Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Spikedace (Meda fulgida) and the Loach Minnow (Tiaroga cobitis)

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AU33

Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Spikedace (Meda fulgida) and the Loach Minnow (Tiaroga cobitis)

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), are designating critical habitat for the spikedace (

Meda fulgida

) and loach minnow (

Tiaroga cobitis

) pursuant to the Endangered Species Act of 1973, as amended (Act). In total, approximately 522.2 river miles (mi) (840.4 kilometers (km)) are designated as critical habitat. Critical habitat is located in Catron, Grant, and Hidalgo Counties in New Mexico, and Apache, Graham, Greenlee, Pinal, and Yavapai Counties in Arizona.

DATES:

This final rule is effective April 20, 2007.

ADDRESSES:

Comments and materials received, as well as supporting documentation used in the preparation of this final rule, are available for public inspection, by appointment, during normal business hours at the U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office, 2321 West Royal Palm Road, Suite 103, Phoenix, AZ 85021-4951. The final rule, economic analysis, environmental assessment, and more-detailed color maps of the critical habitat designation are also available via the Internet at

http://www.fws.gov/arizonaes/.

Geographic Information System (GIS) files of the critical habitat maps are also available via the Internet at

http://criticalhabitat.fws.gov/.

FOR FURTHER INFORMATION CONTACT:

Steven L. Spangle, Field Supervisor, U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office, 2321 West Royal Palm Road, Suite 103, Phoenix, AZ 85021-4951 (telephone 602-242-0210; facsimile 602-242-2513). Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339, 7 days a week and 24 hours a day.

SUPPLEMENTARY INFORMATION:

Background

It is our intent to discuss only those topics directly relevant to designation of critical habitat in this rule. For more information on the spikedace or the loach minnow, refer to the previous final critical habitat designation for the spikedace and loach minnow published in the

Federal Register

on April 25, 2000 (65 FR 24328).

Spikedace

Description and taxonomy.

The spikedace is a member of the minnow family Cyprinidae. The spikedace was first collected in 1851 from the Rio San Pedro in Arizona and was described from those specimens in 1856 by Girard. It is the only species in the genus Meda. The spikedace is a small, slim fish less than 3 inches (in) (75 millimeters (mm) in length (Sublette et al. 1990, p. 136). It is characterized by an olive gray to brownish back and silvery sides with vertically elongated black specks. Spikedace have spines in the dorsal fin (Minckley 1973, pp. 82, 112, 115).

Distribution and Habitat.

Spikedace are found in moderate to large perennial streams, where they inhabit shallow riffles (shallow areas in a streambed causing ripples) with sand, gravel, and rubble substrates (Barber and Minckley 1966, p. 321; Propst et al. 1986, p. 12; Rinne and Kroeger 1988, p. 1). Recurrent flooding and a natural hydrograph (physical conditions, boundaries, flow, and related characteristics of water) are very important in maintaining the habitat of spikedace and in helping the species maintain a competitive edge over invading nonnative aquatic species (Minckley and Meffe 1987, p. 103-104; Propst et al. 1986, pp. 3, 81, 85).

The spikedace was once common throughout much of the Gila River basin, including the mainstem Gila River upstream of Phoenix, and the Verde, Agua Fria, Salt, San Pedro, and San Francisco subbasins. It occupies suitable habitat in both the mainstem reaches and moderate-gradient tributaries, up to approximately 6,500 feet (ft) (2,000 meters (m)) in elevation (Chamberlain 1904, p. 8; Cope and Yarrow 1875, pp. 641-642; Gilbert and Scofield 1898, pp. 487, 497; Miller 1960 and Hubbs, pp. 32-33).

Habitat destruction and competition and predation by nonnative aquatic species have severely reduced its range and abundance. It is now restricted to portions of the upper Gila River and the East, West, and Middle Forks of the Gila River in New Mexico and the middle Gila River, lower San Pedro River, Aravaipa Creek, Eagle Creek, and the Verde River in Arizona (Anderson 1978, pp. 14-17, 61-62; Bestgen 1985, p. 6; Jakle 1992, p. 6; Marsh et al. 1989, pp. 2-3; Paroz et al. 2006, pp. 26, 37-41, 62-67; Propst et al. 1986, p. 1; Sublette et al. 1990, pp. 138-139), and is only commonly found in surveys of Aravaipa Creek and some parts of the upper Gila River in New Mexico (Arizona Game and Fish Department (AGFD) 2004; Arizona State University 2002; Propst 2002, pp. 4, 16-33, Appendix II—Table 2; Propst et al. 1986, p. iv; Rienthal 2006, p. 2). Based on the available maps and survey information, we estimate its present range to be approximately 10 to 15 percent or less of its historical range, and the status of the species within occupied areas ranges from common to very rare. Recent data indicate the population in New Mexico has declined in recent years (Paroz et al. 2006, p. 56). Table 1 summarizes critical habitat areas designated as critical habitat in this final rule for spikedace, as well as potential threats and records of spikedace within those areas.

Loach Minnow

Description and taxonomy.

The loach minnow is a member of the minnow family Cyprinidae. The loach minnow was first collected in 1851 from the Rio San Pedro in Arizona and was described from those specimens in 1865 by Girard (pp. 191-192). The loach minnow is a small, slender, elongated fish less than 3 in (80 mm) in length. It is olive colored overall, with black mottling or splotches. Breeding males have vivid red to red-orange markings on the bases of fins and adjacent body, on the mouth and lower head, and often on the abdomen (Minckley 1973, p. 134; Sublette et al. 1990, p. 186).

Distribution and Habitat.

Loach minnow are found in small to large perennial streams, and use shallow, turbulent riffles with primarily cobble on the bottom in areas of swift currents (Minckley 1973, p. 134; Propst and Bestgen 1991, p. 32; Propst et al. 1988, pp. 36-43; Rinne 1989, p. 111). The loach minnow uses the space between, and in the lee (sheltered) side of rocks for resting and spawning. It is rare or absent from habitats where fine sediments fill the interstitial spaces (small, narrow spaces between rocks or other substrate) (Propst and Bestgen 1991; p. 33). Recurrent flooding and a natural hydrograph are very important in maintaining the habitat of loach minnow and in helping the species maintain a competitive edge over invading nonnative aquatic species (Propst and Bestgen 1991, pp. 33, 37).

The loach minnow was once locally common throughout much of the Gila River basin, including the mainstem Gila River upstream of Phoenix, and the Verde, Salt, San Pedro, and San Francisco subbasins (Minckley 1973, p. 133-134; Lee et al. 1980, p. 365). It

occupies suitable habitat in both the mainstem reaches and moderate-gradient tributaries, up to about 8,200 ft (2,500 m) in elevation. Habitat destruction and competition and predation by nonnative aquatic species have severely reduced its range and abundance (Carlson and Muth 1989, pp. 232-233; Fuller et al. 1990, p. 1; Lachner et al. 1970, p. 22; Miller 1961, pp. 365, 377, 397-398; Minckley 1973, p. 135; Moyle 1986, pp. 28-34; Moyle et al. 1986, pp. 416-423; Ono et al. 1983, p. 90; Propst et al. 1988, p. 2, 64). It is now restricted to portions of the upper Gila, the San Francisco, and Tularosa rivers in New Mexico; and the Blue River and its tributaries Dry Blue, Campbell Blue, Little Blue, Pace, and Frieborn creeks; Aravaipa Creek and its tributaries Turkey and Deer creeks; Eagle Creek; East Fork White River; and the Black River and the North Fork East Fork Black River in Arizona (Bagley et al. 1998, pp. 3-6, 8; Bagley et al. 1995, multiple survey records; Barber and Minckley 1966, p. 321; Britt 1982, pp. 6-7; Leon 1989, p. 1; Marsh et al. 1989, pp. 7-8; Paroz et al. 2006, pp. 26, 37-41, 62-67; Propst et al. 1988, pp. 12-17; Propst and Bestgen 1991, p. 29; Propst 1996, multiple survey records; Springer 1995, pp. 6-7, 9-10), and is only common in Aravaipa Creek and the Blue River in Arizona, and limited portions of the upper San Francisco River, the upper Gila River, and Tularosa River in New Mexico (Paroz et al. 2006, pp. 55-60; Propst and Bestgen 1991, pp. 29, 37). The present range of the loach minnow is estimated at 10 percent of its historical range (Propst et al. 1988, p. 12), and the status of the species within occupied areas ranges from common to very rare. Table 1 summarizes critical habitat areas designated for loach minnow, as well as potential threats and records of loach minnow within those areas.

Table 1.—Locations of Spikedace and Loach Minnow Stream Segments Designated as Critical Habitat, Threats to the Species, Last Year of Documented Occupancy, and Source of Occupancy Information

Spikedace and/or loach minnow critical habitat areas

Threats

Last year occupancy

confirmed

Critical habitat distance

in mi (km)

Source

Complex 1—Verde River

Verde River—Spikedace

Nonnative fish species, grazing, water diversions

1999

43.0 mi (69.2 km)

AGFD 2004; ASU 2002; Brouder 2002, p. 1.

Complex 2—Black River Complex

Boneyard Creek—Loach minnow

Recreational pressures, nonnative fish species, recent fire and related retardant application, ash, and sediment

1996

1.4 mi (2.3 km)

AGFD 2004; ASU 2002.

East Fork Black—Loach minnow

Recreational pressures, nonnative fish species, recent fire and related retardant application, ash, and sediment

2004

12.2 mi (19.7 km)

AGFD 2004; ASU 2002.

North Fork East Fork Black—Loach minnow

Recreational pressures, nonnative fish species, recent fire and related retardant application, ash, and sediment

2004

4.4 mi (7.1 km)

AGFD 2004; ASU 2002; Bagley et al. 1995, multiple surveys; Lopez 2000, p. 1.

Complex 3—Middle Gila/Lower San Pedro/Aravaipa Creek

Aravaipa Creek—Spikedace and Loach minnow

Fire, some recreational pressure, nonnative pressures, water diversion, contaminants

2005

28.1 mi (45.3 km)

ADEQ 2006; AGFD 2004; ASU 2002; Rienthal 2006, pp. 2-3.

Deer Creek—Loach minnow

Fire, some recreational pressure, low nonnative pressures

2005

2.3 mi (3.6 km)

AGFD 2004; ASU 2002; Rienthal 2006, p. 2.

Turkey Creek—Loach minnow

Fire, some recreational pressure, nonnative pressures

2005

2.7 mi (4.3 km)

AGFD 2004; ASU 2002; Rienthal 2006, p. 2.

Gila River—Ashurst-Hayden Dam to San Pedro

Spikedace

Water diversions, grazing, nonnative fish species

1991

39.0 mi (62.8 km)

AGFD 2004; ASU 2002; Jakle 1992, p. 6.

San Pedro River (lower)— Spikedace

Water diversions, grazing, nonnative fish species, mining

1966 (directly connected to Aravaipa Creek, with records from 2005)

13.4 mi (21.5 km)

AGFD 2004; ASU 2002.

Complex 4—San Francisco and Blue Rivers

Eagle Creek—Loach minnow

Grazing, nonnative fish species, water diversions, mining

1997

17.7 mi (28.5 km)

AGFD 2004; ASU 2002; Bagley and Marsh 1997, pp. 1-2; Knowles 1994, pp. 1-2, 5; Marsh et al. 2003, pp. 666-668.

San Francisco River—Loach minnow

Grazing, water diversions, nonnative fish species, road construction and maintenance, channelization

2005

126.5 mi (203.5 km)

AGFD 2004; ASU 2002; Paroz et al. 2006, p. 67; Propst 2002, p. 13; Propst 2005, p. 10; Propst 2006, p. 2.

Tularosa River—Loach minnow

Grazing, watershed disturbances

2002

18.6 mi (30.0 km)

ASU 2002; Propst 2002, p. 9; Propst 2005, p. 6.

Frieborn Creek—Loach minnow

Dispersed livestock grazing

1998

1.1 mi (1.8 km)

ASU 2002.

Negrito Creek—Loach minnow

Grazing, watershed disturbances

1998

4.2 mi (6.8 km)

Miller 1998, pp. 4-5.

Whitewater Creek—Loach minnow

Grazing, watershed disturbances

1984 (directly connected to the San Francisco River, with records from 2005)

1.1 mi (1.8 km)

ASU 2002; Propst et al. 1988, p.15.

Blue River—Loach minnow

Water diversions, nonnative fish species, livestock grazing, road construction

2004

51.1 mi (82.2 km)

AGFD 2004; ASU 2002; Carter 2005; Propst 2002, p. 4.

Campbell Blue Creek—Loach minnow

Grazing, nonnative fish species

2004

8.1 mi (13.1 km)

AGFD 2004; ASU 2002; Carter 2005.

Little Blue Creek—Loach minnow

Grazing, nonnative fish species

1981 (directly connected to the Blue River, with records from 2004)

2.8 mi (4.5 km)

AGFD 2004; ASU 2002.

Dry Blue Creek—Loach minnow

Grazing

2001

3.0 mi (4.8 km)

ASU 2002; Propst 2006, p. 2.

Pace Creek—Loach minnow

Grazing, nonnative fish species

1998

0.8 mi (1.2 km)

ASU 2002.

Complex 5—Upper Gila River

East Fork Gila River—Spikedace and Loach minnow

Grazing, nonnative fish species, ash flows from wildfires

2000, 1998

26.1 mi (42.0 km)

ASU 2002; Propst 2002, p. 27; Propst et al. 1998, p.14-15; Propst 2006, pp. 2.

Upper Gila River—Spikedace and Loach minnow

Recreation, roads, grazing, nonnative fish species, water diversion

2005

94.9 mi (152.7 km)

ASU 2002; Propst 2002, pp. 4, 31.

Middle Fork Gila River—Spikedace and Loach minnow

Nonnative fish species, Grazing, ash flows from wildfires

1995, 1998

7.7 mi (12.3 km), 11.9 mi (19.1 km)

ASU 2002; Paroz et al. 2006, p. 63; Propst 2002, p. 22; Propst, 2006, p. 2.

West Fork Gila River—Spikedace and Loach minnow

Nonnative fish species, roads, ash flows from wildfires

2005, 2002

7.7 mi (12.4 km)

ASU 2002; Paroz et al. 2006, p. 64; Propst 2002, p. 18; Propst 2006, p. 2.

Previous Federal Actions

We previously published a final critical habitat designation on April 25, 2000 (65 FR 24328). In

New Mexico Cattle Growers' Association and Coalition of Arizona/New Mexico Counties for Stable Economic Growth

v.

United States Fish and Wildlife Service

, CIV 02-0199 JB/LCS (D.N.M), the plaintiffs challenged the April 25, 2000, critical habitat designation for the spikedace and loach minnow because the economic analysis had been prepared using the same methods which the Tenth Circuit had held to be invalid. The Center for Biological Diversity joined the lawsuit as a Defendant-Intervenor. The Service agreed to a voluntary vacatur of the critical habitat designation, except for the Tonto Creek Complex. On August 31, 2004, the United States District Court for the District of New Mexico set aside the April 25, 2000, critical habitat designation in its entirety and remanded it to the Service for preparation of a new proposed and final designation. On December 20, 2005, we published a proposed critical habitat designation (70 FR 75546).

For more information on previous Federal actions concerning the spikedace and loach minnow, including listing documents published in 1985 and 1986 (50 FR 25380, June 18, 1985; 51 FR 39468, October 28, 1986; 51 FR 23769, July 1, 1986) as well as the first critical habitat designation in 1994 (59 FR 10898, March 8, 1994; 59 FR 10906, March 8, 1994), refer to the critical habitat designation published in the

Federal Register

on April 25, 2000 (65 FR 24328).

