82_FR_17047 82 FR 16981 - Endangered and Threatened Wildlife and Plants; Threatened Species Status for the Headwater Chub and Roundtail Chub Distinct Population Segment

82 FR 16981 - Endangered and Threatened Wildlife and Plants; Threatened Species Status for the Headwater Chub and Roundtail Chub Distinct Population Segment

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service

Federal Register Volume 82, Issue 66 (April 7, 2017)

Page Range16981-16988
FR Document2017-06995

We, the U.S. Fish and Wildlife Service (Service), withdraw the proposed rule to list the headwater chub (Gila nigra) and a distinct population segment (DPS) of the roundtail chub (Gila robusta) from the lower Colorado River basin as threatened species under the Endangered Species Act (Act). This withdrawal is based on a thorough review of the best scientific and commercial data available, which indicate that the headwater chub and the roundtail chub DPS are not discrete taxonomic entities and do not meet the definition of a species under the Act. These fish are now recognized as a part of a single taxonomic species--the roundtail chub (Gila robusta). Because the entities previously proposed for listing are no longer recognized as species, as defined by the Act, we have determined that they are not listable entities and we are withdrawing our proposed rule to add them to the List of Endangered and Threatened Wildlife. Section 4(b)(6) of the Act and implementing regulations at 50 CFR 424.17 provide that the Service must, within 1 year of a proposed rule to list, delist, or reclassify species, or to designate or revise critical habitat, withdraw the proposal if the available evidence does not justify the proposed action. The document withdrawing the rule must set forth the basis upon which the proposed rule has been found not to be supported by available evidence. Once withdrawn, the action may not be re-proposed unless sufficient new information is available.

Federal Register, Volume 82 Issue 66 (Friday, April 7, 2017)
[Federal Register Volume 82, Number 66 (Friday, April 7, 2017)]
[Proposed Rules]
[Pages 16981-16988]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2017-06995]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2015-0148; 4500030113]
RIN 1018-BA86


Endangered and Threatened Wildlife and Plants; Threatened Species 
Status for the Headwater Chub and Roundtail Chub Distinct Population 
Segment

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule; withdrawal.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), withdraw the 
proposed rule to list the headwater chub (Gila nigra) and a distinct 
population segment (DPS) of the roundtail chub (Gila robusta) from the 
lower Colorado River basin as threatened species under the Endangered 
Species Act (Act). This withdrawal is based on a thorough review of the 
best scientific and commercial data available, which indicate that the 
headwater chub and

[[Page 16982]]

the roundtail chub DPS are not discrete taxonomic entities and do not 
meet the definition of a species under the Act. These fish are now 
recognized as a part of a single taxonomic species--the roundtail chub 
(Gila robusta). Because the entities previously proposed for listing 
are no longer recognized as species, as defined by the Act, we have 
determined that they are not listable entities and we are withdrawing 
our proposed rule to add them to the List of Endangered and Threatened 
Wildlife.
    Section 4(b)(6) of the Act and implementing regulations at 50 CFR 
424.17 provide that the Service must, within 1 year of a proposed rule 
to list, delist, or reclassify species, or to designate or revise 
critical habitat, withdraw the proposal if the available evidence does 
not justify the proposed action. The document withdrawing the rule must 
set forth the basis upon which the proposed rule has been found not to 
be supported by available evidence. Once withdrawn, the action may not 
be re-proposed unless sufficient new information is available.

FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor, U.S. 
Fish and Wildlife Service, Arizona Ecological Services Office, 9828 
North 31st Ave., #C3, Phoenix, AZ 85051-2517; telephone 602-242-0210. 
Persons who use a telecommunications device for the deaf (TDD) may call 
the Federal Relay Services at 800-877-8339.

SUPPLEMENTARY INFORMATION: 

Previous Federal Action

    On October 7, 2015 (80 FR 60754), we published a proposed rule to 
list the headwater chub and the lower Colorado River basin roundtail 
chub DPS (roundtail chub DPS) as threatened species under the Act (16 
U.S.C. 1531 et seq.). On August 15, 2016 (81 FR 54018), we announced a 
6-month extension on the final listing determination that the Act 
allows when there is substantial disagreement regarding the sufficiency 
or accuracy of the available data, and reopened the comment period on 
the proposed listings for 30 days. During this comment period we 
received new information. On November 1, 2016 (81 FR 75801), we 
reopened the comment period on the proposed listings for an additional 
45 days to provide the public additional time to review and consider 
the proposed rulemakings in light of this new information. As a result 
of the 6-month extension, the deadline to finalize, modify, or withdraw 
the proposed rule is April 7, 2017.
    For a description of additional previous Federal actions concerning 
these species, please refer to the October 7, 2015, proposed listing 
rule (80 FR 60754).

