to water quality are anticipated to occur during seasonal rains over the next several years in the Big Tujunga Creek and surrounding San Gabriel Mountains (USGS 2009, p. 7). Anticipated post-fire impacts to streams within the critical habitat designation for Santa Ana sucker include ash and debris deposition that may physically alter streambeds and pools, increased scouring of riparian and aquatic vegetation, and increased water temperature from the short-term loss of canopy shading (USFS 2009, p. 5). Post-fire impacts to water quality (such as increased turbidity) are also anticipated along with release and mobilization of toxic chemicals such as gas, oil, and building materials from burned structures and their contents (USFS 2009, p. 6). The impacts associated with post-fire winter flows include but are not limited to changes in sediment composition, high flows that flush Santa Ana suckers into unsuitable habitats, and changes in water quality (such as increased turbidity and the introduction of chemicals from debris and fire retardant).

Recreational uses of streams may pose significant impacts to Santa Ana sucker habitat. Throughout the drainage systems where Santa Ana suckers persist, there are varying levels of recreational use. On U.S. Forest Service lands, recreational pressures may be considerable. Permanent or intermittent dams are frequently created for recreational purposes, such as those used for suction dredging or bathing. These dams may degrade instream and bank habitat, decrease water quality by increasing turbidity (affect PCE 4), disrupt sediment transport (affect PCEs 1 and 2), impede upstream movement, degrade habitat by slowing water velocities (affect PCE 3), increase water temperatures (affect PCE 5), and encourage excessive growth of algae (Ally 2003, p. 3). In addition, presumably, since water depths increase and velocities decrease, these areas may harbor nonnative predators (Ally 2003, p. 1; Chambers Group 2004, p. 6-4). Recreational residences located within the riparian area of the San Gabriel River and Big Tujunga Creek may impact Santa Ana sucker because of the improperly functioning septic systems at these residences which can degrade water quality conditions by increasing water turbidity (PCE 4) as a result of the increased nutrient loads in the water (USFS 2007, p. 18), which lead to excessive algal growth.

Geographic Range and Status

As discussed in detail in the Geographic Range and Status section of the proposed revised rule (74 FR 65056; December 9, 2009), genetic introgression (when a hybrid breeds with one of the parent species) has been detected in both Santa Ana sucker and Owens sucker (

Catostomus fumeiventris

) within the Santa Clara River (Ferguson 2009, p. 1; Chabot

et al.

2009, p. 24), indicating that hybridization between these two species has occurred. Moyle (2002, p. 184) and Chabot

et al.

(2009, p. 1) recently described hybridization of Santa Ana sucker with Owens sucker in the lower Santa Clara River in the vicinity of Fillmore and Sespe Creek. As stated in the proposed revised critical habitat rule (74 FR 65056; December 9, 2009), a genetic analysis of the populations in all four watersheds would provide information on the status of the fish throughout the range, including whether the Santa Clara population is native, introduced, or hybridized. However, this analysis has not been completed to date. Researcher and species' expert opinions on the status of the population in the Santa Clara River vary widely. Additional research is needed to determine the impact and extent of hybridization on genetically pure Santa Ana sucker in the Santa Clara River. Given the lack of new genetic information to help us determine whether Santa Ana suckers in the Santa Clara River are native or introduced, as well as a lack of information on the impact and extent of hybridization on genetically pure Santa Ana sucker, we continue to adhere to our 2000 decision not to include the Santa Clara River population of the Santa Ana sucker as part of the listed entity. Therefore, the Santa Clara River area was not included in the proposed revision to critical habitat or this final rule.

The Santa Ana sucker is considered a listed species in the Los Angeles, San Gabriel, and Santa Ana River drainages (Service 2000, pp. 19686-19687). Additionally, the listing rule states that Arroyo Tesquesquite, Sunnyslope Creek, Anza Park Drain, and the lower outlet of Hidden Valley Drain are used for spawning and nurseries (Service 2000, p. 19687), and therefore Santa Ana sucker in those areas are considered part of the listed entity. The historical survey records for this species are not considered complete, and the precise areas occupied by the species are difficult to determine with certainty because not all areas were surveyed exhaustively and distribution literature states that the Los Angeles, San Gabriel, and Santa Ana River drainages as a whole were occupied (Moyle 2002, p. 183; Greenfield

et al.

1970, p. 166; Smith 1966, pp. 53-56). In particular, the upper limit of habitat occupied by the Santa Ana sucker within each of the Los Angeles, San Gabriel, and Santa Ana River drainages is difficult to determine. However, as we note in our analysis of criteria used to define critical habitat (

see

Criteria Used To Identify Critical Habitat section below), Santa Ana suckers have not been observed in streams or rivers where the instream gradient exceeds 7 degrees. Even in areas where the stream gradient is less than 7 degrees, the upper limits of occupied habitat within the drainages likely have varied through time because of the dynamic nature of these drainage systems. Portions of streams may dry out in some years while the same area may become occupied by Santa Ana suckers in subsequent years due to the

presence of water (Baskin

et al.

2005, pp. 1-2).

The current status of Santa Ana sucker in the Santa Ana River appears to be declining. In 2009, the lowest Santa Ana sucker density since sampling began in 2001was reported by the Santa Ana Sucker Conservation Program Team (Team). Although densities of Santa Ana sucker have been variable from year to year, the overall density trend in the Santa Ana River is decreasing (SMEA 2009, p. 2). Recent research conducted by Thompson

et al.

(2010, pp. 321-332) indicates that the areas in the Santa Ana River with the highest quality habitat (gravel and cobbles) available for adult, juvenile, and larval stages of Santa Ana sucker occur just downstream of Riverside Avenue near the Riverside-San Bernardino County line. Further, they believe Santa Ana sucker abundance is directly related to the abundance of cobbles and gravel and that the lower portion of the survey area contains little to no suitable substrates (Thompson

et al.

2010, pp. 328-331). Monitoring and research results from both the Team (SMEA 2009, pp. 1-5) and Thompson

et al.

(2010, pp. 328-330) show that low abundance of suitable habitat is correlated with low Santa Ana sucker abundance, indicating that altered fluvial processes (

i.e.,

diminished transport of water and coarse sediments), lack of suitable substrate, and impediments to movement continue to fragment much of the current distribution of Santa Ana sucker in the Santa Ana River watershed.

Recent survey reports from the West Fork of the San Gabriel River indicate that there may be a decreasing trend in Santa Ana sucker population (Ecorp Inc. 2007, p. 9; Ecorp Inc. 2010b, p. 9). Monitoring of the West Fork of the San Gabriel River within and outside of the off-highway vehicle (OHV) area has indicated that Santa Ana sucker is generally more abundant at the control sites than in the OHV area (Haglund and Baskin 2002, pp. 9-15; Ecorp Inc. 2007, p. 9; Ecorp Inc. 2010b, p. 9). However, during the 2009 monitoring period, very low numbers of Santa Ana suckers and hundreds of nonnative predators were captured at all sites within the study area (Ecorp Inc. 2010b, p. 9). The report postulates that the flood basin of the San Gabriel Dam was full and flooded into areas where Santa Ana suckers are normally present; however, water quality measurements do not indicate any measureable change (Ecorp Inc. 2010b, p. 7). It is possible that the operations of the Cogswell and San Gabriel Dams have impacted the habitat suitability for Santa Ana sucker, and, in turn, abundance has decreased in the West Fork of the San Gabriel River. More information is needed to evaluate the status of Santa Ana sucker in the West Fork of the San Gabriel River.

Previous Federal Actions

Santa Ana sucker was listed as a threatened species under the Endangered Species Act of 1973, as amended (Act; 16 U.S.C. 1531

et seq.

) on April 12, 2000 (65 FR 19686), in the Los Angeles River basin, San Gabriel River basin, and Santa Ana River basin. A fourth population in the Santa Clara River was not listed because it was presumed to be introduced into that watershed. Critical habitat was designated on January 4, 2005 (70 FR 425).

On November 15, 2007, California Trout, Inc., the California-Nevada Chapter of the American Fisheries Society, the Center for Biological Diversity, and the Friends of the River filed suit against the Service alleging the 2005 final designation of critical habitat violated provisions of the Act and Administrative Procedure Act [(

California Trout, Inc., et al.,

v.

United States Fish and Wildlife, et al.,

Case No. 07-CV-05798 (N.D. Cal.)

transferred

Case No. CV 08-4811 (C.D. Cal.)]. We entered into a stipulated settlement agreement with plaintiffs that was approved by the district court on January 21, 2009.

The stipulated agreement required that we submit a proposed revised critical habitat for the Santa Ana sucker to the

Federal Register

by December 1, 2009, and a final revised critical habitat by December 1, 2010. On December 9, 2009, we published in the

Federal Register

a proposed revised critical habitat for the Santa Ana sucker (74 FR 65056). On July 2, 2010, we published a notice in the

Federal Register

reopening the comment period on the proposed rule and making available the DEA (75 FR 38441). With this final rule, we are submitting a final revised critical habitat designation to the

Federal Register

by December 1, 2010, in accordance with the stipulated agreement. For additional information, please

see

the Previous Federal Actions section of the proposed rule (74 FR 65056; December 9, 2009).

Critical Habitat

Background

Critical habitat is defined in section 3 of the Act as:

(i) 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

(I) Essential to the conservation of the species and

(II) That may require special management considerations or protection; and

(ii) Specific areas outside the geographical area occupied by a species at the time it is listed, upon a determination that such areas are essential for the conservation of the species.

Conservation, as defined under section 3 of the Act, means the use of all methods and procedures that are necessary to bring any 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 resources management such as research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping, transplantation, and in the extraordinary case where population pressures within a given ecosystem cannot otherwise be relieved, may include regulated taking.

Critical habitat receives protection under section 7(a)(2) 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) of the Act 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 it was listed must contain the physical and biological features essential to the conservation of the species, and be included if those features may require special

management considerations or protection. Critical habitat designations identify, to the extent known using the best scientific and commercial data available, habitat areas that provide essential life cycle needs of the species (areas on which are found the physical and biological features laid out in the appropriate quantity and spatial arrangement essential to the conservation of the species). Under the Act and regulations at 50 CFR 424.12, we can designate critical habitat in areas outside the geographical area occupied by the species at the time it is listed only when we determine that those areas are essential for the conservation of the species and that designation limited to those areas occupied at the time of listing would be inadequate to ensure the conservation of the species.

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. 106-554; H.R. 5658), and our associated Information Quality Guidelines provide criteria, establish procedures, and provide guidance to ensure that our decisions are based on the best scientific data available. They require our biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat.

When we are determining which areas should be designated as critical habitat, our primary source of information is generally the information developed during the listing process for the species. Additional information sources may include the recovery plan for the species, articles in peer-reviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, or other unpublished materials and expert opinion or personal knowledge.

Habitat is often dynamic, and species may move from one area to another over time. Furthermore, we recognize that critical habitat designated at a particular point in time may not include all habitat areas that we may later determine are necessary for the recovery of the species. For these reasons, a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not be required for recovery of the species.

Areas that are important to the conservation of the species, but are outside the critical habitat designation, will continue to be subject to conservation actions we implement under section 7(a)(1) of the Act. Areas that support populations are also subject to the regulatory protections afforded by the section 7(a)(2) jeopardy standard, as determined on the basis of the best available scientific information at the time of the agency action. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. Similarly, critical habitat designations made on the basis of the best available information at the time of designation will not control the direction and substance of future recovery plans, habitat conservation plans (HCPs), or other species conservation planning efforts if information available at the time of these planning efforts calls for a different outcome.

Physical and Biological Features

In accordance with section 3(5)(A)(i) and 4(b)(1)(A) of the Act and the regulations at 50 CFR 424.12, in determining which areas within the geographical area occupied by the species at the time of listing to designate as critical habitat, we consider the physical and biological features essential to the conservation of the species which may require special management considerations or protection. 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 historic, geographical, and ecological distributions of a species.

We consider the specific physical and biological features essential to the conservation of the species laid out in the appropriate quantity and spatial arrangement for the conservation of the species. We derive the specific physical and biological features for Santa Ana sucker from the biological needs of this species as described in the Critical Habitat section of the proposed rule to designate critical habitat for Santa Ana sucker, which published in the

Federal Register

on December 9, 2009 (74 FR 65056).

Based on the needs and our current knowledge of the life-history, biology, and ecology of the species and the habitat requirements for sustaining the essential life history functions of the species, we determined that Santa Ana sucker's physical and biological features consist of flowing stream habitat (

see

Primary Constituent Elements section for further discussion). However, some portions of this habitat may experience significant reductions in, or an absence of, surface flows during certain portions of the year (such as during summer months) or under certain conditions (such as during severe droughts or when artificial sources of water are temporarily suspended). Some areas that we consider essential to the conservation of Santa Ana sucker may not experience flows except during major storms events. However, these areas are critically important components of naturally occurring hydrologic and geologic processes because they provide a connected hydrologic system within the historical range of this species. We have attempted to capture the dynamic nature and importance of these processes in identifying the habitat upon which Santa Ana sucker depends.

Habitats That Are Representative of the Historic Geographical and Ecological Distribution of the Species

Santa Ana sucker inhabits flowing streams, and has not been collected from reservoirs (Swift 2001, p. 15; Moyle 2002, p. 184). Water depths and velocities, as well as bed substrates, vary over the reaches of these streams creating various habitat features including:

1. Moderate currents over a uniform, unbroken stream bottom (

i.e.,

runs);

2. Water flowing over gravel and cobble substrates that causes ripples to form on the surface of the water (

i.e.,

riffles); and

3. Deep water areas created by submerged boulders where water is cool and relatively still (

i.e.,

pools).

Streams in southern California are subject to periodic, severe flooding that alters channel configuration, instream habitat conditions, and vegetation structure (Moyle 2002, p. 183). Hence, as stream conditions change, the characteristics of stream and bank habitats and their suitability for Santa Ana sucker change, influencing the distribution of the fish over time. Therefore, even stream reaches where flows may periodically be interrupted or dewatered become essential during periods of high flows to allow Santa

Ana suckers to move between other habitat areas necessary for breeding, feeding, and sheltering.

Gravel beds in shallow, but clear, flowing stream reaches are needed for spawning. Shallow areas with sandy substrates and overhanging vegetation are needed to support larvae and fry. Juvenile and adult Santa Ana suckers require deeper pools of water for foraging, shelter during storms, and cover.

Santa Ana sucker prefers cool water temperatures but has been found in waters between 59 and 82 °Fahrenheit (F) (15 and 28 °Celsius (C)) in the Santa Ana River (Swift 2001, p. 18). Cooler water temperatures are only maintained in some areas by the upwelling of cooler groundwater, tributary flows, or shade from overhanging vegetation. Overhanging and instream vegetation are also needed for the development of an aquatic invertebrate community to supply food for adult suckers as well as for protective cover, and shade, which reduces water temperature during summer and fall months. Therefore, a complex and integrated stream system is needed that: (1) Encompasses sand, gravel, cobble, and rock substrates; (2) harbors diverse bed morphologies found in deep canyons and alluvial floodplains; (3) provides varying water depths and velocities; (4) contains tributaries that provide fish with areas of refuge (refugia) from predators and during floods and that can also provide suitable breeding habitat; and (5) harbors sources of coarse sediment for renewal of substrate in occupied areas. The primary constituent elements (PCEs;

see

Primary Constituent Elements for Santa Ana Sucker section for detailed discussion) and the resulting physical and biological features essential to the conservation of Santa Ana sucker are derived from studies of this species' habitat, ecology, and life history as described below, in the Background section of the proposed revised rule published in the

Federal Register

on December 9, 2009 (74 FR 65056), in the final listing rule published in the

Federal Register

on April 12, 2000 (65 FR 19686), in the final critical habitat designation published in the

Federal Register

on February 26, 2004 (69 FR 8839), and in the final revised critical habitat designation published in the

Federal Register

on January 4, 2005 (70 FR 425).