Summary of Comments and Recommendations

We requested written comments from the public on the proposed designation of critical habitat for the spikedace and loach minnow on December 20, 2005 (70 FR 75546), and in two notices to reopen the comment period on June 6, 2006 (71 FR 32496) and October 4, 2006 (71 FR 58574). We also contacted appropriate Federal, State, and local agencies; scientific organizations; and other interested parties and invited them to comment on the proposed rule. We requested information on the current status, distribution, and threats

to the spikedace and loach minnow, as well as information on the status of other aquatic species in the historical range of the spikedace and loach minnow. We requested this information in order to make a final critical habitat determination based on the best available scientific and commercial data. We also requested information on proposed exclusions of various areas from the final critical habitat designation. In addition, we held public hearings on June 13 and 20, 2006, in Silver City, NM, and Camp Verde, AZ, respectively, to solicit comments on the proposed rule. We published newspaper articles inviting public comment and announcing these public hearings in the

Arizona Republic

,

Arizona Daily Star

,

Camp Verde Bugle

,

Sierra Vista Herald

,

Tucson Citizen

,

Verde Independent

, and

White Mountain Independent

in Arizona, and the

Albuquerque Journal

,

Albuquerque Tribune

, and

Silver City Daily Press

in New Mexico.

During the first public comment period, which opened on December 20, 2005, and closed on February 21, 2006, we received 23 comments directly addressing the proposed critical habitat designation (e-mails, letters, and faxes). Of these, we received two comments from peer reviewers, three from Federal agencies, five from Tribes, one from a State agency, seven from organizations, and five from individuals. We also received two requests for public hearings. During the second comment period, which opened on June 6, 2006, and closed on July 6, 2006, we received 39 comments. Of these latter comments, 2 were from Federal agencies, 3 from State agencies, and 34 from organizations or individuals. During the third comment period, which opened on October 4, 2006, and closed on October 16, 2006, we received 11 comment letters. Of these comments, three were from Federal agencies and eight from organizations and individuals.

Of the written comments received during the first comment period, four supported, eight were opposed, and six included comments or information but did not express support for or opposition to the proposed critical habitat designation. Of the written comments received during the second comment period, nine supported, 23 were opposed, and seven included comments or information but did not express support for or opposition to the proposed listing and critical habitat designation. Written comments received during the third comment period were specific to the proposals to exclude portions of various streams due to receipt of management plans for those streams. Of these written comments, two supported exclusions in Eagle Creek and the upper Gila River, three opposed these exclusions, four proposed additional exclusions in other areas, and three included comments or information but did not express support for or opposition to the proposed exclusions.

We also received numerous comments on the content and soundness of the environmental assessment and economic analysis. For the environmental assessment, comments focused on the adequacy of completing an environmental assessment rather than an environmental impact statement, the inadequacy of the comment period and opportunities for public participation, the use of the 300-foot buffer for the lateral extent of the designation, the application of the destruction or adverse modification language, the adequacy of the discussion of impacts of the proposed action to water use and water rights, the range of alternatives covered, and the economic information provided in the environmental assessment.

Comments on the economic analysis included the suggestion that we failed to estimate benefits of the proposed designation; the adequacy and scope of the analysis; impacts to small business entities, ranching and farming communities, and water use and water rights; the Regulatory Flexibility Act; the Verde River and estimated costs and benefits of including it in the final designation; and Tribal lands and impacts to Tribes.

Responses to comments were grouped into three categories below. Peer review comments are listed first, followed by comments received from the States. Comments received from the public are listed last. Because staff from the New Mexico Department of Game and Fish (NMDGF) responded as peer reviewers, their comments are listed in the peer review section, while those of the AGFD are listed under State comments.

Peer Review

In accordance with our policy published on July 1, 1994 (59 FR 34270), we solicited expert opinions from 13 knowledgeable individuals with scientific expertise that included familiarity with the species, the geographic region in which the species occurs, and conservation biology principles. These individuals represented Federal agencies, State agencies, university researchers, or themselves as private individuals. We received responses from two of the peer reviewers, one as a private individual and the other in the capacity of an individual who works for the New Mexico Department of Game and Fish. Peer review comments focused on the reduction in the proposed critical habitat designation from previous designations, the area encompassed by critical habitat, and potential threats to the species, including the need to expand “nonnative fish” to include “nonnative aquatic species.”

We reviewed all comments received from the peer reviewers and the public for substantive issues and new information regarding critical habitat for the spikedace and loach minnow, and addressed them in the following summary.

Peer Reviewer Comments

(1)

Comment:

The reduction in stream miles of critical habitat proposed for designation from that previously designated for the spikedace and loach minnow provides no incentive for land and resource management agencies to launch projects that would restore conditions for the enhancement of spikedace and loach minnow. All of the major stream course and complexes, and many of the smaller tributaries, have potential to provide elements necessary for the recovery of these species and should be included in critical habitat.

Our response:

The Service's process for designating critical habitat has evolved since prior designations of critical habitat for the spikedace and loach minnow. As required by section 4(b)(1)(A) of the Act, we used the best scientific and commercial data available in determining areas for designation as critical habitat.

(2)

Comment:

In primary constituent element (PCE) 4, “nonnative fish” should be modified to include any and all nonnative aquatic species, including the current component of nonnative fishes and those that may become established in the future, as well as crayfishes, macroinvertebrates, parasites, and disease-causing pathogens.

Our response:

We agree and we have changed “nonnative aquatic fishes” in the final rule to “nonnative aquatic species.” In addition, language has been added addressing additional nonnatives and their sources, as well as their potential effects on the native fish community.

(3)

Comment:

Designating critical habitat serves positive purposes. The prohibition against adverse modification is a powerful tool to protect unoccupied seasonal or migratory habitat and unoccupied habitat for population expansion as part of recovery. The most effective benefit from designating critical habitat is the impetus it provides to agencies and people to initiate conservation activities for the target

species and voluntarily curtail adverse impacts. No evidence is provided concluding that the (1) jeopardy standard is sufficient to protect habitat better than a critical habitat designation, (2) that critical habitat designation provides no education benefits better obtained otherwise, or (3) that conservation can be better achieved through implementing management plans rather than through implementing section 7 and other provisions of the Act.

Our response:

Designation of critical habitat is one tool for managing listed species habitat. In addition to the designation of critical habitat, we have determined that other conservation mechanisms including the recovery planning process, section 6 funding to States, section 7 consultations, management plans, Safe Harbor agreements, and other on-the-ground strategies contribute to species conservation. We believe these other conservation measures provide greater incentives and often greater conservation. Please see “Exclusions under Section 4(b)(2) of the Act” for additional discussion.

(4)

Comment:

The Service should reclassify both species to endangered status, as a warranted but precluded finding was published in 1994. Both species have experienced significant reductions in range and abundance since that time, and their status in the wild continues to deteriorate. Reclassification would recognize the precarious status of the species and give higher priority for recovery actions.

Our response:

We agree and in the 2006 Candidate Notice of Review (CNOR) (71 FR 53756; September 12, 2006) we resubmit our 12-month finding where we determine that reclassification of both the spikedace and loach minnow is warranted but precluded by other higher priority listing actions. The 2006 CNOR provides a detailed discussion of why these listing actions are precluded by other higher priority listing actions. We note that Federal and State agencies and other cooperators are continuing with recovery actions for the spikedace and loach minnow in a concerted effort to improve the status of these two fish.

(5)

Comment:

No information is presented on effects of wildfire on habitats (PCEs) each species occupies. Since 2000, wildfires have burned much of the West Fork Gila River watershed, fine sediment deposition has increased noticeably, and abundance of both spikedace and loach minnow have declined substantially at a permanent site on West Fork Gila River that is annually sampled.

Our response:

We have added wildfire to the threats discussion within the unit descriptions below and within Table 1 as a threat to the West Fork Gila River.

(6)

Comment:

The lateral extent of the areas proposed for critical habitat is logical considering the dynamic nature of streams in the Gila River basin, and the scientific understanding of the role flood plains play in stream course functioning. Defining a measurable width that is wide enough to incorporate flood flows beyond the bankfull width is reasonable.

Our response:

We agree with the commenter on this point.

State Comments

(7)

Comment:

We suggest a rewording of the statement regarding water quality in the PCE section for both spikedace and loach minnow to not require low levels of pollutants in the water. As written, these statements could be interpreted to mean that low levels of pollutants are needed.

Our response:

We agree with this comment, and have revised the wording in the discussion of PCEs in the final rule to indicate that suitable water quality for spikedace and loach minnow will contain no or only minimal pollutant levels.

(8)

Comment:

The Arizona Department of Transportation requests that the Service provide estimated acreages of proposed critical habitat for each habitat complex. The total mileage figures are inconsistent and total miles should be provided for spikedace and loach minnow. The total mileages in Table 3 for New Mexico and Arizona are reversed.

Our response:

Because fishes occupy stream habitat, we have determined it is more appropriate to quantify the delineation in terms of stream miles rather than total acres. All mileage figures throughout the rule and in the tables have been checked for consistency and adjusted where necessary.

General Comments Issue 1: Biological Concerns

(9) Some commentors have noted that we have misinterpreted or over-extrapolated information from various sources, in particular the proposed rule did not appear to include any studies that specifically define ranges for “fine sediment” or “substrate embeddedness”; therefore, the phrase “low or moderate amounts” appears open to subjective interpretation.

Our response:

For purposes of critical habitat designation, low to moderate amount of substrate embeddedness means embeddedness that does not preclude deposition of eggs among sand and gravel for spikedace, or on the undersurfaces of large rocks for loach minnow. Please see the discussion under “Substrates” for both spikedace and loach minnow for additional information.

(10)

Comment:

The statement within the proposed rule that “Flooding, as part of a natural hydrograph, temporarily removes nonnative fish species, which are not adapted to flooding” is an over-generalization. Minckley and Meffe (1987) concluded that nonnative fishes fared poorly in canyon reaches by noting that some nonnative species like green sunfish and smallmouth bass rebounded quickly from floods because they were stream-adapted. Flooding may also kill or displace native fishes. Some native fishes exhibit the potential to reproduce quickly after flooding, which could account for some of the effects reported by Minckley and Meffe (1987).

Our response:

We have adjusted the text to better reflect Minckley and Meffe (1987).

(11)

Comment:

The most thriving populations of these fishes tend to be in flood blasted, warm, shallow, braided channel refugia and at places where vehicles splashed through streams, inside corrals (through which streams flowed), and in river channels within mine sites which are regularly bulldozed. The loach minnow is thriving on private land at a mine where heavy trucks cross the road several times a day, resulting in an area that is shallow and full of sediment.

Our response:

We disagree with this conclusion. While spikedace and/or loach minnow are sometimes found in association with low water crossings, and while flooding is an important component of habitat maintenance for these species, we are not aware of any locations where they occur in streams flowing through corrals or within mine sites which are regularly bulldozed. We currently have survey records dating from the late 1800s to the present for these species, as well as numerous studies that detail the habitat requirements for the species, all of which indicate that they occur in habitat different than that described by the commenter.

(12)

Comment:

The Gila River is not critical habitat for the minnows because extreme flood waters may kill small fish. Small streams are better suited for small fish, because large fish will predate on the smaller fish.

Our response:

Please refer to the discussion on “Flooding” below under the PCE discussion for spikedace. As noted in that discussion, Minckley and

Meffe (1987, p. 99-100) studied the differential responses of native and nonnative fishes in seven unregulated and three regulated streams or stream reaches that were sampled before and after major flooding. They noted that fish faunas of canyon-bound reaches of unregulated streams invariably shifted from a mixture of native and nonnative fish species to predominantly, and in some cases exclusively, native forms after large floods.

(13)

Comment:

One commenter notes that many of these minnows can be seen in the Gila River.

Our response:

While spikedace and loach minnow do occur in the Gila River, it is important to note that the “minnows” seen in the Gila River may or may not be spikedace or loach minnow. There are approximately 235 species of fishes that are within the minnow family, Cyprinidae, in North America (Bond 1979, p. 170). Spikedace and loach minnow are members of this family. Other small-bodied, native minnows which are more commonly found within the Gila River include longfin dace (

Agosia chrysogaster

) and speckled dace (

Rhinichthys osculus

). These fish, even as adults, can be confused with spikedace and loach minnow. There are several other species which are technically minnows and may be confused with spikedace and loach minnow when young. These include native roundtail chub (

Gila robusta

) and nonnative common carp (

Cyrpinus carpio

), goldfish (

Carassius auratus

), and fathead minnow (

Pimephales promelas

) (Lee

et al.

1980, pp. 140-367).

(14)

Comment:

Spikedace were last seen in the Verde River in 1999. They may already be extinct.

Our response:

Because the last record for spikedace on the Verde River was from 1999, this area still meets the 10-year occupancy criteria used in developing the critical habitat. We are also aware of gaps in the survey record in which spikedace were not found for greater than 10 years, but then reappeared. Surveys do not allow for 100 percent detection of a species, particularly for species such as spikedace that are hard to detect.

General Comments Issue 2: Procedural and Legal Compliance

(15)

Comment:

Several commenters requested a 60-day extension of the comment period, or indicated that two public hearings and the comment periods provided were inadequate to provide comment on the proposed rule, draft economic analysis, and the draft environmental assessment.

Our response:

We believe the three comment periods allowed for adequate opportunity for public comment. A total of 100 days was provided for document review and the public to submit comments.

(16)

Comment:

Reintroduction of the spikedace and loach minnow to the Verde River will result in killing and poisoning of the non-native fish, leaving the public with a non-fishable river. The general public will be banned from setting foot or paddling on the river area or using the Verde River for recreation.

Our response:

The designation of critical habitat does not entail reintroduction efforts of spikedace or loach minnow. In addition, designation of critical habitat does not set up wildlife refuges or preserves, or require the exclusion of all other uses. Critical habitat was designated previously on the Verde River for spikedace and loach minnow from 2000 to 2004, during which time recreation and use of this area by the public continued.

(17)

Comment:

The Service appears inconsistent in their critical habitat designations in terms of the lateral extent of the critical habitat designation. There is no reference for best scientific evidence in the determination of 300 ft (91.4 m) as lateral extent. Prior rulings for razorback sucker, Colorado pikeminnow, humpback chub, and bonytail chub define the lateral extent of critical habitat as the 100-year floodplain where PCEs occur, with the caveat that potential areas of critical habitat should be evaluated on a case by case basis. The final ruling for woundfin and Virgin River chub use the 100-year floodplain.

Our response:

Although we considered using the 100-year floodplain, as defined by the Federal Emergency Management Agency (FEMA), we found that it was not included on standard topographic maps, and the information was not readily available from FEMA or from the U.S. Army Corps of Engineers for the areas designated as critical habitat, possibly due to the remoteness of various stream reaches. Therefore, we selected the 300-foot lateral extent, rather than some other delineation, for three reasons: (1) The biological integrity and natural dynamics of the river system are maintained within this area (i.e., the floodplain and its riparian vegetation provide space for natural flooding patterns and latitude for necessary natural channel adjustments to maintain appropriate channel morphology and geometry, store water for slow release to maintain base flows, provide protected side channels and other protected areas, and allow the river to meander within its main channel in response to large flow events); (2) conservation of the adjacent riparian area also helps provide nutrient recharge and protection from sediment and pollutants; and (3) vegetated lateral zones are widely recognized as providing a variety of aquatic habitat functions and values (e.g., aquatic habitat for fish and other aquatic organisms, moderation of water temperature changes, and detritus for aquatic food webs) and help improve or maintain local water quality (see U.S. Army Corps of Engineers' final notice concerning Issuance and Modification of Nationwide Permits, March 9, 2000, 65 FR 12818-12899). Please see the section entitled “Lateral Extent” below for more information. In addition, in more recent rules we have used the 300 ft (91.4 m) width to define the lateral extent of critical habitat for the Rio Grande silvery minnow (February 19, 2003; 68 FR 8088), the Gila chub (November 2, 2005; 70 FR 66664), and the Arkansas River shiner (October 13, 2005; 70 FR 59808).

