# Endangered and Threatened Wildlife and Plants; Endangered Species Status for the Zuni Bluehead Sucker

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A2014-17205

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** July 24, 2014
- **Citation:** 79 FR 43132

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2012-0101; 4500030113]
RIN 1018-AY25
Endangered and Threatened Wildlife and Plants; Endangered Species Status for the Zuni Bluehead Sucker

AGENCY:

Fish and Wildlife Service, Interior.

AGENCY:

Final rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), determine endangered species status under the Endangered Species Act of 1973 (Act), as amended, for the Zuni bluehead sucker (
Catostomus discobolus yarrowi
), a fish species from Arizona and New Mexico. The effect of this regulation will be to add this species to the List of Endangered and Threatened Wildlife.

DATES:

This rule becomes effective August 25, 2014.

ADDRESSES:

This final rule is available on the Internet at
http://www.regulations.gov
and on the New Mexico Ecological Service Field Office Web site at
http://www.fws.gov/southwest/es/newmexico.
Comments and materials we received, as well as supporting documentation we used in preparing this rule, are available for public inspection at
http://www.regulations.gov.
All of the comments, materials, and documentation that we considered in this rulemaking are available by appointment, during normal business hours at: U.S. Fish and Wildlife Service, New Mexico Ecological Services Field Office, 2105 Osuna NE., Albuquerque, NM 87113; telephone 505-346-2525; facsimile 505-346-2542.

FOR FURTHER INFORMATION CONTACT:

Wally “J” Murphy, Field Supervisor, U.S. Fish and Wildlife Service, New Mexico Ecological Services Field Office, 2105 Osuna NE., Albuquerque, NM 87113, by telephone 505-346-2525 or by facsimile 505-346-2542. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

Why we need to publish a rule.
Under the Act, a species may warrant protection through listing if it is endangered or threatened throughout all or a significant portion of its range. Listing a species as an endangered or threatened species can be completed only by issuing a rule.

This rule will
finalize the listing of the Zuni bluehead sucker
(Catostomus discobolus yarrowi)
as an endangered species.

The Endangered Species Act provides the basis for our action.
Under the Act, we can determine that a species is an endangered or threatened species based on any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) Overutilization for commercial, recreational, scientific, or educational purposes; (C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms; or (E) Other natural or manmade factors affecting its continued existence.

We have determined that the Zuni bluehead sucker meets the definition of an endangered species due to the combined effects of:

• Habitat destruction, modification, and degradation resulting from water withdrawal (stream drying); sedimentation; impoundments; livestock grazing; and the spread of nonnative species.

• Predation by nonnative species such as the green sunfish
(Lepomis cyanellus),
northern crayfish
(Orconectes virilis),
and red swamp crayfish
(Procambarus clarkii),
which limit recruitment and reduce population size.

• Existing Federal, State, or Tribal regulatory mechanisms that could provide protection to the Zuni bluehead sucker do provide limited protection; however, many are inadequate to protect the species from existing and future threats.

• Small population size and restricted ranges of the species make the Zuni bluehead sucker population vulnerable to stochastic events, such as wildfire and drought.

We requested peer review of the methods used in making our final determination.
We obtained opinions from five knowledgeable individuals having scientific expertise in this species and solicited review of the scientific information and methods that we used in developing the proposal. During the public comment period following the 6-month extension notice, we also obtained opinions and information from three knowledgeable individuals with genetic and morphological expertise. These individuals reviewed all available relevant information for the Zuni bluehead sucker to determine whether we had used the best available information. These peer reviewers generally concurred with our methods and conclusion, and provided additional information, clarification, and suggestions to improve this final listing rule.

We sought public comment on the proposed listing rule.
During the first comment period, we received four comment letters directly addressing the proposed listing. During the second comment period, we received six comment letters addressing the proposed listing rule.

Previous Federal Action

We first identified the Zuni bluehead sucker as a candidate species in the September 18, 1985, Review of Vertebrate Wildlife; Notice of Review (50 FR 37958). The Zuni bluehead sucker was identified as a Category 2 Candidate species at that time; Category 2 Candidates were defined as species for which we had information that proposed listing was possibly appropriate, but conclusive data on biological vulnerability and threats were not available to support a proposed rule at the time. The species remained so designated in subsequent annual Candidate Notices of Review (CNOR) (54 FR 554, January 6, 1989; 56 FR 58804, November 21, 1991; and 59 FR 58982, November 15, 1994). In the February 28, 1996, CNOR (61 FR 7596), we discontinued the designation of Category 2 species as candidates; therefore, the Zuni bluehead sucker was no longer a candidate species.

Subsequently, in 2001, the Zuni bluehead sucker was added to the candidate list (66 FR 54807, October 30, 2001). Candidates are those fish, wildlife, and plants for which we have on file sufficient information on biological vulnerability and threats to support preparation of a listing proposal, but for which development of a listing regulation is precluded by other higher priority listing activities. The Zuni bluehead sucker was included in all of our subsequent annual CNORs (67 FR 40657, June 13, 2002; 69 FR 24876, May 4, 2004; 70 FR 24870, May 11, 2005; 71 FR 53756, September 12, 2006; 72 FR 69034, December 6, 2007; 73 FR 75176, December 10, 2008; 74 FR 578034 November 9, 2009; 75 FR 69222, November 10, 2010; and 76 FR 66370, October 26, 2011). On May 11, 2004, we were petitioned to list Zuni bluehead sucker, although no new information was provided in the petition. Because we had already found that the species warranted proposed listing, no further action was taken on the petition. Zuni bluehead sucker has a listing priority number of 3, which reflects a subspecies with threats that are both imminent and high in magnitude.

On January 25, 2013, we published in the
Federal Register
a proposed rule (78 FR 5369) to list the Zuni bluehead sucker as an endangered species under the Act. On the same date, we also published in the
Federal Register
a proposed rule to designate critical habitat for the Zuni bluehead sucker (78 FR 5351; January 25, 2013). Both the proposed listing rule and the proposed critical habitat rule had a 60-day comment period, ending March 26, 2013.

After the publication of the proposed rules, we found there was substantial scientific disagreement regarding the taxonomic status of some populations that we considered Zuni bluehead sucker in the proposed rule, and we reopened the comment period for the proposed listing rule and extended the schedule for the final determination for 6 months in order to solicit and analyze information that would help to clarify the issues. On January 9, 2014, we published in the
Federal Register
a notice that extended the final determination for the Zuni bluehead sucker by 6 months due to substantial disagreement regarding the Zuni bluehead sucker's taxonomic status in some locations (79 FR 1615). That comment period closed on February 10, 2014.

Background

Species Information

The Zuni bluehead sucker has a fusiform (torpedo-shaped), slender body with a subterminal mouth (mouth posterior to the tip of the snout) (Propst 1999, p. 49). Most individuals do not exceed 20.3 centimeters (cm) (8 inches (in)) in total length, although the species has been known to exceed 25 cm (9 in) in total length (Propst and Hobbes 1996, pp. 22-34). The Zuni bluehead sucker has a bluish head, silvery-tan to dark green back, and yellowish to silvery-white sides and abdomen. Adults are mottled slate-gray to almost black dorsally (upper part of the body) and cream-white ventrally (toward the abdomen). During the spawning season, males may be differentiated by coarse tubercles (wart-like projections) on the rear fins and the caudal peduncle (the narrow part of the fish's body to which the tail fin is attached). Males also have distinctive breeding coloration, becoming intensely black dorsally with a bright red horizontal band and a white abdomen (Propst 1999, p. 49; Propst
et al.
2001, p. 163).

Habitat and Life History

Carman (2008, p. 2) described Zuni bluehead sucker habitat as stream reaches with clean, perennial water flowing over hard substrate (material on the stream bottom), such as bedrock. Propst and Hobbes (1996, pp. 13, 16) reported that Zuni bluehead suckers were collected mainly in pool and pool-run habitats. These habitat areas were shaded with water velocities of less than 0.1 meter per second (0.3 feet per second) (Propst and Hobbes 1996, p. 13). Most specimens were found in water that was 30 to 50 cm (12 to 20 in) deep with cobble, boulders, and bedrock substrate (Propst and Hobbes 1996, pp. 13, 16). In general, Zuni bluehead sucker was rare or absent in reaches where the substrate was dominated by silt or sand (New Mexico Department of Game and Fish (NMDGF) 2004, p. 7). Pools were often edged by emergent aquatic plants and riparian vegetation (mainly willows (
Salix
spp.)) (Propst and Hobbes 1996, p. 16).

Zuni bluehead sucker feed primarily on algae scraped from rocks, rubble, and gravel substrates (Winter 1979, p. 4; Sublette
et al.
1990, p. 211). Algae attached to rocks and plants are generally abundant in reaches where Zuni bluehead suckers are common (NMDGF 2004, p. 8). Bluehead suckers, including the Zuni bluehead sucker, require clean gravel substrate with minimal silt for spawning (Maddux and Kepner 1988, p. 364) because silt covers eggs and leads to suffocation.

Taxonomy and Genetics

To help understand the information that follows in this “Taxonomy and Genetics” section and throughout the entirety of this final rule, we provide a geographic introduction to orient the reader. There are three main areas discussed in this final rule: The Zuni River watershed, the Kinlichee Creek watershed, and the Canyon de Chelly watershed. The Zuni River watershed of the Little Colorado River watershed in New Mexico contains the following streams: Zuni River, Rio Pescado, Rio Nutria, Tampico Draw, and Cebolla Creek. In addition, there are two headwater springs to the Rio Nutria; these are Tampico Spring (formerly known as Deans Creek) and Agua Remora (formerly known as Radosevich Creek). The Kinlichee Creek watershed occurs in eastern Arizona on the Navajo Nation near Ft. Defiance and is part of the Little Colorado River watershed. Streams in this watershed include Red Clay Wash, Black Soil Wash, Scattered Willow Wash, and Kinlichee Creek itself. Lastly, the Canyon de Chelly watershed occurs on the Navajo Nation in the Lower San Juan River watershed located in northeastern Arizona and northwestern New Mexico, and includes the following streams: Tsaile Creek, Sonsela Creek, Wheatfields Creek, Whiskey Creek, Coyote Wash, Little Whiskey Creek, and Crystal Creek. Most of the Canyon de Chelly watershed is not discussed in depth in this final rule because the best available information does not support a determination that Zuni bluehead sucker occurs in the Canyon de Chelly watershed; however, this is explained in more detail below and in the Summary of Comments and Recommendations section. A geographical reference map is available on
http://www.regulations.gov
and on the New Mexico Ecological Services Field Office Web site at
http://www.fws.gov/southwest/es/NewMexico/
. In addition, Table 1 (below) outlines where the various streams discussed in this rule occur.

Table 1—Geographical Reference Information Regarding Watersheds Discussed in Final Listing Rule

Subwatershed
State
Watershed
Streams

Zuni River
New Mexico
Little Colorado River
Zuni River, Rio Pescado, Rio Nutria, Tampico Draw, Cebolla Creek, Tampico Spring, Agua Remora.

Kinlichee Creek
Arizona
Little Colorado River
Red Clay Wash, Black Soil Wash, Scattered Willow Wash, Kinlichee Creek.

Canyon de Chelly
Arizona & New Mexico
Lower San Juan River
Tsaile Creek, Sonsela Creek, Wheatfields Creek, Whiskey Creek, Coyote Wash, Little Whiskey Creek, and Crystal Creek.

The 6-month extension notice (79 FR 1615, January 9, 2014) included a detailed discussion of the taxonomy and genetics of the Zuni bluehead sucker. Rather than repeating that information here, we have narrowed our discussion in this final rule to address information from public comments received since the time of the proposed listing rule and to explain our overall conclusions.

Our evaluation of morphological (pertaining to the physical form and structure of the fish) and genetic information supports recognition of the Zuni bluehead sucker as being a valid subspecies distinct from both the Rio Grande sucker (
Catostomus plebeius
) and the bluehead sucker (
C. discobolus
) (Smith 1966, pp. 87-90; Smith
et al.
1983, pp. 37-38; Crabtree and Buth 1987, p. 843; Propst 1999, p. 49). The Zuni bluehead sucker subspecies likely originated from a prehistoric geological event in which water of a Rio Grande tributary (where the Rio Grande sucker occurred) were brought into the headwaters of a Little Colorado River tributary (where the bluehead sucker occurred); this event caused the Rio Grande sucker and the bluehead sucker (which were formerly geographically isolated from one another) to come into contact and begin exchanging genes during the late Pleistocene (more than 1.1 million years ago) (Smith 1966, pp. 87-90; Smith
et al.
1983, pp. 37-38; Unmack
et al.
2014, p. 12). This process of the movement of a gene from one species into the gene pool of another species is known as introgression. Introgression results in a complex mixture of the parental genes in the offspring. In the case of the Zuni bluehead sucker, this genetic mixing of Rio Grande sucker genes with bluehead sucker genes occurred over an unknown length of time and created the distinct subspecies.