Background

    At the time we published our proposed rule (October 7, 2015; 80 FR 
60754), the Committee on Names of Fishes, a joint committee of the 
American Fisheries Society and American Society of Ichthyologists and 
Herpetologists (the Societies) (Page et al. 2013, p. 71), considered 
headwater chub and roundtail chub to be separate species. As a 
consortium of fisheries scientists, the American Fisheries Society is 
the recognized and accepted scientific authority on fish taxonomy. 
Accordingly, our proposed rule assessed the headwater chub and 
roundtail chub as separate species. However, commenters on our proposed 
rule raised questions during the public comment period regarding the 
taxonomic distinctness of the headwater and roundtail chubs, as related 
to the Gila chub (Gila intermedia). At that time, some scientists 
knowledgeable about the fish contended that the three entities were not 
separate species (Carter et al. 2016 in press; Copus et al. 2016). For 
this reason, the Arizona Game and Fish Department requested that the 
Societies evaluate the most recent literature associated with roundtail 
chub, headwater chub, and Gila chub taxonomy. In their final report to 
the Arizona Game and Fish Department, the Societies panel concluded 
that ``no morphological or genetic data define populations of Gila in 
the lower Colorado River basin (which, as defined by the Service, 
includes the Little Colorado River, Bill Williams River, Gila River, 
Verde River, and Salt River drainages) as members of more than one 
species'' and ``that the data available support recognition of only one 
species of Gila, the roundtail chub, Gila robusta'' (Page et al. 2016, 
p. 1). These three fish are now considered by the Societies to be a 
single species, roundtail chub (Gila robusta) because data do not 
support recognition of three species.

Taxonomy

Introduction
    The taxonomic history of the genus Gila in the Colorado River basin 
has changed over time, especially for the three forms (roundtail, 
headwater, and Gila chub) found in the Gila River basin. These forms 
have been variously classified as full species, assigned as different 
species, subspecies of Gila robusta, or as part of a ``Gila robusta 
complex'' (Miller 1945; Holden 1968; Rinne 1969; Holden and Stalnaker 
1970; Rinne 1976; Smith et al. 1977; DeMarais 1986; Rosenfeld and 
Wilkinson 1989; Dowling and DeMarais 1993; Douglas et al. 1998; 
Minckley and DeMarais 2000; Gerber et al. 2001). As noted by nearly all 
researchers investigating the systematics of Gila spp., the taxonomic 
situation is complicated and problematic (Holden and Stalnaker 1970; 
Minckley 1973; Minckley and DeMarais 2000; Gerber et al. 2001; 
Sch[ouml]nhuth et al. 2014) due to various factors including multiple 
independent hybridization events over time (Rinne 1976; DeMarais 1986; 
Rosenfeld and Wilkinson 1989; DeMarais et al. 1992; Dowling and 
DeMarais 1993; Minckley and DeMarais 2000; Gerber et al. 2001; Schwemm 
2006; Sch[ouml]nhuth et al. 2014; Brandenburg et al. 2015,) potential 
past introgression (the transfer of genetic information from one 
species to another as a result of hybridization between them and 
repeated backcrossing) (DeMarais et al. 1992; Minckley and DeMarais 
2000), recent divergence within the three fish (Schwemm 2006). Further, 
the original assignment to species was based on the assumption that the 
three fish do not overlap geographically (parapatry), which we 
recognize now is not an accurate assumption. Additionally, in some 
instances when the same fish was identified based on morphology 
(physical characteristics) it was identified as one species and when 
identified based on genetic analysis it was identified as a different 
species (Dowling et al. 2015, pp. 14-15). Recent and ongoing genetic 
and morphologic analyses of chubs in the Gila River basin continue to 
yield conflicting results (DeMarais et al. 1992; Schwemm 2006; Dowling 
et al. 2008 and 2015; Sch[ouml]nhuth et al. 2014; Marsh et al. 2016, 
all entire).
History
    Gila robusta (roundtail chub) was first described by Baird and 
Girard (1853, p. 365-369) from specimens collected in 1851 from the 
Zuni River (tributary to Little Colorado River). Gila nigra (headwater 
chub; formerly known as G. robusta graham or G. grahami) was first 
described as a subspecies (G. robusta graham) from Ash Creek in the San 
Carlos River in east-central Arizona in 1874 (Cope and Yarrow 1875, p. 
663), but not returned to full species status (G. robusta) until 
proposed so by Minckley and DeMarais (2000, p. entire). The Societies 
accepted Gila nigra as a full species (Nelson et al. 2004, p. 71), as 
did the New Mexico Department of Game, Fish (Carman 2006, p. 3), 
Arizona Game, and Fish

[[Page 16983]]