(18)

Comment:

A designation of 300 ft (91.4 m) may impact roads or facilities. Roads or facilities impacted by flooding may require periodic maintenance. Additionally, if a river shifts in response to flooding, critical habitat would have to shift and potentially affect the rebuilding of diversion structures. The proposed rule does not address what happens when a river channel moves.

Our response:

Prior critical habitat designations for spikedace and loach minnow from 2000 to 2004 did not prevent maintenance or rebuilding of structures damaged by flooding nor will this final designation. Where critical habitat is designated, activities funded, authorized, or carried out in these areas by Federal action agencies that may affect the PCEs of the critical habitat, may require consultation pursuant to section 7 of the Act. The purpose of the consultation is not to stop activities from occurring, but to ensure that such activities do not result in jeopardy to listed species or adverse modification of critical habitat. When determining final critical habitat map boundaries, we made every effort to avoid including developed areas such as buildings, paved areas, and other structures that lack any PCEs for the spikedace and loach minnow. Any such structures and the land under them inadvertently left inside critical habitat boundaries of this final rule are excluded by text and are not designated as critical habitat. Specifically, lands located within the boundaries of the critical habitat designation, but that do not contain any of the PCEs essential to the conservation of the spikedace and loach minnow

include: Existing paved roads; bridges; parking lots; railroad tracks; railroad trestles; water diversion and irrigation canals outside natural stream channels; active sand and gravel pits; regularly cultivated agricultural land; and residential, commercial, and industrial developments.

Critical habitat includes the area of bankfull width plus 300 ft (91.4 m) on either side of the banks. Should the active channel meander or shift we anticipate that it would still be contained within the 300 foot (91.4 m) lateral extent of the designation (i.e. our current critical habitat boundary); thus we do not find that critical habitat will shift as a result.

(19)

Comment:

The 300 ft (91.4 m) lateral extent likely represents an expansion of critical habitat to areas that are not necessarily riparian habitat, particularly on small streams.

Our response:

Although the spikedace and loach minnow cannot be found in the riparian areas when they are dry, these areas are periodically flooded and provide habitat during high-water periods. These areas also contribute to PCEs 1 and 2 and contain PCEs 3 and 5. As noted in response to 18 above, vegetated lateral zones are widely recognized as providing a variety of aquatic habitat for fish and other aquatic organisms, moderation of water temperature changes, and detritus for aquatic food webs, and help improve or maintain local water quality.

(20)

Comment:

The 300 ft (91.4 m) designation needs additional defining. It is unclear if it is to be measured up to the slope of the bank or horizontally on a map. In many reaches of the specific rivers and streams in the designation, the flowing channels are confined within narrow canyon bottoms, and a 300 ft (91.4 m) buffer in some cases extends several hundred feet vertically up the side of the canyon. In addition, bankfull width, while scientifically valid and useful, may be hard to determine in the field.

Our response:

Critical habitat includes the area of bankfull width plus 300 ft (91.4 m) on either side of the banks, except where bordered by a canyon wall. Since a canyon wall is not defined as a PCE for the spikedace and loach minnow it would not be considered critical habitat. The 300 foot lateral extent is not for the purpose of creating a “buffer zone.” Rather, it defines the lateral extent of those areas we have determined contain or contribute to the features (PCEs 3 and 5) that are essential to the conservation of these species (e.g., water quality, food source, etc.).

(21)

Comment:

The Service is inconsistent in its treatment of, and fails to properly analyze the impacts of, groundwater wells and other potential detrimental activities that are located outside the 300 ft (91.4 m) lateral extent of critical habitat.

Our response:

Activities funded, authorized, or carried out by Federal action agencies that may affect the PCEs of the critical habitat, may require consultation pursuant to section 7 of the Act. Thus, groundwater pumping activities may require consultation pursuant to section 7 of the Act if the action agency determines that the activity may affect the PCEs for the spikedace or loach minnow, regardless of whether the activity is occurring within or outside the critical habitat designation.

(22)

Comment:

The Service should designate the areas within the active floodplain that are necessary to support the PCEs of spikedace and loach minnow critical habitat for the recovery of the species, as demonstrated by the best available science. We suggest that the Service look at hydrogeomorphic and biological features to determine the width along each segment where the PCEs are likely to exist. Such information may include specific return intervals (5-, 10-, 50-year events), floodplain features (ordinary high water mark), or floodplain vegetation as indicators of important habitat, which can be mapped in the field along with bankfull flow width.

Our response:

As noted in our response to comment 17 above, we do not have this type of information available to us and thus we selected the 300 ft (91.4 m) lateral extent as the best available science to map the areas that contain or contribute to the features that are essential to the conservation of these species.

(23)

Comment:

The best scientific information currently available recognizes that for most native fish species, conservation cannot be achieved without eliminating or greatly suppressing nonnative fishes (Clarkson et al. 2005). The common nonnative fish occupying the same or overlapping geographic areas with spikedace and loach minnow are known to compete with or prey on all life stages of native fish (Pacey and Marsh 1998). Thus, where nonnative fishes have high abundance, and where there is limited opportunity or ability for the Service to manage these nonnative species due to physical constraints of the river system or political/social constraints, these segments are unlikely to provide important habitat for any of the spikedace and loach minnow life stages regardless of the condition of other PCEs. Nonnatives are especially a problem for the San Francisco River, Gila River, and Eagle Creek.

Our response:

Critical habitat designation is not the process through which we rule out habitat suitability due to threats, but the process through which we identify habitat that provides for one or more of the life history functions of the species. As defined in section 3(5)(A) of the Act, critical habitat means “(i) the specific areas within the geographical area occupied by the species, at the time it is listed in accordance with the provisions of section 4 of the Act, on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection.” During the designation process, the Service identifies threats to the best of our ability where they exist. Identification of a threat within an area does not mean that that area is no longer suitable, rather that special management or protections may be required. If an area contains sufficient PCEs to provide for one or more of the life history functions of spikedace or loach minnow, and if it was occupied at the time the species was listed and is currently occupied, it is reasonable to include it within a proposed critical habitat designation. The need to address a particular threat, such as nonnative fishes, in a portion of the critical habitat designation may or may not arise in the future. Further, describing both the areas which support PCEs and the threats to those areas assists resource managers in their conservation planning efforts for threatened and endangered species like spikedace and loach minnow.

(24)

Comment:

Absent clear scientific evidence that intermittent stream reaches are used by spikedace or loach minnow to move between occupied habitats, and are critical to their recovery, the fifth PCE should not be included as part of the final designation.

Our response:

It was not our intent to imply that spikedace or loach minnow occupy intermittent reaches when water is not present. We included interconnected waters because spikedace and loach minnow have the ability to move between populated, wetted areas, at least during certain flow regimes or seasons. Because streams provide continuous habitat when connected, and because fish are mobile, it is reasonable to conclude that intermittent areas, when wetted, may be used during fish movement. In addition, some complexes include stream reaches that play a role in the overall health of

the aquatic ecosystem, and therefore, the integrity of upstream and downstream spikedace and loach minnow habitat. Again, because stream habitat is continuous, actions taking place in an intermittent portion of the channel can have effects in upstream and downstream areas. Inclusion of these intervening areas assures protection of adjacent, perennial reaches.

(25)

Comment:

There is no record or document that summarizes or describes in detail the PCE conditions that the Service used as a decision-making tool to select reaches.

Our response:

As stated under the “Critical Habitat” subheading in the final rule, the areas included within the proposed critical habitat designation are based not only on PCE conditions, but also on whether or not an area was occupied at listing and may require special management considerations or protections. There is no single record or document that summarizes this information. Instead, the Service looked at various databases and survey records to determine occupancy, as well as habitat descriptions at various locations. We relied on information provided in survey reports and research documents to describe conditions at various locations. This information was then synthesized to develop the proposed critical habitat designation.

(26)

Comment:

As a final step before the issuance of the proposed rule, the Service should have ranked the suitable habitat to determine which areas possess the highest quality of PCEs. Based on this ranking, the Service would then have published the proposed rule designating the portions of suitable habitat needed to achieve recovery goals. The proposed rule would have also described areas of suitable habitat identified by the Service but not included in the proposed rule.

Our response:

The regulations governing critical habitat designations do not require ranking of suitable habitat. With species such as spikedace and loach minnow, whose current distribution is severely reduced compared to historical distribution, determining the highest quality of PCEs is not a useful tool in developing a recommendation, and inclusion of only the highest ranking areas would not be sufficient for recovery of these species. The Service has developed a rule set that we have determined identifies those areas to be included as final critical habitat. We have coupled that rule set with the best scientific and commercial information available regarding species distribution, habitat parameters, and life history, and have included those areas within the designation.

(27)

Comment:

The preamble articulates the following important concept: “Where a subset of PCEs are present (e.g., water temperature during spawning), only those PCEs present at designation will be protected.” This concept should be reflected in the rule language itself. The proposal is not always clear as to what PCEs are present in each stretch of river. For example, with respect to the 39 mile stretch of the Gila River included in the proposal, the preamble states only that it contains “one or more” of four PCEs. This creates uncertainty about what PCEs are present in which segments, which could in turn cause difficulties in future section 7 consultations regarding possible adverse effects on critical habitat.

Our response:

Within the discussion immediately following Table 1, PCEs are described for each complex. For example, for the 39 mile stretch of the Gila River addressed in this comment, the proposed rule states that “Those portions of the Gila River proposed for designation contain one or more of the PCEs, including sufficient flow velocities and appropriate gradients, substrates, depths, and habitat types (i.e., pools, riffles).” This information should be useful in future section 7 consultations.

(28)

Comment:

Page 75556 of the proposed rule states “Where a subset of the PCEs are present (e.g., water temperature during spawning), only those PCEs present at the time of designation will be protected.” Implementation of this misguided approach negates the conservation value of the critical habitat designation because lack of perennial water, appropriate stream habitat, or high abundance of predatory nonnative fish precludes the survival or recovery of spikedace or loach minnow. We believe the Service needs to fully consider the implication of this language in the Proposed Rule, and reevaluate the proposed reaches in light of the need to contain all PCEs at the time of designation, especially those reaches that contain high numbers of nonnative fish species.

Our response:

Stream complexes as part of this final rule making were designated based on sufficient PCEs being present to support spikedace and loach minnow life processes. Some complexes contain all PCEs and support multiple life processes. Some segments contain only a portion of the PCEs necessary to support the spikedace and loach minnow's particular use of that habitat. Where a subset of the PCEs are present (such as water temperature during migration flows), it has been noted that only PCEs present at designation will be protected.

(29)

Comment:

With respect to the PCEs, an additional quantitative value that should be measured is the large wood present in a system.

Our response:

We agree that large wood is an important factor to analyze in assessing riparian ecosystem health; however, we are not aware of any data at this time that illustrates what amount of large woody debris within a system would constitute ideal conditions for spikedace and loach minnow. Should such information be developed in the future, it would be another useful factor in evaluating river system health and habitat suitability for spikedace and loach minnow.

(30)

Comment:

Flow velocity values should be in feet per second, which is a more appropriate field estimate and ensures greater accuracy between readings and reader. These values can also be better correlated with historical and stream gauge data.

Our response:

While it may be more useful to report flow velocity values in feet per second, it is our practice to use values and units of measurement as they were reported by the author of the research summarized.

(31) Microhabitat flows are highly related to habitat complexity. Though it is appropriate to define these flows, there should be more emphasis on habitat complexity and the functions needed to create it such as floodplain interaction, riparian condition, and large wood recruitment.

Our response:

We believe the final rule accomplishes both of these objectives. We have chosen to consider overall riparian health, as well as floodplain interaction and stream health, by including riparian vegetation and floodplain areas within the critical habitat designation, as encompassed by the 300 foot lateral zone. In addition, we have attempted to define key components of occupied habitat, as defined in the PCEs. One of those components relates to flow velocities. We have incorporated the information we have relevant to spikedace and loach minnow within the rule.

(32)

Comment:

Because microhabitat is variable and transient, gradient values should be more generalized and at the geomorphic reach level.

Our response:

We are required to use the best scientific and commercial information available. At this time, no assessment of gradient values at a geomorphic reach level has been completed for occupied or suitable spikedace and loach minnow habitat.

(33)

Comment:

In evaluating riparian habitat, there should be two or more native, riparian-obligate woody species and two or more riparian-obligate herbaceous species present and vigorous (Winward 2000). In terms of species diversity, all four age classes of native, riparian-obligate woody species must be present and vigorous. These classes are seedling/sprout, young/sapling, mature/decadent, and dead (Winward 2000).

Our response:

We agree that a diversity of composition leads to healthier riparian habitat; however, we do not have sufficient information of this type tied to occupied spikedace and loach minnow critical habitat to use in developing an individual PCE. The individual PCEs represent the actual physical and biological parameters of habitat used by the fish.

(34)

Comment:

Conflicting comments were received on the temperature ranges listed within the PCEs for spikedace and loach minnow. In summary, we received comments that the PCE temperature range is broader (35 to 85 °F) than the literature indicates (48.2 and 71.6 °F), with the potential net effect being an extension of stream reaches both upstream and downstream from areas actually likely to support the species. A second commenter noted that the Bonar et al. (2005) study found 100 percent survival of loach minnow at 28 °C (82 °F) and 100 percent survival of spikedace at 30 °C (86 °F) corresponded quite well with upper limits in the proposed rule PCEs. A third commenter noted that appropriate values should be a maximum seven day average.

Our response:

We have reviewed the study completed by the University of Arizona (Bonar et al. 2005) and incorporated its findings into discussions of temperature tolerances within the final rule. The PCEs serve as guidelines to resource managers in evaluating the suitability of areas for spikedace and loach minnow. Temperature ranges provided are based on the studies completed at various occupied locations, and adequately represent the habitat most suitable for spikedace and loach minnow. In most instances, resource managers do not have the ability to develop seven day averages. With respect to broadening the range of the species by incorporating too wide a range of suitable temperatures, we note that we are using the Act's standard of best available scientific information, and should temperatures at these sites be found at the high point of the range provided in this PCE, it would already be within an area occupied by the species, so the species' range would not be broadened.

(35)

Comment:

Water depths of 1 to 30 inches are specified as a PCE for adult, juvenile, and larval loach minnow. No data or references are cited to support any specific range of depths. Additionally, pools aren't appropriate for spikedace and loach minnow, but are suitable for predatory non-natives that are significantly detrimental.

Our response:

Water depths are known for all occupied spikedace and loach minnow sites, as discussed below. Therefore, the range described in the PCEs reflects the range considered to provide suitable habitat for these fishes by biologists familiar with the species.

Spikedace and loach minnow are less likely to use pool habitat than other types of habitat, however, Sublette et al. (1990, p. 138) and Propst et al. (1986, p. 40) note that spikedace juveniles and larvae are occasionally found in quiet pools or backwaters lacking streamflow (Sublette et al. 1990, p. 138). Barber et al. (1970, pp. 11-12) also noted that female spikedace occupy deeper pools and eddies during portions of the breeding season. In addition, Schreiber (1978, pp. 40-41) found that the availability of pool and run habitats affects availability of prey species consumed by loach minnow.