Space for Individual and Population Growth and for Normal Behavior

Santa Ana suckers use various water depths, depending on their life-history stage and activity, and do not occupy all reaches of their habitat at any one time (Saiki 2000, p. 19; Haglund and Baskin 2003, p. 53). Larval- and early-stage juvenile Santa Ana suckers prefer the shallow margins of streams in water of 2 to 4 inches (in) (5 to 10 centimeters (cm) in depth; as fish mature, they move into deeper water. Adults prefer deep pools for feeding and seeking refuge, riffles of varying depths for spawning, and riffles and runs of varying depths for movement between pools (Haglund

et al.

2003, p. 102). For example, in the Santa Ana River, adult Santa Ana suckers have been found in diverse habitat areas, including shallow runs of less than 4 in (10 cm) in depth, in flowing water up to 5 feet (ft) (150 cm) deep (Saiki 2000, p. 19; Swift 2001, p. 66), and in pools 6 to 10 ft (200 to 300 cm) deep (Allen 2004). They have been found in similarly varying water depths in the San Gabriel River (Saiki 2000, p. 48), and Saiki speculates that their capture in these various depths is reflective of their ability to take advantage of a variety of habitat conditions (2000, p. 25). Flows within occupied habitat areas may occasionally become very shallow due to seasonal reductions in flow volumes or be interrupted as a result of dam operations or releases from wastewater treatment plants (such as in the Santa Ana River) in some portions of a stream reach. When stream depth is significantly reduced, deep pools become a critically important refuge for fish.

Surface water flows must be present within the stream, but water velocities where Santa Ana suckers occur can vary from slight to swift (Haglund and Baskin 2003, p. 2). Larvae and fry congregate exclusively in almost-still waters, not moving into swifter currents until they have matured into later juvenile stages (Swift 2001, pp. 17-18). Swift (2001, p. 61) suggests that juvenile fish prefer areas with less water-velocity than do adults because they can expend less energy maintaining their position in the stream. Adult and juvenile Santa Ana suckers in the San Gabriel River have been found in waters with bottom velocities ranging from 0.17 to 0.51 ft per second (0.05 and 0.15 m per second) and mid-column velocities reaching 1.95 ft per second (0.6 m per second) (Haglund and Baskin 2002, pp. 38-39). Haglund and Baskin (2003, pp. 39 and 53) concluded that there was no evident pattern in the locations Santa Ana suckers selected relative to water velocity and suggested that they preferentially seek out locations that provide the best combination of habitat parameters. In the Santa Ana River, Santa Ana suckers have been found in areas with water velocities of up to 2.4 ft per second (0.74 m per second) where wastewater discharges and channelization of the river bed increase water velocity (Saiki 2000, pp. 18-19).

Stream beds containing the mosaic of rock, cobble, and gravel preferred by Santa Ana suckers are most prevalent in the San Gabriel River (Saiki 2000, pp. 18-19). Within the Santa Ana River, shifting sands are the primary substrate constituent upstream of the Prado Basin. In the Santa Ana River bed, substrates containing at least 10 percent gravel, cobble, and rock were documented for a distance of 7 mi (12.3 km) downstream from the Rialto Drain in 1999 and 2000 (Swift 2001, pp. 4, 68-75). Habitat assessments conducted between 2006 and 2008 indicated that these substrates fluctuated from 2.6 to 6.0 mi (4.2 to 9.6 km) downstream of the Rialto Drain (Thompson

et al.

2010, p. 328).

The distribution of Santa Ana suckers across streams varies depending upon bed conditions and stream depth. Santa Ana suckers within the San Gabriel River are often found mid-channel adjacent to submerged cobble, boulders, or manmade structures such as culverts. In the Santa Ana River where the streambed is sandier, they are rarely found mid-channel, but rather adjacent to shoreline areas near rooted vegetation (Saiki 2000, pp. 25, 27). Where preferred habitat conditions are absent, Santa Ana suckers make use of available habitats that provide some of the same functions provided by preferred habitats (Saiki 2000, p. 19).

The distribution of Santa Ana suckers is also likely dependent on instream gradient. While several authors have acknowledged that this species cannot access high gradient areas, we are not aware of any research quantifying the maximum slope passable by Santa Ana suckers. In an attempt to estimate the maximum slope passable by the species, we used GIS to analyze the slopes associated with Santa Ana sucker occurrence polygons and points in our database for the Santa Ana River, San Gabriel River, and Big Tujunga Creek. Based on our analysis, Santa Ana suckers have not been found in areas where the instream slope exceeds 7 degrees. This could be due to the species' inability to swim up these higher gradients or due to the lack of suitable habitat in these areas as a result of higher water velocity and a subsequent lack of suitable spawning and feeding substrates or both. Also, the probability of encountering vertical barriers (such as waterfalls) increases as the overall slope across a given distance increases; therefore, even if habitat is suitable upstream, it may be inaccessible to the species. However,

more extensive analysis is needed to determine the gradient limitations of the species.

A comparative analysis of suckers within the Santa Ana and San Gabriel Rivers revealed that only two cohorts are generally present within the Santa Ana River, compared with three in the San Gabriel River, indicating that few individual suckers live beyond their second year of life in the Santa Ana River (Saiki 2000, p. 13). No investigations have occurred to determine the relative lifespan or fecundity of Santa Ana suckers as they relate to habitat conditions. However, overall habitat conditions for Santa Ana suckers are generally better in the San Gabriel River than in the Santa Ana River, which is reflected in the overall greater abundance of fish and their better body condition in the San Gabriel River (Saiki 2000, pp. 18-28).

Food, Water, Air, Light, Minerals, or Other Nutritional or Physiological Requirements

Suckers (Family Catostomidae) are primarily bottom feeders, sucking up algae, small invertebrates, and organic detritus from gravel, cobble, rock, and other hard surfaces (Moyle 2002, p. 179). Forage for adult Santa Ana suckers is also found in pools (Allen 2003, p. 6). Riparian vegetation and emergent aquatic vegetation provide additional sources of detritus and aquatic invertebrates such as insects (Leidy

et al.

2001, p. 5-2). Insects may provide a high energy source of food for adult Santa Ana suckers (Saiki 2000, p. 23). In a comparative analysis of Santa Ana suckers in the Santa Ana and San Gabriel Rivers, Saiki (2000, pp. 27, 98) found that body condition (length-weight relationship) of Santa Ana suckers in the San Gabriel River was better than that of fish in the Santa Ana River, possibly due to a greater abundance of food resources (including algae and insects) found on the rocky substrate in the San Gabriel River relative to the sandy substrate in the Santa Ana River.

Although the specific tolerances to water quality variables have not been evaluated for Santa Ana sucker, water temperature, dissolved oxygen content, and turbidity (such as excessive detritus in the water column or protracted suspension of fine-grained sediments) are all important aspects of water quality that affect the physiology of fish (California Regional Water Quality Control Board (CRWQCB) 1995, pp. 4-1—4-15). This species has been found in waters between 59 and 82 °F (15 and 28 °C) in the Santa Ana River (Swift 2001, p. 18). Swift (2001, p. 34) states that although a lethal limit for water temperature is unknown, water temperatures much above 86 °F (30 °C) likely limit distribution and movement of this species. Santa Ana suckers are generally more abundant in the cooler waters of the San Gabriel River than they are in the warmer waters of the Santa Ana River (Saiki 2000, pp. 27-28). Researchers conclude that in addition to having poor habitat conditions such as sandy substrate and lack of instream cover, areas of the Santa Ana River may be devoid of Santa Ana suckers due to higher water temperatures (Chadwick and Associates, Inc. 1992, p. 37).

Adequate dissolved oxygen is necessary for aquatic life and as water warms, its concentration of dissolved oxygen drops, stressing fish (CRWQCB 1995, p. 4-3). In general, waters occupied by Santa Ana suckers are high in dissolved oxygen (Saiki 2000, pp. 18-19).

Santa Ana suckers are more abundant in clear rather than in turbid (cloudy or hazy) water conditions (Saiki 2000, pp. 28, 52; 2007, p. 95). This is most likely because suspended sediments interrupt light penetration through the water column, causing a reduction in algal growth and thus limiting the primary food source of Santa Ana sucker. However, while Santa Ana suckers likely avoid turbid waters when possible, they have been documented in turbid conditions on occasion (Haglund

et al.

2002, p. 11). One measurement of turbidity is Nephelometric Turbidity Units (NTU), where turbidity level of 1.0 NTU equals 1 milligram of particulate per liter of water. Saiki

et al.

(2007, pp. 95-96) found that Santa Ana suckers were more abundant in the San Gabriel River where turbidity averaged 5.9 NTUs (ranging from 4.3 to 8.2 NTUs), and less abundant but not absent in more turbid areas of the Santa Ana River where turbidity averaged 29 NTUs (ranging from 10.1 to 83.4 NTUs). However, Santa Ana suckers have been found in the Santa Ana River in an area where turbidity was measured between 85 and 112 NTUs (Baskin and Haglund 2001, p. 6). Saiki (2000, p. 25) speculates that fish occur under less-than-optimal ambient conditions because they are using whatever habitat is available to them and cites these conditions as a possible reason for reduced abundance of Santa Ana suckers in the Santa Ana River relative to their abundance in the San Gabriel River.

Multiple wastewater treatment plants discharge into the Santa Ana River and its tributaries and account for most of the dry-season flows within the river (CRWQCB 1995, pp. 1-7). The City of San Bernardino Municipal Water District's Rapid Infiltration and Extraction Facility, Rialto Treatment Plant, and the City of Riverside Regional Water Quality Control Plant all discharge into the Santa Ana River. As a result of rising groundwater, nonpoint source urban runoff, and these wastewater discharges, perennial flows are maintained from the vicinity of the Rialto Drain and downstream. Although these discharges contain contaminants not found in natural runoff, there is no evidence that the concentrations of regulated compounds found in Santa Ana suckers in this river exceed mean concentrations found in freshwater fish in other areas of the United States (Saiki 2000, p. 24). However, research has indicated that anthropogenic chemicals introduced into riverine systems may have lasting negative impacts on fish reproductive success (Service 2008, p. 3). The specific impacts of residual chemicals in discharged treated wastewater (such as inorganic compounds, hydrocarbons, solvents, steroids, and hormones) are the subject of investigation for Santa Ana suckers (Service 2008, p. 2).

Cover or Shelter

Instream emergent and overhanging riparian vegetation along the banks of stream courses provide shade, shelter, and cover for fry, juvenile, and adult Santa Ana suckers. Shading is very important to Santa Ana suckers that inhabit shallow waters because it reduces water temperatures during periods of high summer ambient temperatures. A complex stream system including tributaries that contain submerged boulders, deep pools, and undercut banks provides cover and shelter for juvenile and adult Santa Ana suckers (Saiki

et al.

2007, p. 99; Moyle

et al.

1995, p. 202). Tributaries may provide important shallow-water refugia for larvae and fry from larger, predatory fish and act as refugia for juvenile and adult Santa Ana suckers during storms.

Sites for Breeding, Reproduction, and Rearing (or Development) of Offspring

Adult Santa Ana suckers spawn over gravel beds in flowing water (riffles) where the female deposits the eggs in fine gravel substrate. Substrate collected from two spawning locations in tributaries to the Santa Ana River consisted of gravel-sized particles ranging in diameter from 0.04 to 1.6 in (1.0 to 41.5 mm) (Haglund

et al.

2001, p. 47). The presence of appropriately sized substrate allows for water flow around eggs to prevent sediment from depositing on and smothering the eggs. Eggs deposited on sand or silt are likely

to be washed downstream or be smothered. In addition to appropriate substrate, adequate water velocities are necessary to oxygenate eggs. Observations of Santa Ana sucker spawning have been reported in streams with bottom velocities of 0.65 and 0.77 ft per second (0.20 and 0.23 m per second) (Haglund

et al.

2003, p. 63).

Once emerged from the eggs, Santa Ana sucker larvae congregate in shallow, slow-moving waters from 1 to 5.5 in (3 to 14 cm) deep over very soft sand or mud substrate (Swift 2001, p. 17; Haglund

et al.

2002, pp. 69-71; Haglund

et al.

2003, p. 11). This type of habitat is usually found along the margins of streams in proximity to emergent vegetation. Fry are found almost exclusively found in edgewater habitats over silt or sand in water depths of less than 7 in (17 cm) where there is little measurable flow; Haglund and Baskin (2003, p. 47) speculate this reduces access by larger predatory fish and, because shallow waters are warmer, may increase the growth rates of developing suckers. Juvenile fish move away from edgewater habitats and congregate at the interface of the almost-still waters at the adjacent bank-edge and the main stream flows (Swift 2001, pp. 17-18). By the end of their first summer, juvenile Santa Ana suckers move into deeper water habitats with adults, presumably because they are large enough to compete with adult suckers for forage (Swift 2001, p. 18).

Tributaries may provide essential spawning habitat for the Santa Ana sucker, particularly in the Santa Ana River (Chadwick and Associates, Inc. 1992, p. 49; Chadwick Ecological Consultants, Inc. 1996, p. 16; Haglund

et al.

2002, pp. 54-60). An abundance of juvenile fish has been recorded in multiple tributaries in the Santa Ana River (such as the Tequesquite Arroyo and the Evans and Anza drains), and, hence, these have been considered possible spawning sites (Chadwick and Associates, Inc. 1992, p. 49). However, Swift (2001, p. 26) concluded that the species may be attracted to tributaries due to the relatively colder water temperatures found there. He stated that most tributaries to the Santa Ana River lack either suitable substrates or water velocities to support successful spawning. Swift (2001, p. 26) considered that only the Rialto Drain and Sunnyslope Creek provided habitat conditions suitable to support spawning. These sites are two of the few remaining areas containing gravel beds, and management may be required to maintain substrate conditions over time (Orange County Water District (OCWD) 2009, pp. 6-4—6-5).

In the hydrologically altered systems in which Santa Ana suckers exist, tributaries provide another essential function through contribution of water and coarse sediments into the mainstem of rivers. In typical unaltered stream systems periodic high flow events not only remove fine sand and silt that have covered up coarse sediments that are essential for breeding and foraging of Santa Ana sucker, they also deliver and replenish coarse sediments (

i.e.,

gravel and cobble) to occupied areas from upstream sources. Historical records indicate that the upper Santa Ana River above Seven Oaks Dam was a principle contributor of sediment to the lower reaches of the Santa Ana River (Humphrey

et al.

2004, p. 3). However, much of the input of gravel and cobble substrate to the lower reaches of the river has decreased since the construction and operation of the Seven Oaks Dam in the upper Santa Ana River. Therefore, tributaries are of even greater importance to ensure flow velocities that clear out silt and other fine sediments from occupied areas, and to replenish essential coarse sediment to the lower reaches of the Santa Ana River. A sediment transport study of the Santa Ana River (Humphrey

et al.