As a result of this introgression, the best scientific information available indicates that the Zuni bluehead sucker subspecies exhibits either morphological or genetic traits that trace their ancestry to both bluehead sucker and Rio Grande sucker, with these traits randomly distributed in the population. The Zuni bluehead sucker subspecies is comprised of a complex of populations that may contain a subset of morphological or genetic traits as described above, but these populations (in the various watersheds) can be quite distinct from each other because all populations do not contain all morphological or genetic traits which resulted from the introgression. These morphological traits include several physical characteristics that are different from other bluehead suckers or Rio Grande suckers (such as fin-ray, lip, and jaw characteristics). These morphological traits are discussed in more detail in Smith
et al.
(1983, pp. 46-47). The populations described below in the “Range and Distribution” section all have at least one or both morphological or genetic traits that provide evidence and confirm that these populations are in fact Zuni bluehead sucker. If in the future, new information becomes available that indicates a population is confirmed to be Zuni bluehead sucker, that population would be considered part of the listed Zuni bluehead sucker entity and, thus, be protected under the Act.

Both morphological and genetic data demonstrates that the Zuni bluehead sucker is present in the Zuni River watershed. However, the taxonomy of the occurrences of the subspecies outside of the Zuni River watershed has been disputed. Studies by Smith
et al.
(1983, entire) and Crabtree and Buth (1987, entire) support their conclusion that Zuni bluehead sucker occurs in both the Kinlichee Creek watershed of eastern Arizona and the Zuni River watershed in New Mexico. Alternatively, the Schwemm and Dowling (2008, entire) analysis extended the geographical range of the Zuni bluehead sucker to include bluehead suckers in the Lower San Juan River watershed (specifically in the Canyon de Chelly watershed, as discussed in the proposed rule). Lastly, Hopken
et al.
(2013, pp. 958, 966) and Douglas
et al.
(2013, pp. 2-3) provided evidence that the Zuni bluehead sucker occurred only in the Zuni River watershed (and not in the Kinlichee Creek watershed or the Canyon de Chelly watershed). These studies provided comprehensive data on the genetic variation across the range of the species, and we use these studies to evaluate which populations contain morphological or genetic evidence to support recognition as Zuni bluehead suckers. We also reviewed other relevant information (such as fisheries management in the Zuni River watershed) to contribute to our interpretation of the above-mentioned studies.

Initially, the proposed rule described the Zuni bluehead sucker subspecies as including the bluehead sucker populations from Canyon de Chelly because nuclear DNA (nDNA) analysis by Schwemm and Dowling (2008, p. 12) reported the presence of Rio Grande sucker genetics, providing new evidence that introgression of Rio Grande sucker with bluehead sucker expanded beyond the Little Colorado River watershed into the Lower San Juan River watershed. However, since the publication of the proposed rule, we received peer review comments from Dowling (2014, entire) that re-evaluated and summarized Schwemm and Dowling (2008, entire). Schwemm and Dowling (2008, entire) and Dowling (2014, entire) are, therefore, referred to as the same study. Dowling (2014, p. 2) stated that an error was recently discovered in the genetic data of Schwemm and Dowling (2008, entire). This error provides evidence that the bluehead suckers in the Lower San Juan River watershed (Canyon de Chelly watershed) should not currently be definitively recognized as Zuni bluehead sucker because the nDNA analysis was determined to be inaccurate. There is no other morphological or genetic evidence to support that the Zuni bluehead sucker occurs in the Canyon de Chelly populations; these populations do not exhibit evidence of either a genetic signature of the Rio Grande sucker or unique Zuni bluehead sucker genetics. Thus, the Canyon de Chelly populations will no longer be discussed in this final listing rule. The Canyon de Chelly populations are bluehead suckers but are not part of the Zuni bluehead sucker subspecies' range based on both literature and peer review comments received during the open comment period of the 6-month extension.

Similarly, the taxonomy of the occurrences of the Zuni bluehead sucker subspecies in the Kinlichee Creek watershed has also been disputed. The error that Dowling (2014, p. 2) described in the genetic data of Schwemm and Dowling (2008, entire) also discounts that introgression between the Rio Grande sucker and bluehead sucker established the Zuni bluehead sucker subspecies in the Kinlichee Creek watershed. Specifically, Dowling (2014, p. 5) states that there is no genetic evidence of the Rio Grande sucker in the specimens sampled from the Kinlichee Creek watershed. However, despite a lack of genetic evidence to support this conclusion, Smith
et al.
(1983, entire) provides morphological evidence supporting that introgression between the two species likely did establish the Zuni bluehead sucker subspecies in the Kinlichee Creek watershed. Some of the physical attributes evaluated by Smith
et al.
(1983, entire) include width of the specimen's jaw, standard length, and tail length; all of these attributes are consistent with the hypothesis of introgression between Rio Grande suckers and bluehead suckers. Thus, Dowling (2014, p. 5) concludes that Kinlichee Creek should be identified as part of the Zuni bluehead sucker range

based on the morphological evidence. In addition to the morphological evidence of Smith
et al.
and emphasized by Dowling, Crabtree and Buth (1987, pp. 848, Table 2, 852) concluded that specimens in the upper Little Colorado River watershed, where Kinlichee Creek is located, contained genetics unique to the Zuni bluehead sucker. This further supports that Zuni bluehead sucker likely occurs in the Kinlichee Creek watershed.

The two studies that discount the presence of Zuni bluehead sucker in the Kinlichee Creek watershed are Hopken
et al.
(2013, entire) and Douglas
et al.
(2013, entire). However, Hopken
et al.
(2013, entire) did not evaluate samples from this watershed. Alternatively, Douglas
et al.
(2013, entire) evaluated samples from the Kinlichee Creek watershed and failed to detect Rio Grande sucker genetics in the specimens sampled. The lack of the Rio Grande sucker genetic signature in Kinlichee Creek may be due to genetic bottlenecks. A genetic bottleneck is an event during which only a few individuals survive to continue the existence of the population; these bottlenecks result in a loss of genetic diversity and a loss of especially rare genetics such as those that may be in a Rio Grande sucker or the Zuni bluehead sucker itself. The Kinlichee Creek watershed is geographically isolated from the Zuni River watershed population, and, within the Kinlichee Creek watershed, the population faces periodic fragmentation that can limit gene flow and contribute to genetic bottlenecks. Thus, Douglas
et al.
(2013, p. 15) concluded that several populations within the Kinlichee Creek watershed have experienced genetic bottlenecks at some point in time. Furthermore, although the genetic analysis did not find the presence of the Rio Grande sucker genetics in specimens from Kinlichee Creek, the specimens throughout the Little Colorado River watershed sampled by Crabtree and Buth (1987, pp. 848, Table 2, 852) contained genetics unique to the Zuni bluehead sucker as described above. Based on the morphological evidence and the presence of unique Zuni bluehead sucker genetics in some sites within the watershed, we conclude that the streams we have described as the Kinlichee Creek area should be identified as part of the Zuni bluehead sucker subspecies' range. Given the information and rationale explained above, we conclude that the Zuni bluehead sucker currently occurs in two discrete watersheds—the Zuni River watershed and the Kinlichee Creek watershed.

There are also genetic issues for the subspecies located within the Zuni River watershed. It is important to note that the Agua Remora population was established by a translocation effort made by the Radosevich family in the 1920s (Winter 1979, p. 4) or 1930s (Merkel 1979, p. 11). An unknown number of Zuni bluehead sucker were translocated from the Rio Nutria to Agua Remora (Merkel 1979, p. 11), and it is also unknown if this was a single or multiple translocation events. Then, beginning in the 1960s and ending in 1975, a series of chemical treatments were initiated in both the Rio Nutria and Rio Pescado to eradicate several species of fish that were problematic for the establishment of rainbow trout (
Oncorhynchus mykiss
) populations in the reservoirs connected to the Rio Nutria on the Zuni Indian Reservation (Merkel 1979, entire). Although these treatments did not include Agua Remora because it was on private land, one of the species eradicated by these chemical treatments was the Zuni bluehead sucker, which was not present in the post-treatment surveys conducted, including within the Nutria Box (chemically treated in 1960, 1962, and 1967) (Merkel 1979, p. 13). Later, during a survey in 1971, a sizeable population of Zuni bluehead sucker was found within and below the Nutria Box, and Merkel (1979, p. 10) hypothesized that this population was either reestablished with individuals from Agua Remora during high flow events or that the fish were not completely eradicated from the Nutria Box. Further surveys of the upper Rio Nutria watershed in 1972 and 1973 found two populations, one at Agua Remora and another below Nutria Reservoir Number 2 (Merkel 1979, pp. 11-12).

Starting in 1975, a series of translocation events were conducted using fish from Agua Remora (Merkel 1979, p. 15). The new populations included Tampico Draw (100 fry and 15 yearlings), Tampico Spring (50 fry and 10 yearlings), Rio Nutria above Nutria Box (200 fry and 40 yearlings), and Cebolla Creek (Rio Pescado tributary; 250-300 fry and 20 yearlings) (Merkel 1979, p. 15). Many of these populations experienced high post-stocking mortality (40-50 percent) including complete mortality (Tampico Draw and Cebolla Creek). Hanson (1980, p. 13) found a number of populations within the Rio Pescado during surveys conducted in 1978 and confirmed the presence of the Zuni bluehead sucker in Agua Remora and the upper portion of the Rio Nutria, including Nutria Box and Tampico Spring. Based on the known history (i.e., fish translocation), we conclude that the Agua Remora population was founded by a few individuals from Rio Nutria; likewise, the Tampico Spring population was founded by a few individuals from Agua Remora. The genetic analysis from Douglas
et al.
(2013, pp. 13-16), and Schwemm and Dowling (2008, p. 12), indicate that the Rio Nutria population has Rio Grande sucker genetics. Alternatively, genetic analysis by Turner and Wilson (2009, p. 9) failed to identify a Rio Grande sucker genetic signature in Rio Nutria; however, this may be attributed to small sample size (n=25). This lack of genetic signature is likely due to the small number of individuals used to establish the new populations, which can create a genetic bottleneck, as explained above. Both Hopken
et al.
(2013, p. 964) and Douglas
et al.
(2013, p. 15), concluded that the Agua Remora population has experienced genetic bottlenecks at some point in time.

It is believed that the Rio Nutria population was reestablished from individuals from Agua Remora (Merkel 1979, p. 11); however, this is unlikely given the lack of Rio Grande sucker genetics in the Agua Remora population. It is more likely that Zuni bluehead sucker individuals within the Rio Nutria or Nutria Box survived chemical treatment. Thus, historical genetic bottlenecks, especially when followed by genetic drift (elevated random loss of genetics corresponding to physical traits that occurs in small populations), can alter the present genetic signature of a population. The lack of a Rio Grande sucker genetic signature in the Tampico Spring population does not imply these fish are not Zuni bluehead sucker because history shows that these populations were established by translocation efforts. This is consistent with the results from Crabtree and Buth (1987, p. 852) supporting a conclusion that Zuni bluehead sucker is a distinct subspecies regardless of its interaction with Rio Grande sucker.

Range and Distribution

New Mexico Distribution

The Zuni River watershed extends west from the continental divide, across the Zuni Pueblo, and drains into the Little Colorado River in Arizona, west of the Zuni Pueblo. In the Zuni River watershed of New Mexico, as mentioned above, the subspecies is believed to be restricted to three isolated populations in the upper Rio Nutria watershed (Carman 2008, pp. 2-3). More specifically, the subspecies occurs in

and upstream of the Rio Nutria from the mouth of Rio Nutria Box Canyon near the eastern boundary of the Zuni Pueblo, and upstream in Tampico Draw. In addition, Zuni bluehead sucker also occurs in separate populations in two headwater springs to the Rio Nutria: Tampico Spring and Agua Remora (Hanson 1980, p. 1; Propst
et al.
2001, p. 161). Although there are two Tampico Springs, the Tampico Spring we discuss in this final listing rule is on private land on the west side of the Oso Ridge and is not identified on a topographic map. This should not be confused with another Tampico Spring identified on topographic maps, located on public land, which is on the east side of the Oso Ridge. Elsewhere in the Zuni River watershed, the Zuni bluehead sucker is rare or absent. Flow is intermittent in the Zuni River, Rio Pescado, and Rio Nutria, except for short reaches that flow permanently in response to discharge from springs (Orr 1987, p. 37; NMDGF 2013, p. 9).