(36)

Comment:

Virtually any perennial stream above 3,000 feet elevation in Arizona displays the characteristics cited by the Service in its PCEs and thus they are not particularly helpful in identifying the areas necessary for the conservation of the spikedace and loach minnow.

Our response:

The PCEs are based on the range of criteria developed following review of research conducted at occupied spikedace and loach minnow sites. Use of the PCEs alone may result in the inclusion of most streams above 3,000 feet in elevation. However, coupled with occupancy information and the geographic range of the species, we are able to identify final critical habitat for the spikedace and loach minnow.

(37)

Comment:

Flood magnitude and frequency deserve careful consideration and incorporation as part of a “flood frequency and magnitude” PCE. The Service has failed to include important hydrologic features in the analysis of current habitat for spikedace and loach minnow.

Our response:

We agree that flooding is a key process in maintaining suitable habitat components for spikedace and loach minnow, and have addressed this in PCE 2. A PCE focused strictly on flooding would be difficult to define, as there is considerable variability in the flood magnitude and frequency of different systems. More importantly, flooding itself would be inappropriate as a PCE as flooding is a process that maintains the necessary components of occupied habitat, whereas PCEs are the features essential to the conservation of the species. We determine those physical and biological features that are essential to the conservation of a given species and that may require special management considerations or protection, rather than looking at the processes that aid in developing those features 50 CFR 424.12(b).

(38)

Comment:

Although the five PCEs appear to be generally correct, they are describing fine-grained characteristics applicable to a square-meter by square-meter assessment. Only two PCEs are coarse-grained; (1) reaches devoid of nonnative fish, and (2) stream reaches that flow sporadically and provide connective corridors between occupied and seasonally occupied reaches. The other PCEs are focused on the biological requirements for individual fish, rather than the population or the species to which it belongs.

Our response:

We disagree with the commenter on this point. It is true that the PCEs focus on the biological needs of the individual fish, but collectively, the biological needs of the fish represent the biological needs of the species. As previously noted, critical habitat, as stated in the Act, is defined as “* * * specific areas * * * on which are found the physical or biological features (I) essential to the conservation of the species * * *.” The Service has determined that the PCEs, as defined by studies in occupied areas, define the features essential to the conservation of the species.

(39)

Comment:

We request exclusion of all areas within roadway right-of-ways or easement limits because section 7 is required in these areas for projects affecting threatened and endangered species. Designation within right-of-ways would have no additional benefit.

Our response:

Developed lands, including roadway right-of-ways, do not contain the PCEs essential to the conservation of the spikedace and loach minnow. Federal action agencies are only required to consult on activities they authorize, fund, or carry out that may affect the physical or biological features determined in this rule to be essential to conservation of these fish. See also response to comment 18 above.

(40)

Comment:

The Bureau of Reclamation lands are on the lower San Pedro River and not the Gila River. This mistake is also continued in the regulation promulgation section.

Our response:

According to GIS landownership layers from the Arizona

Land Resource Information System of the Arizona State Land Department, the Bureau of Reclamation lands referenced by the commenter are on the Gila River beginning at Township 4 South, Range 13 West, section 3.

(41)

Comment:

The critical habitat designation allows for exclusions when special management considerations are not required based on management plans. This policy should allow for land management agencies to adopt species management plans.

Our response:

In this final rule, our exclusion of areas covered by management plans was made pursuant to section 4(b)(2) of the Act, where we determined that the benefits of exclusion outweighed the benefits of inclusion. These determinations were not hindered by landownership.

(42) Ten years is insufficient to determine presence or absence of spikedace and loach minnow given the elusiveness of the species, the difficulty of obtaining a thorough sampling of remote streams with difficult access, and the low efficiency of sampling techniques. There is greater biological support to use a period of 20 to 40 years as the standard for determining “occupancy.”

Our response:

We believe a period of 10 years is reasonable to determine occupancy based on the fact that both species are difficult to detect in surveys, surveys have been infrequent or inconsistent because many of the areas where they occur are remote, and we have areas where these species were not detected for long periods of time (44 years) and then detected again. Specifically, the methodology used considers a stream segment occupied if the spikedace or loach minnow has been detected in the last 10 years or if the stream segment is connected to a stream segment with spikedace or loach minnow records within the last 10 years. For example, we consider the lower San Pedro River and the Gila River “occupied” due to their connections with Aravaipa Creek, an area where we have documented records of these fish from within the last 10 years. We have determined our methodology is reasonable to determine areas that meet the definition of critical habitat.

(43)

Comment:

With respect to occupancy, we do question the assumption that all stream segments with a “direct connection” to occupied areas are themselves occupied. There is little scientific basis for this assumption.

Our response:

The language within the rule states “We consider an area to be occupied by the spikedace or loach minnow if we have records to support occupancy within the last 10 years, or where the stream segment is directly connected to a segment with occupancy records from within the last 10 years.” While we do not have occupancy records for these connected areas within the last 10 years, we believe it is reasonable to consider these connected areas to be occupied for the purposes of critical habitat as they are part of a larger contiguous complex with documented occupancy within the last 10 years. We consider it reasonable because of the elusiveness of the species, the difficulty of obtaining a thorough sampling of remote streams with difficult access, and the low efficiency of sampling techniques.

(44)

Comment:

The North Fork of the White River and the mainstem White River downstream of the confluence of the North and East Forks should be included in the designation. Records of loach minnow within the last 10 years exist for both streams.

Our response:

These stream segments occur on Tribal lands and we have no information available to us to conclude that these areas meet the definition of critical habitat for the loach minnow. Please see “Relationship of Critical Habitat to Tribal Lands” below for additional discussion of Tribal management plan and protections that exist for these fish on those lands.

(45)

Comment:

The Service should use wording similar to that used in the 2000 critical habitat designation which states “We have determined the primary constituent elements essential to the conservation of spikedace include, but are not limited to * * *.” This provides for inclusion of new scientific information without the need for cumbersome and expensive reproposal of critical habitat.

Our response:

We have determined the revised language provides more specifics and certainty about the PCEs, and any revisions to a regulation as a result of new information may only be made through a new rulemaking process.

(46)

Comment:

The proposed rule incorrectly paraphrases the regulatory definition of destruction or adverse modification of critical habitat. The paraphrased definition limits analysis of destruction or adverse modification to “those physical or biological features that were the basis for determining the habitat to be critical”, a limitation not found in the regulatory definition. Instead, the regulatory definition directly addresses effects to the critical habitat rather than a surrogate. The paraphrased definition also omits the regulatory definition's inclusion of diminution of the values of “both the survival and recovery of a listed species.”

Our response:

The Service no longer relies on the regulatory definition of adverse modification of critical habitat. Instead the Service relies on the statutory provision of the Act to complete the analysis on critical habitat. Please see “General Principles of Section 7 Consultations Used in the 4(b)(2) Balancing Process” below for additional information.

(47)

Comment:

There is no “sufficiently unregulated hydrograph” on the Gila River below its confluence with the San Pedro River. We do not believe the PCEs identified by the Service in the proposal are present in this stretch. This section of the Gila River (below the San Pedro) should be removed from the critical habitat designation.

Our response:

While it may not contain all of the PCEs, we have determined it currently supports one or more of them (i.e., low gradient, appropriate water temperatures, and pool, riffle, run, and backwater components), and because of this and its proximity to occupied areas, it remains in the designation.

(48)

Comment:

We dispute the claim that spikedace occupancy of the Verde River was confirmed as recently as 1999. No spikedace have been confirmed from the Verde River since at least 1995. Thus, the Verde River does not meet the Service's own criteria for critical habitat because there are no records within the last 10 years.

Our response:

The 1999 record is considered by the Service as a confirmed record. The spikedace in question was captured and identified by a qualified AGFD fisheries biologist (AGFD 2004).

(49)

Comment:

The large amount of privately owned land that is included in the proposal is too great of a restriction of use.

Our response:

Critical habitat does not affect private actions on private lands. A designation of critical habitat requires that Federal action agencies consult with the Service on activities that they fund, authorize, or carry out that may affect critical habitat. We note that the designated 105 mi (170 km) for spikedace and the 126 mi (203 km) for loach minnow of private lands is part of, not in addition to, the total 522 mi (840 km).

(50)

Comment:

The adverse impacts of critical habitat on non-Federal rights and interests were exacerbated under Gifford Pinchot, which increases the impact of a critical habitat designation on water and land uses by creating a heightened standard for the

“destruction or adverse modification” of critical habitat. More activities that require a Federal permit or other approval will violate section 7(a)(2) of the Act and will require formal consultation. When combined with the Service's use of section 7(a)(2) to “Federalize” and control non-Federal projects, Gifford Pinchot will dramatically increase the economic impacts caused by the critical habitat designation.

Our response:

We recognize that under the Gifford Pinchot decision, critical habitat designations may provide greater benefits to the recovery of a species. This relates to the court's ruling that the two standards (e.g. jeopardy and adverse modification) are distinct and that adverse modification evaluations require consideration of impacts on the recovery of species. As such, where appropriate, we analyze or consider the effects of the Gifford Pinchot decision in this rule, the economic analysis, and the environmental assessment. For example, in light of the uncertainty concerning the regulatory definition of adverse modification, our current methodological approach to conducting economic analyses of our critical habitat designations is to consider all conservation-related costs. This approach would include costs related to sections 4, 7, 9, and 10 of the Act, and should encompass costs that would be considered and evaluated in light of the

Gifford Pinchot

ruling. Additionally, in this critical habitat designation, we are designating areas that are occupied, as defined elsewhere in this rule, by one or both species; thus, there is already a requirement for consultation with the Service over any water and land use actions that may affect these species. The purpose of the consultation process is not to “Federalize” private projects, but to ensure that federally-sponsored activities do not jeopardize listed species or adversely modify or destroy designated critical habitat.

(51)

Comment:

The Gila Settlement and associated agreements allow the State of New Mexico to divert for consumptive use 14,000 acre feet of water originally set aside under the Central Arizona Project authorizing legislation. The diversion of this additional 14,000 acre-feet of water almost doubles current adjudicated withdrawal from the Gila and San Francisco rivers and could significantly impair river function and riparian conditions and threaten native species such as the loach minnow and spikedace.

Our response:

The Service is an active partner on the Gila and San Francisco Rivers Technical Subcommittee, which is evaluating the environmental impacts of these water diversions from the upper Gila and San Francisco rivers. Considerations for spikedace and loach minnow are prominent in those discussions. We have identified water diversions as a threat for spikedace and loach minnow within this complex.

(52)

Comment:

The Upper Eagle Creek Watershed Association has developed a watershed plan in collaboration with the Forest Service and the Arizona Department of Environmental Quality. This plan has addressed the loach minnow and spikedace as endangered fish that may occupy areas covered by the plan. The plan guides the community, permittees, and agencies in developing the Upper Eagle Creek Watershed into its greatest potential for all species. On the basis of this plan and the partnership with the people on the land with all agencies, it would be best to exclude Eagle Creek from the critical habitat designation.

Our response:

We appreciate the efforts the Upper Eagle Creek Watershed Association has taken to work collaboratively with the Forest Service, cooperators, and the Service. Unfortunately, the Upper Eagle Creek Watershed Management Plan was received on the last day of the third comment period, and was still in draft form. For these reasons, we are not able to consider the plan as a basis for excluding Eagle Creek at this time. We understand it is the intention of the Association to finalize and implement the plan, and we look forward to working cooperatively with the Association in these efforts. Once the plan has been finalized and implemented, we have the option of excluding those portions of Eagle Creek covered by the plan. As discussed in “Exclusions under Section 4(b)(2) of the Act” below, we have excluded other portions of Eagle Creek from critical habitat based on other information available to us.

(53)

Comment:

The Blue River should be excluded from critical habitat in order to ensure that the ongoing coordination between the Service and the Blue River Native Fisheries, Research and Education Center is unencumbered.

Our response:

At this time we have no documentation, such as a management plan, to evaluate in terms of a potential exclusion of the Blue River from the critical habitat designation. Additionally, the majority of property along the Blue River is under Forest Service management and management activities for the conservation of the spikedace and loach minnow would require coordination with the Forest Service. We fully intend to continue our ongoing coordination with the Blue River Native Fisheries, Research and Education Center. The designation of critical habitat is a separate process which will not hinder these efforts and we commend the Center for their interest in conserving the Blue River.

(54)

Comment:

The Service should remove the Middle Verde River from the final rule and retain the Upper Verde River segment as critical habitat based on: (1) The current biological conditions within each river segment to conserve the spikedace; (2) the existing physical barrier (i.e., Allen Ditch Diversion) between the Upper and Middle Verde River, which likely precludes movement and connectivity between reaches; (3) the prevailing technical feasibility and fisheries management emphasis of each river segment; and (4) the high potential economic burden to groundwater and surface water users in the Middle Verde River (i.e., Verde Valley) compared to the Upper Verde River.

Our response:

Pursuant to section 4(b)(2) of the Act we have excluded the lower portion of the Verde River based on economic costs. See exclusion discussion below.

(55)

Comment:

One of the requirements of critical habitat is that these areas should be “protected from disturbance or are representative of the historic geographical and ecological distributions of a species (50 CFR § 424.12(b)(1)-(5); 70 FR 75551; December 20, 2005).” In other words, if suitable locations are available elsewhere, it does not make sense to designate critical habitat along stream reaches that are already impacted by land or water use activities or will soon be impacted by those activities. The Service applied this criterion in some places (e.g., the upper San Pedro River, p. 75546) and portions of the Black River complex (p. 75560) that were found to have too high an abundance of nonnative fish to be important habitat), but did not apply it in others (i.e., middle Verde River, Gila River, and lower San Pedro River). The Service should apply this criteria and standards consistently to evaluate each PCE among all potentially suitable habitats in a transparent process.

Our response:

We do not agree that critical habitat should not be designated in areas that have experienced some level of impact to the habitat. As previously stated, designation of critical habitat focuses on the areas that contain the PCEs and provide for the conservation of the species, rather than the threats that may be present in an area. Thus, our methodology focuses on

occupied areas that contain the PCEs and not on the type or level of threat that occur in these areas. In addition, we note that we have limited suitable habitat remaining for these species such that additional suitable locations are not available elsewhere. See also our response to comment 58 below.

(56)

Comment:

Bear Creek should be designated as loach minnow critical habitat from its junction with the Gila River upstream to the junction with its tributaries Cherry Creek and Little Cherry Creek.

Our response:

As noted in the notice to reopen the comment period published on June 6, 2006 (71 FR 32498, p. 32496), we did not propose Bear Creek because of the timeframe for completion of the final rule and associated documents. Information on occupancy of Bear Creek was received late in the process. Should critical habitat be revised in the future, Bear Creek would be considered for inclusion.

(57)

Comment:

Due to seasonal lack of water flows, Eagle Creek is unsuitable habitat for designation below the Gila and Salt River base line to the confluence with Willow Creek. Additionally, from Willow Creek to the Phelps Dodge diversion dam, flows are augmented to provide fresh water for mining operations and for potable use at the Morenci and Clifton townsites. This portion of Eagle Creek does not qualify for designation because: (1) These augmented flows do not provide a natural, unregulated hydrograph that allow for adequate river functions; (2) flow velocities are frequently higher than those required for these native fish; (3) pool, riffle, run, and backwater components are not present; and (4) non-native fish dominate this reach to an extent detrimental to natives and prevents the persistence or even occupancy of loach minnow or spikedace.

Our response:

We do not agree with this comment. While this portion of Eagle Creek has been modified by both addition of flows and by the diversion structure, suitable habitat still exists. As stated previously, we consider those areas that meet our definition of occupancy and support one or more of the PCEs as areas the meet the definition of critical habitat. Eagle Creek met these criteria. As discussed below, we have excluded portions of Eagle Creek pursuant to section 4(b)(2) of the Act.