Department (AGFD 2006, p. 3) and continued to recognize G. robusta as a 
distinct species. Therefore, based on the best available commercial and 
scientific data the Service accepted both Gila robusta and Gila nigra 
as full species as documented in our 12-month findings (May 3, 2006; 71 
FR 26007 and July 7, 2009; 74 FR 32352). In their 2013 publication of 
Common and Scientific Names of Fishes from the United States, Canada, 
and Mexico, the Societies continued to list both Gila robusta and Gila 
nigra as distinct species (Page et al. 2013, p. 71). A summary of the 
historic and current nomenclature from Rinne (1976, entire), Sublette 
et al. (1990, entire), and Minckley and DeMarais (2000, entire) is 
summarized in Voeltz (2002, pp. 8) and Copus et al. (2016, pp. 1&6). 
The Gila chub (Gila intermedia) is currently listed as an endangered 
species (November 2, 2005; 70 FR 66664).
    These entities were originally classified based on the streams in 
which they were found (Minckley and DeMarais 2000, p. 252), under the 
assumption that G. robusta and G. nigra either did not overlap 
(allopatric, no gene flow) or there was only a narrow overlap 
(parapatric; limited interaction and opportunity for gene flow) 
(Minckley and DeMarais 2000 pp. 252-254). Because hybridization between 
G. robusta and G. intermedia indicates that these fish must co-occur in 
some streams (Minckley and DeMarais 2000, entire), we conclude that 
Minckley and DeMarais's (2000) assumption they did not overlap was 
unfounded. Further, other studies have found that fish designated as G. 
robusta, G. nigra, and G. intermedia overlap geographically or occur 
adjacent to one another (Dowling and Marsh 2009, p. 1; Marsh et al. 
2016, p. 57; Brandenburg et al. 2015, p. 18).
Morphology
    The approach for classifying G. robusta, G. nigra, and G. 
intermedia developed by Minckley and DeMarais (2000, pp. 254-255) 
presumes there is little intraspecific variation (differences within a 
species) in the morphologic and meristic (counting quantitative 
characteristics such as fins) characteristics used to distinguish these 
three taxa. However, the three purported species overlap in physical 
characteristics, and many fish have intermediate physical 
characteristics. Those characteristics that do not overlap are 
separated by very small margins, making species-level identification of 
individual fish problematic, even when the geographic origin of the 
species is known (Brandenburg 2015, entire). Minckley and DeMarais 
(2000, pp. 253-254) indicate that G. nigra is physically different from 
G. intermedia even though they appear physically more similar to one 
another than either is to G. robusta. In addition, Copus et al. (2016, 
p. 13) did not find physical characteristics in the Minckley and 
DeMarais (2000, pp. 254-255) classification key to reliably 
differentiate G. robusta, G. nigra, and G. intermedia from one another. 
Copus et al. (2016 p. 16) concluded that there was no morphological 
basis for taxonomic distinctions within the Gila spp. complex.
Genetics
    Multiple genetic analysis studies have been conducted that reveal 
differences between different chub populations, but have been unable to 
identify differences between G. robusta, G. nigra, and G. intermedia 
(DeMarais et al. 1992, pp. 2748-2749; Schwemm 2006, p. 29; Dowling et 
al. 2008, p. 2, and 2015, p. 13; Copus et al. 2016, pp. 14-15; Marsh et 
al, 2016, p.58). Mitochondrial DNA analysis (Sch[ouml]nhuth et al. 
2014, p. 223) indicates that G. robusta, G. nigra, and G. intermedia 
belong to one clade (a grouping that includes a common ancestor and all 
its descendants, living and extinct, of that ancestor). Sch[ouml]nhuth 
et al. (2014, p. 223) hypothesized that this could reflect 
hybridization or incomplete lineage sorting (when the lineage of a 
specific gene is not the same as the lineage of the species, obscuring 
the true species relationship).
    However, when nuclear DNA (rather than mitochondrial DNA) was 
analyzed, a broader grouping was identified that included G. seminude 
and G. elegans, but when mitochondrial and nuclear DNA results are 
combined G. robusta, G. nigra, and G. intermedia were in one grouping 
(Sch[ouml]nhuth et al. 2014, p. 223). Preliminary studies by Chafin et 
al. (2016) indicate evolutionary independent lineages for G. robusta, 
G. nigra, and G. intermedia, and that the hybrid origin of G. nigra is 
not supported. Studies by Marsh et al. (2016, entire) point to genetic 
variation between populations of G. robusta and G. nigra, and 
demonstrate evidence that distinct ecological differences between some 
populations are now thought to exist. Minckley and DeMarais (2000, 
entire) supported recognition of three species, but acknowledged that 
most genetic variation was within populations for G. robusta, and was 
among populations for G. intermedia and G. nigra. Minckley and DeMarais 
(2000, p. 253) also indicated that these three fishes share genetic 
features (that had been studied so far) while behaving as separate non-
overlapping (allopatric) morphological species. In addition, some 
populations assigned to species based on genetics appeared to conflict 
with the species level-assignment based on morphology (Dowling et al. 
2008, p. 27).
Speciation
    Minckley and DeMarais (2000, p. 253) describe three different 
taxonomic options for chubs in the Gila River basin: a single species 
with many different forms or stages (polymorphic species), a species 
containing multiple subspecies, or three full species. They acknowledge 
that none of these taxonomic options is biologically justified without 
knowing if these fish naturally occur in the same geographic area 
(sympatry, indicating an initial interbreeding population that split), 
or occur immediately adjacent to each other but not significantly 
overlapping (parapatry, indicating there is no barrier to gene flow). 
They further acknowledge that a persistent narrow interaction zone 
(parapatry, indicating there is no barrier to gene flow) of 
morphologically distinguishable G. robusta, G. intermedia, and G. nigra 
has been confirmed, but note that in no instance was any two of the 
three caught at the same locality (allopatric, no gene flow; p. 251). 
However, they also acknowledge that hybridization (between G. robusta 
and G. intermedia, resulting in G. nigra) in the past must have 
occurred in some places and not others, thereby demonstrating 
occurrence in the same geographic area (sympatry) (p. 253). They 
conversely hypothesized that the current minimal overlap in an area 
where species are adjacent (parapatry, indicating there is no barrier 
to gene flow) may thus reflect an ancestral ecological segregation area 
(sympatry, indicating an initial interbreeding population that split 
due to the use of different habitats and resources) that promoted 
persistence in the ever-increasing aridity of the Southwest (p. 253).
    In Fossil Creek, G. nigra and G. robusta appear to be sympatric, 
including hybrids between G. robusta and G. nigra (Marsh et al. 2016, 
p. 57). Brandenburg et al. (2015, p. 18) concluded that the 
morphological assessment of Gila spp. in New Mexico confirmed that the 
three fish were found in the same geographic area (sympatric) in almost 
all cases, contradicting Minckley and DeMarais' results (2000, p. 251) 
as well as other previous literature suggesting that these Gila spp. 
are occurring in separate non-overlapping geographical areas 
(allopatric) through their ranges (Rinne