Zuni bluehead sucker numbers have been starkly reduced in the Zuni River watershed in New Mexico, largely due to 27 chemical treatments during the 1960s to remove green sunfish and fathead minnow (
Pimephales promelas
) from the Rio Nutria to aid in the establishment of a rainbow trout sport fishery in reservoirs on Zuni Pueblo (Winter 1979, p. 4). These treatments eliminated the Zuni bluehead sucker from most of the Zuni River watershed (Winter 1979, p. 4). As a result, by the late 1970s, the Zuni bluehead sucker range in New Mexico had been reduced. While records are largely incomplete, it is known that a population of Zuni bluehead suckers near the mouth of the Rio Nutria Box Canyon was extirpated due to chemical treatments and that substantial numbers were also eliminated in other reaches of the Rio Nutria and Rio Pescado (NMDGF 2004, p. 16).

The Zuni bluehead sucker has not been collected from the mainstem Zuni River since 1978 or from the Rio Pescado since 1993 (Hanson 1980, pp. 12-13; Propst and Hobbs 1996, pp. 11-12). Much of the lower portions of historical habitat in the Zuni River and Rio Pescado are dry during certain times of the year. Continued monitoring of these streams since 2004 has confirmed the extirpation of the Zuni bluehead sucker from these rivers (NMDGF 2004, p. 4; Carman 2007, p. 1; 2008, p. 1; 2009, p. 1). Additionally, Cebolla Creek, a Zuni River tributary, was surveyed in 1979, and no Zuni bluehead suckers were found, although habitat appeared suitable (Hanson 1980, pp. 29, 34).

The population of Zuni bluehead suckers in the Rio Nutria was maintained by dispersal of individuals from upstream untreated reaches, such as Agua Remora (Winter 1979, p. 4; Propst 1999, pp. 49-50). The Zuni bluehead sucker persists in the upper Rio Nutria watershed in three isolated populations over 3.7 kilometers (km) (2.3 miles (mi)), mainly upstream of the mouth of the Rio Nutria Box Canyon and two springs (Propst 1999, pp. 49-50; Propst
et al.
2001, p. 168; Carman 2008, pp. 2-3; Service 2014a, pers. comm., entire). Within this watershed, it is most common near the Rio Nutria Box Canyon mouth, the confluence of the Rio Nutria and Tampico Draw, and headwater springs such as Agua Remora and Tampico Spring (Stroh and Propst 1993, p. 34; Propst and Hobbes 1996, p. 10; Propst 1999, p. 50; Propst
et al.
2001, p. 162; Carman 2007, p. 1; 2008, p. 1; 2009, p. 2; 2010, p. 1; Gilbert and Carman 2011, p. 1; NMDGF 2013, p. 1). Within the 3.7-km (2.3-mi) occupied reach, the largest extent of perennial stream with limited levels of siltation is found in the Rio Nutria Box Canyon, from the confluence with Tampico Draw downstream to the canyon mouth.

Population Status of the Species in New Mexico

Population abundance has not been estimated because of the difficulty of detecting and sampling all habitats. However, results from numerous survey efforts confirm that Zuni bluehead sucker populations in New Mexico are fragmented and low in numbers. Fish surveys have been conducted within the Zuni River watershed in 1977-1979, 1984, 1990-1993, 2000-2001, and every year since 2004 (Winter 1977, p. 1; Hanson 1980, p. 29; Stefferud 1985, p. 1; Propst and Hobbes 1996, p. 14, Carman 2010, pp. 13-15, Gilbert and Carman 2011, p. 23; NMDGF 2013, p. 25). Based on available maps and survey information, we estimate the present range of the Zuni bluehead sucker in New Mexico to be approximately 5 percent or less of its historical range.

The first extensive survey for the Zuni bluehead sucker in the Zuni River watershed was during 1978 and 1979 (Hanson 1980, p. 1). Hanson (1980, pp. 7, 8, 11, 13, 25, 27) provides a detailed map of areas surveyed, which included the following locations: Zuni River, Rio Pescado, Rio Nutria, Tampico Draw, Agua Remora, Tampico Spring, Galestino Creek, Yellowhouse Spring, Six Mile Creek, and Cebolla Creek. Zuni bluehead suckers were confirmed at all locations, except Galestino Creek, Yellowhouse Spring, Six Mile Creek, and Cebolla Creek. Surveys were sporadic between 1977 and 2003; then, in 2004, NMDGF began an annual monitoring program to assess the status of the Zuni bluehead sucker as a part of the NMDGF's efforts to recover the fish (Carman 2004, p. 2).

In this rule, we rely upon catch per unit effort, or catch rates, to evaluate Zuni bluehead sucker population trends after 1991 because of the limitations of survey data and variability in sampling effort. Catch rates are measured by the number of fish caught per second of electrofishing and provide a metric for evaluating population trends. No information on catch and effort is available prior to 1991; therefore, we may only make qualitative comparisons of the number or evaluate presence and absence of Zuni bluehead sucker collected over time for data prior to 1991. While catch per unit effort is valuable for assessing trends over time, it unfortunately does not allow us to develop overall population estimates for the species.

For example, in Tampico Draw, a tributary to Rio Nutria, Zuni bluehead sucker catch rates declined dramatically in 2005, from as high as 0.111 suckers per second to 0.0004 suckers per second. The decline is presumed to be a result of beaver (
Castor Canadensis
) dams (Gilbert and Carman 2011, p. 20). Catch rates appeared to rebound somewhat in 2009 (0.065 suckers per second) (Table 2), after high spring flows washed out the beaver dams, creating more suitable habitat for Zuni bluehead sucker (Gilbert and Carman 2011, p. 5). Larval Zuni bluehead suckers have been confirmed in the Rio Nutria and its headwater springs, including Tampico Draw, each year between 2007 and 2012, indicating successful spawning (Carman 2008, p. 1; Carman 2009, p. 18; Carman 2010, p. 15; Gilbert and Carman 2011, p. 1; NMDGF 2013, p. 25).

BILLING CODE 4310-55-P

ER24JY14.000

Zuni bluehead suckers have persisted at Agua Remora, with catch rates ranging from 0.02 Zuni bluehead suckers per second to 0.34 fish per second (Table 2). Young (less than 5 cm (2 in) total length) Zuni bluehead

suckers have not been observed in the Agua Remora headwater spring habitat, and only mature adults were present there in 2005, 2006, and 2008 (Carman 2006, p. 8; Carman 2007, p. 13; Carman 2009, p. 14). The absence of young Zuni bluehead sucker correlates with low catch rate years and also with the presence of green sunfish, as evidenced by improved catch rates documented once the habitat was void of green sunfish after 2009.

Catch rates at Tampico Spring, within the Rio Nutria watershed, have been declining consistently in recent years; while this site once exhibited the highest catch rates for the species, at 0.589 suckers per second in 2007, numbers have since declined, with 0.106 fish caught per second in 2011 (Table 2). However, this population has shown improvement based on the 2012 survey with 0.210 fish caught per second (Table 2). Despite the prior declines at Tampico Spring, this population is showing signs of improvement (albeit one year), and the site continues to maintain the highest catch rates among sites within the Zuni River watershed for each year (NMDGF 2013, p. 26).

Although we cannot make statistical comparisons of all the catch data due to the lack of quantitative data prior to 1991, the presence of Zuni bluehead suckers collected throughout the Zuni River watershed can be assessed since 1977, where detections range from absent to few individuals (Table 3). For example, the number of Zuni bluehead suckers captured declined from 160 in 1977 (Winter 1977, p. 1), to 16 individuals in 2010 (Gilbert and Carman 2011, p. 23) (Table 3), but the population has shown improvement with 163 individuals being captured in 2012 (NMDGF 2013, p. 25). Both the Zuni River and Rio Pescado have been surveyed since 1993, but investigators have failed to collect Zuni bluehead sucker at either site since 1993 (as illustrated in Table 3). Both the Zuni River and Rio Pescado habitat are degraded and contain few areas with permanent flow. Where perennial water exists, suitable habitat is lacking and nonnative predators such as green sunfish and Northern pike (
Esox lucius
) dominate (Carman 2009, p. 2).

ER24JY14.001

In summary, in New Mexico, the Zuni bluehead sucker persists in three isolated populations over 3.7 km (2.3 mi), and fish surveys from 1990 to 2012 show that Zuni bluehead sucker populations in headwater springs like

Agua Remora and upper Rio Nutria have declined significantly from numbers seen in the 1970s. In the 1990s, the population at the Zuni River confluence with Rio Nutria and Rio Pescado was declining, and the populations in the Rio Pescado and lower Zuni River were almost depleted (Stroh and Propst 1993, p. 1). However, all persisting populations of Zuni bluehead sucker did show improvement in the last 2 years (NMDGF 2013, p. 26). These populations are highly sensitive to change, whether it is the presence of nonnative fish, beaver activity, or stream flow. The Zuni bluehead sucker has not been collected from the Zuni River or Rio Pescado since 1993 (Gilbert and Carman 2011, p. 1). In occupied areas, dispersal from upstream populations (i.e., Rio Nutria) may augment downstream populations, but both downstream and upstream movement is generally blocked by physical obstructions, such as natural waterfalls, irrigation diversions, and impoundments (Propst
et al.
2001, p. 168). The irregular occurrence of the Zuni bluehead sucker in reaches downstream from the mouth of Rio Nutria Canyon (Rio Nutria, Zuni River, and Rio Pescado) indicates limited downstream dispersal from occupied stream reaches. No Zuni bluehead suckers were found in the Rio Nutria between the canyon mouth and the confluence of the Rio Pescado.

Arizona Distribution

In Arizona, Zuni bluehead suckers are found on the Navajo Indian Reservation in the Kinlichee Creek watershed. The Kinlichee Creek watershed is part of the Little Colorado River watershed west of Fort Defiance, Arizona, and the Zuni bluehead sucker has been documented in several locations over a 47-km (29-mi) area (Smith
et al.
1983, p. 39; Crabtree and Buth 1987, p. 843; Hobbes 2000, pp. 9-16). This 47-km (29-mi) area includes Kinlichee Creek, Red Clay Wash, Black Soil Wash (also referred to as Black Soil Spring), and Scattered Willow Wash.

Zuni bluehead sucker survey efforts have been more irregular in Arizona than in New Mexico. Populations of Zuni bluehead sucker are found in several locations over approximately 47 km (29 mi) of Kinlichee Creek (Smith
et al.
1983, p. 39; Crabtree and Buth 1987, p. 843; Hobbes 2000, pp. 9-16). It is unlikely that the whole length of the Kinlichee Creek watershed is occupied, because the streams are susceptible to drying during drought. In addition, no comprehensive surveys have been done along this stream reach. Within the watershed, the species occurs in Kinlichee Creek, Black Soil Wash, Red Clay Wash, and Scattered Willow Wash based on collections made in 2000, 2001, 2004, and 2012 (Hobbes 2000, pp. 9-16; Hobbes 2001a, pp. 38, 43; Hobbes 2001b, entire; Carman 2004, pp. 1-8; Kitcheyan and Mata 2013, p. 10).

Population Status of the Species in Arizona

For several years (2000, 2001, and 2004), Zuni bluehead sucker surveys were conducted in the Kinlichee Creek watershed in Arizona on the Navajo Indian Reservation (Hobbes 2001a, entire; Carman 2004, entire). These were historical collection sites that had not been sampled since 1987, when the Zuni bluehead sucker was last documented by Crabtree and Buth (1987, p. 851). The species was collected in low numbers in Kinlichee Creek, Black Soil Wash, and Scattered Willow Wash in 2000, 2001, and 2004. In 2012, collections occurred in Black Soil Wash and Kinlichee Creek, with 664 and 92 Zuni bluehead suckers, respectively (Kitcheyan and Mata 2013, p. 10), indicating the species' continued presence in these streams. Because these were only presence/absence surveys, we have no population estimates for the subspecies in Arizona.

Summary of Zuni Bluehead Sucker Distribution

Zuni bluehead sucker distribution has been reduced by an estimated 95 percent in the last 30 years in New Mexico (Propst 1999, p. 51; NMDGF 2004, p. 15; Service 2014a, pers. comm.). The extent of potential range reduction in Arizona is not known. The entire Kinlichee Creek watershed encompasses approximately 47 km (29 mi) (Smith
et al.
1983, p. 39; Crabtree and Buth 1987, p. 843; Hobbes 2000, pp. 9-16). It is unlikely that the entirety of the Kinlichee Creek watershed is occupied because the streams are susceptible to drying during drought. The number of Zuni bluehead sucker found in the Kinlichee Creek watershed in Arizona range from zero to 664 individuals between 2000 and 2012 (Hobbes 2000, pp. 9-16; Albert 2001, pp. 10-14; NMDGF
et al.
2003, p. 6-10); David 2006, p. 35, Kitcheyan and Mata 2013, pp. 10-11). The subspecies is restricted to three isolated populations in the upper Rio Nutria watershed in west-central New Mexico (Carman 2008, pp. 2-3).