(58)

Comment:

Areas without threats such as the San Francisco and the middle reach of the mainstem Gila River do not require special management considerations or protection and thus can not be designated as critical habitat under the Act. The critical habitat designation will not protect the loach minnow from the threat of nonnatives and therefore special management is not required.

Our response:

The Act does not require that critical habitat alleviate threats to the species. We have determined that various threats are present in all the rivers we proposed as critical habitat, as identified in Table 1. As required by the Act and the definition of critical habitat, we provide a discussion of known threats for each area to indicate that the biological and physical features essential to the conservation for these fish may require special management considerations or protection.

(59)

Comment:

Habitat requirements for both of the species are different and the Service should recognize this and not combine them.

Our response:

We agree that there are differences in the habitat requirements of both species and we have distinguished this in our PCEs for each of the fish. We note that it is not unusual for streams to support habitat types for both the spikedace and loach minnow, often within the same reach, and some streams are occupied by both species (e.g., the Gila River and Aravaipa Creek).

(60)

Comment:

The proposed rule states that “individual streams are not isolated, but are connected with others to form areas or complexes.” This statement does not hold true for Complex 4. Eagle Creek is currently isolated from the San Francisco and Blue River complexes by a diversion dam. The Blue River will become inaccessible to upstream migration from the rest of the complex if a proposed fish barrier is constructed on the Blue River.

Our response:

We have clarified the language in this final rule to indicate that collections of streams in proximity to each other were grouped together to form a category called “complexes.” Streams need not be hydrologically connected in order to be grouped together.

(61)

Comment:

No spikedace have been observed in Eagle Creek for 17 years, thus the segment does not meet the criteria for occupancy.

Our response:

We agree, as the last record for spikedace in Eagle Creek was in 1989. Thus, critical habitat for spikedace in Eagle Creek has been removed from the final rule. However, Eagle Creek is considered critical habitat for the loach minnow. As discussed in the exclusion section below, portions of Eagle Creek have been excluded from the final rule.

(62)

Comment:

For spikedace, the Verde River from Tapco Diversion Dam down to Fossil Creek should be excluded. Although spikedace were found in 1999 in areas upstream, they have not been found downstream of the Sycamore Creek confluence in over 20 years. Although this area is connected to the occupied areas upstream, the Tapco Dam and numerous nonnative fishes occupy this reach and may serve to disconnect it from the upstream areas.

Our response:

We believe the Verde River meets the definition of critical habitat for spikedace as we consider this area occupied based on occupancy records from 1999. Additionally, the Verde contains one or more of the PCEs including appropriate flow velocities, gradients, temperatures, habitat components (pool, riffle, run and backwater), and an abundant aquatic insect food base, and it requires special management or protection. However, pursuant to section 4(b)(2) of the Act, we have excluded the lower portion of the Verde River (see “Exclusions under Section 4(b)(2) of the Act” below).

(63)

Comment:

Regarding definition of adverse modification, the Service's definition erroneously eliminates congressional intent that critical habitat designations provide protection not just to survival of a species but to its recovery as well. It was the opinion of the court that “the purpose of establishing ‘critical habitat’ is for government to carve out territory that is not only necessary for the species' survival but also important for the species' recovery.” (

Sierra Club

v.

USFWS

, 245 F.3d 434 (5th Cir. 2001). The proposed rule for spikedace and loach minnow rejects that approach and relies on Service policy limiting critical habitat to only those areas occupied by the species.

Our response:

The Act states, at section 3(5)(c), that except in particular circumstances determined by the Secretary, critical habitat shall not include the entire geographical area which can be occupied by the threatened or endangered species. Thus, it is not the intent of the Act that we designate critical habitat in all areas that have the potential to become suitable habitat or in all areas of historic habitat. We have determined that our methodology for determining those areas containing features essential to the conservation of the spikedace and loach minnow complies with the intent of the Act and does not include all areas which can be occupied. Our methodology resulted in areas being proposed as critical habitat that are within the geographical range occupied by the spikedace and loach minnow and

that contain the biological or physical features essential to their conservation and that may require special management.

(64)

Comment:

The approach proposed by the Service for determining whether to exclude Tribal lands from the final rule places undue weight on the argument that inclusion of Tribal lands will compromise government-to-government relations, to the potential detriment of species conservation goals. Additionally, under relevant Federal court precedent in Arizona, the Service is not permitted to rely upon assurances by the tribes that habitat will be “adequately managed” through the implementation of Tribal management plans as a basis for exclusion.

Our response:

We disagree. See below for our analyses of the exclusion of Tribal lands pursuant to section 4(b)(2) of the Act.

(65)

Comment:

Ten days is not enough time to review all of these new documents. There should be a delay in designating critical habitat until the information can be properly reviewed.

Our response:

We agree that the last comment period was shorter than we would have preferred. However, we have an obligation to submit for publication a final rule on December 20, 2005, and thus we were not able to accommodate a longer comment period. In addition, we believe the three comment periods allowed for adequate opportunity for public comment. A total of 100 days was provided for document review and the public to submit comments.

(66)

Comment:

The Phelps Dodge plans should undergo peer review and revision before being considered as sufficient conservation management.

Our response:

Although formal peer review of management plans is not conducted or required, the documents are available for public review and comment during the open comment period.

(67)

Comment:

Phelps Dodge's Management Plan does not assure the maintenance of the PCEs for the spikedace and loach minnow.

Our response:

We have determined the formation of this working relationship will promote the conservation of the loach minnow and spikedace and their PCEs on Phelps Dodge's property. See exclusion section below for a more detailed discussion of their management plans and analysis of this exclusion.

(68)

Comment:

The proposed rule is an inappropriate venue for changing the regulatory definition of section 7 consultation “baseline.” Section 7 regulations (51 FR 19958) define environmental baseline to include the past and present impacts of all Federal, State, or private actions and other human activities in the action area, the anticipated impacts of all proposed Federal projects in the action area that have already undergone formal or early section 7 consultation, and the impact of State or private actions which are contemporaneous with the consultation in process. The proposed rule would expand that definition to include “ongoing Federal actions at the time of designation” regardless of whether they have already undergone formal or early section 7 consultation.

Our response:

The language referenced above has been removed from this final rule.

General Comments Issue 3: National Environmental Policy Act Compliance

(69)

Comment:

We believe the analysis in the draft environmental assessment to be simplistic and conclusory (See

Middle Rio Grande Conservancy Dist.

v.

Norton

). The impacts on the environment will be significant and controversial. The critical habitat designation as proposed is likely to result in adverse impacts on riparian areas, not only within the critical habitat itself, but also in the areas located upstream and downstream. The impacts on water use and management are significant and controversial.

Our response:

We determined through the EA that the overall environmental effects of this action are insignificant. An EIS is required only if we find that the proposed action is expected to have a significant impact on the human environment. The completed studies, evaluations, and public outreach conducted by the Service have not identified impacts resulting from the proposed designation of critical habitat that are clearly

significant.

The Service has afforded substantial public input and involvement, with two public hearings and open houses. Each of these events had a small participation level by the public (less than 10 in Arizona, less than 20 in New Mexico, and less than 30 written comments on the draft environmental assessment). Based on our analysis and comments received from the public, we prepared a final EA and made a Finding of No Significant Impact (FONSI), negating the need for preparation of an EIS. We have determined our EA is consistent with the spirit and intent of NEPA. The final EA, FONSI, and final economic analysis provide our rationale for determining that critical habitat designation would not have a significant effect on the human environment. Those documents are available for public review (see

ADDRESSES

section).

(70)

Comment:

The draft EA fails to consider the impacts of critical habitat on the Arizona Water Settlements Act of 2004, which authorizes the exchange of Central Arizona Project (CAP) water diverted from the Colorado River into New Mexico from the Gila River. The project is reasonably foreseeable because New Mexico recently negotiated and executed an exchange agreement. The draft EA (p. 45) acknowledges the project but fails to discuss the impacts.

Our response:

Page 49 of the EA states that the San Carlos Apache Tribe is concerned that the designation of critical habitat for the spikedace and loach minnow would further complicate the procedure for getting the CAP project approved. The Bureau of Reclamation states that this project would be reevaluated before an exchange could occur and a new consultation is likely.

(71)

Comment:

The Service failed to consider a reasonable range of alternatives to the proposed action in its EA.

Our response:

We disagree. The draft EA considered a no-action alternative and several action alternatives and analyzed the adverse and beneficial environmental impacts of each.

(72)

Comment:

One alternative that seems worthy of consideration is the designation of known occupied habitat, rather than the designation of an entire stream based upon limited sightings in a limited area (e.g., Eagle Creek) or consideration of designating only Federal lands. The Service's failure to “rigorously explore” and evaluate reasonable alternatives is per se arbitrary and capricious.

Our response:

We disagree. The alternatives considered are consistent with the purpose and need of the action of designating critical habitat. In compliance with the Act, we must propose for designation those areas that we have determined are essential, as well as those areas containing features essential, to the conservation of the spikedace and loach minnow. Only considering Federal lands for designation would not, in this case, comply with the intent of the Act. As discussed elsewhere in this rule, the areas proposed for designation were based on our definition of occupancy. See also response to comment 71 above.

(73)

Comments:

In the NEPA analysis, it should be recognized that there are positive aspects that have been observed from human culture and interaction. That analysis is required by law.

Our response:

The purpose of a NEPA analysis is to determine the potential impacts of a proposed set of alternative actions on the human environment. It is not the purpose of NEPA to evaluate the positive aspects of humans and their environment.

General Comments Issue 4: Economic Analysis

General Methodology

(74)

Comment:

Two commenters recommend that the Economic Analysis discuss impact estimates for the Verde River unit as two separate subunits: An Upper Verde reach from Sullivan Dam to the Allen Diversion and a Lower Verde reach from the Allen Diversion to Fossil Creek.

Our response:

The Final Economic Analysis (FEA) incorporates new information received, and separates costs associated with the Upper Verde and Lower Verde River segments where possible. This distinction is made most apparent in sections 7 and 8, and Appendix B of the FEA.

(75)

Comment:

One commenter states that the economic analysis fails to quantify the benefits associated with critical habitat designation. The commenter further states that although the Verde Valley Complex is singled out as the reach where the largest impacts will occur, there is no basis for this conclusion without exploring the “net impacts” through incorporation of benefit estimates and comparisons to baseline.

Our response:

Section 4(b)(2) of the Act requires the Secretary to designate critical habitat based on the best scientific data available after taking into consideration the economic impact, and any other relevant impact, of specifying any particular area as critical habitat. The Service believes that society places a value on conserving any and all threatened and endangered species and the habitats upon which they depend. In our 4(b)(2) analysis below, we discuss the economic benefits of excluding portions of the Verde River and the conservation benefits related to the inclusion of this stream segment. Although, in this case, we are not able to quantify the monetary value of critical habitat benefits in the Verde Valley Complex, we did consider the benefits that may be derived from a critical habitat designation when considering an exclusion pursuant to section 4(b)(2).

The Service's approach for estimating economic impacts includes both economic efficiency and distributional effects. The measurement of economic efficiency is based on the concept of opportunity costs, which reflect the value of goods and services foregone in order to comply with the effects of the designation (e.g., lost economic opportunity associated with restrictions on land use). Where data are available, the economic analysis does attempt to measure the net economic impact. For example, if the fencing of spikedace and loach minnow habitat to restrict riparian access for cattle is expected to result in an increase in the number of individuals visiting the site for wildlife viewing, then the analysis would attempt to net out the positive, offsetting economic impacts associated with their visits (e.g., impacts that would be associated with an increase in tourism spending). However, no data were found that would allow for the measurement of such an impact, nor was such information submitted during the public comment period.

(76)

Comment:

One commenter states that many of the economic impacts attributed to spikedace and loach minnow critical habitat in the Verde Valley could be attributed to razorback sucker critical habitat.

Our response:

To the extent possible, the FEA distinguishes costs related specifically to spikedace and loach minnow conservation where multiple species are the subject of a single conservation effort or section 7 consultation. In the case that another species clearly drives a project modification or conservation effort, the associated costs are appropriately not attributed to the spikedace and loach minnow. In Section 6, the FEA includes language that clarifies that the Verde River is designated as critical habitat for the razorback sucker.

Recreational Activities

(77)

Comment:

One commenter expressed concern that the designation of critical habitat will cause a loss of recreational activities on units such as the Verde River.

Our response:

Potential changes to recreational activities are discussed in Section 6 of the FEA. Potential impacts on recreational fishing losses are specifically discussed and estimated in Section 6.4.2 of the FEA. Potential costs associated with lost recreational fishing activity on the two stream segments where non-native fish stocking currently occurs are estimated to be $0 to $8.6 million, using a discount rate of seven percent. As noted in Section 6.1.2, the future impact of proposed critical habitat on the stocking regimes in affected reaches is unknown, as is the reduction in fishing activity that would occur if stocking is curtailed. Further, it is unknown whether non-native trout may be replaced with stocked native fish (e.g. Gila trout). Thus, this analysis estimates the value of angler days at risk if sportfish stocking were discontinued on these reaches as part of the high end estimates.

(78)

Comment:

One commenter states concerns that the Economic Analysis does not take into consideration the past effects of fishing closures on the Blue River and Eagle Creek on local businesses. The comment states that one store in Greenlee County closed as a result of reduced fishing activity.

Our response:

Section 6.1.1 of the FEA states that “the AZGFD ceased stocking of sportfish in Eagle Creek and the Blue River in Apache-Sitgreaves National Forest due to native fish considerations in the late 1990s and began stocking endangered Gila trout in these reaches instead. Spikedace and loach minnow were among numerous species considered when these stocking cessations were put in place. Although several citizens at a public hearing held in Thatcher, Arizona, in 1999 voiced disappointment that the sites are no longer stocked, these changes in stocking have not affected the overall number of fish stocked in Arizona. However, there may have been consumer surplus losses associated with these closures because anglers may now take trips to less preferred sites. It should be noted that any past impacts would have occurred prior to this critical habitat rule taking effect.” Section 6 and Appendix B of the FEA now highlight that the curtailment of stocking in these reaches has caused some economic impacts on local businesses.

Water Use and Grazing Issues

(79)

Comment:

One commenter states that exclusion of livestock from riparian areas using fencing has actually had an adverse effect on the spikedace and loach minnow.

Our response:

The Economic Analysis recognizes that some controversy surrounds the issue of the impacts of livestock on native fish species. Section 4.1 of the FEA now states that “in public comments, private ranchers have suggested that current management has been successful at mitigating the negative effects of grazing on spikedace and loach minnow habitat and that further limitation of grazing would create conditions conducive to non-native species. Some commenters have also suggested that fencing may be detrimental to the species.”

(80)

Comment:

One commenter stated that estimates of riparian fencing and maintenance costs in the Economic Analysis are low.

Our response:

As presented in Section 4.4 of the FEA, fencing and maintenance costs were developed using numerous published sources, as well as through discussions with both Forest Service and BLM. Fencing costs are presented as a range between $1,500 and $15,000 per river mile of fence construction, with an additional $110 to $2,600 in fence maintenance.

(81)

Comment:

One commenter suggests that data in the Economic Analysis on agricultural establishments in Greenlee County are incorrect. The commenter provides information on ranching operations on Eagle Creek. The comment states that the Four Drag Ranch, Seven Cross A Ranch, Anchor Ranch, Double Circle Ranch, and Tule Ranch are located on Eagle Creek.