[[Page 16984]]

1969, p. entire; DeMarais 1986, p. entire; Minckley and DeMarais 2000, 
p. 253). In Fossil Creek, they found that G. nigra and G. robusta are 
locally in the same geographic area (sympatric) and have hybridized 
(Marsh et al. 2016, p. 57). Marsh et al. (2016, p. 58) concluded there 
are two morphologically similar, but genetically distinguishable, chub 
in Fossil Creek, G. robusta and G. nigra.
Conservation Implications
    Dowling et al. (2015, pp. 14-15) reasoned that the lack of 
diagnostic molecular characteristics does not inform the status of 
these three fish, but rather highlights the role that local evolution 
has played in shaping patterns of variation in these taxa and the 
importance of accounting for this variation when managing the complex. 
Most, if not all, scientists agree that conservation actions for these 
chubs must be directed at the population level and must include 
consideration of the complex as a whole (Dowling et al. 2008, pp. 30-
31; Dowling and DeMarais 1993, p. 445; Gerber et al. 2001, p. 2037; 
Schwemm et al. 2006, pp. 32-33). The Arizona Game and Fish Department 
recognizes the importance of conserving the currently recognized 
roundtail chub population rangewide (including the formerly known 
headwater chub and Gila chub) and is committed to the conservation 
agreements and practices that have been in place since 2006 (AGFD 2017, 
entire; AGFD 2006, entire).

Public Comments

    In our October 7, 2015 proposed rule (80 FR 60754), we requested 
that all interested parties submit comments or information concerning 
the proposed listings during a 60 day comment period, ending December 
7, 2015. We particularly sought comments concerning genetics and 
taxonomy. In our August 15, 2016, 6-month extension document (81 FR 
54018), we reopened the comment period on the proposed rule for 30 
days, ending September 14, 2016, and we again requested comments and 
information regarding genetics and morphology that would aid in 
resolving the ongoing taxonomic issues regarding classification of 
these fish. On November 1, 2016 (81 FR 75801, we announced an 
additional 45-day comment period, ending December 16, 2016, on the 
October 7, 2015 proposed rule.
    We provided notification of these publications and their comment 
periods through email, letters, and news releases faxed and/or mailed 
to the appropriate Federal, State, and local agencies; county 
governments; elected officials; media outlets; local jurisdictions; 
scientific organizations; interested groups; and other interested 
parties.
    In accordance with our peer review policy published in the Federal 
Register on July 1, 1994 (59 FR 34270), we solicited independent 
opinions from at least three knowledgeable individuals who have 
expertise with these fish, who possess a current knowledge of the 
geographic region where the fish occurs, and/or are familiar with the 
principles of conservation biology.
    We reviewed all comments received from peer reviewers and the 
public for substantive issues and new information regarding the 
proposed listing of G. nigra and the G. robusta DPS. Substantive 
comments pertaining to the taxonomy of these fish received during the 
comment period are addressed below. We also received several comments 
from both the public and peer reviewers concerning threats to these 
fish; however, because our withdrawal is due to taxonomic revision such 
comments are outside the scope of this withdrawal.

Peer Review Comments

    (1) Comment: One peer reviewed stated that there are no recent 
(since 2000) publications in the peer-reviewed literature that provide 
evidence that Gila intermedia, G. nigra, and G. robusta are other than 
separate and distinct species. The peer reviewer further stated that 
there are articles that study the genetics or morphology of these fish 
without questioning its taxonomy, specifically Sch[ouml]nhuth et al. 
2014, Sch[ouml]nhuth et al. 2012, and Marsh et al. in press.
    Response: Multiple studies since 2000 provide information on the 
genetic analysis for these fish, including Schwemm 2006, Dowling et al. 
2008 and 2015, and Copus et al. 2016. While these studies may not have 
questioned the taxonomic classification, they also have not been able 
to identify genetic markers that have the ability to distinguish among 
G. robusta, G. nigra, and G. intermedia. Sch[ouml]nhuth et al. (2008, 
p. 213; 2014, p. 223), using mitochondrial and nuclear DNA sequencing, 
found that G. robusta, G. nigra, and G. intermedia were well supported 
as having a common ancestor. Using mitochondrial DNA, Sch[ouml]nhuth et 
al. (2008, p. 213; 2014, p. 223) found that G. robusta, G. nigra, and 
G. intermedia were in one grouping that included a common ancestor and 
all the descendants (living and extinct) of that ancestor (clade), and 
this could reflect incomplete lineage sorting or hybridization. 
However, when nuclear DNA was analyzed, a broader grouping was 
identified that included G. seminuda and G. elegans, but when 
mitochondrial and nuclear DNA results were combined, G. robusta, G. 
nigra, and G. intermedia were alone in one grouping. While Marsh et al. 
(2016, entire) concluded there are two similar but genetically 
distinguishable species in the creek they studied, their findings 
differ somewhat from Schwemm (2006) and Dowling et al. (2008 and 2015, 
entire), who were unable to conclusively identify distinct species 
using genetic markers across a much wider range. Further, the Societies 
conducted a review of the literature and found no evidence to support 
three species. The Service has reviewed the best available scientific 
and commercial data and also found a lack of sufficient evidence to 
support more than one species.
    (2) Comment: Recognized authorities on the taxonomy and ecology of 
these fish recognized these fish as separate species based on 
morphological diagnostics.
    Response: Minckley and DeMarais (2000), Miller et al. (2005), and 
Minckley and Marsh (2009) report identification of three species using 
a diagnostic morphological key. However, additional reports were unable 
to reliably identify these three fish to species using the same 
diagnostic key (Carter et al. 2016, p. 2 and 20, in press; Brandenburg 
2015, entire; Copus et al. 2016, p. 13). Further, Minckley and DeMarais 
(2000, pp. 253-254) stated that G. nigra is morphologically separate 
from G. intermedia, but that G. nigra and G. intermedia appear 
morphologically more similar to one another than either is to G. 
robusta. In addition to issues surrounding morphological 
identification, multiple genetic analysis studies have found 
population-level differences, but have been unable to identify genetic 
markers that have the ability to distinguish among G. robusta, G. 
nigra, and G. intermedia (DeMarais 1992, pp. 2748-2749; Schwemm 2006, 
p. 29; Dowling et al. 2008, p. 2, and 2015, p. 13; Copus et al. 2016, 
pp. 14-15). There are also the findings of Sch[ouml]nhuth et al. 
(2014), Sch[ouml]nhuth et al. (2012) as described in Response to 
Comment 1.
    (3) Comment: Conclusions are mainly based on two ``gray 
literature'' reports that have not undergone peer review (Copus et al. 
2016) or were not available for public consideration (Carter et al. 
2016, in press).
    Response: Section 4(b)(1)(A) of the Act requires the Service to 
make listing or delisting decisions based on the best scientific and 
commercial data available. Further, our Policy on Information Standards 
under the Act