Summary of Comments and Recommendations

We requested comments from the public on the proposed listing for the Zuni bluehead sucker during two comment periods. The first comment period associated with the publication of the proposed rule (78 FR 5369) opened on January 25, 2013, and closed on March 11, 2013. During our 6-month extension on the final determination for the Zuni bluehead sucker, we reopened the comment period from January 9, 2014 to February 10, 2014 (79 FR 1615). We also contacted appropriate Federal and State agencies, scientific experts and organizations, and other interested parties and invited them to comment on the proposal. Newspaper notices inviting general public comment were published in both the Gallup Independent and Navajo Times on January 25, 2013, and January 31, 2013, respectively. We did not receive any requests for a public hearing.

All substantive information provided during comment periods has either been incorporated directly into this final determination or addressed below.

Peer Reviewer Comments

In accordance with our peer review policy published on July 1, 1994 (59 FR 34270), we solicited expert opinion from six knowledgeable individuals with scientific expertise that included familiarity with the Zuni bluehead sucker and its habitat, biological needs, and threats. We received responses from five of the peer reviewers. During the first comment period, we received some contradictory public comments, and we received new information relevant to the listing determination. For these reasons, we solicited expert opinions from 25 geneticists and taxonomists specifically to review the substantive discussion and information presented in the 6-month extension notice in light of disagreement regarding the taxonomic status of some populations that we considered Zuni bluehead sucker in the proposed rule. We received responses from three knowledgeable individuals with expertise in genetics and taxonomy. The peer reviewers generally concurred with our methods and conclusions and provided additional information, clarifications, and suggestions to improve the final listing rule. Peer reviewer comments are addressed in the following summary and incorporated into the final rule as appropriate.

(1) Comment:
The primary reason for the imperilment of the species (habitat loss due to stream drying) was not adequately explained. The fact that nearly all historical habitat has been dewatered was buried in other information. This could be corrected by an upfront statement that the species is currently restricted to the only 4.8 km

(3 mi) of perennial water left within their historical habitat.

Our Response:
Habitat loss due to stream drying is the primary reason for the imperilment of the species. However, in determining and evaluating threats to the Zuni bluehead sucker, we identify the sources of those threats. We identified water withdrawal and dams/impoundments as a source of habitat loss and stream drying, which is then exacerbated by climate change. In addition, we have refined our analysis and language in the
New Mexico Distribution, Population Status of the Species in New Mexico,
and Determination sections. The final rule mentions repeatedly that the species' distribution is limited to 3.7 km (2.3 mi) of stream habitat in New Mexico based on our reevaluation of the species' distribution in New Mexico.

(2) Comment:
The discussion of disease is overstated; there is no evidence that black grub (
Neascus
spp.) is a threat to Zuni bluehead sucker.

Our Response:
We acknowledge that the specific effects of black grub on the Zuni bluehead sucker are unknown. In determining whether or not disease is a threat to the Zuni bluehead sucker, we used the best scientific and commercial data available. This included articles published in peer-reviewed journals, data collected by NMDGF, and comments received on both the proposed rule and the 6-month extension of the final determination. Some of our citations are not specific to this species or geographic area. Nevertheless, the best scientific and commercial information available does not indicate that disease is a threat to the species rangewide, as stated in both the proposed and final rules. However, we conclude that black and yellow grub (a parasite that may affect the subspecies) may be a threat to the species in the future, as the parasite has profound effects on many other species of fish and has been detected in the Zuni bluehead sucker.

(3) Comment:
The inclusion of the Canyon de Chelly populations is not appropriate based on the lack of published genetic support and the geographic separation between this population and those in the Little Colorado River watershed. Therefore, it is not appropriate to classify bluehead sucker in Canyon de Chelly as Zuni bluehead sucker. In addition, why did the Service include information on a catostomid (sucker family) population of uncertainty? This suggests that a comprehensive genetic investigation of all definitive and suspected Zuni bluehead suckers is needed prior to publishing a proposal to list the Zuni bluehead sucker as endangered. In addition, until genetic studies of catostomid populations are published in a peer-reviewed journal, it is inappropriate to consider these populations Zuni bluehead sucker.

Our Response:
In the proposed rule, we identified populations in the Canyon de Chelly watershed as Zuni bluehead sucker because previous genetic analysis (Schwemm and Dowling 2008, entire) provided evidence supporting this conclusion. As mentioned in the “Taxonomy and Genetics” section, this conclusion was based on inaccurate information. Dowling (2014, entire) reevaluated and summarized Schwemm and Dowling (2008, entire) work during the open comment period for the 6-month extension notice, and he noted that our conclusion to identify the bluehead suckers in Canyon de Chelly as Zuni bluehead suckers was based on an error in the Schwemm and Dowling (2008, entire) genetic data. We made the appropriate changes in the final rule to reflect the correct identification of populations as Zuni bluehead sucker.

We used the best scientific and commercial data available to understand the contemporary and ancestral genetic patterns for the Zuni bluehead sucker. This included articles published in peer-reviewed journals, data not yet published, data collected by the Service, and data collected by NMDGF. When we announced the 6-month extension on the final determination for the Zuni bluehead sucker, we reopened the comment period and made all of the taxonomic and genetic information available to the public. Comments and information received were incorporated into our evaluation, as discussed in the “Taxonomy and Genetics” section. As discussed above, we identified populations of uncertainty (Canyon de Chelly in the Lower San Juan River watershed) as Zuni bluehead sucker at the time of the proposed rule because Schwemm and Dowling (2008) suggested that the Canyon de Chelly populations were Zuni bluehead sucker based on the presence of the Rio Grande sucker genetic signature. The Canyon de Chelly populations of bluehead sucker are not included in this final listing determination, however, because there is no longer morphological or genetic evidence to indicate that they are Zuni bluehead sucker. However, it is possible that future analysis of these populations in Canyon de Chelly may indicate the presence of Zuni bluehead suckers.

(4) Comment:
The taxonomy and genetics discussion is confusing in the proposed rule. It is not sufficient to say that populations that are geographically proximate (near each other) are the same taxonomically.

Our Response:
The reference to proximity in the proposed rule was intended to describe past and present connectivity of streams in the Canyon de Chelly watershed and to describe that the bluehead sucker population within the Canyon de Chelly watershed were considered to be genetically related to one another. However, our evaluation of the taxonomy and genetics information no longer supports that bluehead suckers in the Canyon de Chelly watershed are Zuni bluehead suckers (see response to comment 3 and “Taxonomy and Genetics” section).

(5) Comment:
One peer reviewer suggested that the Service clarify that investigators conducting their bluehead sucker surveys in Kinlichee Creek correctly identified their fish captured as bluehead suckers and produced their reports on that basis, and the Service later attributed their bluehead sucker to the subspecies of the Zuni bluehead sucker.

Our Response:
In response to this comment, we added language after first use of the NMDGF
et al.
(2003, entire) and David (2006, entire) citation in the
Arizona Distribution
section. As stated, in the
Arizona Distribution
section, investigators could not determine whether the bluehead suckers captured were bluehead suckers or Zuni bluehead suckers through external features and believed the taxon designation as a Zuni bluehead sucker was uncertain. However, Smith
et al.
(1983, p. 46), provides information on how to morphologically distinguish a Zuni bluehead sucker from a Rio Grande sucker and bluehead sucker based on several characters (gill rakers, lower jaw, lips, vertebral counts, and fin ray counts). Based on the Smith
et al.
(1983, p. 46) morphological analysis of Zuni bluehead sucker in Kinlichee Creek, the Service attributed the bluehead suckers captured in NMDGF
et al.
(2003, entire) and David (2006, entire), as Zuni bluehead sucker.

Comments From States

We received one comment from the Arizona Game and Fish Department (AGFD) supporting the listing. The NMDGF provided their most recent Zuni bluehead sucker annual report that was used to update population status of the Zuni bluehead sucker in the Zuni River watershed. Please refer to the
Population Status of the Species in New Mexico
section, above.

(6) Comment:
Prior to 1991, catch data were not standardized by effort (catch per unit effort) and cannot be compared with catch data that was standardized.

Conclusions derived from comparisons of data prior to 1991 are methodologically erroneous.

Our Response:
As stated within the
Population Status of the Species in New Mexico
section, we acknowledge both the correct and incorrect use of catch per unit effort data. While catch per unit effort is valuable for assessing population trends over time and assessing species' status, this metric does not allow us to develop overall population estimates for the species. We have revised this discussion and added additional language for accuracy and clarification.

(7) Comment:
Historical population data are not provided for Zuni bluehead sucker habitat in New Mexico, and, therefore, the effect of habitat loss on the species' populations is unknowable; a 90 percent reduction in habitat does not unequivocally suggest any significant loss to population. In addition, the Service makes no remark on the suitability of the lost habitat.

Our Response:
Since the proposed rule, the Service has acknowledged that we do not know the historical range for the Kinlichee Creek watershed of the Little Colorado River watershed in Arizona. However, based on available maps and survey information, we estimate the present range of the Zuni bluehead sucker in New Mexico to be approximately 5 percent or less of its historical range, and the status of the species within the occupied areas range from common to absent (see
Population Status of the Species in New Mexico
section). Habitat loss and range reduction is directly related to loss of populations given that the species was historically found in habitats that are no longer suitable and the Zuni bluehead sucker are now absent in those habitats. In addition, we have included language within the
Population Status of the Species in New Mexico
section to remark on the suitability of habitat where the Zuni bluehead sucker is absent.

(8) Comment:
Without a clear definition of the subspecies and the populations that comprise that subspecies, the Service does not have adequate information to clearly state this subspecies warrants protection under the Act.

Our Response:
Our evaluation of morphological and genetic information supports the recognition of the Zuni bluehead sucker as being distinct from both the Rio Grande sucker and the bluehead sucker (Smith 1966, pp. 87-90; Smith
et al.
1983, pp. 37-38; Crabtree and Buth 1987, p. 843; Propst 1999, p. 49). Based on our review of the best available scientific and commercial data, we conclude that the Zuni bluehead sucker is a valid subspecies. As discussed in the “Taxonomy and Genetics” section we have assessed all populations that comprise the Zuni bluehead sucker.

(9) Comment:
The Service does not adequately understand the contemporary and historical distribution of the Zuni bluehead sucker to assert that the Zuni bluehead sucker is in danger of extinction throughout all or a significant portion of its range.

Our Response:
We used the best scientific and commercial data available to understand the contemporary and historical distribution of the Zuni bluehead sucker. This included articles published in peer-reviewed journals, data collected by the Service and data collected by NMDGF. Please refer to the “Distribution” section for an explanation of the contemporary and historical distribution of the Zuni bluehead sucker.

(10) Comment:
The Service exaggerates the level of threat to Zuni bluehead sucker resulting from exotic species. The limited geographic distribution and rarity of the nonnative species in the Zuni River watershed serve to lessen their widespread impact to the Zuni bluehead sucker.

Our Response:
The Zuni bluehead sucker occurs only in stream and spring habitats that are comparatively free of nonnative fishes. The Zuni bluehead sucker has coexisted with several introduced piscivorous (primarily eats fish) nonnative fish (e.g., sunfish, northern pike, and largemouth bass). However, several surveys and reports have provided evidence that Zuni bluehead sucker are low or absent in the presence of piscivorous nonnative fishes (Hanson 1980, p. 2; Propst and Hobbes 1996, pp. 38-39, Propst
et al.
2001, p. 162; Carman 2008, p. 17). In addition, we have provided additional information regarding effects of exotic crayfish on benthic fishes within the “Factor C: Disease and Predation” section.

(11) Comment:
The Service fails to consider the adequacy of all relevant and applicable existing mechanisms that provide protection for the Zuni bluehead sucker in New Mexico. In addition, the Service fails to incorporate analysis of the 2004 New Mexico Game and Fish Department's Zuni bluehead sucker recovery plan in the proposed listing.

Our Response:
In response to this comment, we added language within the “State Regulation” section. We acknowledge the NMDGF developed a recovery plan for the Zuni bluehead sucker in 2004 (NMDGF 2004, entire). The objective of the recovery plan is that, by 2015, the populations and distribution of the Zuni bluehead sucker are sufficient to ensure its persistence within New Mexico and thereby warrant its removal from the State endangered species list. The recovery plan does not restrict activities that would be likely to adversely affect the species or its habitat and, likewise, does not require activities that would be likely to benefit the species or its habitat; however, the recovery plan and implementation has vital information on the Zuni bluehead sucker. As noted above, the State's recovery plan does not ensure any long-term protection for the Zuni bluehead sucker because there are no mandatory elements or funding dedicated to ensure the recovery plan is implemented. In addition, NMDGF's does not have the authorization to restrict proposed projects that may adversely affect these species or their habitat.