Our response:

Appendix B, Exhibits B-2, B-3, and B-4 provide data on the number of farm operations, number of ranching operations, and annual sales by county, as reported by the National Agricultural Statistics Survey. Section 2 presents the number of establishments and employees in the Agriculture, Forestry, Hunting, and Fishing Support industries, as reported by the U.S. Census. A note was added to Exhibit 2-7 that clarifies the source of the data used and also refers readers to Appendix B, Exhibits B-2 through B-4. Although specific ranches are not named, Section 4 estimates that impacts on grazing activities on Eagle Creek may range from $5,000 to $126,000 over the next 20 years (discounted at seven percent).

(82)

Comment:

One commenter states that the potential loss of the ability to divert surface water and possibly groundwater is the most important economic, social, and environmental consideration in the Verde River unit, and that the cost associated with such a loss of water is not calculated into the examples provided in Chapter 7 of the Draft Economic Analysis.

Our response:

Chapter 7 of the FEA focuses on potential impacts to residential and commercial development construction activities in critical habitat areas. Issues related to water use are discussed in Chapter 3 of the analysis. Section 3.5.1 specifically discusses water use in the Verde Valley, and provides estimates of the number of potentially affected surface water users and groundwater wells. Potentially affected agricultural lands within the Verde River Complex are valued at between $3.1 million and $30.3 million.

(83)

Comment:

One commenter states that the Economic Analysis did not discuss decreed water rights associated with surface water diversion ditches and how those decreed rights will be adversely impacted by the critical habitat designation, or what data will be relied upon in determining subflow.

Our response:

Section 3 of the Economic Analysis states that future impacts on water users are possible due to spikedace and loach minnow conservation efforts if less water is made available for diversion to accommodate the spikedace and loach minnow. The analysis also states that there are currently no data that indicate whether existing or future diversions of water (including groundwater use) reduce stream flow or modify hydrologic conditions to a degree that adversely impact the spikedace and loach minnow or their habitat. In addition, hydrologic models are unavailable to assess the role of any specific groundwater pumping activity or surface water diversion in determining stream flow or other hydrologic conditions within critical habitat. As such, this analysis does not quantify the probability or extent to which water use would need to be curtailed or modified to remedy impacts on spikedace and loach minnow. It does, however, provide information on the potential scale of the economic impacts that could occur if requirements associated with spikedace and loach minnow conservation result in changes in water diversions or conveyance.

Specifically, the analysis addresses potential impacts on water used for irrigated agriculture. The analysis states that it is possible that irrigation activities could be affected if farmers make efforts to maintain adequate water quantity and flow for the spikedace and loach minnow in the future. Because agricultural water use comprises 98 percent of surface water use and 81 percent of groundwater use in counties that contain critical habitat, it appears most likely that, if additional water supplies are needed for these species, they would come from current agricultural water use. Thus, the analysis assumes that to accommodate spikedace and loach minnow, farmers may give up water and cease to farm, resulting in losses of agricultural land value. Should irrigated agriculture be curtailed to accommodate spikedace and loach minnow, approximately 830 acres within proposed critical habitat, or 6,310 acres that fall in the vicinity of critical habitat that are currently irrigated for cropland agriculture could be retired from production. The irrigated crop production at risk of being lost is valued at approximately $4.5 million ($2005) within proposed critical habitat areas, or approximately $38.5 million ($2005) including lands that rely on water diverted from proposed critical habitat. Thus, the total cropland value potentially foregone ($38.5 million in $2005) is included in high end estimates of impacts on water use.

(84)

Comment:

One commenter states that nothing was included on the costs to retire farm and ranchland along the San Pedro River.

Our response:

Section 3 of the Economic Analysis identifies, to the extent possible, water users potentially affected by spikedace and loach minnow conservation efforts. Exhibit 3-7 includes a description of 64 acres of cropland that fall within the San Pedro River segment, and 720 acres of cropland that fall within the vicinity of proposed critical habitat. These acres are valued at $394,000 to $4.5 million (2005 dollars).

(85)

Comment:

Two commenters state that the Economic Analysis fails to consider impacts of the rule on the Arizona Water Settlements Act of 2004, Public Law 108-451.

Our response:

Section 3.5.5 of the FEA provides additional detail provided by the commenters about the 2004 Arizona Water Settlements Act (Pub. L. 108-451) as it relates to the proposed stretch of the Gila River in New Mexico.

(86)

Comment:

One commenter states that the Economic Analysis makes no attempt to quantify the impacts to farming activities in the Gila Valley. The commenter further states that the Service cannot simply declare that, due to data and model limitations, the analysis is not able to answer the question of whether impacts to water users are likely.

Our response:

Section 3.5.3 of the FEA discusses potential impacts of spikedace and loach minnow conservation activities on the Middle Gila/Lower San Pedro/Aravaipa Creek Complex (Complex 3). As stated in the analysis, “approximately 135 acres of lands used for cropland irrigation are located within Complex 3, and 1,220 acres are located in the valley that contains proposed critical habitat. The value of croplands in proposed critical habitat is approximately $11,000, while lands in the vicinity of proposed critical habitat are valued at approximately $7.5 million. Approximately $15,000 in Natural Resource Conservation Service funding was allocated to farms in proposed critical habitat areas on these segments in 2005.” The value of these at-risk agricultural lands are included in impact estimates for this unit. Thus, while the Economic Analysis does not identify the likelihood of these impacts, it does quantify them and include them in potential future cost estimates.

(87)

Comment:

One commenter states that the projected project modification costs are estimated at $13,500 per water

project resulting from the critical habitat designation, and that this estimate is based on estimates of costs at Fort Huachuca. The commenter states that project modification costs at Fort Huachuca are costing “tens-of-millions of dollars.” The commenter states that Phelps Dodge has recently incurred costs in excess of one million dollars for southwestern willow flycatcher mitigation, and thus water project cost estimates for spikedace and loach minnow critical habitat are low.

Our response:

The FEA includes specific cost estimates for particular water projects expected to occur within proposed critical habitat areas in Chapter 3 of the FEA. Typical project modifications for water projects in the past have included minimizing activities within the wetted channel, ensuring no pollutants enter surface waters, replanting riparian vegetation, monitoring for up to ten years, and conducting research studies. Future project modifications are assumed to be similar to those associated with a low-flow gauge installation to measure flow in the Verde River that occurred as part of a section 404 permit from U.S. Army Corps of Engineers, or $13,500 per project. Costs associated with the past consultation on Fort Huachuca are not included as part of these estimates, nor are they included in the analysis, as Fort Huachuca falls well outside the boundaries of proposed critical habitat, and downstream of proposed habitat areas. Quantified costs associated with water-related projects also include potential costs associated with costs of retiring agricultural cropland in order to provide sufficient water for the species. Potential costs to municipal, industrial and Tribal water use are also discussed, but not quantified. Expenditures made on behalf of the southwestern willow flycatcher are not relevant to this analysis.

Mining Impacts

(88)

Comment:

One commenter states that the Economic Analysis failed to adequately evaluate impacts to mining operations and water use in the arid southwest as a result of the proposed designation, resulting in a dramatic understatement of economic impacts. The commenter commissioned a report that estimates economic impacts to Phelps's Dodge's operations at the Tyrone Mine alone to exceed $100 million.

Our response:

Section 5 of the FEA evaluates potential impacts to mining operations. Section 3 of the analysis addresses impacts to water use that may occur in order to protect the spikedace and loach minnow. Specifically, the analysis states that:

“While few active mineral mining activities occur within the proposed critical habitat, the mining industry has expressed concern that water use by existing or potential mining operations could be affected by endangered species conservation activities, particularly the designation of critical habitat. Critical to an understanding of the potential for impacts on water diversions or conveyance is an understanding of the probability and magnitude of any such changes. As detailed in this section, there is currently no data that indicates whether existing or future diversions of water for mining activities (including groundwater use) reduces stream flow or modifies hydrologic conditions to a degree that adversely impacts the spikedace and loach minnow or their habitat. In addition, hydrologic models are unavailable to assess the role of any specific mining facility's groundwater pumping or surface water diversions in determining stream flow or other hydrologic conditions within critical habitat. As such, this analysis does not quantify the probability or extent to which water use for mining purposes would need to be curtailed or modified to remedy impacts on spikedace and loach minnow.

Given these data and model limitations, this analysis does not answer the question of whether impacts to mining operations are likely (i.e., the probability of such impacts), or define the expected magnitude of these impacts. It does, however, provide information on the potential scale of the economic impact that could occur if requirements associated with spikedace and loach minnow conservation result in changes in water diversions or conveyance. Specifically, to allow for an understanding of the economic activities that could be at risk if modifications to water use or conveyance are required, this analysis provides data on the location of mining activities potentially associated with CHD (critical habitat designation) areas, as well as data on the regional economic importance of these operations.”

The commenter provides hypothetical situations in which water currently used by mining operations may be lost to mining activities, and calculates a value of the lost water rights and associated replacement costs. While we do not disagree that, should the water be lost to mining activities, such costs could occur, there remains considerable uncertainty as to the likelihood of such events. Nonetheless, the revised analysis includes estimates of potential losses provided by the commenter in Section 5 of the analysis, to provide additional context for understanding the potential magnitude of impacts, should they occur.

(89)

Comment:

One commenter states that the Economic Analysis does not identify all of the Phelps Dodge mines that may be affected by critical habitat designation. Potentially affected mines include Morenci Mine, Tyrone Mine, Christmas Mine, and United Verde Mine. The commenter further states that the Economic Analysis does not consider potential effects to Phelps Dodge grazing and agricultural activities related to proposed critical habitat.

Our response:

Section 5 of the Draft Economic Analysis identified the Morenci Mine, the Tyrone Mine, and the Christmas Mine as being potentially affected by proposed critical habitat. Because the United Verde Mine falls outside of proposed critical habitat and has been inactive since 1953, it was not specifically described in the Draft Economic Analysis. The FEA now includes a discussion of impacts to United Verde Mine along with the other mines. As described by the commenter, current activities at the United Verde Mine area primarily include leasing water to agricultural activities. Potential impacts of proposed critical habitat on agricultural water use are addressed in Section 3 of the FEA. Potential impacts of proposed critical habitat on ranching activities, for all landowners, are addressed in Section 4 of the FEA.

(90)

Comment:

One commenter states that the Economic Analysis fails to consider the replacement costs associated with water users that may be impacted by the critical habitat designation. These costs are extremely high because water supplies in the west are scarce and not easily replaceable. Other costs relating to impacts on water use not considered include search, infrastructure, and lost profits from curtailed operations at mining facilities.

Our response:

The revised analysis includes estimates of potential losses provided by the commenter in Section 5 of the analysis. As stated in Response 87, it is not contested that, should water be lost to mining activities as a result of conservation activities for the spikedace and loach minnow, costs to the mining industry would be incurred. However, considerable uncertainty exists as to the likelihood, magnitude, and specific costs of water losses.

Small Business Impacts

(91)

Comment:

One commenter states that the Economic Analysis would be clearer if it reported the number of developers that are likely to be affected in the small business analysis.

Our response:

Appendix B, Small Business and Energy Impacts Analyses, considers the extent to which the analytic results presented in the main body of the FEA reflect potential future impacts to small businesses. Appendix B has been revised to provide additional details about the number of developers

potentially affected by proposed critical habitat designation.

(92)

Comment:

One commenter states that the Economic Analysis would be stronger if it provided data on the impact of critical habitat on small entities that thrive on the area's recreational activities. To collect such information, the commenter suggests that the Service seek public input on the reduction of fishing activity if stocking is curtailed.

Our response:

Appendix B considers the extent to which the analytic results presented in the main body of the FEA reflect potential future impacts to small businesses. As stated in the Appendix, “the future impact of proposed CHD on the stocking regimes in these reaches is unknown, as is the reduction in fishing activity that would occur if stocking is curtailed. Further, it is unknown whether non-native fish stocking may be replaced with catchable native fish stocking (e.g. Apache trout). Thus, this analysis estimates the value of angler days at risk if sportfish stocking were discontinued on these reaches as part of the high end estimates. Angling trips are valued at approximately $8.6 million over 20 years (or $816,000 annually), assuming a discount rate of 7 percent. It should be noted that because State fish managers typically identify alternative sites for stocked fish when areas are closed to stocking, these angler days are likely to be redistributed to other areas rather than lost altogether. Thus, the high-end estimate does not consider the possibility that rather than not fishing at all, recreators will visit alternative, less desirable fishing sites. Existing models of angler behavior in these areas were not available to refine this estimate.” The Appendix further states that “if, as in the high-end estimate of impacts, angler trips to the two stream reaches that currently stock non-native fish are not undertaken, localized impacts on anglers and, in turn, small businesses that rely on fishing activities could occur. These impacts would be spread across a variety of industries including food and beverage stores, food service and drinking places, accommodations, transportation, and sporting goods.” To conduct a survey of specific potential effects of closures is beyond the scope of this analysis. The revised Appendix does, however, include a reference to public comment received regarding a past store closure that occurred due to past area closures.

(93)

Comment:

One commenter states that the average number of acres in farms applied in the small business analysis is skewed due to the inclusion of a few very large (non small-business) farms. The commenter suggests that using the median farm size would improve results. The commenter also states that, because the Economic Analysis does not provide data on the impacts on beef cattle ranching operations, it is difficult to determine whether there will be a significant impact on this industry. The commenter also states that using the average revenues of all ranching operations, including both large and small business, likely skews the average to the upper end by including a few large ranches.

Our response:

Appendix B considers the extent to which the analytic results presented in the main body of the FEA reflect potential future impacts to small businesses. Appendix B has been revised to estimate the number of affected farms using average revenues as well as using median revenues. Appendix B does provide data on the impact to beef cattle ranching operations, including revenue data for beef cattle ranching operations, the number of ranches in each county, and the expected impact of the proposed rule on these entities. While specific revenue data for affected small beef cattle ranches is not readily available, a proxy for this is developed in the revised Appendix by eliminating the revenue outlier (Pinal County) from the average revenue estimates. This results in an estimate of average revenues for small ranches in the region of $42,500. The analysis therefore estimates that approximately 72 small ranching operations may experience a reduction in revenues of between 0.9 and 22 percent of annual revenues annually. These ranches represent 4.7 percent of ranches in affected counties, or one percent of ranches in New Mexico and Arizona.

(94)

Comment:

One commenter states that estimated average revenue for ranchers in Greenlee County of $133,000 is incorrect, and that, given the current drought, it is likely to be too high.

Our response:

Appendix B of the FEA lists the average revenues for cattle and calf ranches in Greenlee County as $19,100. We have incorporated an acknowledgement that revenue is dependent on, and may fluctuate with, natural conditions such as drought.

(95)

Comment:

One commenter states that there is no attempt to define baseline conditions in order to conduct a “with” and “without” analysis as prescribed by Executive Order 12866.

Our response:

The economic analysis estimates the total cost of species conservation activities without subtracting the impact of pre-existing baseline regulations (i.e., the cost estimates are fully co-extensive). In 2001, the U.S. 10th Circuit Court of Appeals instructed the Service to conduct a full analysis of all of the economic impacts of proposed critical habitat designation, regardless of whether those impacts are attributable co-extensively to other causes (

New Mexico Cattle Growers Ass'n

v.

U.S.F.W.S.

, 248 F.3d 1277 (10th Cir. 2001)). The economic analysis complies with direction from the U.S. 10th Circuit Court of Appeals.

Summary of Changes From Proposed Rule

Based upon our review of the public comments, economic analysis, environmental assessment, issues addressed at the public hearings, and any new relevant information that may have become available since the publication of the proposal, we reevaluated our proposed critical habitat designation and made changes as appropriate. Other than minor clarifications and incorporation of additional information on the species' biology, status, and threats, this final rule differs from the proposal by the following:

(1) We excluded lands of the San Carlos Apache, White Mountain Apache, and Yavapai-Apache Tribes pursuant to section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section below).