[[Page 16985]]

(July 1, 1994; 59 FR 34271), the Information Quality Act (section 515 
of the Treasury and General Government Appropriations Act for Fiscal 
Year 2001 (Pub. L. 106-554; H.R. 5658)), and our associated Information 
Quality Guidelines (https://www.fws.gov/informationquality), provide 
criteria and, guidance, and establish procedures to ensure that our 
decisions are based on the best scientific data available. They require 
us, to the extent consistent with the Act and with the use of the best 
scientific data available, to use primary and original sources of 
information as the basis for our determinations. Primary or original 
information sources are those that are closest to the subject being 
studied, as opposed to those that cite, comment on, or build upon 
primary sources. The Act and our regulations do not require us to use 
only peer-reviewed literature, but instead they require us to use the 
``best scientific and commercial data available.'' We use information 
from many different sources, including articles in peer-reviewed 
journals, scientific status surveys and studies completed by qualified 
individuals, Master's thesis research that has been reviewed but not 
published in a journal, other unpublished governmental and 
nongovernmental reports, reports prepared by industry, personal 
communication about management or other relevant topics, conservation 
plans developed by States and counties, biological assessments, other 
unpublished materials, experts' opinions or personal knowledge, and 
other sources. For these reasons, we think it is appropriate to include 
review of Copus et al. (2016) and Carter et al. (2016, in press), as 
well as other sources, within our review.
    (4) Comment: Several authors presented data and conclusions that 
conflicted with the previously cited Carter et al. (2016, in press) and 
Copus et al. (2016) reports pertaining to morphological identification, 
DNA analysis, and ecological equivalency to a subset of the Joint 
Committee convened in April 2016, to specifically address the taxonomy 
of the roundtail chub complex.
    Response: We were present at the April 2016 Joint Committee 
webinar, and experts beyond Carter and Copus, such as Brandenburg, 
Schwemm, Dowling, O'Neill, and Chafin, also provided information based 
on research they either had previously conducted or are currently 
conducting on Gila. A complete list of references cited may be obtained 
on the Internet at http://www.regulations.gov and upon request from the 
Arizona Ecological Services Office (see FOR FURTHER INFORMATION 
CONTACT). The Service has reviewed the best available scientific and 
commercial data and found a lack of sufficient evidence to support more 
than one species.
    (5) Comment: This taxonomic dispute is not simply an academic 
exercise of whether to lump or split taxa, because the decision has 
enormous implications for the conservation of imperiled species. 
Multiple experts recommended that the roundtail chub complex, however 
it is constituted, be managed as separate populations or managed as a 
complex.
    Response: The Service recognizes that multiple experts agree that 
conservation actions must be directed at the population level and must 
include consideration of the complex as a whole (Dowling et al. 2008, 
pp. 30-31; Dowling and DeMarais 1993, p. 445; Gerber et al. 2001, p. 
2037; Schwemm 2006, pp. 32-33). However, the Service must adhere to the 
Act and its implementing regulations, which define a ``species'' as any 
species or subspecies of fish, wildlife, or plant, and any distinct 
population segment of any vertebrate species which interbreeds when 
mature (16 U.S.C. 1532(16) and 50 CFR 424.02). The best available 
scientific and commercial data as discussed above in the Taxonomy 
section, support recognition of only one species, Gila robusta. The 
Service's withdrawal of our proposed rule to list the headwater and 
roundtail chub based on new taxonomic classification does not diminish 
the conservation efforts of our partners to conserve this species and 
habitat, nor does our decision affect the State's ability to conserve 
this species under its own authority. The Arizona Game and Fish 
Department recognizes the importance of conserving the currently 
recognized roundtail chub population rangewide (including the formerly 
known headwater chub and Gila chub) and is committed to the 
conservation agreements and practices that have been in place since 
2006 (AGFD 2017, entire; AGFD 2006, entire).
    (6) Comment: Multiple commenters raised concerns with Copus et al. 
(2016) methods and conclusions, particularly small sample size, lack of 
key analytical and laboratory steps, the study's DNA sequence data 
filtering and analyses that failed to follow best practices for 
phylogenetic analysis, and specimen shrinkage associated with duration 
of preservation impacting morphological diagnostics.
    Response: The Service did not rely solely on Copus et al. 2016. We 
considered the best available commercial and scientific data; you may 
obtain a complete list of references cited on the Internet at http://www.regulations.gov and upon request from the Arizona Ecological 
Services Office (see FOR FURTHER INFORMATION CONTACT). In regards to 
the mitochondrial DNA and phylogenetic analysis, Copus et al.'s 
findings are consistent with Sch[ouml]nhuth et al.'s (2014) and 
Sch[ouml]nhuth et al.'s (2012) mitochondrial DNA and phylogenetic 
analysis. In addition, multiple genetic analysis studies have been 
conducted that indicate population-level differences, but do not 
identify genetic markers that have the ability to distinguish among G. 
robusta, G. nigra, and G. intermedia (DeMarais 1992, pp. 2748-2749; 
Schwemm 2006, p. 29; Dowling et al. 2008, p. 2, and 2015, p. 13).
    In regards to morphological diagnostic errors due to using 
preserved specimens, Copus et al. (2016) did use preserved specimens. 
However, they also analyzed fresh material and concluded that no single 
diagnostic character can be used for species identification, and with 
considerable overlap among species in every morphological character, no 
suite of characters can distinguish species unambiguously (Copus et al. 
2016, p. 13). Brandenburg et al. (2015, entire) also reported overlap 
in the meristic and morphometric characteristics, records of many 
individual fish with intermediate physical characteristics, and even 
those characters that do not overlap are separated by very small 
margins making species-level identification of individual fish 
problematic, even when the geographic origin of the species is known.