2004, p. 2) indicates that historically the upper Santa Ana River (above Seven Oaks Dam), City Creek, Plunge Creek, and Mill Creek were significant contributors of coarse sediment to the occupied reaches of the Santa Ana River. However, currently City Creek and Mill Creek are the remaining contributors of coarse sediment into the occupied reaches of the Santa Ana River since the coarse sediment that was historically delivered by the upper Santa Ana River has been trapped behind Seven Oaks Dam and Plunge Creek now contains a settling basin that has been modified for mining. Therefore, these two tributaries are the only remaining significant sources of essential coarse sediment into the mainstem of the Santa Ana River below the Seven Oaks Dam, which supplies coarse sediment downstream to the occupied reaches of the river.

Presumably there has been a reduction in transported cobble and gravel from the upper Santa Ana River because periodic high flow events have been controlled by Seven Oaks Dam, which has also trapped coarse sediment behind it. However, there has not been a similar reduction in fine sediments, such as silt and sand, to the lower reaches of the Santa Ana River (Humphrey

et al.

2004, p. 5; Warrick and Rubin 2007, p. 3). Gravel and cobbles are essential coarse sediments for Santa Ana sucker spawning habitat (Moyle 2002, pp. 182-185). Fine sand and silt may be deposited on top of suitable coarse spawning sediment because flows have declined due to the altered fluvial process in the Santa Ana River. Tributaries and lower order streams (upstream areas) provide a source of water and coarse sediments that are transported downstream (to higher order streams) where the presence of water and coarse sediments are essential to the conservation of the species. Therefore, flows to clear out fine sand and silt from suitable spawning substrate (

i.e.,

gravel and cobble) and flows to transport suitable materials from upstream sources for maintenance of spawning substrate are essential to the conservation of Santa Ana sucker.

In the Santa Ana River, Humphrey

et al.

(2004, p. 7) states a critical flow of water of 4,000 cubic feet per second (cfs) or more is necessary to transport gravel and cobbles downstream and lower velocity flows (500-4,000 cfs) have the ability to move silt and other fine sediment that accumulates on top of suitable spawning substrates. The critical velocity necessary to move gravel and cobbles is variable depending on the conditions and location within the system. For example, during a test release of water from behind Seven Oaks Dam of approximately 2,500 cfs, boulder-sized rocks were observed moving within several hundred feet of the plunge pool (Wood 2010, pers. comm.). United States Geological Survey gauging stations along the Santa Ana River and City Creek indicate that there are flows sufficient to clear out fine sand and silt, and also flows that reach approximately 4,000 cfs and above that would deliver essential gravel and cobble substrates from upstream sources to downstream to occupied areas. These coarse sediments are a component of the physical and biological features essential to the conservation of the species (

see

Primary Constituent Elements for the Santa Ana Sucker below). In all three of the watersheds where Santa Ana sucker persists, the existence of dams has regulated flows and trapped sediments from being transported downstream. Therefore, sources of water and coarse sediments and the transport of these materials to occupied areas to create and maintain habitat conditions suitable for Santa Ana sucker breeding and foraging within these tributaries and lower order streams is essential to the conservation of the species.

Primary Constituent Elements (PCEs) for Santa Ana Sucker

Under the Act and its implementing regulations, we are required to identify the physical and biological features within the geographical area occupied by Santa Ana sucker at the time of listing that are essential to the conservation of the species and which may require special management considerations or protection. The physical and biological features are those PCEs laid out in a specific spatial arrangement and quantity determined to be essential to the conservation of the species. We are designating critical habitat in areas within the geographical area that were occupied by the species at the time of listing that continue to be occupied, and that contain the PCEs in the quantity and spatial arrangement to support life-history functions essential to the conservation of the species. We are also designating areas outside the geographical area occupied by the species at the time of listing that are not occupied but are essential for the conservation of the species.

See

Criteria Used To Identify Critical Habitat section below for a discussion of the species' geographic range.

We believe conservation of Santa Ana sucker is dependent upon multiple factors, including the conservation and management of areas to maintain suitable ecological functions where existing populations survive and reproduce. The areas we are designating as critical habitat provide some or all of the physical or biological features essential for the conservation of this species. Based on the best available information, the PCEs essential to the conservation of Santa Ana sucker are the following:

1. A functioning hydrological system within the historical geographic range of Santa Ana sucker that experiences peaks and ebbs in the water volume (either naturally or regulated) that encompasses areas that provide or contain sources of water and coarse sediment necessary to maintain all life stages of the species, including adults, juveniles, larvae, and eggs, in the riverine environment;

2. Stream channel substrate consisting of a mosaic of loose sand, gravel, cobble, and boulder substrates in a series of riffles, runs, pools, and shallow sandy stream margins necessary to maintain various life stages of the species, including adults, juveniles, larvae, and eggs, in the riverine environment;

3. Water depths greater than 1.2 in (3 cm) and bottom water velocities greater than 0.01 ft per second (0.03 m per second);

4. Clear or only occasionally turbid water;

5. Water temperatures less than 86 °F (30 °C);

6. Instream habitat that includes food sources (such as zooplankton, phytoplankton, and aquatic invertebrates), and associated vegetation such as aquatic emergent vegetation and adjacent riparian vegetation to provide: (a) Shading to reduce water temperature when ambient temperatures are high, (b) shelter during periods of high water velocity, and (c) protective cover from predators; and

7. Areas within perennial stream courses that may be periodically dewatered, but that serve as connective corridors between occupied or seasonally occupied habitat and through which the species may move when the habitat is wetted.

All occupied units designated as critical habitat contain the PCEs in the appropriate quantity and spatial arrangement essential to the conservation of this species and support multiple life processes for Santa Ana sucker.

Special Management Considerations or Protection

When designating critical habitat, we assess whether the specific areas within the geographical area occupied by the species at the time of listing contain the physical and biological features that are essential to the conservation of the species and may require special management considerations or protection.

All areas included in this final critical habitat designation will require some level of management to address the current and future threats to the physical and biological features essential to the conservation of Santa Ana sucker. Special management considerations or protection may be required to minimize habitat destruction, degradation, and fragmentation associated with the following threats, among others: Water diversion; alteration of stream channels and watersheds; reduction of water quantity associated with urban development and human recreational activities, including swimming, and construction and operation of golf courses; and OHV use. For discussion of the threats to Santa Ana sucker and its habitat, please

see

the Summary of Comments and Recommendations and Summary of Factors Affecting the Species sections of the final listing rule (65 FR 19686; April 12, 2000) and the Public Comments and Critical Habitat Unit Descriptions sections of the 2005 final critical habitat rule (70 FR 425; January 4, 2005). Please also

see

Critical Habitat Units section below for a discussion of the threats in each critical habitat unit.

In addition to the threats to Santa Ana sucker and its habitat described in the final listing and previous critical habitat rules, the physical and biological features essential to the conservation of Santa Ana sucker may require special management considerations or protection to minimize habitat destruction, degradation, and fragmentation associated with the construction of dams, the operation of recreational residences, the construction of road crossings and bridges across waterways, nonnative vegetation and predators, the impacts of wildfires to riparian and instream conditions, and the degradation of water quality.

Recreational Dams

Artificial manmade dams are often constructed from boulders, logs, and trash to create pools within these rivers for fishing, swimming, wading, and bathing (Ally 2003, p. 1; Chambers Group 2004, p. 6-4). The construction of these “recreational” dams degrades instream and possibly bank habitat, increases turbidity (PCE 4), disrupts sediment transport, and impedes upstream movement of Santa Ana suckers, especially during droughts (Ally 2003, pp. 1-3), thereby fragmenting habitat connectivity within occupied habitat. During the spawning season, these dams cause instream disruptions that can bury gravel beds (PCE 2) used for spawning (Ally 2003, p. 1). Recreational dams can also further degrade habitat by slowing water velocities (PCE 3), increasing water temperatures (PCE 5), and encouraging excessive growth of algae (Ally 2003, p. 3). In addition, presumably, because water depths increase and velocities decrease, these areas may harbor nonnative predators. Management activities that could ameliorate these threats include patrolling by enforcement officers or rangers throughout the accessible recreational areas within the critical habitat designation. Prevention of recreational dams will help protect the PCEs by ensuring the hydrologic system continues to function (PCE 1) by delivering cool, clear water with sufficient food sources (PCEs 2 through 6) that are essential to the conservation of Santa Ana sucker.

Recreational Residences

The U.S. Forest Service (USFS) issues special use permits for the operation and maintenance of private recreational residences within the boundaries of the

Angeles National Forest along Big Tujunga Creek and the North and West Forks of the San Gabriel River. Improperly functioning septic systems at these residences can degrade water quality conditions by increasing water turbidity (PCE 4) as a result of the increased nutrient loads in the water (USFS 2007, p. 18), which lead to excessive algal growth. Management activities that could ameliorate these threats include limiting the number of allowable recreational residences and requiring that septic systems are properly functioning within areas that are hydrologically connected to areas designated as critical habitat. Limiting the number of residences and ensuring the proper function of their septic systems will help protect PCE 4 by preventing additional nutrient loads from entering the water and increasing water turbidity (PCE 4) to the detriment of Santa Ana sucker.

Road Crossings and Bridges

Road crossings and bridges constructed across waterways can impact Santa Ana sucker by creating permanent or intermittent barriers to upstream movement and fragmenting connective corridors between areas of occupied habitat (PCE 7). Bridge footings and pier protections (such as concrete aprons that span the waterway) accelerate water velocities (PCE 3) and, in the absence of sediment in the water (PCE 2), scour sediments from the streambed immediately downstream. With sufficient scouring, the elevation of the downstream bed of the stream may become so low that Santa Ana suckers cannot swim upstream from that point; scouring can also create pools that favor predatory nonnative fish. Culverts constructed under road crossings can act as barriers to movement when a culvert becomes filled in with sediment, reducing the amount of water (PCE 1) and sediment (PCE 2) that could be transported downstream. Drop structures that function as a support for road crossings or bridges as a result of gradient changes within the river may also create a temporary barrier to water and sediment transport and Santa Ana sucker movement. The extent, however, to which these structures constitute barriers depends on the quantity of water flowing and sediment transport in a given year and over time. For example, sediment-filled culverts that create a barrier to movement one year may be passable in another year if high water flows remove trapped sediments. Road crossings and bridges can also impact the species by altering the hydrology of the system (PCE 1), rerouting water flow into less suitable habitat. Management activities that could ameliorate these threats include modifying culverts or drop structures to ensure the connective corridor is maintained through a gradient that is passable by water and sediment and Santa Ana suckers (

i.e.,

7 degrees as described in the Criteria Used To Identify Critical Habitat section) within the critical habitat designation. Maintenance of these corridors (PCE 7) and ensuring a passable gradient (PCE 1) will help protect the PCEs (2 through 5) that are essential to the conservation of Santa Ana sucker.

Water and Sediment Transport or Removal

The transport of both water and sediment are essential components to the conservation of Santa Ana sucker (PCEs 1 through 5). The presence of sufficient water and appropriate sediment may be impacted by operations attributed, but not limited to, dams operation of hydroelectric power facilities, water diversion, sediment removal, or flood control activities. Natural flow regimes have inevitably been impacted in the Santa Ana River, Los Angeles River, and San Gabriel River basins as a result of alterations such as dams, diversions, channelization, or other flood control activities. The impacts to Santa Ana sucker and its habitat attributable to these activities have yet to be fully described or understood. However, as these activities continue, there appear to be impacts to Santa Ana sucker and its habitat through alteration of the hydrologic system and the function of the watershed as a whole. Recent research indicates that the presence of preferred substrates such as gravel and cobble in the Santa Ana River are less common at sites farther downstream compared to sites that are closer the Seven Oaks Dam (Thompson

et al.

2010, p. 328). This is likely due to the presence of flowing water from the Rialto/RIX sewage treatment plant immediately upstream that clears out silt and fine sand and exposes gravel and cobbles; however, the flow diminishes downstream due to percolation. Therefore, in the occupied areas of the Santa Ana River, downstream areas contain less suitable habitat for Santa Ana sucker (Thompson

et al.

2010, pp. 327-328).

The extant populations of Santa Ana suckers throughout the species' range are currently isolated from one another as a result of water diversions or dams that have likely resulted in their exclusion from suitable spawning and rearing habitat (Service 2000, p. 19693). Management activities that could ameliorate these threats throughout the species' range include removing or preventing channelization and restoring the river with its natural substrates and riparian vegetation, increasing flows into occupied areas by decreasing the amount of water contained by dams or removed from the hydrologic system, preventing mining activities that remove coarse sediments, and preventing further instream modifications from flood control activities throughout the critical habitat designation. Maintenance of the natural flow (PCEs 3, 4, and 5) and sediment transport (PCE 2) will help protect the PCEs that are essential to the conservation of Santa Ana sucker.

Off-Highway or Off-Road Vehicles (OHVs)

Throughout the designated critical habitat, OHV use occurs in authorized and unauthorized areas. We are aware of authorized OHV activity in the USFS's San Gabriel Canyon OHV Area at the junction of the East, North, and West Forks of the San Gabriel River. There have been reports of unauthorized OHV activity in the Santa Ana River, although the level of impact and frequency of use have not been quantified. However, the reach where the unauthorized OHV activities have been reported occurs just upstream of one of the remaining Santa Ana sucker populations (near Rialto/RIX; SAWPA 2010, p. 1-10). This area has recently been cleared of the nonnative plant,

Arundo donax,

which may have facilitated access for OHVs. The use of the river as an OHV recreational area may result in adverse effects to Santa Ana sucker by increasing turbidity (PCE 4); disrupting the physical structure of habitat for spawning, resting, and feeding (PCE 2); and introducing pollutants (such as oil and gas) into streams (PCE 4) (65 FR 19686; April 12, 2000). Management activities that could ameliorate these threats include patrolling by enforcement officers or rangers throughout the accessible recreational areas, providing signage to discourage access, or installing fencing where access is unauthorized within the critical habitat designation. Minimizing the impacts to the hydrologic system (PCE 1) and reducing the instream impacts (

i.e.,

increased turbidity (PCEs 2 and 4)) and impacts to instream and riparian vegetation (PCE 6) attributed to OHVs will help protect the PCEs that are essential to the conservation of Santa Ana sucker.

Nonnative Vegetation and Nonnative Predators

The presence of nonnative vegetation (such as

Arundo donax

) may alter the hydrology and provide habitat conditions preferred by nonnative predators (such as largemouth bass and green sunfish) in the Santa Ana River and Big Tujunga Creek, and possibly (but to a lesser degree) in the San Gabriel River. These impacts may include (but not be limited to) decreased flow rates (PCE 3), increased turbidity (PCE 4), increased presence of pools and lack of preferred habitat (PCE 2), and increased abundance of nonnative predators (Service unpublished information 2010b, pp. 24-25). However, these types of impacts would need to be evaluated within the context of potential threats to the Santa Ana sucker. If this potential threat is found to impact the species, management activities to ameliorate this threat could include removal of nonnative vegetation and predators.