(2) We excluded lands owned by the Phelps Dodge Corporation on the Gila River and Eagle Creek pursuant to section 4(b)(2) of the Act (see “Exclusion Under Section 4(b)(2) of the Act” section below.)

(3) We excluded a portion of the Verde River pursuant to section 4(b)(2) of the Act (see “Exclusion Under Section 4(b)(2) of the Act” section below.)

(4) We modified the primary constituent elements for clarity and to reflect additional information received during the public comment period.

(5) We made technical corrections to township, range, section legal descriptions, the confluence point of the East Fork Black and North Fork East Fork Black rivers, and the upstream endpoint on Eagle Creek. Overall mileage from the proposed to the final designation was slightly reduced by approximately 0.5 river miles as a result of these corrections.

(6) Eagle Creek is no longer included in the designation of critical habitat for the spikedace, as further review of the available information shows this area does not meet our definition of occupied, and therefore does not meet

our criteria for defining critical habitat for the spikedace.

Critical Habitat

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 to use and the use of all methods and procedures necessary that bring any endangered species or threatened species to the point at which the measures provided pursuant to the Act are no longer necessary. Such methods and procedures include, but are not limited to, all activities associated with scientific resources management such as research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping, and transplantation, and, in the extraordinary case where population pressures within a given ecosystem cannot be otherwise relieved, regulated taking.

Critical habitat receives protection under section 7 of the Act through the prohibition against destruction or adverse modification of critical habitat with regard to actions carried out, funded, or authorized by a Federal agency. Section 7 requires consultation on Federal actions that are likely to result in the destruction or adverse modification of critical habitat. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. Such designation does not allow government or public access to private lands. Section 7 is a purely protective measure and does not require implementation of restoration, recovery, or enhancement measures.

To be included in a critical habitat designation, the habitat within the area occupied by the species must first have features that are essential to the conservation of the species. Critical habitat designations identify, to the extent known, using the best scientific data available, habitat areas that provide essential life cycle needs of the species (i.e., areas on which are found the primary constituent elements, as defined at 50 CFR 424.12(b)).

Habitat occupied at the time of listing may be included in critical habitat only if the features essential to the conservation of the species therein may require special management or protection. Thus, we do not include areas where existing management is sufficient to conserve the species. (As discussed below, such areas may also be excluded from critical habitat pursuant to section 4(b)(2).) Accordingly, when the best available scientific data do not demonstrate that the conservation needs of the species require additional areas, we will not designate critical habitat in areas outside the geographical area occupied by the species at the time of listing. An area currently occupied by the species but that was not known to be occupied at the time of listing will likely, but not always, be essential to the conservation of the species and, therefore, included in the critical habitat designation.

The Service's Policy on Information Standards Under the Endangered Species Act, published in the

Federal Register

on July 1, 1994 (59 FR 34271), along with Section 515 of the Treasury and General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658) and the associated Information Quality Guidelines issued by the Service provide criteria and establish procedures to ensure that decisions made by the Service represent the best scientific data available. They require Service biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat. When determining which areas are critical habitat, the Service generally uses the listing package as a primary source of information. Additional information sources 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. All information is used in accordance with the provisions of Section 515 of the Treasury and General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658) and the associated Information Quality Guidelines issued by the Service.

Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific and commercial data available. Habitat is often dynamic, and species may move from one area to another over time. Furthermore, we recognize that designation of critical habitat may not include all of the habitat areas that may eventually be determined to be necessary for the recovery of the species. For these reasons, critical habitat designations do not signal that habitat outside the designation is unimportant or may not be required for recovery.

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

Primary Constituent Elements

In accordance with section 3(5)(A)(i) of the Act and regulations at 50 CFR 424.12, in determining which areas to propose as critical habitat, we consider those physical and biological features (primary constituent elements (PCEs)) that are essential to the conservation of the species, and within areas occupied by the species at the time of listing, that may require special management considerations and protection. These include, but are not limited to, space for individual and population growth and for normal behavior; food, water, air, light, minerals or other nutritional or physiological requirements; cover or shelter; sites for breeding, reproduction, or rearing of offspring; and habitats that are protected from disturbance or are representative of the historical, geographical, and ecological distributions of a species.

We determined the primary constituent elements for spikedace and loach minnow from studies on their habitat requirements and population biology including, but not limited to, Barber et al. 1970, pp. 10-12; Minckley 1973; Anderson 1978, p. 7, 17, 31-37, 41, 54; Barber and Minckley 1983, pp. 34-39; Turner and Tafanelli 1983, pp. 15-20; Propst et al. 1986, p. 40-72, 82-83; Hardy et al. 1990, pp. 19-20, 39; Douglas et al. 1994, pp. 12-14; Rinne

and Stefferud 1996, p. 14-17; and Velasco 1997, pp. 5-6.

Spikedace

The specific primary constituent elements required for the spikedace are derived from the biological needs of the species as described in the Background section of this document and below.

Space for Individual and Population Growth and Normal Behavior

Habitat Preferences

Spikedace have differing habitat requirements through their various life stages. Generally, adult spikedace prefer intermediate-sized streams with moderate to swift currents over sand, gravel, and cobble substrates (i.e., stream bottoms). Preferred water depths of adults are less than 11.8 in (30 cm) (Barber and Minckley 1966, p. 321; Minckley 1973, p. 114; Anderson 1978, p. 17; Rinne and Kroeger 1988, p. 1; Hardy 1990, pp. 19-20, 39; Sublette et al. 1990, p. 138; Rinne 1991, pp. 8-10; Rinne 1999, p. 6). As discussed below, larval and juvenile spikedace occupy different habitats than adults.

Flow Velocities.

Studies on flow velocity have been completed on the Gila River, Aravaipa Creek, and the Verde River. In these studies, flows measured in habitat occupied by adult spikedace ranged from 23.3 to 70.0 cm/second (9.2-27.6 in/second) (Barber and Minckley 1966, p. 321; Hardy 1990, pp. 19-20, 39; Propst et al. 1986, p. 41; Rinne 1991, pp. 9-10; Rinne and Kroeger 1988, p. 1; Schreiber 1978, p. 4). Studies on the Gila River indicated that juvenile spikedace occupy areas with velocities of approximately 16.8 cm/second (6.6 in/second) while larval spikedace were found in velocities of 8.4 cm/second (3.3 in/second) (Propst et al. 1986, p. 41).

Propst et al. 1986 (pp. 47-49) examined flow velocities in occupied spikedace habitats as they varied by season. During the warm season (June-November), occupied spikedace habitats in the Gila River had mean flow velocities of 19.3 in/second (49.1 cm/second) at one site and 7.4 in/second (18.8 cm/second) at the second site. During the cold season (December-May), mean flow velocities at these same sites were 15.5 in/second (39.4 cm/second) and 8.4 in/second (21.4 cm/second). It is believed that spikedace seek areas in the stream that offer warmer water temperatures during cooler seasons to offset their decreased metabolic rates. Where water depth remains fairly constant throughout the year (

e.g.,

the first site), slower velocities provided pockets of warmer water temperatures in the stream. In areas of fairly constant flow velocities (e.g., the second site), warmer water temperatures were found in those portions of the stream with shallower water (Propst et al. 1986, pp. 47-49).

Larval and juvenile spikedace, which occupy different habitats than adults, tend to occupy shallow, peripheral portions of streams that have slower currents (Anderson 1978, p.17; Propst et al. 1986, pp. 40-41). Once they emerge from the gravel of the spawning riffles, spikedace larvae disperse to stream margins where water velocity is very slow or still. Larger larval and juvenile spikedace (those fish 1.0 to 1.4 inches (25.4 to 35.6 mm) in length) occurred over a greater range of water velocities than smaller larvae, but still occupied water depths of less than 12.6 inches (32.0 cm) (Propst et al. 1986, p. 40). Juveniles and larvae are also occasionally found in quiet pools or backwaters (e.g., pools that are connected with, but out of, the main river channel) lacking streamflow (Sublette et al. 1990, p. 138).

Outside of the breeding season, which occurs between April and June, eighty percent of the spikedace collected in a Verde River study used run and glide habitat. For this study, a glide was defined as a portion of the stream with a lower gradient (0.3 percent), versus a run which had a slightly steeper gradient (0.3-0.5 percent) (Rinne and Stefferud 1996, p. 14). Spikedace in the Gila River were most commonly found in riffle areas of the stream with moderate to swift currents (Anderson 1978, p. 17) and some run habitats (J.M. Montgomery 1985, p. 21), as were spikedace in Aravaipa Creek (Barber and Minckley 1966, p. 321).

Seasonal differences in habitats utilized by spikedace have been noted in the upper Gila drainage, for both the winter and breeding seasons. For example, spikedace were found to use shallower habitats (<6.6 inches, <16.8 cm) in the winter, and deeper habitats (6.6 to 12.6 inches, 16.8-32.0 cm) during warmer months (Propst et al. 1986, p. 47).

Specific habitat usage has been noted for the breeding season as well. During the breeding season, female and male spikedace become segregated, with females occupying deeper pools and eddies and males occupying riffles flowing over sand and gravel beds in water approximately 3.1 to 5.9 inches (7.9-15.0 cm) deep. Females then enter the riffles occupied by the males before ova are released into the water column (Barber et al. 1970, pp.11-12).

Streams in the southwestern United States have a wide fluctuation in flows and some are periodically dewatered. While portions of stream segments included in this designation may experience dry periods, they are still considered important because the spikedace is adapted to stream systems with fluctuating water levels. While they can not persist in dewatered areas, spikedace will use these areas as connective corridors between occupied or seasonally occupied habitat when they are wetted.

Substrates.

Spikedace are known to occur in areas with low to moderate amounts of fine sediment and substrate embeddedness (filling in of spaces by fine sediments), which are important features for healthy development of eggs. Spawning has been observed in areas with sand and gravel beds and not in areas where fine materials of a particle size less than sand coats the sand or gravel substrate, as described above. Additionally, low to moderate fine sediments ensure that eggs remain well-oxygenated and will not suffocate due to sediment deposition (Propst et al. 1986, p. 40).

Spikedace were found over sand and gravel substrates in the glide-run and low-gradient riffle habitats in both the upper Verde (Rinne and Stefferud 1996, p. 21) and the upper Gila (Propst et al. 1986, p. 40; Rinne and Deason 2000, p. 106). In a study of a small portion of the Verde River, spikedace were found in glide-run habitats where substrates were characterized by approximately 29 percent sand or fines (silty sand) (Rinne 2001, p. 68). In other studies of the Verde River over a two-year period, spikedace were found in areas with a percentage of fine content substrate that varied from 1 to 28 percent (Rinne 2001, p. 68). Neary et al. (1996, p. 24) noted that spikedace were found in habitats with substrates of less than 10 percent sand. While there is some variability in the percent of sand or fine substrate in occupied spikedace habitat, Neary et al. (1996, p. 24) concluded that, based on the higher density of spikedace present in areas with lower percentages of sand in the substrate, spikedace favored habitats with lower sand content.

Substrates are, in part, a reflection of the gradients and velocities of the streams in which they are found. Sand and gravel typically decrease as gradient and velocity increase (Rinne and Stefferud 1996, p. 14). Spikedace numbers in the Verde River increased almost three times (from 18 to 52 individuals) when the fine component of the substrate decreased from about 27 percent down to 7 percent (Neary et al. 1996, p. 26), indicating that spikedace prefer habitats with lower amounts of fines. Sand content in all glide-run

spikedace habitats in the Verde and Gila Rivers in 2000 was 18 and 20 percent (Rinne 2001, p. 68). However, because substrates are determined in part by gradient and velocity of the stream, the type of substrate should not be used alone in determining suitable spikedace habitat.

Sixty percent of spikedace larvae in the Gila River were found over sand-dominated substrates, while 18 percent were found over gravel, and an additional 18 percent found over cobble-dominated substrates. While 45 percent of juvenile spikedace were found over sand substrates, an additional 45 percent of the juveniles were found over gravel substrates, with the remaining 9 percent associated with cobble-dominated substrates (Propst et al. 1986, p. 40).

The degree of substrate embeddedness may also affect the prey base for spikedace. As discussed below, mayflies constitute a significant portion of the spikedace diet. Suitable habitat for some mayflies includes pebbles or gravel for clinging (Pennak 1978, p. 539). Excess sedimentation would cover or blanket smaller pebbles and gravel, resulting in a lack of suitable habitat for mayflies, and a subsequent decrease in available prey items for spikedace.

Flooding.

Rainfall in the southwest is generally characterized as bimodal, with winter rains of longer duration and less intensity and summer rains of shorter duration and higher intensity. As we discuss below, periodic flooding appears to benefit spikedace in three ways: (1) Removing excess sediment from some portions of the stream; (2) removing nonnative fish species from a given area; and (3) increasing prey species diversity.

Flooding in Aravaipa Creek has resulted in the transport of heavier loads of sediments such as cobble, gravel, and sand that are deposited where the stream widens, gradient flattens, and velocity and turbulence decrease. Dams formed by such deposition can temporarily cause water to back up and break into braids downstream of the dam. The braided areas provide excellent nurseries for larval and juvenile fishes (Velasco 1997, pp. 28-29).

On the Gila River in New Mexico, flows fluctuate seasonally with snowmelt, causing spring pulses and occasional floods, and late-summer or monsoonal rains producing floods of varying intensity and duration. These high flows benefit spikedace spawning and foraging habitat (Propst et al. 1986, p. 3) as described above. Peak floods can modify channel morphology and sort and rearrange stream bed materials (Stefferud and Rinne 1996, p. 80).

Floods likely benefit native fish by breaking up embedded bottom materials (Mueller 1984, p. 355). A study of the Verde River analyzed the effects of flooding in 1993 and 1995, finding that these floods had notable effects on both native and nonnative fish species. Among other effects, these floods on the Verde River either stimulated spawning or enhanced recruitment of three of the native species or may have eliminated one of the nonnative fish species (Rinne and Stefferud 1997, pp. 159, 162; Stefferud and Rinne 1996, p. 80).

Minckley and Meffe 1987 (pp. 99, 100) found that flooding, as part of a natural hydrograph, may temporarily remove nonnative fish species, which are not adapted to flooding. Thus flooding consequently removes the competitive pressures of nonnative fish species on native fish species which persist following the flood. Minckley and Meffe (1987, p. 99-100) studied the differential responses of native and nonnative fishes in seven unregulated and three regulated streams or stream reaches that were sampled before and after major flooding noted that fish faunas of canyon-bound reaches of unregulated streams invariably shifted from a mixture of native and nonnative fish species to predominantly, and in some cases exclusively, native forms after large floods. Samples from regulated systems indicated relatively few or no changes in species composition due to releases from upstream dams at low, controlled volumes. However, during emergency releases, effects to nonnative fish species were similar to those seen with flooding on unregulated systems.

There is some variability in fish response to flooding. Some nonnative species, such as smallmouth bass (

Micropterus dolomieui

) and green sunfish (

Lepomis cyanellus

), appear to be partially adapted to flooding, and often reappear in a few weeks (Minckley and Meffe, p. 100). In addition, Stefferud and Rinne (1996, p. 75) found that late-winter flooding affected the entire fish community, either stimulating reproduction or promoting recruitment (at least among the larger-size fishes), and possibly eliminating some nonnative species.