Public Comments

    (7) Comment: Multiple commenters requested various listing 
alternatives under the Act including: List G. robusta as threatened and 
encompass all populations of the chub complex within the Gila basin 
requiring a revision of the recovery plan, list G. robusta and G. nigra 
as threatened and retain the current endangered species status of G. 
intermedia, list G. robusta as threatened and retain the current 
endangered species status of G. intermedia, or other combinations.
    Response: The Service must adhere to the Act and its implementing 
regulations, which define a ``species'' as any species or subspecies of 
fish, wildlife, or plant, and any distinct population segment of any 
vertebrate species which interbreeds when mature (16 U.S.C. 1532(16) 
and 50 CFR 424.02), and based on our review, the best available 
scientific and commercial data

[[Page 16986]]

support recognition of only one species, Gila robusta. As the headwater 
chub and roundtail chub DPS no longer meet the definition of a 
``species'' under the Act, we must withdraw our proposed rule to list 
them as threatened species.
    (8) Comment: Multiple commenters stated that there is a great 
amount of morphological overlap among counts and measures for these 
chub taxa and that this has long been recognized. If a taxonomic key is 
not 100 percent correct, that does not necessarily mean that these are 
not taxa that are biologically distinct at the specific level. A test 
of the key would require the a priori identification of each individual 
to species. Rather than dismiss the species' taxonomic status, 
biologists should be working to make a better key that can be used in 
the field for the effective identification and management of the 
species.
    Response: We recognize that diagnostic keys do not produce correct 
results all the time, whether due to human error or morphological 
similarities among purported species. However, Copus et al. (2016, p. 
13) concluded that, based on genetic analysis, no single diagnostic 
character can be used for species identification, and with considerable 
overlap among species in every morphological character, no suite of 
characters can distinguish species unambiguously. Brandenburg et al. 
(2015, entire) also reported overlap in the meristic and morphometric 
characteristics, and there are many individual fish whose morphology 
resides on an intermediate spectrum, and even those characters that do 
not overlap are separated by very small margins, making species-level 
identification of individual fish problematic, even if the geographic 
origin of the species is known. In regards to a priori identification 
of fish, assignment to species has been based on the stream in which 
the fish occurs (Minckley and DeMarais 2000, p. 252), so the 
identification of the fish that occurs in each stream is assumed to be 
known. Consequently, there exists the ability to compare findings from 
the diagnostic key to the fish within a particular stream. An updated 
key may be prudent; however, the Service must use the best available 
scientific and commercial data available, and we have concluded from 
our review that the data currently support only one species, Gila 
robusta. Further, given the overlap in diagnostic characteristics, the 
development of a valid key seems unlikely.
    (9) Comment: Multiple commenters stated that it has long been 
hypothesized that G. nigra formed as the result of hybridization 
between the other two taxa, so we would expect the greatest 
morphological overlap from that species with the other two taxa. The 
question then becomes, is G. nigra continuing to differentiate from 
ancestral G. robusta? When in sympatry, G. nigra and G. robusta are 
becoming increasingly reproductively isolated from one another (Desert 
Fishes Council meeting, Dowling et al. 2016).
    Response: We recognize that multiple studies have indicated that 
hybridization has occurred among G. intermedia and G. robusta resulting 
in G. nigra and that continuing evolution may occur (Schwemm 2006; 
Dowling et al. 2008, entire). However, there has also been information 
presented showing no evidence of the hybrid origin of G. nigra, and 
that G. intermedia and G. nigra evolved separately in non-overlapping 
areas (parapatry) (Chafin 2016, entire). In addition, past research 
(Dowling et al. 2008, 2015; Schwemm 2006) indicate that there is more 
variation among populations and unique genetics within specific 
populations (streams).
    (10) Comment: If only G. robusta and G. intermedia are evaluated, 
there is no question that they would be considered distinct 
morphological species.
    Response: Carter et al. (2016, in press) found that the physical 
characteristics did not reliably differentiate among G. robusta, G. 
intermedia, and G. nigra. In addition, Brandenburg et al. (2015, pp. 8-
9) found physically similarity of the three species, as numerous 
individuals exhibited intermediate characters along the species 
gradient. The discriminant function analysis (a statistical analysis 
tool to determine which variables discriminate between two or more 
naturally occurring groups) classified only 16 percent (n = 42) of G. 
intermedia (the fewest) while the majority of the samples were 
classified as G. robusta (53.2 percent, n = 140), which indicates that 
the ability to classify these fish correctly to G. intermedia or G. 
robusta based on physical characteristics was low. Due to the complex 
genetic makeup and observable characteristics or traits (i.e., physical 
appearance, behavior, or physiology) of these species, there are some 
stream locations where we do not know where the geographic overlap of 
headwater, roundtail, and, in some cases Gila chub, begins and ends, 
because of the plasticity of observable characteristics or traits of 
these fish within individual streams. Our review of the data does 
indicate that there are differences in observable characteristics or 
traits between the fish in different streams, but the Societies' 
review, as well as the Service review, of the best available scientific 
and commercial data did not result in a species-level differentiation 
between G. robusta and G. intermedia, or among G. robusta, G. 
intermedia, and G. nigra.
    (11) Comment: One commenter recommend that we proceed with an 
amended recovery plan to list the status of this species as threatened 
under the Act. The listing of this species is necessary even if all 
populations of G. intermedia and G. nigra are subsumed into G. robusta.
    Response: An assessment of the entire range of the new taxonomic 
group of roundtail chub is planned. We are initiating a status review 
of the new taxonomic entity in 2 to 4 years. Following that review, we 
will take action as appropriate.