Comments From Navajo Nation

(12) Comment:
The genetic information does not support the assertion by the Service that bluehead sucker populations in the Chuska Mountains (referred to in the listing rule as Canyon de Chelly) and Defiance Plateau (referred to as Kinlichee Creek watershed) should be identified as Zuni bluehead sucker populations; rather, these populations may be a unique variation of bluehead sucker. It is necessary to conduct peer-reviewed publication of a genetic analysis of these bluehead suckers and to include a morphological study to determine the taxon of the suckers.

Our Response:
Based on our updated analysis, which includes information received since the publication of the proposed rule, the best scientific and commercial information available on taxonomy and genetics of Zuni bluehead suckers supports that the bluehead sucker populations in the Canyon de Chelly watershed are not Zuni bluehead sucker. Thus, we no longer consider the bluehead suckers in the Canyon de Chelly watershed of the Lower San Juan River watershed at the border of Arizona and New Mexico to be Zuni bluehead suckers. Please refer to the “Taxonomy and Genetics” section, and response to Comment 3.

Alternatively, based on our assessment of the best scientific and commercial information available, the literature supports the presence of Zuni bluehead sucker on Navajo Nation in the Kinlichee Creek watershed. Smith
et al.
(1983, pp. 38, 42) identified samples collected from Kinlichee Creek as Zuni bluehead sucker, primarily based on morphological similarities to Zuni

bluehead suckers found in the Rio Nutria.

At the time of the proposed listing rule and the 6-month extension notice, we specifically solicited peer review from knowledgeable individuals with scientific expertise that included familiarity with the subspecies, the geographic region in which the subspecies occurs, and taxonomy of the subspecies. Additionally, we requested comments or information from other concerned governmental agencies, Native American Tribes, the scientific community, industry, and any other interested parties concerning the proposed rule. Comments and information we received helped inform this final rule. We used multiple sources of information, including: Results of numerous surveys, peer-reviewed literature, unpublished reports by scientists and biological consultants, geospatial analysis, and expert opinion from biologists with experience studying the subspecies. This information constitutes the best scientific and commercial data available and has been incorporated into this final listing rule.

(13) Comment:
More genetic markers need to be reviewed to make an accurate decision on what populations should and should not be identified as Zuni bluehead suckers.

Our Response:
We are charged with using the best scientific and commercially available information in a listing determination. We acknowledge that additional research would be valuable; however, we are required by law to use the best information currently available for the species. The Act requires that we adhere to a timeframe in developing our determination and we do not have the funding or authority to delay our determination in order to conduct studies to collect empirical data on each topic of discussion.

(14) Comment:
The Navajo Nation does not consider logging to be a threat to their bluehead suckers and provided information regarding the Navajo Nation 10-year Forest Management Plan (Navajo Nation 2000, entire).

Our Response:
We have incorporated the Navajo Nation 10-year Forest Management Plan within the Tribal Regulations section. The Navajo Nation 10-year Forest Management Plan will reduce this threat in the Kinlichee Creek watershed, where logging prescriptions are in place to protect the riparian areas. However, this plan does not provide protection from other threats to the species, and it does not provide protection to the species throughout the entirety of its range (specifically in the Zuni River watershed).

(15) Comment:
The Navajo Nation identified several publications to support their assertion that the bluehead suckers on the Navajo Nation (Kinlichee Creek watershed and Canyon de Chelly watershed) are not Zuni bluehead suckers. The following citations were provided:

a. Crabtree and Buth (1987, entire) looked at sucker allozymes and determined that the Kinlichee Creek population of suckers was bluehead suckers rather than Zuni bluehead suckers.

b. Hopken
et al.
(2013, entire) determined that the Canyon de Chelly population of suckers is bluehead suckers and not Zuni bluehead suckers.

c. Douglas
et al.
(2009, entire) determined that the populations of suckers found within the area of Navajo Nation are bluehead suckers, not Zuni bluehead suckers.

d. Smith
et al.
(1983, entire) determined Canyon de Chelly and Whiskey Creek suckers are not Zuni bluehead sucker.

Our Response:
Hopken
et al.
(2013, entire) and Douglas
et al.
(2009, entire) are the same studies using the same genetic samples and analysis. Both of their studies included genetic samples from bluehead sucker found in the Canyon de Chelly watershed only. As noted previously, the Canyon de Chelly taxon has been attributed to the bluehead sucker and not the Zuni bluehead sucker in this final listing rule. During our review of Crabtree and Buth (1987, entire), we understand that they identified fish from Kinlichee Creek as Zuni bluehead sucker based on the expression of several unique allozymes that were genetically distinct from bluehead sucker or Rio Grande suckers (Crabtree and Buth 1987, pp. 843, 848, Table 2, 852). Crabtree and Buth (1987, pp. 851-852) suggested that the genetic interaction between the Rio Grande sucker and bluehead sucker is limited to the upper Rio Nutria populations in the Zuni River watershed. However, Crabtree and Buth (1987, p. 852) state that the Zuni bluehead sucker is a distinct subspecies regardless of its genetic interaction with the Rio Grande sucker. Smith
et al.
(1983, entire) could not genetically distinguish the bluehead sucker from Kinlichee Creek or Whiskey Creek; however, they attributed their taxon recognition of Zuni bluehead sucker based on morphological similarities between the Kinlichee Creek watershed and Zuni River watershed. Please refer to the “Taxonomy and Genetics” for more information.

Public Comments

(16) Comment:
There could be implications imposed on the rights of private property owners as a result of the listing rule.

Our Response:
The Act requires that we make listing determinations “solely on the basis of the best available scientific and commercial data available” (16 U.S.C. 1533(b)(1)(A)). The Act does not allow listing to be avoided based on the potential for perceived economic benefits or burdens that may result from the listing. Listing a species as threatened or endangered does not revoke constitutionally protected property rights (see the Fifth Amendment to the U.S. Constitution). Executive Order 12630 (Government Actions and Interference with Constitutionally Protected Private Property Rights) requires that we analyze the potential takings implications of designating critical habitat for a species in a takings implications assessment.

(17) Comment:
Listing the Zuni bluehead sucker would limit State agencies' ability to manage for this species. Management of species by the Federal Government is unlikely to improve the status of the species.

Our Response:
The potential efficacy of a listing action to conserve a species cannot be considered in making the listing decision. The Service must make its determination based on a consideration of the factors affecting the species, utilizing only the best scientific and commercial information available, and is not able to consider other factors or impacts. Listing recognizes the status of the species and invokes protection and considerations under the Act, including regulatory provisions, consideration of Federal activities that may affect the species, and potential critical habitat designation. In addition, the Service will develop a recovery plan. The recovery plan will likely identify both State and Federal efforts for conservation of these species and establish a framework for agencies and stakeholders to coordinate activities and cooperate with each other in conservation efforts. The plan will set recovery priorities and describe site-specific management actions necessary to achieve conservation and survival of the Zuni bluehead sucker. Thereby, with the help of Federal, State, Tribal, and private partners, we can develop conservation measures to improve the status of the species.

(18) Comment:
The basis for determining whether the species is endangered or threatened appears to have been present in 1996, when the

species was no longer listed as a candidate species. As such, it would appear that listing is as unwarranted now as it was in 1996.

Our Response:
Prior to 1996, the Zuni bluehead sucker was considered a Category 2 candidate species. This designation meant a species for which we had information that proposed listing was possibly appropriate, but conclusive data on biological vulnerability and threats were not available to support a proposed rule at the time. In 1996, however, we discontinued the designation of Category 2 species as candidates, and all existing Category 2 candidates were removed from the candidate list. As stated in the Previous Federal Actions section of both the proposed and final rules, the Zuni bluehead sucker was again added to the candidate list in 2001 (66 FR 54807, October 20, 2001). A candidate species is one for which we have on file sufficient information on biological vulnerability and threats to support a proposal for listing as endangered or threatened, but for which preparation and publication of a proposal is precluded by higher priority listing actions. We have analyzed the threats to the species based upon the five factors described in section 4(a)(1) of the Act. We have determined based on our analysis of threats discussed below in the section Summary of Factors Affecting the Species that the Zuni bluehead sucker is in danger of extinction throughout all of its range.

(19) Comment:
It is unclear whether all historical and currently occupied areas have been surveyed.

Our Response:
A complete overview of the available survey data for the Zuni bluehead sucker is reported in the “Distribution” section, above. All known historical and currently occupied areas have been sampled extensively in New Mexico by NMDGF and its partners. During the development of this rulemaking, the Service and the Navajo Nation initiated surveys to sample all known historical and currently occupied habitats, as well as previously unsurveyed areas of habitat for the Zuni bluehead sucker in Arizona and New Mexico. This information has been added to the “Distribution” section above.

(20) Comment:
In the proposed rule, the Service assumes that there was historically continuous flow in both the Little Colorado River and Zuni River watersheds. However, there is no information offered in the rule to substantiate this assumption.

Our Response:
During the last glaciation period (15 to 24 thousand years ago) the region where the Zuni bluehead sucker is found was much wetter (Thompson
et al.
1983, p. 498; Wagner
et al.
2010, p. 111). There was sufficient precipitation and runoff to sustain a large lake on the San Agustin plain (Allen 2005, p. 112). Under similar precipitation conditions today, watersheds occupied by Zuni bluehead sucker would have been perennial. Thus, based on the best scientific and commercial data available, we believe that, historically, there was continuous flow in both watersheds.

(21) Comment:
In the rule, the Service assumes that there would not be erosion without logging or other activities on the land. However, it is widely known that erosion is directly related to the structure of the soils being more erosive than others, causing sedimentation even in environments that are only affected by the natural elements. As such, it is inappropriate to blame stream sedimentation on logging activities without acknowledging that erosion is normal and the extent to which it increases is influenced by many factors, only one of which could be by harvest activities which are undertaken to reduce wildfire risk.

Our Response:
We acknowledge that both natural and anthropogenic processes can cause erosion. Changes in erosion rates can result from natural causes, such as soil conditions that are highly susceptible to erosion, or these changes may result from historical land-use practices that minimize grass and tree cover, making current conditions more susceptible to erosion. We encourage implementation of best management practices today that can reduce or improve erosional conditions. We need the help of private and public land managers to implement these practices to improve the watershed conditions where the Zuni bluehead sucker occurs.

(22) Comment:
The Service should take immediate action to implement conservation measures to protect the Zuni bluehead sucker.

Our Response:
The final listing of any species imposes some restrictions on activities that may impact the species (i.e., water development, forestry management). As outlined in Section 9 of the Act and our Interagency Cooperative Policy for Endangered Species Act Section 9 Prohibitions (July 1, 1994; 59 FR 34272), “take” of species listed as endangered or threatened is prohibited. Take is defined as harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect, or attempt any of these, import, export, ship in interstate commerce in the course of commercial activity, or sell or offer for sale in interstate or foreign commerce any listed species. We identified in the proposed rule those activities that we believe would or would not constitute a violation of the prohibitions identified in section 9 of the Act. The final Federal listing of the Zuni bluehead sucker under the Act requires that Federal agencies consult with the Service on activities involving Federal funding, a Federal permit, Federal authorization, or other Federal actions. Consultation (under section 7 of the Act) is required when activities have the potential to affect the Zuni bluehead sucker or designated critical habitat. The consultation will analyze and determine to what degree the species is impacted by the proposed action. Section 7 of the Act prohibits actions funded, authorized, or carried out by Federal agencies from jeopardizing the continued existence of a listed species or destroying or adversely modifying the listed species' critical habitat. Therefore, restriction or mitigation for certain activities may be appropriate if identified during a section 7 consultation, where a Federal nexus exists.

In addition, management recommendations as may be necessary to achieve conservation and survival of the species can also be addressed through recovery planning efforts. Under section 4(f)(1) of the Act, we are required to develop and implement plans for the conservation and survival of endangered and threatened species, unless the Secretary of the Interior finds that such a plan will not promote the conservation of the species. We will move to accomplish these tasks as soon as feasible.

(23) Comment:
The proposed listing of a subspecies is unscientific and unwarranted.

Our Response:
Section 3 of the Act provides definitions for the purposes of the Act. As stated in section 3(16), the term “species” includes any subspecies of fish or wildlife or plants. The Zuni bluehead sucker is recognized by the biological community as a valid subspecies, and thus, meets the definition of a species under the Act. Therefore, it is appropriate for the Service to evaluate the Zuni bluehead sucker for listing under the Act.

(24) Comment:
The proposed rule does not clarify which Tampico Spring is being referenced where the Zuni bluehead sucker are known to occur.