The onset of flooding also corresponds with an increased diversity of food items for spikedace. Reductions in the mainstream invertebrates, such as mayflies, cause the fish to expand its food base in an opportunistic manner. In addition, inflowing flood waters carry terrestrial invertebrates, such as ants, bees, and wasps (Hymenopterans), into aquatic areas (Barber and Minckley 1983, p.39).

Stream Gradient.

Spikedace occupy streams with low to moderate gradients (Propst et al. 1986, p. 3; Rinne and Stefferud 1996, p. 14; Stefferud and Rinne 1996, p. 21; Sublette et al. 1990, p. 138). Specific gradient data are generally lacking, but the gradient of occupied portions of Aravaipa Creek and the Verde River varied between approximately 0.3 to <1.0 percent (Barber et al. 1970, p. 10; Rinne and Kroeger 1988, p. 2; Rinne and Stefferud 1996, p. 14).

Habitat Protected From Disturbance or Representative of the Historic Geographical and Ecological Distribution of a Species

Nonnative aquatic species.

One of the primary reasons for the decline of native species is the presence of nonnative fishes. Fish evolution in the arid American west is linked to disruptive geologic and climatic events that acted in concert over evolutionary time to decrease the availability and reliability of aquatic ecosystems. The fragmentation and reduction of aquatic ecosystems resulted in a fish fauna that was both diminished and restricted in the arid west. Lacking exposure to a wider range of species, western species seem to lack the competitive abilities and predator defenses developed by fishes from regions where more species are present (Douglas et al. 1994, pp. 9-10). The introduction and spread of nonnative species has been identified as one of the major factors in the continuing decline of native fishes throughout North America and particularly in the southwestern United States (Miller 1961, p. 365, 377, 397-398; Lachner et al. 1970, p. 22; Ono et al. 1983, p. 90; Moyle 1986, pp. 28-34; Moyle et al. 1986, pp. 416-423; Carlson and Muth 1989, pp. 232-233; Fuller et al. 1990, p. 1). Miller et al. (1989, p. 1) concluded that nonnative species were a causal factor in 68 percent of the fish extinctions in North America in the last 100 years. For 70 percent of those fish still extant, but considered to be endangered or threatened, introduced nonnative species are a primary cause of the decline (Lassuy 1995, p. 392). In Arizona, release or dispersal of recently introduced nonnative aquatic organisms is a continuing phenomenon (Rosen et al. 1995, pp. 255-256, 258; U.S. Fish and Wildlife Service 2001a, pp. 26-32). Aquatic nonnative species are introduced and spread into new areas through a variety of mechanisms, intentional and accidental, authorized and unauthorized. Mechanisms for nonnative dispersal in the southwestern

United States include interbasin water transfer, sport fish stocking, aquaculture, aquarium releases, baitbucket release (release of fish used as bait by anglers), and biological control (e.g., the introduction of one species to control another species) (U.S. Fish and Wildlife Service 2001a, pp. 13, 37).

In the Gila River basin, introduction of nonnatives is considered a major factor in the decline of all native fish species (Minckley 1985, p. 20-21; Williams et al. 1985, p. 1; Minckley and Deacon 1991, p. 17). Aquatic and semi-aquatic mammals, reptiles, amphibians, crustaceans, mollusks (snails and clams), insects, zoo- and phytoplankton, parasites, disease organisms, algae, and aquatic and riparian vascular plants that are outside of their historical range have all been documented to adversely affect aquatic ecosystems (Cohen and Carlton 1995, pp. 1-8). As described below, the nonnative fishes have been demonstrated to pose a significant threat to Gila River basin native fishes, including spikedace and loach minnow (Minckley 1985, p. 108-109; Williams et al. 1985, p. 19). The aquatic ecosystem of the central Gila River basin has relatively small streams with warm water and low gradients, and many of the native aquatic species are small in size. Therefore, much of the threat to native fishes comes from small nonnative fish species, as has also been noted for southern Nevada aquatic ecosystems (Deacon et al. 1964, p. 385). Examples of this are the impacts of mosquitofish (

Gambusia affinis

) and red shiner (

Cyprinella lutrensis

), which may compete with or prey upon native fish in the Gila River basin (Meffe 1985, p. 173-174, 176-180; Douglas et al. 1994, pp. 13-17).

The effects of nonnative fish competition on spikedace can be classified as either interference or exploitive. Interference competition occurs when individuals directly affect others, such as by fighting, producing toxins, or preying upon them (Schoener 1983, p. 257). Exploitive competition occurs when individuals affect others indirectly, such as through use of common resources (Douglas et al. 1994, p. 14).

Nonnative fishes known to occur within the historical range of the spikedace include channel catfish (

Ictalurus punctatus

), flathead catfish (

Pylodictis olivaris

), red shiner, fathead minnow (

Pimephales promelas

), green sunfish (

Lepomis cyanellus

), largemouth bass (

Micropterus salmoides

), smallmouth bass (

Micropterus dolomieui

), rainbow trout (

Oncorynchus mykiss

), mosquitofish, carp (

Cyprinus carpo

), bluegill (

Lepomis macrochiris

), yellow bullhead (

Ameiurus natalis

), black bullhead (

Ameiurus melas

), and goldfish (

Carassius auratus

) (AGFD Native Fish Database 2005, ASU 2002). Additionally, as discussed below, nonnative parasites introduced incidentally with nonnative species may threaten spikedace populations. Although parasites are normal in fish populations and typically do not cause mortality in their host, the effects of nonnative parasites can be significant, especially when combined with other stressors such as poor habitat conditions (U.S. Geological Survey 2004, p. 1; 2005, p. 2-3).

There is evidence of the negative impacts of nonnative predators on native fishes for several stream reaches. The effect of nonnative fish preying on natives such as spikedace is classified as interference competition. Channel catfish, flathead catfish, and smallmouth bass all prey on native fishes including spikedace, as evidenced by prey remains of native fishes in the stomachs of these predatory species (Propst et al. 1986, p. 82, Bonar et al. 2004, p. 13, 16-21). Native fish species declines appear linked to increases in nonnative fish species. For example, in 1949, 52 spikedace were collected at Red Rock while channel catfish composed only 1.65 percent of the 607 fish collected. However, in 1977, only six spikedace were located at the same site, and the percentage of channel catfish had risen to 14.5 percent of 169 fish collected. The decline of spikedace and the increase of channel catfish is likely related (Anderson 1978, p. 51) because of this correlation and the evidence of predation by catfish on spikedace.

Similar interactions between native and nonnative fishes were observed in the upper reaches of the East Fork of the Gila River. In this system, native fish were limited, with spikedace being rare or absent, while nonnative channel catfish and smallmouth bass were moderately common prior to 1983 and 1984 floods. Post-1983 flooding, adult nonnative predators were generally absent and spikedace were collected in moderate numbers in 1985 (Propst et al. 1986, p. 83).

Green sunfish (

Lepomis cyanellus

) is also thought to be a predator, likely responsible for replacement of natives like spikedace, through predation. While no direct studies have been completed on predation by green sunfish on spikedace, they are a known predator that occurs within occupied spikedace areas.

Interference competition occurs with species such as red shiner. Red shiner appear to be particularly detrimental to spikedace because although spikedace and shiners are naturally separated by geography (i.e., allopatric), they occupy essentially the same habitat types. Red shiner has an inverse distribution pattern to spikedace in that, generally, where red shiner is present, spikedace are absent (Minckley 1973, p. 138). Where the two species occur together, there is evidence of displacement of spikedace to less suitable habitats that it otherwise did not occupy (Marsh et al. 1989, pp. 67, 107). As a result, if red shiners are present, suitable habitat available for spikedace is reduced. Range expansion and species recovery may then be curtailed due to red shiner presence.

One study focused on potential impacts of red shiner on spikedace in three areas; (1) Portions of the Gila River and Aravaipa Creek having only spikedace; (2) a portion of the Verde River where spikedace and red shiner have co-occurred for three decades; and (3) a portion of the Gila River where red shiner recently invaded areas and where spikedace had never been recorded. The study indicated that, for reaches where only spikedace were present, spikedace displayed a preference for slower currents and smaller particles in the substrate than were generally available throughout the Gila River and Aravaipa Creek systems. Where red shiner occur in the Verde River, the study showed that red shiner occupied waters that were generally slower and with smaller particle size in the substrate than were, on average, available in the system. The study concludes that spikedace, where co-occurring with red shiner, move into currents swifter than those selected when in isolation, while red shiner occupy the slower habitat, whether they are alone or with spikedace (Douglas et al. 1994, pp. 14-16).

Western mosquitofish were introduced outside of their native range to help control mosquitoes. Because of their aggressive and predatory behavior, mosquitofish may negatively affect populations of small fish through predation and competition (Courtenay and Meffe 1989, p. 320, 322, 324). Introduced mosquitofish have been particularly destructive in the American west where they have contributed to the elimination or decline of populations of federally threatened and endangered species, such as the Gila topminnow (

Poeciliopsis occidentalis occidentalis

) (Courtenay and Meffe 1989, p. 323-324).

The Asian tapeworm (

Bothriocephalus acheilognathi

) was introduced into the United States via imported grass carp in the early 1970s. It has since become well established in

the southeast and mid-southern United States and has been recently found in the southwest including the Gila Basin. The definitive host in the life cycle of the Asian tapeworm is cyprinid (fish in the minnow family) fishes. There is a potential threat to spikedace as well as to the other native fishes in Arizona because of the presence of this parasite in the Gila Basin and the presence of cyprinid fish. The Asian tapeworm affects fish health in several ways. The direct impacts to fish are through impeding digestion of food as it passes through the intestinal track, and loss of nutrients as the worm feeds off the fish; large enough numbers of worms cause emaciation and starvation. An indirect effect is that weakened fish are more susceptible to infection by other pathogens. This parasite can infest many species of fish and is carried into new areas along with nonnative fishes or native fishes from contaminated areas. Asian tapeworm may be a significant source of mortality of other fish species in the Colorado River basin (U.S. Geological Survey 2004, p. 1, 2005, p. 2).

Anchor worm (

Lernaea cyprinacea

) (Copepoda), also a nonnative species, is an external parasite, and is unusual in that it has little host specificity, infecting a wide range of fishes and amphibians. Additionally, infection has been known to kill large numbers of fish due to tissue damage and secondary infection of the attachment site (Hoffnagle and Cole 1997, p. 24). Presence of this parasite in the Gila River basin is a threat to the Gila chub and other native fish. In July 1992, the Bureau of Land Management (BLM) found Gila chub that were heavily parasitized by

Lernaea cyprinacea

in Bonita Creek. These fish were likely more susceptible to parasites due to physiological stress as a result of degraded habitat and decreased water flows due to water withdrawals. Creef and Clarkson (1993, p. 1, p. 5) suspected that infestations by

Lernaea cyprinacea

caused high mortality of stocked native fish, razorback sucker (

Xyrauchen texanus

) and Colorado pikeminnow (

Ptycocheilus lucius

).

The nonnative parasite

Ichthyophthirius multifiliis

(“Ich”) is a potential threat to spikedace. “Ich” disease has occurred in some Arizona streams, probably favored by high temperatures and crowding as a result of drought (Mpoame 1982, p. 46). This protozoan becomes embedded under the skin and within the gill tissues of infected fish. When the “Ich” matures, it leaves the fish, causing fluid loss, physiological stress, and sites that are susceptible to infection by other pathogens. If “Ich” is present in large enough numbers they can also impact respiration because of damaged gill tissue. This parasite has been observed on the Sonora sucker (

Catostomus insignis

), a species common throughout the Gila River basin, and “Ich” does not appear to be hostspecific, so it could be transmitted to other species. “Ich” is known to be present in Aravaipa Creek (Mpoame 1982, p. 46).

Food

Food Items.

Spikedace are active, highly mobile fish that visually inspect drifting materials both at the surface and within the water column. Gustatory inspection, or taking potential prey items into the mouth before either swallowing or rejecting it, is also common (Barber and Minckley 1983, p. 37). Prey body size is small, typically ranging from 0.08 to 0.20 inches (2 to 5 mm) long (Anderson 1978, p. 36).

Stomach content analysis of spikedace determined that mayflies, caddisflies, true flies, stoneflies, and dragonflies are all prey items for spikedace. In one Gila River study, the frequency of occurrence was 71 percent for mayflies, 34 percent for true flies, and 25 percent for caddisflies (Propst et al. 1986, p. 59). A second Gila River study of four samples determined that total food volume was comprised of 72.7 percent mayflies, 17.6 percent caddisflies, and 4.5 percent true flies (Anderson 1978, pp. 31-32). At Aravaipa Creek, mayflies, caddisflies, true flies, stoneflies, and dragonflies were all prey items for spikedace, as were some winged insects and plant materials (Schreiber 1978, pp. 12-16, 29, 35-37).

At Aravaipa Creek, spikedace consumed a total of 36 different prey items. Mayflies constituted the majority of prey items, followed by true flies. Of the mayflies consumed, 36.5 percent were adults, while 33.3 percent were nymphs. Terrestrial invertebrates, including ants, wasps, and spiders, were also consumed, as were beetles, true bugs, caddisflies, and water fleas (Barber and Minckley 1983, pp. 34-38).

Spikedace diet varies seasonally (Barber and Minckley 1983, pp. 34-35). Mayflies dominated stomach contents in July, but declined in August and September, increasing in importance again between October and June. When mayflies were available in lower numbers, spikedace consumed a greater variety of foods, including true bugs, true flies, beetles, and spiders.

Spikedace diet varies with age class as well. Young spikedace, which measure less than 0.9 inches (22.9 mm) long, fed on a diversity of small-bodied invertebrates occurring in and on sediments along the margins of the creek. True flies were found most frequently, but water fleas and aerial adults of aquatic and terrestrial insects also provide significant parts of the diet. As juveniles grow and migrate into the swifter currents of the channel, mayfly nymphs (invertebrates between the larval and adult life stages, similar to juveniles) and adults increase in importance (Barber and Minckley 1983, pp. 36-37).

Spikedace are very dependent on aquatic insects for sustenance, and the production of the aquatic insects consumed by spikedace occurs mainly in riffle habitats (Propst et al. 1986, p. 59). As a result, habitat selection influences food items found in stomach content analyses. Spikedace in pools had eaten the least diverse foods while those from riffles contained a greater variety of taxa, indicating that the presence of riffles in good condition and abundance help to ensure that a sufficient number and variety of prey items will continue to be available for spikedace (Barber and Minckley 1983, pp. 36-37, 40).

Aquatic invertebrates that constitute the bulk of the spikedace diet have specific habitat parameters of their own. Mayflies, which constituted the largest percentage of prey items, spend their immature stages in fresh water. Mayfly nymphs occur in all types of fresh waters, wherever there is an abundance of oxygen, but they are most characteristic of shallow water. Mayflies found in spikedace stomach content analyses consisted of individuals from several genera, with individuals from the genus

Baetidae

constituting the highest percentage of prey from the mayfly order in the study by Schreiber (1978, p. 36).

Baetidae

are free-ranging species of rapid waters that maintain themselves in currents by clinging to pebbles. Spikedace also consumed individuals from two other mayfly genera (

Heptageniidae

and

Ephemerellidae

), which are considered “clinging species” as they cling tightly to stones and other objects and may be found in greatest abundance in crevices and on the undersides of stones (Pennak 1978, p. 539). The importance of gravel and cobble substrates is illustrated by the fact that these prey species, which make up the bulk of the spikedace diet, require these surfaces to persist.

Water Quality

Pollutants.

Water with no or only minimal pollutant levels is essential for the survival of spikedace. Spikedace occur in areas where mining, agriculture, livestock operations, and

road construction and use are prevalent. Various pollutants are associated with these types of activities. For spikedace, waters sho

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