Post-Wildfire Management

The Station Fire of 2009 (described in more detail in Critical Habitat Units—Unit 3: Big Tujunga and Haines Creeks section below) may have long-lasting impacts to the Big Tujunga and Haines Creeks. These impacts may include (but not be limited to) increased debris-flow and flow velocity (PCEs 3 and 6) due to the lack of vegetation and increased run-off, increased turbidity (PCE 4) from the residual ash in the area and increased flow speeds, and possible residual contaminants entering the system as a result of the firefighting retardant chemicals which can alter water chemistry. The loss of riparian vegetation is likely to increase water temperature in the river due to the lack of shading available to instream habitats (USFS 2009, pp. 5-6). Management activities that could ameliorate these threats include revegetation of upland and riparian areas to stabilize hillsides and riparian zones to prevent erosion, and removal of large debris within the critical habitat designation before winter rains commence. Revegetation of upland and riparian areas will decrease debris flow and stabilize soils (PCEs 2, 4, and 6), which will help protect the PCEs that are essential to the conservation of Santa Ana sucker.

Water Quality Degradation

Although specific water quality tolerances have not been evaluated for Santa Ana sucker, elevated water temperature, diminished dissolved, oxygen, elevated turbidity, elevated specific conductance, and presence of certain chemicals (such as pharmaceuticals or endocrine disrupting compounds) from treated wastewater may impact Santa Ana sucker. These impacts may affect the physical and biological features essential to the conservation of the Santa Ana sucker and may include (but not be limited to) increased water temperatures (PCE 5), increased turbidity (PCE 4), and changes in instream food sources (PCE 6) that may have long-lasting effects on individual and population growth (reproductive success) and other normal behaviors. Management activities that could ameliorate these threats include identification of thresholds and tolerance levels specifically for Santa Ana sucker, implementation of water quality standards or regulations throughout its range, and minimization of discharges of harmful chemicals into the watersheds. Water quality regulations that address Santa Ana sucker's water quality requirements (PCEs 4, 5, and 6) will help protect the PCEs that are essential to the conservation of Santa Ana sucker.

Criteria Used To Identify Critical Habitat

As required by section 4(b) of the Act, we used the best scientific and commercial data available to designate critical habitat. We only designate areas outside the geographical area occupied by a species when a designation limited to its present range would be inadequate to ensure the conservation of the species (50 CFR 424.12(e)).

At the time Santa Ana sucker was listed in 2000, the geographical area occupied by the species was considered to include the Los Angeles, San Gabriel, and Santa Ana River basins (65 FR 19686; April 12, 2000). The listing rule details survey results that identify the following areas in each river basin as being within the geographical range occupied by the species: (1) The Santa Ana River basin including the Santa Ana River below Prado Dam, the Santa Ana River above Prado Dam to the City of Riverside, and the following tributaries: Tequesquite Arroyo, Sunnyslope Channel, and Anza Park Drain; (2) the San Gabriel River basin, including the West, North, and East forks of the San Gabriel River and Bear [Canyon] Creek, which is a tributary of the West Fork of the San Gabriel River; and (3) the Los Angeles River basin, including Big Tujunga Creek, between Big Tujunga Dam and Hansen Dam, and Haines Creek.

For the purposes of this final revised critical habitat designation for Santa Ana sucker, the geographical area occupied by the species at the time of listing is defined to include those areas specifically identified in the listing rule (65 FR 19686; April 12, 2000), and the following additional areas not specifically identified in the listing rule but documented to be occupied at the time of listing and documented to be currently occupied: (1) In the Santa Ana River system: Rialto Drain; and (2) in the San Gabriel River system: Big Mermaids Canyon Creek, West Fork of Bear Creek, Bichota Canyon Creek, Cattle Canyon Creek, and Cow Canyon Creek. The following areas were not specifically identified in the listing rule and are not currently occupied; they are therefore considered outside the geographical area occupied by the species at the time of listing: the upper Santa Ana River watershed, including City and Mill Creeks and the Santa Ana River (above La Cadena Drive in San Bernardino County to above Seven Oaks Dam), and the following three tributaries to Big Tujunga Creek: Gold Canyon, Delta Canyon, and Stone Canyon Creeks.

We are including in this final critical habitat designation all areas within the geographical area occupied by the listed Santa Ana sucker at the time of listing that also meet Criteria 1 through 3 below. These areas are all currently occupied. We are also including areas in this final critical habitat designation that were not within the geographical area occupied by the species at the time of listing and are not currently occupied but that are essential for the conservation of the species under Criteria 4 through 7 below. This final revised rule updates our 2005 final critical habitat designation for Santa Ana sucker with the best available data. For some areas that were analyzed in 2005, we have new information that led us to either add or remove an area from the proposed revised critical habitat designation and subsequently from this final rule.

For areas within the geographical area occupied by the species at the time of listing, we delineated critical habitat unit boundaries using the following steps:

1. We mapped historical and current digital occurrence data for Santa Ana sucker in the form of polygons and points on the digital aerial photography using ArcMap 9.3.1 (ESRI 2009). Areas between occupancy polygons or points were assumed to be occupied if there are no significant instream barriers (such as dams, culverts, or drop structures) preventing further movement between occupied stream sections. We utilized imagery acquired in Spring 2008 at 1-ft (0.33-m) resolution for the

Santa Ana River Unit in Riverside County and imagery acquired in January 2006 at 1-ft (0.33-m) resolution for the San Gabriel and Big Tujunga units provided by the U.S. Geological Survey. We also utilized imagery acquired in Spring 2005 at 3.25-ft (1-m) resolution provided by the National Aerial Imagery Program (NAIP) for the Santa Ana River Unit in Orange County. The resolution of the imagery allowed us to detect the presence of instream barriers.

We recognize that the historical and recent collection records for this species are incomplete. River segments or small tributaries not included in this final designation may harbor small populations of Santa Ana sucker or may become occupied in the future.

2. Using aerial imagery, we delineated the lateral extent (width) of the final revised critical habitat associated with occupied areas to include areas that provide sufficient riverine and associated floodplain area for breeding, feeding, and sheltering of adult and juvenile Santa Ana suckers and for the habitat needs of larval stage fish. Given the dynamic nature of these streams and the seasonal variation of the quantity of flow and the location of stream channels in any given year, we delineated the lateral extent of the final revised critical habitat to encompass the entire floodplain up to the upper limit of riparian vegetation or to the edge of a permanent barrier (such as a levee). Areas within the lateral extent exhibit the PCEs because they contain: (a) A functioning hydrological system characterized by peaks and ebbs in the water volume that encompasses areas that provide or contain sources of water and coarse sediment (PCE 1); (b) complex channels (such as alluvial fans and braided channels) and a mosaic of loose sand, gravel, cobble, and boulder substrates in a series of riffles, runs, pools, and shallow sandy stream margins (PCE 2); and (c) adjacent riparian vegetation (PCE 6).

The presence of PCEs may be seasonally variable and sporadic in distribution because of the dynamic nature of these streams and seasonal variation of flows in these streams throughout the year. Areas that may be seasonally lacking in PCEs and contain marginal habitat were included if they are contiguous with areas containing one or more of the PCEs and contribute to the hydrologic and geologic processes essential to the ecological function of the system. These areas are essential to maintain connectivity (PCE 7) within populations, allow for species movement throughout the course of a given year, and allow for population expansion.

3. Using aerial imagery, we delineated the upstream and downstream extents of the final revised critical habitat for areas within the geographical area occupied at the time of listing using the nearest occurrence polygon or point to either the point of a natural or manmade barrier or to the point where the instream gradient exceeds a 7 degree slope, either of which would prevent further movement of Santa Ana sucker. While several authors have acknowledged that this species cannot access high-gradient areas, we are not aware of any research quantifying the maximum slope passable by Santa Ana sucker. Therefore, in an attempt to estimate the maximum slope passable by the species, we used GIS to analyze the slopes associated with Santa Ana sucker occurrence polygons and points in our database for the Santa Ana River, San Gabriel River, and Big Tujunga Creek. Based on our analysis, Santa Ana suckers have not been found in areas where the instream slope exceeds 7 degrees. In the absence of additional research on this subject, we made the assumption that a slope of 7 degrees constitutes the maximum instream gradient passable by Santa Ana sucker and applied this assumption when delineating the upstream extent of the final revised critical habitat in the San Gabriel River system (Big Mermaids Canyon Creek, Bear Canyon Creek, West Fork of Bear Creek, Bichota Canyon Creek, Cattle Canyon Creek, and Cow Canyon Creek).

As discussed in the Physical and Biological Features section above, the absence of the species in these high-gradient areas could be due to the species' inability to swim up these higher gradients or due to the lack of suitable habitat in these areas as a result of higher water velocity and a subsequent lack of suitable spawning and feeding substrates or both. Therefore, we assume these high-gradient (greater than 7 degrees) areas do not contain the physical and biological features essential to the conservation of the species.

4. For areas outside the geographical area occupied by the species at the time it was listed, we evaluated stream reaches to determine if additional occupied or unoccupied areas are essential for the conservation of this species and should be included in the final revised designation. We determined that certain areas outside the geographical area occupied by the species at the time it was listed are essential for the conservation of the species because they are areas that provide or contain sources of water and coarse sediment (PCE 1) necessary to maintain preferred substrate conditions (PCE 2) in occupied portions of the species' range.

a. For the San Gabriel River, we determined that the areas within the geographical area occupied by the species at the time of listing and currently occupied are adequate for the conservation of the species based on our current understanding of the species' requirements. However, as discussed in the Critical Habitat section above, we recognize that designation of critical habitat may not include all habitat areas that we may eventually determine are necessary for the recovery of the species, and that for this reason, a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not promote the recovery of the species.

b. In the upper Santa Ana River Subunit (Subunit 1A), we determined that the following three areas outside the geographical area occupied by the species at the time of listing are essential for the conservation of the species: Mill Creek, City Creek, and the Santa Ana River from Tippecanoe Avenue to just below Seven Oaks Dam. Mill Creek has never been documented as being occupied by Santa Ana sucker. City Creek and the Santa Ana River above Tippecanoe Avenue are not currently occupied, but were historically occupied based on a 1982 California Natural Diversity Database record and a 1940 University of Michigan Museum of Zoology (UMMZ) Fish Collection database record, respectively.

We determined that the Santa Ana River above Tippecanoe Avenue, Mill Creek, and City Creek are essential for the conservation of the species because they are areas that provide or contain sources of water and coarse sediment (PCE 1) that may be transported downstream and are necessary to maintain preferred substrate (PCE 2) conditions in occupied portions in the Santa Ana River. Using aerial imagery, we determined that the Santa Ana River above Tippecanoe Avenue, Mill Creek, and City Creek have large, unimpeded watersheds based on the following morphological characteristics: (i) A wide floodplain area; (ii) the presence of complex channels (such as braided channels); and (iii) a mosaic of loose sand, gravel, cobble, and boulder substrates in a series of riffles, runs, pools, and shallow sandy stream margins (PCE 2). The area above Tippecanoe Avenue provides a source of water that is essential to the conservation of the species. Although the Seven Oaks Dam does regulate the flow of water downstream, it cannot

operate as a water holding or conservation facility without further consultation (Service 2002, p. 5; CRWQCB 2009, p. 24), and water must be passed through the dam. Water released from the dam is most important when winter storm water is transported downstream in high quantity and velocity. These flow events allow the river to meander through the floodplain and expose buried gravel and cobbles that are essential to the conservation of Santa Ana sucker. Given the extent to which the hydrology and the habitat of the occupied section of the Santa Ana River have been altered and degraded due to the construction and operation of flood control structures (such as Prado and Seven Oaks Dams) and operation of water treatment facilities, maintenance of the Santa Ana River (including areas above Tippecanoe Avenue), City Creek, and Mill Creek as pathways to transport storm and stream waters (PCE 1) and sediments necessary to maintain preferred substrates (PCE 2) to occupied portions of the Santa Ana River is essential for the conservation of the species.

c. In Big Tujunga Creek, we determined that the following unoccupied areas outside the geographical area occupied by the species at the time of listing are essential for the conservation of the species: Gold Canyon, Delta Canyon, and Stone Canyon Creeks. These areas provide sufficient quantities of stream and storm waters (PCE 1) necessary to transport sediments to maintain preferred substrate (PCE 2) conditions in occupied portions in Big Tujunga Creek. Using aerial imagery, we determined that Gold Canyon, Delta Canyon, and Stone Canyon Creeks have large, unimpeded watersheds flowing into Big Tujunga Creek, based on the following morphological characteristics: (i) A wide floodplain area; (ii) the presence of complex channels (such as braided channels); and (iii) a mosaic of loose sand, gravel, cobble, and boulder substrates in a series of riffles, runs, pools, and shallow sandy stream margins (PCE 2). Given the extent to which the hydrology and the habitat of the occupied section of Big Tujunga Creek have been altered and degraded due to the construction and operation of flood control structures, such as Big Tujunga and Hansen Dams, maintenance of Gold Canyon, Delta Canyon, and Stone Canyon Creeks as pathways to transport water (PCE 1) and sediments necessary to maintain preferred substrates (PCE 2) in Big Tujunga Creek is essential for the conservation of the species.

While we are not aware of any surveys for Santa Ana sucker conducted in these creeks, based on our calculation of maximum slope (

see

Criterion 3 above), it appears that the slope of Delta Canyon and Stone Canyon Creeks from near their confluence with Big Tujunga Creek is likely too steep to be passable by Santa Ana sucker. The slope of Gold Canyon Creek from approximately 0.49 mi (0.8 km) upstream from its confluence with Big Tujunga Creek also appears to be too steep to be passable by Santa Ana sucker.

5. Using aerial imagery, we delineated the lateral extent of final revised critical habitat in the Santa Ana River above Tippecanoe Avenue, and in City, Mill, Gold Canyon, Delta Canyon, and Stone Canyon Creeks, to include areas containing: (a) A wide floodplain area; (b) complex channels (such as alluvial fans and braided channels); and (c) a mosaic of loose sand, gravel, cobble, and boulder substrates in a series of riffles, runs, pools, and shallow sandy stream margins (PCE 2) needed to provide stream and storm waters (PCE 1) necessary to transport sediments to maintain preferred substrate conditions (PCE 2) in the downstream occupied portions of the Santa Ana River and Big Tujunga Creek, respectively.

6. We delineated the upstream limits of final revised critical habitat in the Santa Ana River above Tippecanoe Avenue, and in City, Mill, Gold Canyon, Delta Canyon, and Stone Canyon Creeks, by identifying the upstream origin of sediment transport in these tributaries to provide stream and storm waters (PCE 1) necessary to transport sediments to maintain preferred substrate conditions (PCE 2) in the downstream occupied portions of the Santa Ana River and Big Tujunga Creek, respectively. Using aerial imagery, we determined the origin of sediment transport in each creek to be the upstream area where complex channels (such as alluvial and braided channels) containing a mosaic of loose sand, gravel, cobble, and boulder substrates in a series of riffles, runs, pools, and shallow sandy stream margins (PCE 2) are visible.

7. We delineated the upstream and downstream extents of the final revised critical habitat in historically occupied areas of City Creek and the Santa Ana River above Tippecanoe Avenue using the same methodology as described under Criterion 3 above by extending the boundary from the nearest occurrence polygon or point to either the point of a natural or manmade barrier or to the point where the instream gradient exceeds a 7 degree slope, either of which we have assumed prevents further movement of Santa Ana sucker.

When determining critical habitat boundaries within this final rule, we made every effort to avoid including developed areas such as lands covered by buildings, pavement, and other structures because such lands lack physical and biological features for Santa Ana sucker. The scale of the maps we prepared under the parameters for publication within the Code of Federal Regulations may not reflect the exclusion of such developed lands. Any such lands inadvertently left inside critical habitat boundaries shown on the maps of this final rule are excluded by text in the rule and are not designated as critical habitat. Therefore, a Federal action involving these lands would not trigger section 7 consultation with respect to critical habitat and the requirement of no adverse modification unless the specific action would affect the physical and biological features in the adjacent critical habitat.