Our Response:
We have added language to clarify that the Tampico Spring occupied by Zuni bluehead suckers occurs on private land on the west side of the Oso Ridge and is not identified on a topographic map. This Tampico Spring should not be confused

with the Tampico Spring on the east side of Oso Ridge identified on topographic maps and located on public land,. Please see
New Mexico Distribution
section for the description of Tampico Spring.

(25) Comment:
The proposed rule states that, in 2001, NMDGF received permission from the landowner to conduct sampling at Tampico Spring for the first time since 1994. Zuni bluehead sucker were removed from Tampico Spring by the Service, NMDGF, and Albuquerque Biopark biologists. The proposal claims the rate of catch at Tampico Spring subsequently declined. Was the cause of the decline the removal of specimen, electrofishing, or the introduction of organisms that may have been on the sampling gear, the buckets, or the waders?

Our Response:
As stated in the
Population Status of the Species in New Mexico
section, Tampico Spring and all other occupied areas of Zuni bluehead sucker in the Zuni River watershed have all seen a period of decline. However, all catch rates for the Zuni bluehead sucker have shown improvement in the 2012 survey efforts. The observed decline of the population was not an artifact of fish removal, electrofishing, or an introduced organism. We know this because approximately 50 individuals were collected from Tampico Spring between 2007 and 2008 (NMDGF 2013, p. 33), and Zuni bluehead suckers have been spawning and producing offspring (NMDGF 2013, p. 23). Electrofishing can be lethal, but, when used properly, potentially harmful effects of electrofishing are significantly reduced and mortality is minimal. We are unaware of any introduced organism in Tampico Spring, and it is common practice to disinfect waders and fish collection gear to reduce the chance of introduction of any organism to a system. We do not have a direct link for the observed decline, other than it is likely a combination of factors, such as the habitat being inundated with silt; furthermore, the population exhibits facial deformities, and whether that effects survival is unknown.

(26) Comment:
We received comments regarding the correct use of scientific literature in the livestock grazing section of the proposed rule and whether the documents were unbiased. In addition, it is not clear how Larsen
et al.
(1998, entire) can be used as a reference to support the statement that livestock grazing causes adverse impacts to native fishes and their habitat because the reference shows that Larsen questions the defensibility of the wealth of the literature on livestock grazing. Thus, it seems the literature exhibits personal opinion or commentary interspersed with little scientifically valid experimentation.

Our Response:
We are charged with using the best scientific and commercially available information in a listing determination. The discussion on livestock grazing in the proposed and final rules cites many studies and authors on the topic of livestock grazing impacts to aquatic systems. Although some of our citations are not specific to this species or the geographic area, the citations offer evidence that certain threats exist because similar examples have been documented elsewhere, and, based on biological principles and effects observed in other fishes, we can draw reasonable conclusions about what we would expect to happen to this species. It is well understood in the scientific community that improper grazing has impacts on stream habitat and fish communities. We have added or modified several of the livestock grazing citations to reflect effects of livestock grazing on fish habitats and populations.

We have also made some changes in the livestock grazing section of the final rule in direct response to the commenter's question on the incorporation of Larsen
et al.
(1998, entire). Larsen
et al.
(1998, pp. 161, 164) was an incorrect use for the specific statement the commenter referenced, and, in fact, the page numbers do not match with that publication. This citation was removed from the final rule. Although Larsen
et al.
1998 (p. 664) concludes that the base of the commonly accepted body of knowledge of livestock influences on riparian zones and fish habitat is made up of many reports that are not experimentally or statistically adequate, the authors were able to generalize several points from their literature review. These generalizations include: (1) It is clear that livestock or big game can and do coexist within sustainable riparian systems; likewise, livestock and big game can and sometimes do change riparian vegetation structure in undesirable ways; (2) Vegetation responses are highly site specific; and (3) Ecosystems are highly variable in space and time. Most driving forces that change ecosystems seem to result from interactions of factors (Larsen
et al.
1998, p. 664). Therefore, based on the generalization, livestock grazing impacts are site-specific and can be exacerbated by other factors in the environment.

(27) Comment:
The citation used for the conclusion paragraph for historical logging, overgrazing by livestock, and road construction does not have a single empirical data point to support the conclusion.

Our Response:
We are charged with using the best scientific and commercially available information in a rule. We acknowledge that additional research would be valuable; however, the Act requires that we use the best information currently available for the species or similar species. The Act requires that we adhere to a timeframe in developing our determination, and we do not have the funding or authority to conduct studies to collect empirical data on each topic of discussion. We have updated and included additional information in the “Summary of Factors Affecting the Species” in which we describe the types of land management practices (logging, livestock grazing, and road construction) both in the past and present that have influenced the landscape inhabited by the Zuni bluehead sucker. In addition, we provide information related to these land management practices that have been seen to influence many fish species and their habitats. We will need the help of private and public land managers to implement best management practices to improve conditions where the Zuni bluehead sucker occurs. This may include the need to increase the genetic diversity by introducing other Zuni bluehead suckers into the system to increase diversity as we have done for other fish species.

(28) Comment:
The proposal cites Miller (1961, pp. 394-395) in the discussion of grazing and erosion, but it would have been better to have embraced the following citation from Miller (1961, p. 398):

“The use of toxic chemicals, such as rotenone and toxaphene, for the control or eradication of fish populations may have serious consequences for the native species. Such a management tool is being employed more and more widely in the control of “rough fish”; without prior determination of its harmful effects, this practice may needlessly exterminate localized species or relict populations (see above and Koster, 1957: 106). Its relatively indiscriminate use in streams has already reduced certain native fishes to dangerously low levels or has seemingly brought about extinction (Clark Hubbs. In litt., 1960). Conservationists should make a determined effort to prevent the decimation of aquatic biota in this way, if necessary through the enactment of protective legislation.”

Our Response:
In the
New Mexico Distribution Section,
we acknowledge that Zuni bluehead sucker numbers have been starkly reduced in the Zuni

River watershed in New Mexico, largely due to 27 chemical treatments during the 1960s. The past use of chemical treatments in the 1960s and 1970s has affected the Zuni bluehead sucker; however, going forward, the use of chemical treatments can be beneficial to native fishes if used properly. As Miller suggests, “Conservationists should make a determined effort to prevent the decimation of aquatic biota . . .” and as a practice when the Service is conducting nonnative fish eradication, we collect and hold native fishes for reintroduction until the chemical treatment is complete.

(29) Comment:
The “Water Withdrawal” section of the proposed rule does not have any empirical data, and the citations used are not relevant to the Zuni bluehead sucker or the Zuni River watershed. How do agricultural and industrial water needs compare to vacation home needs?

Our Response:
Our assessment that water withdrawal is a threat to the Zuni bluehead sucker is based on the best scientific and commercial data available. We reviewed articles published in peer-reviewed journals, agency reports, and comments received on both the proposed rule and the 6-month extension of the final determination. Some of our citations are not specific to this species or the geographic area; nevertheless, we can ascertain that water withdrawal can have negative impacts on the Zuni bluehead sucker and their habitat. The “Water Withdrawal” section assesses all sources of water withdrawal, including agriculture, livestock, mining, and municipal water use. The majority of the water within the Lower Colorado River Basin in New Mexico is consumed for agriculture and mining; however, additional uses include domestic (self-supplied) and public water supply (New Mexico Office of the State Engineer 2010, p. 1). As stated in Orr (1987, p. 1), the population of the Pueblo of Zuni was increasing rapidly and, thus, increasing the need for additional municipal and domestic water supplies; therefore, the U.S. Geological Survey conducted a comprehensive water-resources study on Zuni Tribal lands. The results of this study identified that several aquifers' water-levels were in decline during a 10-year period, which could be the result of pumping for well withdrawals (Orr 1987, pp. 42-44). The consumption of water within the Lower Colorado River Basin through various sources has increased by as much as 56 percent between 1990 and 2005 (New Mexico Office of the State Engineer 1990, p. 1; New Mexico Office of the State Engineer 2005, p. 1). Based on our review of the available information, we conclude that the effects of water withdrawal are a continuing threat to the Zuni bluehead sucker habitat across its range and, as a result, are negatively affecting the species. We used these examples in the rule to depict how water withdrawals for agriculture and mining have impacted flow to rivers or springs. Water withdrawal within the range of the Zuni bluehead sucker is not just the result of vacation homes (see description above), but is the result of a culmination of municipal, agricultural, and livestock activities.

(30) Comment:
The hydrological studies referenced by the 2011 Final Environmental Impact Statement by the U.S. Forest Service for the Forest Roads 191 and 191D project indicates minimal anticipated impact on the discharge into the Rio Nutria even in a worst-case scenario.

Our Response:
The U.S. Forest Service (2011, p. 32) states that MJDarrconsult, Inc. (2007, entire) and Glorieta Geoscience, Inc. (2007, entire) show a small amount of drawdown, from 0.03 to 0.04 meters (m) (0.09 to 0.14 feet (ft)), could occur at Nutria Springs. However, neither model takes into account current natural recharge or return flow, and, when either of these factors is considered, the drawdown predicted at Nutria Springs becomes negligible (Congdon, 2009, entire). As discussed in the “Climate Change” section below, the outlook presented for the Southwest predicts warmer, drier, drought-like conditions (Seager
et al.
2007, p. 1181; Hoerling and Eischeid 2007, p. 19). A decline in water resources will be a significant factor in the compromised watersheds of the Desert Southwest, ultimately affecting the future natural recharges rates for aquifers.

(31) Comment:
There is no empirical data that connects sedimentation with adverse effects on the Zuni bluehead sucker, and the citations used in the “Sedimentation” section of the proposed rule are questionable. Much of the language used is the section uses the word “may”, which characterizes many of the statements as a yet-to-be-tested hypothesis.

Our Response:
Please see the response to comment 27 regarding empirical data. We are charged with using the best scientific and commercially available information in a rule. We have added additional language in the “Sedimentation” section to describe known impacts of sedimentation on fishes and fish habitats. Although these examples are not species-specific, we can ascertain that similar effects may occur for the Zuni bluehead sucker. We are using the best scientific and commercial information available and that information can sometimes only lead us to a “may” conclusion rather than a definitive statement.

(32) Comment:
Does the existence of the inbred colonies at Agua Remora and Tampico Springs, with their mutations and limited genetic diversity, pose a threat to the overall survival of the subspecies? Fish from the Rio Nutria cannot travel upstream past the waterfall barriers. But mutated fish from the Agua Remora and Tampico Springs can be washed downstream with seasonal runoff. These fish can then breed with the main population and introduce their mutated genes into the Rio Nutria population. Would that fertilization then reduce the survival rate of the Rio Nutria population over time? Has a decline in the population in the Rio Nutria already been observed?

Our Response:
A species relies on genetic diversity to survive, and low diversity usually indicates that the population has been inbreeding due to a decrease in populations, which is described in the “Taxonomy and Genetics” section. We have determined that small population sizes and limited genetic diversity are a concern for the Zuni bluehead sucker viability. This is why the New Mexico Department of Game and Fish funded research efforts to look at the genetic diversity of the Zuni bluehead sucker in the Zuni River watershed and established a captive rearing program. Zuni bluehead sucker both from Aqua Remora and Tampico Spring are successfully reproducing in captivity. In addition, these populations were combined and successfully reproduced as well. We will need help of private and public land managers to implement management practice to improve conditions where the Zuni bluehead sucker occurs. This may include the need to increase the genetic diversity by introducing other Zuni bluehead suckers into the system to increase diversity as done for other fish species. We do not anticipate the mixing of these populations to be a threat because, if the population mixed, it may increase the genetic diversity. In addition, as described in the “
Population Status of the Species in New Mexico”
section, Rio Nutria has experienced declines since the 1970s, as have all other locations in the Zuni River watershed. However, the Zuni bluehead sucker does appear to be on the rise in Rio Nutria.

Summary of Changes From Proposed Rule

Based upon our review of the public comments, comments from State and

Tribal agencies, peer review comments, and any new relevant information that may have been available since the publication of the proposal, we reevaluated our proposed rule and made changes as appropriate. During the open comment periods, we were asked to incorporate additional information, which was provided or suggested, and to provide clarification in some areas. We have added both additional and clarifying language regarding our understanding of water withdrawal, sedimentation, logging, livestock grazing, and housing development. We also added additional language to Factor D regarding existing conservation plans and agreements, including the New Mexico Zuni bluehead sucker recovery plan (NMDGF 2004, entire). Navajo Nation provided substantial information regarding several plans and policies that have been developed by the Navajo Nation Department of Fish and Wildlife, the Navajo Nation Environmental Protection Agency, and the Navajo Nation Forestry Department. All of these plans and policies have been incorporated into the Tribal Regulations section in Factor D.