Determinations

    An entity may only be listed under the Act if that entity meets the 
Act's definition of a species. The recent report by the Societies 
indicates that neither the headwater chub nor the roundtail chub can be 
considered species, as defined by the Act. Under section 3 of the Act 
(16 U.S.C. 1532(16)) and associated implementing regulations at 50 CFR 
424.02, a ``species'' is defined to include any species or subspecies 
of fish, wildlife, or plant, and any distinct population segment of any 
vertebrate species which interbreeds when mature. The Act's 
implementing regulations at 50 CFR 424.11(a) and the Service Director's 
November 25, 1992, ``Taxonomy and the Endangered Species Act'' 
Memorandum (Memo) provide additional guidance on how to consider 
taxonomic information when assessing a species for listing under the 
Act. The regulations at 50 CFR 424.11(a) state, ``In determining 
whether a particular taxon or population is a species for the purposes 
of the Act, the Secretary [of the Interior] shall rely on standard 
taxonomic distinction and the biological expertise of the Department 
[of the Interior] and the scientific community concerning the relevant 
taxonomic group.'' The Director's Memo specifies that the Service is 
``required to exercise a degree of scientific judgment regarding the 
acceptance of taxonomic interpretations, particularly when more than 
one possible interpretation is available. The Memo further states, 
``When informed taxonomic opinion is not unanimous, we evaluate 
available published and unpublished information and come to our own 
adequately documented conclusion regarding the validity of taxa.''
    The Act requires that we finalize, modify, or withdraw the proposed 
rule

[[Page 16987]]