In summary, we are designating as critical habitat lands that we determined were occupied at the time of listing and contain sufficient physical and biological features to support life-history functions essential to the conservation of the species and lands outside the geographical area occupied at the time of listing that we determined are essential for the conservation of Santa Ana sucker.

Summary of Changes From Previously Designated Critical Habitat

The areas designated as critical habitat in this final rule constitute a revision of the critical habitat for Santa Ana sucker we designated on January 4, 2005 (70 FR 425). In this revised rulemaking we:

1. Refined the primary constituent elements (PCEs) to more accurately define the physical and biological features that are essential to the conservation of Santa Ana sucker;

2. Revised criteria to more accurately identify critical habitat;

3. Improved mapping methodology to more accurately define critical habitat boundaries and better represent areas that contain PCEs;

4. Reevaluated areas considered for exclusion from critical habitat designation under section 4(b)(2) of the Act; and

5. Added to, subtracted from, and revised those areas previously identified as essential to the conservation of Santa Ana sucker to accurately portray lands that meet the definition of critical habitat based on the best scientific data available. Table 1 provides an overview of the differences between 2004 and

2005 final critical habitat rules, 2009 proposed revised critical habitat, and this final critical habitat rule for Santa Ana sucker at the Unit and Subunit level.

The areas identified in this final rule constitute a revision of the areas designated as critical habitat for Santa Ana sucker on January 4, 2005 (70 FR 425). In the 2005 final rule, we designated 8,305 ac (3,361 ha) of critical habitat in Units 2 and 3 in Los Angeles County. In the 2005 final rule, we removed all of Subunit 1A (Northern Prado Basin; 3,535 ac (1,431 ha)) and Subunit 1B (Santa Ana Wash; 8,174 ac (3,308 ha)) in San Bernardino County from the critical habitat designation (

see

below for additional discussion), and excluded the remainder of Unit 1 (which totaled 15,414 ac (6,238 ha)) in San Bernardino, Riverside, and Orange Counties under section 4(b)(2) of the Act.

In the 2009 proposed revised rule, we proposed to designate a total of 9,605 ac (3,887 ha) in San Bernardino, Riverside, Orange, and Los Angeles Counties as critical habitat for Santa Ana sucker. In the subsequent document that made available the DEA (75 FR 38441; July 2, 2010), we proposed to designate an additional 38 ac (15.38 ha) in Subunit 1A as critical habitat for Santa Ana sucker. In this final rule, we are designating a total of 9,331 ac (3,776 ha) in Los Angeles, Orange, San Bernardino, and Riverside Counties. Table 1 below outlines the changes in areas in each Unit or Subunit between the 2004 and 2005 critical habitat designations and this revised critical habitat designation.

Table 1—Changes Between the February 26, 2004, Critical Habitat Designation (2004 fCH); the January 4, 2005, Critical Habitat Designation (2005 fCH); the December 9, 2009, Proposed Critical Habitat Designation (2009 prCH); the July 2, 2010,

Federal Register

Document Making Available the DEA (2010 NOA); and This Final Revised Critical Habitat Designation (2010 fCH)

[Values in this table may not sum due to rounding; * indicates area that was not included in the critical habitat designation]

County

2004 fCH

Unit/subunit

Area designated or essential

2005 fCH

Unit/subunit

Area designated or essential

2009 prCH

Unit/subunit

Area designated or essential

2010 NOA

Unit/subunit

Area designated or essential

2010 fCH

Unit/subunit

Area designated or essential

Los Angeles

3

3,655 ac (1,479 ha)

3

2,540 ac (1,028 ha)

3A

1,189 ac (481 ha)

3A

1,189 ac (481 ha)

3A

1,189 ac (481 ha)

3B

44 ac (18 ha)

3B

44 ac (18 ha)

3B

44 ac (18 ha)

2

5,765 ac (2,333 ha)

2

5,765 ac (2,333 ha)

2

1,000 ac (405 ha)

2

1,000 ac (405 ha)

2

1,000 ac (405 ha)

San Bernardino

1A

3,535 ac (1,431 ha)

1A

1,900 ac (768 ha)

1A

1,938 ac (784 ha)

1A

1,559 ac (631 ha)

1B

8,174 ac (3,308 ha)

San Bernardino and Riverside

N/A

N/A

1

15,414 ac (6,238 ha)*

1B

4,704 ac (1,903 ha)

1B

4,704 ac (1,903 ha)

1B

4,771 ac (1,931 ha)

Riverside and Orange

N/A

N/A

1C

767 ac (311 ha)

1C

767 ac (311 ha)

1C

767 ac (311 ha)

Total Designated

21,129 ac (8,551 ha)

8,305 ac (3,361 ha)

9,605 ac (3,887 ha)

9,643 ac (3,902 ha)

9,331 ac (3,776 ha)

Summary of Changes From the 2005 Final Critical Habitat to This Final Critical Habitat Designation

As described below, some areas designated in the 2005 final rule are not being designated as critical habitat in this final rule. Also, some areas are designated as critical habitat in this final rule that were not designated in the 2005 final rule because we have subsequently concluded that these areas are essential to the conservation of the species. These changes resulted in an overall addition of 1,026 ac (415 ha) in this final rule compared to the January 4, 2005, final revised designation (70 FR 425) (Table 1). These differences primarily resulted from the following changes to all of the units included in this final revised critical habitat designation, as well as the unit-specific revisions discussed below.

1. Enhanced resolution of aerial imagery allowed us to improve our mapping methodology to more accurately define the critical habitat boundaries and to better represent those areas that possess the physical and biological features essential to the conservation of the species. In the 2005 final rule, we used a 100-meter grid to delineate critical habitat. In this final rule, we delineated areas that contain the PCEs using current aerial imagery (

see

Criteria Used To Identify Critical Habitat section). This revised mapping method resulted in a significant overall decrease in the areas deemed essential and included in the final revised critical habitat boundaries. However, even with more refined mapping methods, we acknowledge the possibility that, due to mapping, data, and resource constraints, there may be some undeveloped areas mapped as critical habitat that do not contain the PCEs.

2. We revised the criteria used to identify critical habitat in the Santa Ana River, the San Gabriel River, and Big Tujunga Creek. The revised criteria allowed us to more precisely delineate the upstream boundaries of areas determined to contain the physical and biological features essential to the conservation of the species. We described the criteria and methods we used to identify and delineate the areas that we are designating as critical habitat in more detail than we did in the 2005 critical habitat designation to ensure that the public better understands why the areas are being designated as critical habitat (

see

Criteria Used To Identify Critical Habitat section of this final rule for a detailed discussion).

3. We reevaluated areas included in the 2005 final critical habitat designation to determine if those areas contain the physical and biological features essential to the conservation of Santa Ana sucker or are otherwise essential for the conservation of the species. As a result, some areas designated as Santa Ana sucker critical habitat in 2005 were removed from the 2009 proposed revised rule and this final rule (as described below) because they do not contain the physical and biological features required by Santa Ana sucker and are not otherwise essential to the species' conservation.

Major revisions in each unit include the following:

Unit 1: Santa Ana River (San Bernardino, Riverside, and Orange Counties)

1. In the 2005 critical habitat rule, we excluded all of Unit 1 (15,414 ac (6,238 ha)) from final critical habitat under section 4(b)(2) of the Act. In this final rule, we are designating a total of 5,535 ac (2,241 ha) as critical habitat in Subunits 1B and 1C, which correspond roughly to Unit 1 in the 2005 final rule and not excluding any areas under section 4(b)(2) of the Act. The 9,879-ac (3,998-ha) difference between the area identified as Unit 1 in the 2005 final rule and Subunits 1B and 1C in this final rule is primarily due to the following revisions:

a. In the 2005 critical habitat rule, numerous tributaries and channels that drain into the Santa Ana River were

considered essential to the conservation of the species but excluded under section 4(b)(2) of the Act. In this final rule, we removed from Subunits 1B and 1C (the area roughly corresponding to Unit 1 in the 2005 final rule) the following tributaries and channels because these areas do not contain the physical and biological features essential to the conservation of the species (from North to South):

• 1.2 mi (1.9 km) urban drainage through Lake Evans;

• 1.3 mi (2.1 km) urban drainage through Hole Lake;

• 0.9 mi (1.4 km) urban drainage (north side of the Santa Ana River (SAR), east of Pedley);

• 2.3 mi (3.7 km) urban drainage (north side of SAR, west of Pedley);

• 1.0 mi (1.5 km) urban drainage up Lucretia Avenue;

• 0.3 mi (0.47 km) urban drainage up Norco Rd. near California Rehabilitation Center;

• 2.1 mi (3.4 km) of Temescal Wash north of Corona Municipal Airport;

• 0.9 mi (1.5 km) urban drainage north of Temescal Wash; and

• 1.0 mi (1.7 km) urban drainage south of Corona Municipal Airport.

b. In the 2005 critical habitat rule, the Prado Basin where Chino and Temescal Creeks and the Santa Ana River converge was considered essential to the conservation of the species, but we excluded this area under section 4(b)(2) of the Act. In this final rule, we are not designating 4,476 ac (1,811 ha) of the Prado Basin where Chino and Temescal Creeks and the Santa Ana River converge because these areas do not contain the physical and biological features essential to the conservation of the species.

2. In the 2005 critical habitat rule, we did not designate Subunit 1B (Santa Ana Wash; 8,174 ac (3,308 ha)) as critical habitat because we determined this area to be “nonessential.” We revisited that determination in our 2009 proposed revised critical habitat rule and this final critical habitat designation and conclude that portions of the area identified as Subunit 1B in the 2005 rule are essential for the conservation of the Santa Ana sucker. We changed our conclusion because we believe the creeks and rivers in Subunit 1B provide stream and storm waters (PCE 1) required to transport sediments that are necessary to maintain preferred substrate (PCE 2) conditions in occupied portions of the Santa Ana River. These waters are critical to maintain habitat for populations of Santa Ana sucker in the Santa Ana River, one of only three geographical areas where the listed entity survives. Protecting existing habitat on which the Santa Ana River populations depend is essential for the recovery of this species. Based on our reevaluation of this area, we are designating 1,559 ac (631 ha) in City and Mill Creeks and the Santa Ana River (below Seven Oaks Dam) as part of Subunit 1A, which composed a portion of Subunit 1B in the 2005 final rule. Some portions of the Santa Ana Wash area identified as part of Subunit 1B in the 2005 rule do not contain the physical and biological features essential to the conservation of the species and are not otherwise essential for the conservation of the Santa Ana sucker, and we have not included them as part of Subunit 1A.

Unit 2: San Gabriel River (Los Angeles County)

1. In the 2005 critical habitat rule, we designated 5,765 ac (2,333 ha) as critical habitat in Unit 2. In this final rule, we are designating 1,000 ac (405 ha) as critical habitat in Unit 2 (area corresponds roughly to Unit 2 in the 2005 final rule). The 4,765-ac (1,928-ha) reduction in Unit 2 from the 2005 final rule is primarily due to the following revisions:

a. In this final rule, we removed the upstream sections of the following creeks/rivers (which were designated in the 2005 final rule), because our analysis indicates that the slope of these upstream sections exceeds 7 degrees; therefore, we determined these areas do not contain the physical and biological features essential to the conservation of the species (

see

Criterion 3 in the Criteria Used To Identify Critical Habitat section above for a detailed discussion of our slope calculations and assumptions):

• 2.9 mi (4.60 km) of Big Mermaids Canyon Creek;

• 0.5 mi (0.77 km) of Bear Canyon Creek;

• 0.4 mi (0.60 km) of West Fork of Bear Creek;

• 1.6 mi (2.61 km) of North Fork of the San Gabriel River;

• 0.1 mi (0.19 km) of Bichota Canyon Creek;

• 1.9 mi (3.07 km) of Cattle Canyon Creek; and

• 0.3 mi (0.42 km) of Cow Canyon Creek.

While these unoccupied upstream areas do provide pathways to transport water (PCE 1) and sediments necessary to maintain preferred substrates (PCE 2), we determined that the areas within the geographical area occupied by the species in the San Gabriel River at the time of listing and currently occupied are adequate for the conservation of the species in this portion of its range (

see

Criteria Used To Identify Critical Habitat above).

b. In this final rule, we removed the entire extent of Shoemaker Canyon Creek (0.99 mi (1.59 km)) that was designated in the 2005 final rule because based on our calculations, the slope of this creek exceeds 7 degrees; therefore, we determined this area does not contain the physical and biological features essential to the conservation of the species (

see

Criterion 3 in the Criteria Used To Identify Critical Habitat section above for a detailed discussion of our slope calculations and assumptions).

c. In this final rule, we removed the entire extent of Burro Canyon Creek (0.74 mi (1.19 km)) that was designated in the 2005 final rule because habitat in this creek has been degraded due the operation of a mine upstream and does not contain the physical and biological features essential to the conservation of the species.

2. We are extending the upstream boundary of the East Fork of the San Gabriel River approximately 0.85 mi (1.37 km) from the upstream end of an occurrence polygon to the point near the Bridge-of-No-Return. In the 2005 final rule, we acknowledged that this upstream area is essential to the conservation of Santa Ana sucker, but because the area had not been proposed as critical habitat or delineated on the map or the legal description for this unit, it was not included in the 2005 final rule (70 FR 425; January 4, 2005).

Unit 3: Big Tujunga Creek (Los Angeles County)

1. In the 2005 critical habitat rule, we designated 2,540 ac (1,028 ha) as critical habitat in Unit 3. In this final rule, we are designating 1,233 ac (499 ha) as critical habitat in two subunits, Subunits 3A and 3B, which correspond roughly to Unit 3 in the 2005 final rule. Subunit 3A contains the mainstem of Big Tujunga Creek from Hansen Dam to Big Tujunga Dam, and Subunit 3B contains three unoccupied tributaries to Big Tujunga Creek: Gold Canyon, Delta Canyon, and Stone Canyon Creeks. The 1,307-ac (529-ha) reduction in Unit 3 from the 2005 final rule is primarily due to the following revisions:

a. In this final rule, we removed an upstream 0.26-mi (0.42-km) section of Delta Canyon Creek (Subunit 3B) and an upstream 0.13-mi (0.21-km) section of Stone Canyon Creek (Subunit 3B), both designated in the 2005 final rule, because these areas appear to be above the origin of sediment transport in these creeks and not essential to the conservation of the species (

see

Criterion 7 in the Criteria Used To

Identify Critical Habitat section above for a discussion of origin of sediment transport).

b. We are designating additional portions of Gold Canyon Creek (Subunit 3B) by extending the upstream boundary of critical habitat in the creek by approximately 0.29 mi (0.47 km) from the 2005 final critical habitat boundary to capture the upstream origin of sediment transport for this creek, an area we determined is essential for the conservation of the species (

see

Criterion 7 in the Criteria Used To Identify Critical Habitat section above for a discussion of origin of sediment transport).

c. We are designating approximately 160 ac (65 ha) of the privately owned Angeles National Golf Club in Subunit 3A in this final rule. Specifically, we are designating only the alluvial floodplain and multiple low-flow channels that traverse the golf course. However, due to the scale of the habitat areas containing the PCEs within the golf course and the current GIS mapping techniques, we are unable to map precisely only those areas containing the physical and biological features essential to the conservation of the species. Therefore, the entire golf course is mapped as final critical habitat. Permanent structures and facilities associated with the golf course (such as buildings) and fairways and greens outside of the floodplain do not contain the PCEs and are therefore not considered critical habitat.