During the two comment periods on the proposed rule and the 6-month extension, the Service received additional information, clarification, and comment to assist with identifying populations of Zuni bluehead sucker based on taxonomy and genetics. The Service has provided substantial information within the “Taxonomy and Genetics” section of the rule above. The information incorporated above clarifies which populations are considered Zuni bluehead sucker based on information received since the publication of the proposed rule. We are charged with using the best scientific and commercially available information relevant to the taxonomy and genetics and have incorporated this new information into this rule to substantiate the identified populations of the Zuni bluehead sucker. However, this information has also removed populations from the Canyon de Chelly watershed in the Lower San Juan River watershed from this final listing rule because these populations have been identified as bluehead sucker and not Zuni bluehead sucker. This additional information did not alter our threats assessment, but rather confirms that the Service's determination of endangered status is appropriate because fewer geographically isolated populations exist than previously proposed and threats remain high across those populations.

Summary of Factors Affecting the Species

Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, we may list a species based on any of the following five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; and (E) other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination. Each of these factors is discussed below.

Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

The principal threats to Zuni bluehead sucker habitat include water withdrawal, sedimentation, impoundments, housing development, wildfire, and climate change. These threats are intensified by the species' small range. Severe degradation to watersheds occupied by Zuni bluehead sucker has occurred through excessive timber harvest, overgrazing, and road construction. Although most of these activities occurred in the late 1800s and early 1900s, the subsequent erosion, gullying, headcutting (an erosional feature of some intermittent or perennial streams where an abrupt vertical drop occurs in the stream bed creating a steep riffle zone or waterfall that continues to erode), and loss of water have continued to degrade habitat for the Zuni bluehead sucker (as discussed in detail below) (Natural Resources Conservation Service (NRCS) 1998, entire).

Water Withdrawal

Surface and groundwater withdrawal result in the direct loss of habitat as well as fragmentation of Zuni bluehead sucker habitat by reducing stream flow or water depth. Reduced stream velocities result in increased sedimentation, while overall loss of wetted habitat strands Zuni bluehead suckers in isolated shallow pools that may not provide suitable hard substrates for feeding and reproduction. Loss of appropriate habitat may decrease the reproductive success of Zuni bluehead sucker and result in mortality of individuals. Historically, water withdrawals led to the conversion of large portions of flowing streams to intermittent streams or dewatered channels, thus eliminating suitable Zuni bluehead sucker habitat in affected areas (NMDGF 2004, p. 12). Water withdrawals that lead to dewatering or reduced river flows or pool levels reduce the available habitat for the species.

Groundwater withdrawal can cause reduction or loss of spring flow (Brune 2002, p. 356). Within the Zuni River watershed, various springs occur across Zuni Pueblo lands (Orr 1987, p. 37; Drakos and Riesterer 2009, p. 96). Discharge from these springs feeds into several intermittent streams in the watershed, including the Zuni River, the Rio Pescado, and the Rio Nutria. These streams flow intermittently, except for short reaches that flow perennially in response to discharge from springs (Orr 1978, p. 37; NMDGF 2013, p. 9). Because spring ecosystems rely on water discharged to the surface from underground aquifers, groundwater depletion can result in the destruction of riverine habitat through spring drying (Scudday 1977, pp. 515-516). Spring drying or flow reduction resulting from groundwater pumping has also been documented in the Roswell (August 9, 2005; 70 FR 46304) and Mimbres Basins (Summers 1976, pp. 62, 65) of New Mexico. Orr's (1987, pp. 42-44) study identified that several aquifers' water levels were in decline during a 10-year period where pumping from well withdrawals may have been the cause. In addition, spring flow found on Zuni Tribal lands generally declined between 1972 and 2009 (Drakos and Riesterer 2009, p. 96). By definition, a spring is the result of an aquifer being filled to the point that water overflows onto the land surface. Therefore, if enough water is pumped out of an aquifer it could possibly influence ground water discharge (springs and streams) by reducing, or perhaps stopping, streamflow. The lowermost pool in Agua Remora had reduced water depths in 2005 and nearly dried in 2007 and 2009; Zuni bluehead suckers were salvaged from this area and moved upstream to the middle pool or taken to the Albuquerque Bio Park for a rearing program (Carman 2008, p. 17; Carman 2009, p. 24). However, it is unknown whether this observed reduction in water depths is a product of groundwater pumping in the area, effects of climate change, or both.

Groundwater use in the range of the Zuni bluehead sucker is expected to increase due to human population expansion. In early 2007, a development company (Tampico Springs 3000, LLC), presented a preliminary plat to

McKinley County, New Mexico, for Tampico Springs Ranch Subdivision. The subdivision is located just northeast of currently occupied Zuni bluehead sucker habitat. The subdivision would have a total of 490 lots, varying from 1.2 to 4.8 hectares (ha) (3 to 11.9 acres (ac)), each with an individual well and septic system. An increase in the number of wells would affect aquifer drawdowns, and individual septic tanks could potentially lead to water quality concerns. The geohydrologic investigation report, prepared for Phase I of the subdivision, states that water withdrawal is likely to affect flow at Brennan and Tampico Springs (MJDarrconsult, Inc. 2007, p. 26). In January 2008, the plat for Phase I of the subdivision was approved by McKinley County with conditions, including metering of water wells to enforce the 0.3 acre-ft. per year per household restriction (Carman 2008, p. 17). Construction of Phase I has begun, with 17 of 45 lots sold (First United Realty 2012, p. 1).

In Arizona, existing water withdrawals throughout the Navajo Indian Reservation are generally for water haulers (people who collect water in tanks and transport it to another location for use); domestic and municipal use; water storage facilities; commercial, agricultural, mining and industry uses; recreation and wildlife; and wastewater management. Water withdrawals have been documented on the Navajo Indian Reservation for many years. Water levels in wells in the Black Mesa area have declined as much as 70 ft (21.3 m) since 1963 (Littin 1992, p. 1). As of 2003, there were 75 livestock wells on the Navajo Indian Reservation, in both alluvial (connected to the river) and deep-water aquifers (Navajo Nation Department of Water Resources 2003, p. 40). Additionally, water in Kinlichee Creek has been noted as very low in recent years (Kitcheyan and Mata 2012, p. 3), and Scattered Willow Wash, Black Soil Wash, and Kinlichee Creek have been intermittent several years in a row (Carman 2004, pp. 2, 8; Kitcheyan and Mata 2012, p. 3). These low-water events are exacerbated by continued water withdrawal in the region. Given past groundwater use and the likelihood of continued drought (see
Climate Change,
below), groundwater declines will likely continue into the future.

In summary, water withdrawals have affected the Zuni bluehead sucker rangewide in the past, resulting in dry streambeds or very low water levels in the lower Rio Nutria, Rio Pescado, Zuni River, and possibly in Agua Remora in New Mexico and in Scattered Willow Wash, and Kinlichee Creek in Arizona. Based on our review of the available information, we conclude that the effects of water withdrawal are a continuing threat to the Zuni bluehead sucker habitat across its range and as a result are negatively affecting the species.

Sedimentation

Sedimentation occurs when particles suspended in the water column fall out of suspension and cover the streambed, filling in spaces between substrate particles. Sedimentation results in the loss of suitable habitat and available food resources for Zuni bluehead sucker. Fine sediments, in particular, reduce or prevent production of algae, the Zuni bluehead sucker's primary food. Research has shown that heavy sediment loads have the potential to limit algae production by restricting light penetration or smothering (Graham 1990, pp. 107-109, 113-114; Wood and Armitage 1997, pp. 203, 209-210).

High concentrations of fine sediment have been found to affect fishes: (1) By adversely affecting fish swimming and either reducing their rate growth, tolerance to disease, or even resulting in death (Bruton 1985, p. 221); (2) by reducing the suitability of spawning habitat and hindering the development of fish eggs, larvae and juveniles are more susceptible to suspended solids than adult fish (Chapman 1988, p. 15; Moring 1982, p. 297); (3) by modifying the natural migration patterns of fish (Alabaster and Lloyd 1982, pp. 2-3); (4) by reducing the abundance of food available to fish due to a reduction in light penetration (Bruton 1985, p. 231; Gray and Ward 1982, pp. 177, 183); and (5) by affecting the efficiency of hunting, particularly in the case of visual feeders (Bruton 1985, p. 221, 225-226; Ryan 1991, p. 207). If mobilized during the spawning season, fine sediments may also smother and suffocate spawned eggs (Propst and Hobbes 1996, p. 39). The reproductive successes of fishes that require clean gravel substrate have been reduced by increased sedimentation due to smothering of eggs, which may be the case for Zuni bluehead sucker (Berkman and Rabeni 1987, p. 285; Propst and Hobbes 1996, p. 38). Increasing sedimentation in Agua Remora and Rio Nutria has led to the loss of optimal Zuni bluehead sucker habitat (permanent, clear flowing water over hard substrate). Sedimentation throughout the range of Zuni bluehead sucker is primarily caused by logging, livestock grazing, and road construction; these are discussed in detail below.

Logging

Many areas of the landscape where the Zuni bluehead resides have been impacted by past logging activities. For example, in the early 1890s, logging and presence of logging railroads were widespread within the Zuni Mountains, which supported several lumber towns (NRCS 1998, p. 17). Logging activities in the late-1800s likely caused major changes to the watershed; the Zuni Mountains were nearly void of ponderosa pine (
Pinus ponderosa
) during the railroad logging days (Dick-Peddie 1993, p. 68). The Mt. Taylor Ranger District identified the forest to be dominated with Ponderosa pine and small stands of Gambel oak (
Quercus gambelii
), stratified with mature stands of large conifers left over from railroad logging in the early 1900s, including younger and smaller trees, as well as saplings (Forest Service 2011, p. 19).

In general, logging activities have been well documented to impact watershed characteristics and stream morphology (Chamberlin
et al.
1991, pp. 181-205; Ohmart 1996, p. 259). Tree removal along stream riparian zone likely alters water temperature regimes, sediment loading, bank stability, and availability of large woody debris (Chamberlin
et al.
1991, pp. 181-205). Soil surface erosion from logging or logging activities is directly related to the amount of bare compacted areas exposed to rainfall and runoff, which then contributes large quantities of fine sediments to stream channels (Chamberlin
et al.
1991, p. 193). Extensive clearcutting and overgrazing were the primary contributors to the reduction of the original riparian vegetation by 70 to 90 percent in the Zuni Mountains (Ohmart 1996, p. 259). Logging is actively practiced on both private and public lands within the Zuni watershed (NRCS 1998, p. 17). For example, in 2012, the Forest Service funded the Zuni Mountain Collaborative Forest Landscape Restoration project, which will increase logging to reduce fire risk in the Rio Puerco and Rio Nutria watersheds over the next 10 years (Forest Service 2012, pp. 1-2). Ultimately, the reduction in fire risk in these watersheds is likely to benefit the Zuni bluehead sucker; however, the short-term increase in logging is likely to increase sedimentation in these watersheds.

In summary, sedimentation from logging has historically affected Zuni bluehead sucker habitat rangewide, reducing the amount of suitable habitat. Logging rates have much reduced in recent years but will continue into the future, particularly in the Rio Puerco

and Rio Nutria watersheds over the next decade, which will likely contribute to the cumulative effect of sedimentation impacting the Zuni bluehead sucker habitat.

Livestock grazing

Livestock grazing has been one of the most widespread and long-term causes of adverse impacts to native fishes and their habitat (Miller 1961, pp. 394-395, 399; Platts 1991, pp. 389-423; Belsky
et al.
1999, entire; Medina
et al.
2005, pp. 9-98). Widespread livestock grazing and logging likely contributed to habitat modifications, resulting in severe degradation of the Zuni watershed (Hanson 1982, p. 14; NRCS 1998, p. 1; NMDGF 2004, p. 12). Livestock grazing has been shown to increase soil compaction, decrease water infiltration rates, increase runoff, change vegetative species composition, decrease riparian vegetation, increase stream sedimentation, increase stream water temperature, decrease fish populations, and change channel form (Meehan and Platts 1978, pp. 275-276; Kauffman and Krueger 1984, pp. 430-435; Schulz and Leininger 1990, p. 295; Platts 1991, pp. 393-403; Ohmart 1996, pp. 246-274). Although direct impacts to the riparian zone and stream can be the most obvious sign of livestock grazing, upland watershed condition influences the timing and amount of water delivered to stream channels (Ohmart 1996, pp. 260, 268). Increased soil compaction and decreased vegetative cover lead to faster delivery of water to stream channels, increased peak flows, and lower summer base flow (Platts 1991, p. 390; Ohmart 1996, p. 255; Belsky and Blumenthal 1997, pp. 321, 324). Consequently, streams are more likely to experience flood events during monsoon-like weather in summer (water runs off quickly instead of soaking into the ground) that negatively affects the riparian and aquatic habitats. Therefore, heavily grazed streams are more likely to become intermittent or dry in September and October, when groundwater recharge is reduced because water runs off quickly, rather than being absorbed by the soil (Ohmart 1996, p. 268).