The majority of the Angeles National Golf Club area was not included in the 2005 final critical habitat designation. However, this area includes the alluvial floodplain and multiple low-flow channels that traverse the golf course, and lies between the confluence of Big Tujunga and Haines Creeks. Stream flow and storm waters from Big Tujunga Creek transport sediments necessary to maintain preferred substrate conditions (PCE 2) within Haines Creek. These waters flow through the golf course on an irregular basis (

i.e.,

in 2 of the 5 years since the course was opened). Both creeks discharge into occupied habitat downstream, including the Big Tujunga Mitigation Bank, a conserved habitat area, which supports Santa Ana sucker and two other native fishes. Therefore, we believe this area contains the features essential to the conservation of the species because it provides for sediment transport (PCE 2) into the downstream conserved habitat area.

Summary of Changes From 2009 Proposed Critical Habitat to This Final Critical Habitat Designation

Unit 1: Santa Ana River (San Bernardino, Riverside, and Orange Counties)

In the proposed critical habitat revision that published with the document that made available the DEA on July 2, 2010 (75 FR 38441), we added approximately 38 ac (15 ha) to Subunit 1A in a portion of Plunge Creek, a tributary of the Santa Ana River that is located in San Bernardino County upstream of the confluence of the Santa Ana River with City Creek, to serve as an area for possible reintroduction efforts. This area was proposed in response to public comment during the first comment period. Additionally, the portion of Subunit 1A located above Seven Oaks Dam was included in the 2009 proposed revised rule (74 FR 65056; December 9, 2009). In this final critical habitat designation, we conclude that these areas are not essential. We lack information indicating that these areas were historically occupied by the species and lack sufficient information to support a determination that these areas are needed for the species' recovery. In particular, we lack supporting information regarding the feasibility of introducing Santa Ana sucker at either location (such as water quality conditions, reliability of water flows, and presence of predatory and competing species). Furthermore, upstream movement of Santa Ana suckers from the Santa Ana River mainstem into Plunge Creek is precluded due to mining operations that make the habitat unsuitable for the fish (including a dry stretch of the creek), while such movement is also precluded into the upper Santa Ana River and Bear Creek because of the Seven Oaks Dam. Additionally, we lack a comprehensive conservation strategy for Santa Ana sucker. Therefore, we cannot conclude at this time that these areas are essential for the conservation of the species.

As discussed in the Critical Habitat section below, because any designation of critical habitat may not include all habitat areas that we may eventually determine are necessary for the recovery of a species, this critical habitat designation should not signal that habitat outside the designated area is unimportant or may not promote the recovery of Santa Ana sucker (

e.g.,

reintroduction sites). We plan to initiate development of a recovery plan in 2011, which may include the establishment of a recovery team that would seek the involvement of species experts, habitat experts, and stakeholders. We anticipate this recovery effort would evaluate the need for reintroduction and, if needed, evaluate these areas and other sites within the historical range of the species for potential recovery efforts.

In the proposed revised critical habitat rule (74 FR 65056; December 9, 2009) and for the document that made available the DEA (75 FR 38441; July 2, 2010), we misprinted area estimates of acreages by land owners in Unit 1. We have corrected this error, and acreages are correctly represented in Table 2 below and the textual descriptions of each Subunit in Unit 1 below.

In the proposed revised critical habitat rule (74 FR 65056; December 9, 2009) and document making available the DEA (75 FR 38441; July 2, 2010), we evaluated areas considered for exclusion under section 4(b)(2) of the Act in the Santa Ana River that are covered by the Santa Ana Sucker Conservation Program (SAS Conservation Program) and the Western Riverside County MSHCP, including identifying whether or not these areas are or are going to be conserved and managed for the benefit of Santa Ana sucker. In this rule, we determined whether the areas were already conserved and managed for the benefit of Santa Ana sucker, and analyzed, under section 4(b)(2) of the Act, whether the benefits of exclusion from the critical habitat designation outweigh the benefits of including these areas.

Final Critical Habitat Designation

We are designating three units as critical habitat for Santa Ana sucker. The critical habitat areas described below constitute our best assessment at this time of areas that meet the definition of critical habitat for Santa Ana sucker. Table 2 identifies the approximate area of each critical habitat unit by land ownership. These units replace the current critical habitat designation for Santa Ana sucker in 50 CFR 17.95(e). The critical habitat areas we describe below constitute our best assessment of (1) areas determined to be within the geographical area occupied by the species at the time of listing that contain the physical and biological features essential to the conservation of the species and which may require special management considerations or protection, and (2) areas that are not within the geographical area occupied by the species at the time of listing but that are essential for the conservation of the species (

see

Criteria Used To Identify Critical Habitat section above for a discussion of geographical area).

Table 2—Area Estimates (Acres (ac) and Hectares (ha)) and Land Ownership for Santa Ana Sucker Final Revised Critical Habitat

[Values in this table may not sum due to rounding]

Critical habitat unit

County

Land ownership

Federal

State or local government

Private

Total area

Unit 1: Santa Ana River

Subunit 1A: Upper Santa Ana River

San Bernardino

74 ac

(30 ha)

95 ac

(38 ha)

1,389 ac

(562 ha)

1,559 ac

(631 ha)

Subunit 1B: Santa Ana River

San Bernardino and Riverside

521 ac

(211 ha)

2,854 ac

(1,155 ha)

1,396 ac

(565 ha)

4,771 ac

(1,931 ha)

Subunit 1C: Lower Santa Ana River

Riverside and Orange

0 ac

(0 ha)

56 ac

(23 ha)

711 ac

(288 ac)

767 ac

(311 ha)

Unit 1 Total

595 ac

(241ha)

3,006 ac

(1,217ha)

3,496 ac

(1,4l5ha)

7,097 ac

(2,872ha)

Unit 2: San Gabriel River

Unit 2: San Gabriel River

Los Angeles

917 ac

(371 ha)

0 ac

(0 ha)

83 ac

(34 ha)

1,000 ac

(405 ha)

Unit 3: Big Tujunga Creek

Subunit 3A: Big Tujunga and Haines Creeks

Los Angeles

242 ac

(98 ha)

0 ac

(0 ha)

947 ac

(383 ha)

1,189 ac

(481 ha)

Subunit 3B: Gold, Delta, and Stone Creeks

Los Angeles

44ac

(18 ha)

0 ac

(0 ha)

0 ac

(0 ha)

44 ac

(18 ha)

Unit 3 Total

286 ac

(116ha)

0 ac

(0 ha)

947 ac

(383 ha)

1,233 ac

(499 ha)

Total

1,798 ac

(728 ha)

3,006 ac

(1,217 ha)

4,526 ac

(1,832 ha)

9,331 ac

(3,776 ha)

Critical Habitat Units

Presented below are brief descriptions of all units and reasons why they meet the definition of critical habitat for Santa Ana sucker.

Unit 1: Santa Ana River

Unit 1 is located in San Bernardino, Riverside, and Orange Counties and consists of three subunits totaling 7,097 ac (2,872 ha) of Federal (U.S. Army Corps of Engineers and USFS), local government, and private land (Table 2). The purpose of this unit is to independently support a population of Santa Ana sucker in a functioning hydrologic system that provides suitable water quality, supply, and coarse sediment. One currently unoccupied subunit (Subunit 1A) provides essential sources of water and coarse sediment to occupied portions of the unit.

Subunit 1A: Upper Santa Ana River

Subunit 1A is located near the Cities of Highland, Mentone, and Redlands in San Bernardino County, California. This subunit includes: 7 mi (12 km) of City Creek (measured from its confluence with the Santa Ana River), 12 mi (19 km) of Mill Creek (measured from its confluence with the Santa Ana River), and 10 mi (17 km) of the Santa Ana River from below the Seven Oaks Dam to near Tippecanoe Avenue. The lower portion of the Santa Ana River below its confluence with City and Mill Creek is adjacent to urban development, while the upstream portions of City Creek and Mill Creek are in the San Bernardino National Forest. Lands in this subunit are under Federal (USFS and Bureau of Land Management (BLM)) (74 ac (111 ha)), State/Local (95 ac (38 ha)), and private (1,389 ac (562 ha)) ownership (Table 2).

Subunit 1A is outside the geographical area occupied by the species at the time of listing and is not currently occupied. While City Creek and the Santa Ana River above Tippecanoe Avenue are not currently occupied, these areas were historically occupied based on a 1982 California Natural Diversity Database record and a 1940 University of Michigan Museum of Zoology Fish Collection (UMMZ) database record, respectively, and City Creek currently provides suitable habitat conditions for Santa Ana sucker (OCWD 2009, pp. 5-71-5-76). Mill Creek is not known to be historically or currently occupied and does not provide suitable habitat conditions for Santa Ana sucker; however, we determined this area to be essential for the conservation of the species because of the process of water and coarse sediment transport that it provides. The Santa Ana River above Tippecanoe Avenue, Mill Creek, and City Creek provide stream and storm waters (PCE 1) which are necessary to transport coarse sediments necessary to maintain preferred substrate (PCE 2) conditions in occupied portions in the Santa Ana River and we determined that these areas are essential for the conservation of the species because of the process of water and coarse sediment transport that they it provide. The creation and operation of Seven Oaks Dam has regulated water flow and impeded the transport of coarse sediment. However, because the operation of Seven Oaks Dam, in coordination with Prado Dam downstream, is currently permitted for flood control operations only (operations only regulate flows throughout the year in an effort to

prevent catastrophic flow events downstream) and not for water storage purposes (Service 2002, pp. 3-6), the flow of water through the dam still provides water necessary for occupied reaches of the Santa Ana River downstream. Storing water for the purpose of water conservation (

i.e.,

diversions or storage for water sales) is not currently authorized, nor was proposed as a purpose for Seven Oaks Dam (Service 2002, p. 5). Although there has recently been a CRWQCB decision to allow up to 200,000 acre-feet to be diverted from the Seven Oaks Dam reservoir, this potential action has not been evaluated or approved by the Federal agencies involved. The CRWQCB stated that water conservation operations will be the responsibility of the water agency and the appropriate Federal agencies will need to be consulted before water can be diverted for water conservation (

i.e.,

sale) purposes (CRWQCB 2009, p. 23).

As stated above, this subunit is relatively unmodified compared to the other subunits in this unit, with the exception of the upper Santa Ana River that contains Seven Oaks Dam and the lower portion of City Creek that is adjacent to urbanized areas. The critical habitat designated in this subunit is threatened by impacts associated with, but not limited to, water diversion, dams, operation of hydro-electrical power facilities, or alteration of streambeds. We consider the magnitude of threats to be less severe than those in the lower watershed because the majority of the subunit is relatively unmodified and portions are within the San Bernardino National Forest. Nonetheless, we also recognize that active management and special management considerations or protection may be needed in this subunit (

see

Special Management Considerations or Protection section above).

Although areas of the Santa Ana River above South La Cadena Drive and some of its associated tributaries generally dry during the summer, portions of the upper Santa Ana River system (within San Bernardino County) have a higher gradient and a greater percentage of gravel and cobble substrate than the occupied areas that are downstream (Warrick and Rubin 2007, pp. 1-2). Santa Ana suckers spawn over gravel substrates, where their eggs can adhere to gravel before hatching into larvae. Flood events or high winter flows from upstream areas annually replenish this coarse substrate and clean sand and silt from it (Kondolf 1997, pp. 533-535). Additionally, Santa Ana suckers feed by scraping algae, insects, and detritus from gravel and cobble. Therefore, the spawning and feeding substrates (gravel and cobble) which are replenished by upstream sources are essential to the reproductive ability and development of Santa Ana suckers in the downstream occupied reaches (Kondolf 1997, pp. 533-535, 536-537). The section of the Santa Ana River from above Tippecanoe Avenue in San Bernardino, City Creek, and Mill Creek (although not currently occupied) have become particularly essential for the conservation of the species since the Seven Oaks Dam has reduced the transport of coarse sediment and altered the natural flow in the downstream, occupied areas of the Santa Ana River. They are in fact the primary sources of coarse sediment in the upper Santa Ana River watershed (PCE 2) and additionally are part of the Santa Ana River hydrologic system (PCE1), and assist in maintaining water quality (PCE 4) and temperature (PCE 5) to occupied reaches of the Santa Ana River; therefore, these areas are essential for the conservation of Santa Ana sucker (

see

Sites for Breeding, Reproduction, and Rearing (or Development) of Offspring section above).

In our process of determining what areas meet the criteria of occupied critical habitat, it became apparent that habitat and hydrological modifications that have been occurring for many years in the Santa Ana River have decreased the areas suitable for occupation by the Santa Ana sucker (Moyle 2002, p. 184; Thompson

et al.

2010, p. 330). The presence of two large dams operating in coordination have altered and will continue to alter the flow of water and coarse sediments in the Santa Ana River (Chang 2000, p. 3) that are necessary for essential life cycle processes of Santa Ana sucker. Specifically, the models used to predict the transport of sediment throughout the Santa Ana River and surveys have confirmed that sediment has been significantly degraded in the Santa Ana River from the E Street USGS gauge (#11059300) to the Metropolitan Water District crossing USGS gauge (#11066460) and deposited above and below these areas (Humphrey

et al.

2004, pp. 6-7). The deposition and degradation of sediments throughout the Santa Ana River will eventually level the gradient of the Santa Ana River between the Seven Oaks and Prado Dams. This ongoing process, which modifies and degrades the Santa Ana sucker's habitat, highlights the importance of designating areas that provide for essential processes, such as water and coarse sediment transport to occupied areas downstream. Therefore, we have determined that City Creek, Mill Creek, and the Santa Ana River above Tippecanoe Avenue are essential for the conservation of the species because they provide for essential processes, such as water and coarse sediment transport.

Subunit 1B: Santa Ana River

Subunit 1B is located near the cities of Colton and Rialto in San Bernardino County and the cities of Riverside, Norco, and Corona in Riverside County, California. This subunit includes approximately 22 mi (35 km) of the mainstem of the Santa Ana River from near Tippecanoe Avenue in San Bernardino County to the Prado Dam and Flood Control Basin in Riverside County. This subunit also includes sections of the following tributaries (distances are measured from the mainstem of the Santa Ana River): 1,647 ft (502 m) of the Rialto Drain and 2,413 ft (736 m) Sunnyslope Creek. Lands within this subunit are under Federal (U.S. Army Corps of Engineers) (521 ac (211 ha)), State/Local (2,854 ac (1,155 ha)), and private (1,396 ac (565 ha)) ownership (Table 2).

Areas within this subunit are within the geographical area occupied by the species at the time of listing, most are currently occupied, and all contain physical and biological features essential to the conservation of the species and may require special management considerations or protection. An approximate 5.1-mile (8.1-km) portion of the Santa Ana River between La Cadena Drive and Tippecanoe Avenue within Subunit 1B is not currently occupied due the barrier to upstream dispersal at La Cadena Drive; however, this areas was considered occupied at the time of listing and is essential to the conservation of the species and contains sources of water and coarse sediment (PCE 1) essential to the conservation of Santa Ana sucker. This subunit has been heavily impacted by urban development and threats to Santa Ana sucker and its essential features in this subunit result from impacts associated with, but not limited to: Water diversion; dams; water quality impacts from non-point source and point source pollution (including untreated urban run-off and discharge of treated wastewater); and altered hydrology throughout the watershed (including alterations from instream barriers, construction of bridges, channelization, and other flood control structures). Special management considerations or protection may be needed in this subunit to protect its essential features (

see

Special Management Considerations or Protection section above).

Recent surveys found Santa Ana suckers at various locations in the mainstem of the Santa Ana River between the Rialto Drain and the Prado Dam (Baskin

et al.,

2005, pp. 1-2; Swift 2009, pp. 1-3). Santa Ana suckers also occupy the Rialto Drain and Sunnyslope Creek at least during portions of the year (Chadwick Ecological Consultants, Inc. 1996, p. 9; Swift 2000, p. 8; Swift 2001, p. 45). At this time, the low-flow channel of the Santa Ana River has moved away from its confluence with Sunnyslope Creek, and accumulated sediments and vegetation are preventing access to this creek by Santa Ana suckers (OCWD 2009, pp. 5-31). However, a connection between the mainstem and Sunnyslope Channel will likely be reestablished following a high-flow event. Santa Ana suckers were found upstream of the Rialto Drain in the vicinity of the La Cadena Bridge drop-structure during spring-time flow releases from the Seven Oaks Dam in 2005 (Baskin

et al.

2005, p. 1). However, the La Cadena Bridge drop-structure currently acts as a barrier to upstream migration at all flow levels. Rialto Drain and Sunnyslope Creek are the only tributaries to the Santa Ana River in this subunit where Santa Ana sucker spawning has been documented. However, the distribution of fry and juvenile fish observed in various locations within the mainstem is a strong indication that spawning areas other than the Rialto Drain and Sunnyslope Creek likely exist within the Santa Ana River.

In the mainstem of the Santa Ana River, dry-season flows are dependent primarily on discharges from tertiary wastewater treatment plants and upwelling of ground water within the Unit (CRWQCB 1995, pp. 1-4-1-8; Chadwick and Associates, Inc. 1992, p. 20), while storm-season flows are regulated by the upstream Seven Oaks Dam. The discharge of treated wastewater effluent maintains stream volume and velocity within the mainstem and the Rialto Drain to maintain habitat patches that support the riverine environment (PCE 1) necessary for Santa Ana sucker. However, it appears that these wastewater flows are not sufficient to deliver coarse sediment downstream (Thompson

et al.

2010, pp. 327-328). The discharge of treated wastewater effluent along with the upwelling of groundwater also lowers instream water temperature to some extent in portions of the Santa Ana River (Chadwick and Associates, Inc. 1992, p. 26) (PCE 5), and rising groundwater in the Riverside Narrows feeds several small tributaries to the Santa Ana River, including the Sunnyslope Creek (CRWQCB 1995, pp. 1-4-1-8; Swift 2001, p. 3) (PCE 1). Rialto Drain and Sunnyslope Creek contain gravel and cobble substrate, with some sand accumulation along channel edges and deep pools, and a riparian overstory (PCEs 2 and 6). Therefore, these areas provide areas for spawning and rearing of fry and juvenile fish (PCE 1) and shallow-water refuge for Santa Ana suckers during storms and during periods of high ambient air temperatures (PCE 6). Almost all other tributaries to the Santa Ana River in this subunit have been channelized, and while these tributaries continue to provide some water and storm water flows to the mainstem, the majority of this water is untreated run-off from surrounding urban areas. Also, with the exception of their confluence with the mainstem, it appears these other tributaries to the Santa Ana River have been modified such that they no longer provide suitable habitat for the species.

In addition to reduced water quality and altered hydrology, habitat within this subunit has been impacted by the construction of several bridges spanning the Santa Ana River and grade-control structures that fragment habitat for Santa Ana sucker. Therefore, the physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats associated with water diversion, alteration of stream channels and watersheds, and reduction of water quantity and quality associated with urban development. Please

see

Special Management Considerations or Protection section for further discussion of the threats to Santa Ana sucker habitat.

Subunit 1C: Lower Santa Ana River

Subunit 1C is located near the City of Corona in Riverside County and the cities of Anaheim and Yorba Linda in Orange County, California. This subunit includes approximately 10.7 mi (17.2 km) of the Santa Ana River mainstem from below the Prado Dam outlet in Riverside County to 0.6 mi (1.03 km) downstream of the State Route 90 (Imperial Highway) Bridge in Orange County. Tributaries to the Santa Ana River in this subunit may provide water and storm water flows necessary to maintain preferred substrate conditions in the occupied portion of the Santa Ana River (PCE 1). However, we do not currently have information on the extent of their contribution and therefore are not proposing any tributaries to the Santa Ana River in Subunit 1C as critical habitat. Lands within this subunit are under State/Local (56 ac (23 ha)) and private (711 ac (288 ha)) ownership (Table 2).

All areas in Subunit 1C are within the geographic area occupied by the species at the time of listing and contain the features essential to the conservation of the species and may require special management considerations or protection. This species has been found in the vicinity of the Gypsum Canyon Bridge, Weir Canyon drop structure, and the Imperial Highway overpass (Chadwick Ecological Consultants, Inc. 1996, p. 9; Swift 2000, pp. 15-20; Baskin and Haglund 2001, pp. 1-5). More recently Santa Ana suckers were collected just below Prado Dam (SMEA 2008, p. 1; Lovan 2010, pers. comm.).

This subunit has been heavily impacted by urban development and threats to Santa Ana sucker and its essential features in this subunit result from impacts associated with, but not limited to: Water diversion; dams; water quality impacts from non-point source and point source pollution (including untreated urban run-off and discharge of treated wastewater); and altered hydrology throughout the watershed (including alterations from instream barriers, construction of bridges, channelization, and other flood control structures). We also recognize that special management considerations or protection may be needed in this subunit to protect its essential features (

see

Special Management Considerations or Protection section above).

Upstream water flows to Subunit 1C are primarily maintained by releases from Prado Dam, a structure that has altered the hydrology of the system, resulting in fluctuating water (PCE 1) and sediment (PCE 2) releases. The numerous tributaries flowing into the Santa Ana River below Prado Dam appear to contribute little dry-season flow. Releases from Prado Dam maintain perennial stream flow in the Santa Ana River, which in turn maintains well-defined banks supporting native riparian vegetation (PCE 6) and deep pools (PCE 2). However, since the velocity is typically high, water released below the dam is often turbid. During storms, water containing fine sediments passes over or through a dam, and because sediments remain suspended within the reservoir pool for several months, downstream turbidity can be increased (PCE 4) (Ally 2004a, p. 36). Releases of turbid water could also degrade downstream foraging and spawning habitat if areas become covered by fine silts. The operation of Prado Dam also traps larger sediments therefore decreasing the deposition of

gravel and cobble needed to maintain spawning and foraging habitat below the dam.

In addition to reduced water quality and altered hydrology, habitat within this subunit has been impacted by the construction of several bridges spanning the Santa Ana River that have constricted or redirected the stream channel in many places. Therefore, the physical and biological features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from water diversion, alteration of stream channels and watersheds, and reduction of water quantity and quality associated with urban development. Please

see

the Special Management Considerations or Protection section of this final rule for discussion of the threats to the Santa Ana sucker habitat.

Unit 2: San Gabriel River

Unit 2 consists of the West, North, and East Forks of the San Gabriel River upstream of the San Gabriel Reservoir, in Los Angeles County, California. This unit includes 9.3 mi (14.9 km) of the West Fork downstream of Cogswell Dam to the San Gabriel Reservoir, 3.2 mi (5.2 km) of the North Fork upstream from the confluence with the West Fork, and 10.4 mi (16.7 km) of the East Fork downstream of the Bridge-of-No-Return to the San Gabriel Reservoir. This unit also includes sections of the following tributaries (distances are measured from the mainstem of the fork): 0.3 mi (0.5 km) of Big Mermaids Canyon Creek and 3.3 mi (5.3 km) Bear Canyon Creek, both tributaries of the West Fork; 0.2 mi (0.2 km) of the West Fork of Bear Canyon Creek, a tributary of Bear Canyon Creek; 1.5 mi (2.4 km) of Bichota Canyon Creek, a tributary of the North Fork; 3.8 mi (6.2 km) of Cattle Canyon Creek, a tributary of the East Fork; and 0.6 mi (0.9 km) of Cow Canyon Creek, a tributary of Cattle Canyon Creek. Lands within this unit are entirely within the Angeles National Forest and are under Federal (USFS) (917 ac (371 ha)) and private (83 ac (34 ha)) ownership (Table 2).

All areas in Unit 2 are within the geographical area occupied by the species at the time of listing, contain the features essential to the conservation of the species and may require special management considerations or protection. Unit 2 is the only unit designated as critical habitat that, overall, has a sediment transport and hydrological regime existing in a near-natural state. The function of Unit 2 is to independently support a population of Santa Ana sucker within a relatively intact watershed that provides good water quality and supply, and sediment transport. The Santa Ana suckers in this unit are the only extant population of the species that is not chronically exposed to urban runoff or tertiary-treated wastewater discharges. Additionally, this unit does not have a regulated water supply (with the exception of the West Fork of the San Gabriel River). However, threats to Santa Ana sucker and its essential features in this unit result from impacts associated with, but not limited to: Water diversion; dams; water quality impacts as a result of increased run-off due to a recent, intense wildfire event; and recreational use impacts from OHVs or other recreational uses on National Forest lands. We also recognize that special management considerations or protection may be needed in this subunit to protect its essential features (

see

Special Management Considerations or Protection section above).

In addition to surveys discussed in the listing rule (65 FR 19686; April 12, 2000) and in the previous designation of critical habitat for Santa Ana sucker (70 FR 425; January 4, 2005), additional surveys have documented Santa Ana suckers in the West, North, and East Forks of the San Gabriel River and the following tributaries: Big Mermaids Canyon, Bear Canyon, Bichota Canyon, Cattle Canyon, and Cow Canyon Creeks (Haglund and Baskin 1992, p. 32; O'Brien 2009a, pp. 2-3; Ally 2004b, pp. 8-9, 14-15, 22, 24-25, 28; Ally 2004c, pp. 9-10, 13-14, 16-17; Tennant 2004, pp. 5-8; Tennant 2006, p. 3). The West, North, and East Forks of the San Gabriel River have one of the most intact native freshwater fish faunas in Southern California (Haglund and Baskin 2003, p. 7), have good water quality, and appear to support the highest abundance of Santa Ana suckers within the species' range.

Natural water flow in the North and East forks, and the tributaries included in this unit, is unimpeded by large-scale dams. However, water flows in the West Fork of the San Gabriel River are affected by Cogswell Dam, a structure that has altered the hydrology of the system, resulting in fluctuating water (PCE 1) and sediment (PCE 2) releases. During its operational life, the Cogswell Reservoir has accumulated a large volume of sediment behind the dam that affects the quality of water released both through operations and unavoidable, uncontrolled leakage (Ally 2004a, p. 1). During the summer months, the only flow into the West Fork of the San Gabriel River is the result of leakage from the dam, and because flow velocities are low, sediments do not travel far downstream (Ally 2004a, p. 36). During storms, water containing fine sediments passes over or through the dam, and because sediments remain suspended within the reservoir pool for several months, downstream turbidity may be increased over usual conditions (PCE 4) (Ally 2004a, p. 36). Previous releases from Cogswell Dam containing more than 200,000 cubic yards (152,911 cubic meters) of silt and other sediment have severely impacted the habitat of the West Fork of the San Gabriel River and San Gabriel Reservoir (Drake 1988, p. 7; Haglund and Baskin 1992, p. 57; Moyle and Yoshiyama 1992, p. 204; Moyle

et al.

1995, p. 203; Moyle 2002, p. 184). These rapid increases in flow volume and velocity along with sediment sluicing may disrupt Santa Ana sucker spawning and flush juvenile Santa Ana suckers into areas with unsuitable habitat.

Along with impacts associated with the operation of Cogswell Dam, habitat within Unit 2 has also been impacted by recreational activities, including OHV use and the construction of recreational dams. Authorized OHV activity occurs in the USFS's San Gabriel Canyon OHV Area at the junction of the East, North, and West Forks. The use of the river as an OHV recreational area may result in adverse effects to Santa Ana sucker by increasing turbidity (PCE 4); disrupting the physical structure of habitat for spawning, resting, and feeding (PCE 2); and introducing pollutants (such as oil and gas) into streams (PCE 4) (65 FR 19686; April 12, 2000). To minimize impacts to Santa Ana sucker from OHV use, the USFS has implemented protection measures (such as establishing designated stream crossings and limiting the number of stream crossings in the OHV area) (Service 2005b, p. 8). The construction of “recreational” dams degrades instream and possibly bank habitat, increases turbidity (PCE 4), and disrupts sediment transport. Over 500 recreational dams were found in 2001 and 2002 within a 7.1-mi (11.4-km) reach of the East Fork of the San Gabriel River (Ally 2001, p. 2; Ally 2003, pp. 1-2). Recreational dams are constructed on a frequent basis in the San Gabriel Canyon OHV Area in the North Fork of this river as well (USFS 2008, p. 6). Therefore, the physical and biological features essential to the conservation of the species in this unit may require special management considerations or protection to address threats associated with water diversion, alteration of stream channels and watersheds, and human recreational activities.

Unit 2 was not directly impacted by the 2009 Station Fire that burned approximately 161,000 ac (64,975 ha) of lands in the San Gabriel Mountains (USFS 2009, p. 4), although indirect impacts associated with post-fire debris flow and changes to water quality may have occurred or could occur in the future. Because this particular area did not burn in the Station Fire, it was not analyzed in the U.S. Geological Survey (USGS 2009) or USFS (2009) reports; however, the burned area is directly adjacent to the West Fork of the San Gabriel River and thus may have some impact to critical habitat. For additional information on this fire and its anticipated impacts,

see

the

Unit 3: Big Tujunga Creek

section below. Please

see

Special Management Considerations or Protection section of this final rule for discussion of the threats to Santa Ana sucker habitat.

Unit 3: Big Tujunga Creek

Unit 3 includes a total of 1,233 ac (499 ha) of land and consists of two subunits located in Los Angeles County, California. Lands within this unit are under Federal (USFS) (286 ac (116 ha)) and private (947 ac (384 ha)) ownership (Table 2). The purpose of this unit is to independently support a population of Santa Ana sucker in a functioning hydrologic system that provides suitable water quality and supply, and coarse sediments. One of the two subunits in Unit 3, Subunit 3B is outside of the geographic range occupied by the species at the time of listing but provides essential sources of water and sediment to the occupied subunit (3A) within the unit.