Improper livestock grazing increases sedimentation through trampling of the steam banks and compacting soil, both of which can result in a reduction or elimination of riparian vegetation, which can be detrimental to stream habitat. Riparian vegetation insulates streams from temperature extremes in both summer and winter. Further, it filters sediment so that it does not enter the stream; sediment can lead to reduction or prevention of algal growth and smothering of newly spawned eggs (Propst and Hobbes 1996, p. 38). Riparian vegetation also provides a source of nutrients to the stream from leaf litter, which increases stream productivity, and it contributes root wads and large and small woody debris to the stream, which provide cover for the fish (Kauffman and Krueger 1984, pp. 430-431; Platts 1991, pp. 395-400; Ohmart 1996, pp. 247-249).

The Cibola National Forest (Forest) commissioned the Zuni Mountain Sucker Habitat Management Plan “to protect, and to enhance, where possible, habitat of threatened and endangered species within the confines of the Forest” (Winter 1979, p. 3). In 1978 and 1979, the Forest fenced off Agua Remora from grazing, which resulted in marked regrowth of the riparian area (Merkel 1979, p. 15; Stefferud 1985, p. 1). In 1988, the NMDGF Share with Wildlife program collaborated with the Forest to increase the fenced area, doubling the amount of protected habitat. However, the fence is occasionally in disrepair leading to unauthorized grazing in Agua Remora, and the fence is checked only if there is evidence of grazing within Agua Remora. A recent field trip to Agua Remora identified that the fence was in disrepair, and five cows were on the site; the riparian area had lost vegetative cover (Gilbert 2012, p. 1). Elk are also known to frequent this area as well (Gilbert and Carman 2011, p. 35). Additionally, several active grazing allotments are north of Agua Remora, with the closest being 2.4 km (1.5 mi) away; livestock grazing also occurs on nearby private land.

During the 1930s, in Arizona, on the Navajo Indian Reservation, nearly one million livestock (sheep, goats, horses, or cattle) ranged across the landscape, exposing soil and increasing erosion (Weisiger 2007, p. 440). Grazing continues today throughout the entire Navajo Indian Reservation, although herd numbers are much lower than in the 1930s. Although grazing has been reduced, the continuing drought has exacerbated effects of depleted forage, and the livestock numbers are considered to be overpopulated, (Davis 2012, p. 1). Additionally, cultural resistance to fencing on the Navajo Indian Reservation (Beatty Davis 1997, p. 49) creates a challenge for range management and stream protection. Direct access to streams and overgrazing by livestock on the Navajo Indian Reservation has been documented repeatedly (Sanchez 1975, p. 1, Service 1982, pp. 3-4; U.S. Army Corps of Engineers 1995, p. 3; Hobbes 2000, p. 14; NMDGF 2003, pp. 6, 13; David 2006, pp. 4, 20; Kitcheyan and Mata 2012, p. 3). Overall, both historical and current livestock grazing within the riparian zone and upland slopes has reduced vegetative cover and accelerated runoff and increased erosion in areas such as Tsaile Creek (Bureau of Reclamation 2011, p. 22).

In summary, Zuni bluehead sucker habitat near or adjacent to areas where livestock grazing occurs is significantly impacted. The resulting habitat degradation is a threat to the remaining Zuni bluehead sucker populations in New Mexico and Arizona. The available information indicates that these activities likely contributed to the reduction in riparian habitat, channel incision, and increased soil compaction, which resulted in unfavorable habitat conditions for Zuni bluehead sucker foraging or reproduction. Such unfavorable habitat conditions affect populations by reducing their viability. Based on our review of the available information, we conclude that the effects of livestock grazing are a threat to Zuni bluehead sucker habitat, and the species, throughout its entire range.

Road Construction

Roads increase surface runoff and sedimentation, which, in turn, increases turbidity, reduces primary production, and reduces numbers of aquatic insects (Burns 1972, p. 1; Eaglin and Hubert 1993, pp. 844-845). Roads require instream structures, such as culverts and bridges that remove aquatic habitat and can act as barriers to fish movement (Warren and Pardew 1998, p. 637). As seen with many other fishes and environments, all of these activities can negatively impact Zuni bluehead suckers and their habitat by lowering water quality, reducing the quality and quantity of pools by filling them with sediments, reducing the quantity of large woody debris necessary to form pools, and by imposing barriers to movement (Burns 1972, p. 1; Eaglin and Hubert 1993, pp. 844-845).

Vehicular use of roads in creek bottoms can degrade Zuni bluehead sucker habitat. Such use inhibits riparian plant growth, breaks down banks, causes erosion, causes sedimentation, and increases turbidity in the stream, particularly where vehicles drive through the stream (especially immediately downstream of the vehicular activity). These effects are likely to result in wider and shallower stream channels (Furniss
et al.
1991, pp. 297-301). This change causes progressive adjustments in other variables of hydraulic geometry and results in changes to the configuration of pools, runs, riffles, and backwaters; levels of fine sediments and substrate

embeddedness (the degree to which rocks and cobble are stuck in the streambed); availability of instream cover; and other fish habitat requirements in the vicinity of vehicle crossings (Sullivan
et al.
1987, pp. 67, 69-70; Rosgen 1994, p. 185). It also changes the way in which flood flows interact with the stream channel and may exacerbate flood damage to banks, channel bottoms, and riparian vegetation. Low-water crossings for vehicle use are seen throughout the Navajo Nation, where the stream channels are wider and shallower, embedded, and create barriers to fish movement (Service 2014b, pers. comm.).

Road construction activities may have direct adverse effects on the watershed from soil erosion and sedimentation to the streams. Past, current, and future road construction activities may ultimately increase the road density in a watershed. Road density is defined as the total kilometers (km) (miles (mi)) of road in a defined area in square kilometers (km
2
) (square miles (mi
2
)). Matthews (1999, p. 86) linked road densities to increased sediment yields in the Noyo River. Aerial photographs from 1935 and 1991 showed road density in the Cebolla and Rio Nutria watersheds rose 138 and 47 percent, respectively (NRCS 1998, pp. 42, 47). In 1991, the road density in Cebolla and Rio Nutria watersheds were more than 3.1 km/km
2
(4.9 mi/mi
2
) and 4.5 km/km
2
(2.8 mi/mi
2
), respectively (NRCS 1998, pp. 42, 47). In addition, the Zuni River Watershed Plan recommends that the road density for these watersheds should be 1.9 km/km
2
(3.1 mi/mi
2
) and 2.9 km/km
2
(1.8 mi/mi
2
), respectively, which both Cebolla and Rio Nutria watersheds exceeded in 1991 and probably continue to exceed today. The excessive miles of roads in this watershed was a concern in 1991, because of the increased erosion, loss of and fragmentation of wildlife habitat, and increased human-wildlife interaction (NRCS 1998, p. 67).

For example, Forest Road 50 in the upper watershed of Zuni bluehead sucker habitat (approximately 5 km (3 mi) away from the closest occupied habitat) was upgraded in 1999, and several roads were developed in 2007 for the Tampico Springs Subdivision. In 2011, the U.S. Forest Service issued an easement to McKinley County to upgrade Forest Road 191D with gravel surface material (Forest Service 2011,p. 1), which may increase vehicle traffic because residents may be able to access their property year round. This road is approximately 3 km (2 mi) from Agua Remora and 1.6 km (1 mi) from Tampico Spring (Forest Service 2011, pp. 31, 44).

On the Navajo Indian Reservation, past road construction continues to affect stream habitat. On Kinlichee Creek, for example, Bridge BR 280 constricts the channel considerably, which increases flow rates, channel scouring, and downstream deposition of sediment (U.S. Army Corps of Engineers 1995, p. 3). In addition, existing roads and bridges have ongoing maintenance requirements that result in alteration of stream channels within Zuni bluehead sucker habitat, as seen in other maintenance projects (Service 2011, pp. 3-5; Service 2012b, pp. 2-4). Sedimentation from road construction has occurred throughout the range of Zuni bluehead sucker in the past and is likely to continue in the future.

In summary, historical logging, overgrazing by livestock, and road construction have destroyed much of the groundcover across the Zuni bluehead sucker's range (Sanchez 1975, pp. 1, 4; Beatty Davis 1997, pp. 3, 7; NRCS 1998, p. 68), resulting in increased erosion, increased stream flow fluctuation, and the accumulation of large quantities of sediment throughout Zuni bluehead sucker habitat (Merkel 1979, p. 1). Livestock grazing and road construction are likely to continue at present rates throughout the species' range, and logging is likely to continue at reduced rates. Sedimentation results in depressed reproductive rates and inhibition of algal growth for food. Therefore, based on our review of the available information, we conclude that the effects of sedimentation are a threat to the Zuni bluehead sucker and its habitat rangewide.

Dams and Impoundments

Much of the primary water use from the Zuni River watershed is for irrigation of agriculture, livestock grazing, and human consumption. Many small impoundments, built primarily for watering livestock, partially prevent flows from reaching the mainstem rivers. According to Merkel (1979, p. 1), the lower Rio Nutria, Rio Pescado, and Zuni River watersheds have been drastically altered by human activities, such as the construction of many small impoundments for livestock watering. Reservoirs and diversion dams for irrigation have depleted stream flows below the dams and inundated stream reaches above the dams (Merkel 1979, p. 1; Hanson 1982, p. 4). Degradation of the upper watershed has led to increased sedimentation and many of the reservoirs are now only shallow, eutrophic (nutrient rich) ponds or wetlands with little or no storage capacity (NMDGF 2004, p. 20). Sediment trapping by these impoundments has also changed the character of the streams by altering channel morphology and substrate composition. The lower Rio Nutria was once a perennial stream with wide meanders bordered by willow and cottonwood (
Populus
spp.). After construction of impoundments in the Rio Nutria below the box canyon meanders, the channel became deeply incised with predominantly silt or silt-sand substrate, which is unsuitable for Zuni bluehead sucker. Flow is intermittent between the ephemeral pools and impoundments. Current habitat conditions are not favorable for Zuni bluehead sucker in much of the watershed downstream from the mouth of Rio Nutria Box Canyon, primarily due to impoundments, dams, and sedimentation from logging and grazing.

Additionally, beaver dams affect Zuni bluehead sucker habitat, particularly in New Mexico. In 2006, beaver activity in Tampico Draw and Rio Nutria increased greatly, fragmenting much Zuni bluehead sucker habitat (Carman 2007, p. 1). A marked decrease in captured Zuni bluehead sucker in Tampico Draw was attributed to increased siltation and water ponding due to beaver activity (Carman 2007, p. 1). In 2010, spring flows washed out the beaver dams in Tampico Draw, creating more suitable habitat for Zuni bluehead sucker (Gilbert and Carman 2011, p. 6). The best available information does not indicate beaver activity is affecting Zuni bluehead sucker populations in Arizona.

In summary, Zuni bluehead sucker habitat has been reduced rangewide due to impoundment construction. Impoundments have lasting effects on stream habitat both up and downstream, subsequently fragmenting fish populations and decreasing their resiliency and long-term persistence. Based on our review of the available information, we conclude that the effects of impoundments are a current threat to Zuni bluehead sucker and are having rangewide impacts on their habitat.

Housing Developments

Subdivision developments within the range of Zuni bluehead sucker would increase the amount of impervious surfaces in this watershed. Impervious surfaces are any surface material that prevents water from filtering into the soils, such as buildings, roads, sidewalks, patios, parking lots, and compacted soil (Brabec
et al.
2002, p. 499, Coles
et al.
2012, pp. 10, 107). An increase in the amount of impervious surfaces could increase the amount of runoff and decrease

infiltration rates. Impacts of urbanization on stormwater runoff leads to various stressors on spring systems, including increased frequency and magnitude of high flows in streams, increased sedimentation, increased contamination and toxicity, and changes in stream morphology and water chemistry (Coles
et al.
2012, pp. 1-3, 24, 38, 50-51). Urbanization can also impact aquatic species by negatively affecting their invertebrate prey base (Coles
et al.
2012, p. 4). The increased frequency and magnitude of water flowing to streams combined with pollutant sources, such as sediment, nutrients, fertilizers, and other contaminants, have been linked to changes in stream hydrology, stream habitat, and degradation of the stream's biological communities (Coles
et al.
2012, p. 10). Urbanization can cause changes in fish population composition and distribution due to habitat changes and lower water table elevations due to groundwater use.

In 2011, the Forest granted an easement to McKinley County for access across Forest Service land via Forest Road 191D (Forest Service 2011 p. v). The granting of the right-of-way allows McKinley County to upgrade and assume maintenance of this

[Text truncated at 120,000 characters. The full text is on the page linked above.]

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2014-17205. Public record. Not legal advice.