In August 2009, the Station Fire began and eventually burned approximately 161,000 ac (64,975 ha) of lands within the San Gabriel Mountains (USFS 2009, p. 4). The fire burned conifer forests, chaparral, and riparian vegetation in the stream corridors, including approximately 81 mi (130.36 km) of perennial channel and 572 mi (920.54 km) of intermittent stream beds (USFS 2009, p. 2). As a result of this fire, excessive debris flows and changes to water quality are anticipated to occur during seasonal rains over the next several years. The greatest potential for significant impacts resulting from elevated debris flows is anticipated in Big Tujunga Canyon, Pacoima Canyon, Arroyo Seco Canyon, the West Fork of the San Gabriel River, and Devil's Canyon (USFS 2009, p. 4). The estimated debris flow probability for a 3-hour duration, 1-year-reoccurence thunderstorm in the area impacted by the Station Fire indicates an 81 to 100 percent probability for impact to critical habitat in all of Unit 3 (USGS 2009, p. 9, Fig 3A). Anticipated post-fire impacts to streams within this unit include ash and debris deposition that may physically alter streambeds and pools, increased scouring of riparian and aquatic vegetation, and increased water temperature from the short-term loss of canopy shading (USFS 2009, p. 5). Changes to water quality (such as increased turbidity) are also anticipated from both post-fire impacts and from the release and mobilization of toxic chemicals such as gas, oil, and building materials as a result of burned structures and their contents (USFS 2009, p. 6). The USFS determined that the future combined impacts attributed to the Station Fire may lead to a temporary loss or reduction of suitable stream habitat and a localized risk of extirpation that may result in threatening the viability of Santa Ana sucker (USFS 2009, p. 7). Additionally, the loss of vegetation and creation of roads for firefighting may allow greater access to streambeds and facilitate increased OHV use, resulting in further habitat degradation (USGS 2009, p. 7).

Subunit 3A: Big Tujunga and Haines Creeks

Subunit 3A includes an approximately 13-mi (21-km) stretch of Big Tujunga Creek (a tributary of the Los Angeles River) between the Big Tujunga Dam and Reservoir and Hansen Dam and Flood Control Basin. This subunit also includes Haines Creek, a small stream within the floodplain of Big Tujunga Creek. The 1,189 ac (481 ha) of land within this subunit is under Federal (USFS) (242 ac (98 ha)) and private (947 ac (384 ha)) ownership (Table 2).

All areas of Subunit 3A are within the geographical area occupied by the species at the time of listing and contain the features essential to the conservation of the species which may require special management considerations or protection. This subunit has been heavily impacted by urban development. Threats to Santa Ana sucker and its essential features in this subunit result from impacts associated with, but not limited to: Water diversion; dams; Water quality impacts from non-point source and point source pollution (including untreated urban run-off and discharge of treated wastewater); and altered hydrology throughout the watershed (including alterations from instream barriers, construction of bridges, channelization and other flood control structures). We also recognize that special management considerations or protection will be required in this subunit to protect its essential features (

see

Special Management Considerations or Protection section above).

In addition to surveys cited in the listing rule (65 FR 19686; April 12, 2000) and in the previous designation of critical habitat for Santa Ana sucker (70 FR 425; January 4, 2005), other surveys have documented Santa Ana suckers in Big Tujunga Creek between Delta Flats and Vogel Flats (Haglund and Baskin 2001, pp. 2-4; O'Brien 2009b, p. 2), and in the Big Tujunga Wash Mitigation Bank, including Haines Creek (Chambers Group 2004, pp. 6-3, 6-4). There has been previous speculation that Big Tujunga Creek between the Big Tujunga Dam and Big Tujunga Canyon Road Bridge may no longer be occupied by Santa Ana sucker; however, recent surveys indicate that Santa Ana suckers are present in this area but in relatively low abundance (Haglund and Baskin 2010, pp. 17-18). Swift (2002, p. 3) speculates that streambed characteristics in three places upstream of Big Tujunga Canyon Road Bridge may prevent upstream movement or make movement possible only during rare high flow events. We currently consider this area occupied because Santa Ana suckers have been documented near and downstream of the Big Tujunga Canyon Road Bridge and because we do not have evidence of the existence of barriers permanently precluding upstream movement to the dam. The upstream sections of Big Tujunga Creek are also important for providing stream and storm waters necessary to transport coarse sediments to maintain preferred substrate conditions (PCE 2) for Santa Ana sucker in occupied areas downstream.

A section of Haines Creek upstream of the Foothill Bridge traverses the Angeles National Golf Course. This 160-ac (65 ha), privately-owned golf course lies between the confluence of Big Tujunga and Haines Creeks and includes the alluvial floodplain and multiple low-flow channels that traverse the golf course. Periodic high storm flows from the Big Tujunga Creek travel through the golf course into Haines Creek on an irregular basis and likely provide the only source of stream and storm waters necessary to transport coarse sediments (from Big Tujunga Creek) to maintain preferred substrate conditions (PCE 2) to the occupied portion of Haines Creek (Chambers Group 2004, p. 6-4). Therefore, the alluvial floodplain and multiple low-flow channels that traverse the golf course are essential to the conservation of the species because they provide the primary (and potentially the sole) source of stream and storm waters (PCEs 1, 4, and 7) downstream into the

Big Tujunga Wash Mitigation Bank that supports Santa Ana sucker (

see

Summary of Changes From Previously Designated Critical Habitat section above for more discussion of the area designated as critical habitat on the Angeles National Golf Course).

The upstream portion of this subunit is within the Angeles National Forest and is therefore not exposed to the effects of urbanization. However, the downstream portion of Big Tujunga Creek between the Oro Vista Bridge and Hansen Dam is adjacent to existing urban development south of the creek, which has altered water flows transporting coarse sediment (PCE 2) into the Big Tujunga Creek. Several tributaries (including the upper portion of Haines Creek) that flow into Big Tujunga Creek through the communities of Sunland and Tujunga have been channelized through urbanized areas for flood control purposes. This channelization has eliminated habitat for Santa Ana sucker, altered the hydrologic regime (PCE 1), and reduced the transport of sediments needed to maintain channel substrate conditions (PCE 2) in the occupied sections of Big Tujunga Creek.

Habitat in Subunit 3A has been altered due to the operation of the Big Tujunga Dam upstream and Hansen Dam downstream. All flows in the occupied reaches of Big Tujunga Creek are moderated by the operation of Big Tujunga Dam, which has eliminated flows along most of the creek during late summer and autumn of dry years (Palavido

et al.

2008, p. 8), thereby reducing not only the amount of water (PCE 1) entering the system but also the amount of coarse sediment (PCE 2) being transported downstream. During these dry periods, Santa Ana suckers are restricted to an approximate 1-mi (1.6-km) section of the creek (Palavido

et al.

2008, p. 8). At times, the creek can be reduced to a series of standing pools with only a trickle of flow between them (Swift 2002, p. 1), further isolating Santa Ana suckers (PCE 1). To minimize impacts to the species, a strategy is being developed with the objective of maintaining and enhancing Santa Ana sucker habitat within the lower Big Tujunga Creek (Mendez 2005, p. 1).

Habitat within this subunit has also been impacted by the construction of several bridges (such as the Foothill, Interstate-210, and Oro Vista bridges). The habitat that serves as a connective corridor (PCE 7) within both Big Tujunga Creek and Haines Creek as they flow under the Foothill and Interstate-210 bridges is often temporarily fragmented during periods of low flow (Swift 2006a, p. 2). Hence, sufficient water flow from the upstream dam is necessary to ensure water and coarse sediment transport to maintain the stream channel substrate conditions required by Santa Ana sucker in this area (PCEs 1, 2, and 7). The physical and biological features essential to the conservation of the species in this unit may require special management considerations or protection to address threats associated with water diversion, alteration of stream channels and watersheds, and human recreational activities. Please

see

Special Management Considerations or Protection section of the 2009 proposed rule and this final rule for discussion of the threats to Santa Ana sucker habitat.

Subunit 3B: Gold, Delta, and Stone Canyon Creeks

Subunit 3B consists of three tributaries to Big Tujunga Creek (measured from their confluence with the mainstem): A 1.89-mi (3.04-km) section of Gold Canyon Creek, a 0.79-mi (1.27-km) section of Delta Canyon Creek, and a 0.67-mi (1.08-km) section of Stone Canyon Creek. The 44 ac (18 ha) of land within this subunit is entirely within the Angeles National Forest and is entirely under Federal (USFS) ownership (Table 2).

The three tributaries in this Subunit 3B are not within the geographical range of the species occupied at the time of listing and are not currently occupied, but are included in this critical habitat designation because they contribute essential coarse sediments and flows to occupied habitats downstream (PCEs 1 and 2). This subunit has been impacted by urban development, although to a lesser extent than the mainstem of Big Tujunga Creek. Threats to the critical habitat designated in this subunit result from impacts associated with, but not limited to, water diversion, dams, and altered hydrology in the lower portion of the watershed. We also recognize that special management considerations or protection may be required in this subunit (

see

Special Management Considerations or Protection section above).

While we are not aware of any surveys for Santa Ana sucker conducted in Gold Canyon, Delta Canyon, or Stone Canyon Creeks, it appears that the slopes of Delta Canyon and Stone Canyon Creeks from near their confluence with Big Tujunga Creek are too steep to be passable by Santa Ana sucker. The slope of Gold Canyon Creek from approximately 0.49 mi (0.8 km) from its confluence with Big Tujunga Creek also appears to be too steep to be passable by Santa Ana sucker. Please

see

the Criteria Used To Identify Critical Habitat section of this final rule for a discussion of how we determined the slope within these creeks.

These tributaries are particularly essential for the conservation of the species given the extent to which the hydrology and the habitat of the downstream occupied section of Big Tujunga Creek has been altered and degraded due to the construction and operation of Big Tujunga Dam. These creeks are essential for the conservation of the species because they provide and transport coarse sediment (PCE 2) and convey stream flows and flood waters (PCE 1) necessary to maintain habitat conditions for the downstream occupied areas of Big Tujunga Creek. The areas of these creeks at their confluence with Big Tujunga Creek also provide protective areas for juvenile Santa Ana suckers during high flow events, during periods of high ambient temperatures, and from predators (PCEs 1 and 6).

Effects of Critical Habitat Designation

Section 7 Consultation

Section 7(a)(2) of the Act requires Federal agencies, including the Service, to ensure that actions they fund, authorize, or carry out are not likely to destroy or adversely modify critical habitat. Decisions by the courts of appeals for the Fifth and Ninth Circuits have invalidated our definition of “destruction or adverse modification” (50 CFR 402.02) (

see Gifford Pinchot Task Force

v.

U.S. Fish and Wildlife Service,

378 F.3d 1059 (9th Cir. 2004) and

Sierra Club

v.

U.S. Fish and Wildlife Service et al.,

245 F.3d 434, 442F (5th Cir. 2001)), and we do not rely on this regulatory definition when analyzing whether an action is likely to destroy or adversely modify critical habitat. Under the statutory provisions of the Act, we determine destruction or adverse modification on the basis of whether, with implementation of the proposed Federal action, the affected critical habitat would remain functional (or retain those physical and biological features or the ability of the PCEs to be functionally established in the area) to serve its intended conservation role for the species.

Section 7(a)(2) of the Act requires Federal agencies to ensure that activities they authorize, fund, or carry out are not likely to jeopardize the continued existence of such a species or to destroy or adversely modify its critical habitat. If a Federal action may affect a listed species or its critical habitat, the responsible Federal agency (action agency) must enter into consultation with us. As a result of this consultation, we document compliance with the

requirements of section 7(a)(2) of the Act through our issuance of:

1. A concurrence letter for Federal actions that may affect, but are not likely to adversely affect, listed species or critical habitat; or

2. A biological opinion for Federal actions that may affect, and are likely to adversely affect, listed species or critical habitat.

An exception to the concurrence process referred to in (1) above occurs in consultations involving National Fire Plan projects. In 2004, USFS and BLM reached agreements with the Service to streamline a portion of the section 7 consultation process (BLM-ACA 2004, pp. 1-8; FS-ACA 2004, pp. 1-8). The agreements allow USFS and BLM the opportunity to make “not likely to adversely affect” determinations for projects implementing the National Fire Plan. Such projects include prescribed fire, mechanical fuels treatments (thinning and removal of fuels to prescribed objectives), emergency stabilization, burned area rehabilitation, road maintenance and operation activities, ecosystem restoration, and culvert replacement actions. The USFS and BLM must ensure staff are properly trained, and both agencies are required to submit monitoring reports to the Service to determine if the procedures are being implemented properly and effects to endangered species and their habitats are being properly evaluated. As a result, we do not believe the alternative consultation processes being implemented as a result of the National Fire Plan will differ significantly from those consultations being conducted by the Service.

When we issue a biological opinion concluding that a project is likely to jeopardize the continued existence of a listed species or destroy or adversely modify critical habitat, we also provide reasonable and prudent alternatives to the project, if any are identifiable. We define reasonable and prudent alternatives at 50 CFR 402.02 as alternative actions identified during consultation that:

1. Can be implemented in a manner consistent with the intended purpose of the action,

2. Can be implemented consistent with the scope of the Federal agency's legal authority and jurisdiction,

3. Are economically and technologically feasible, and

4. Would, in the Director's opinion, avoid jeopardizing the continued existence of the listed species or destroying or adversely modifying critical habitat.

Reasonable and prudent alternatives can vary from slight project modifications to extensive redesign or relocation of the project. Costs associated with implementing a reasonable and prudent alternative are similarly variable.

Regulations at 50 CFR 402.16 require Federal agencies to reinitiate consultation on previously reviewed actions in instances where we have listed a new species or subsequently designated critical habitat that may be affected and the Federal agency has retained discretionary involvement or control over the action (or the agency's discretionary involvement or control is authorized by law). Consequently, Federal agencies may sometimes need to request reinitiation of consultation with us on actions for which formal consultation has been completed, if those actions with discretionary involvement or control may affect subsequently listed species or designated critical habitat.

Federal activities that may affect Santa Ana sucker or its designated critical habitat require section 7 consultation under the Act. Activities on State, Tribal, local, or private lands requiring a Federal permit (such as a permit from the U.S. Army Corps of Engineers under section 404 of the Clean Water Act (33 U.S.C. 1251

et seq.

) or a permit from us under section 10 of the Act) or involving some other Federal action (such as funding from the Federal Highway Administration, Federal Aviation Administration, or the Federal Emergency Management Agency) are subject to the section 7 consultation process. Federal actions not affecting listed species or critical habitat, and actions on State, Tribal, local, or private lands that are not Federally funded, authorized, or permitted, do not require section 7 consultations.

Application of the “Adverse Modification” Standard

The key factor related to the adverse modification determination is whether, with implementation of the proposed Federal action, the affected critical habitat would continue to serve its intended conservation role for the species, or would retain those physical and biological features essential for the conservation of the species. Activities that may destroy or adversely modify critical habitat are those that alter the physical and biological features or the area itself to an extent that appreciably reduces the conservation value of critical habitat for Santa Ana sucker. As discussed above, the role of critical habitat is to support the life-history needs of the species and provide for the conservation of the species.

Section 4(b)(8) of the Act requires us to briefly evaluate and describe, in any proposed or final regulation that designates critical habitat, activities involving a Federal action that may destroy or adversely modify such habitat, or that may be affected by such designation.

Activities that, when carried out, funded, or authorized by a Federal agency, may affect critical habitat and therefore should result in consultation for Santa Ana sucker include, but are not limited to:

1. Actions that would alter the hydrology to a degree that appreciably reduces the value of the critical habitat for either the survival or the recovery of the species. Such activities could include, but are not limited to, impoundment, channelization, water diversion, removal of water from waterways, construction, licensing, relicensing, and operation of dams or other water impoundments. Effects of these activities may include (but are not necessarily limited to) reducing the suitable space for individual and population growth and for normal behavior; reducing or changing sites for breeding, reproduction, and rearing (or development) of offspring; removing cover and shelter necessary for Santa Ana sucker by reducing the availability of suitable habitat for reproduction and survival; decreasing food sources; increasing water temperatures; and facilitating predation by nonnative species.

2. Actions that would significantly alter water quality to a degree that ap

This text is long and has been trimmed here. Open the source document for the complete record.