within 12 months. The Act provides for one 6-month extension for 
scientific uncertainty, which we have used. As such, we are required to 
make a decision regarding the entities' eligibility for listing at this 
time. In addition, section 4(b)(1)(A) of the Act requires the Service 
to make listing or delisting decisions based on the best scientific and 
commercial data available. Further, our Policy on Information Standards 
under the Act (July 1, 1994; 59 FR 34271), the Information Quality Act 
(section 515 of the Treasury and General Government Appropriations Act 
for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), and our associated 
Information Quality Guidelines (https://www.fws.gov/informationquality), provide criteria, guidance, and establish 
procedures to ensure that our decisions are based on the best 
scientific data available. They require us, to the extent consistent 
with the Act and with the use of the best scientific data available, to 
use primary and original sources of information as the basis for 
recommendations. Primary or original information sources are those that 
are closest to the subject being studied, as opposed to those that 
cite, comment on, or build upon primary sources. The Act and our 
regulations do not require us to use only peer-reviewed literature, but 
instead they require us to use the ``best scientific and commercial 
data available.'' We use information from many different sources, 
including articles in peer-reviewed journals, scientific status surveys 
and studies completed by qualified individuals, Master's thesis 
research that has been reviewed but not published in a journal, other 
unpublished governmental and nongovernmental reports, reports prepared 
by industry, personal communication about management or other relevant 
topics, conservation plans developed by States and counties, biological 
assessments, other unpublished materials, experts' opinions or personal 
knowledge, and other sources.
    We conducted a similar internal review of the information presented 
by and available to the Societies in their review. Our review primarily 
focused on Marsh et al. (2016), Carter et al. (2016, in press), Copus 
et al. (2016), Minckley and DeMarais (2000), and Chafin et al. (2015), 
as well as other literature as discussed above in the Taxonomy section. 
In their most recent publication of Common and Scientific Names of 
Fishes (Page et al. 2013, p. 8), the Societies state the following 
regarding the common process of their naming committee: ``In accepting 
species as valid from various works, we made little or no judgment on 
authors' species concepts. Taxa of uncertain status were dealt with on 
a case-by-case basis.'' Based on the Societies' expertise and their 
internal guidance (stated above) on making such decisions, we conclude 
that the preponderance of evidence before them was clear and decisive 
enough to make a taxonomic change.
    After reviewing the best available scientific and commercial 
information (as described above in the Taxonomy section and summarized 
below) and applying statutory and regulatory guidance, we determined 
that the Societies' report considered the best commercial and 
scientific data available. We agree with the conclusion that available 
data support recognition of only one species, Gila robusta. Our 
determination is based on various factors, including the method of 
original assignment to species, hybridization events, conflicting 
identification of species based on morphology versus genetics, 
evolutionary history, morphological identification limitations, and 
lack of genetic markers to identify species. We lack confidence in the 
initial species assignments to G. robusta, G. nigra, and G. intermedia 
due to the scientific methods used (fish were assigned to a species 
based on the stream in which they occurred, the erroneous assumption 
that these fish did not overlap geographically, and the absence of 
genetic or morphological diagnostic information). Minckley and DeMarais 
(2000, entire) based their diagnostic key on the assumption that none 
of these species occurs in the same locality; however, they acknowledge 
hybridization among G. robusta and G. intermedia. Further, other 
studies have found that fish designated as G. robusta, G. nigra, and G. 
intermedia overlap geographically or occur adjacent to one another 
(Dowling and Marsh 2009, p. 1; Marsh et al. 2016, p. 57; Brandenburg et 
al. 2015, p. 18). In addition, some populations appeared to conflict 
genetically with the species-level assignment based on morphology 
(Dowling et al. 2015, pp. 14-15). Multiple scientists (as described 
above) found Minckley and DeMarais's (2000, entire) key for 
identification of G. robusta, G. nigra, and G. intermedia to not 
reliably differentiate among these three fish. In Fossil Creek, Marsh 
et al. (2016, entire) concluded there are two morphologically similar, 
but genetically distinguishable chub. However, there are several 
genetic analysis studies indicating population-level differences among 
these fish, but the studies were not able to identify genetic markers 
distinguishing between the three fish. Finally, Sch[ouml]nhuth et al. 
(2014, p. 223) found that G. robusta, G. nigra, and G. intermedia were 
in one grouping that included a common ancestor and all the descendants 
(living and extinct) of that ancestor (clade), and hypothesized this 
could reflect incomplete lineage sorting or hybridization, but this was 
not studied.
    For the purposes of our determination, we accept the ``single 
species'' finding by the Societies described above and, consequently, 
withdraw the proposed rule to list the headwater chub (Gila nigra) and 
a DPS of the roundtail chub (Gila robusta) from the lower Colorado 
River basin as threatened species under the Act. This withdrawal is 
based on a thorough review of the best scientific and commercial data 
available, which indicate that the headwater chub and the DPS of the 
roundtail chub are not discrete taxonomic entities and do not meet the 
definition of species under the Act. These fish are now recognized as a 
single taxonomic species--the roundtail chub (Gila robusta). Because 
the entities previously proposed for listing are no longer recognized 
as species, as defined by the Act, we have determined that they are not 
listable entities, and we are withdrawing our proposed rule to list.

Future Actions

    Following the publication of this withdrawal, we intend to 
reevaluate the status of the Gila chub (currently listed as endangered) 
in the near future and initiate a range-wide species status assessment 
(SSA) of the newly-recognized roundtail chub (Gila robusta).

References Cited

    A complete list of references cited in this document is available 
on the Internet at http://www.regulations.gov and upon request from the 
Arizona Ecological Services Office (see FOR FURTHER INFORMATION 
CONTACT).

Authors

    The primary authors of this document are the staff members of the 
Arizona Ecological Services Office.

Authority

    The authority for this action is section 4(b)(6)(B)(ii) of the 
Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.)


[[Page 16988]]


    Dated: March 21, 2017.
James W. Kurth,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2017-06995 Filed 4-6-17; 8:45 am]
 BILLING CODE 4333-15-P



                                                                            Federal Register / Vol. 82, No. 66 / Friday, April 7, 2017 / Proposed Rules                                                 16981

                                                 online instructions for submitting                        Dated: March 22, 2017.                               Section, Air Planning and
                                                 comments. Once submitted, comments                      Robert A. Kaplan,                                      Implementation Branch, Air, Pesticides
                                                 cannot be edited or removed from                        Acting Regional Administrator, Region 5.               and Toxics Management Division, U.S.
                                                 Regulations.gov. For either manner of                   [FR Doc. 2017–06883 Filed 4–6–17; 8:45 am]             Environmental Protection Agency,
                                                 submission, EPA may publish any                         BILLING CODE 6560–50–P                                 Region 4, 61 Forsyth Street SW.,
                                                 comment received to its public docket.                                                                         Atlanta, Georgia 30303–8960. Mr. Akers
                                                 Do not submit electronically any                                                                               can be reached via telephone at (404)
                                                 information you consider to be                          ENVIRONMENTAL PROTECTION                               562–9089 or via electronic mail at
                                                 Confidential Business Information (CBI)                 AGENCY                                                 akers.brad@epa.gov.
                                                 or other information whose disclosure is                                                                       SUPPLEMENTARY INFORMATION: In the
                                                 restricted by statute. Multimedia                       40 CFR Part 52                                         Final Rules section of this Federal
                                                 submissions (audio, video, etc.) must be                [EPA–R04–OAR–2016–0575; FRL–9960–56–                   Register, EPA is approving the State’s
                                                 accompanied by a written comment.                       Region 4]                                              SIP revision as a direct final rule
                                                 The written comment is considered the                                                                          without prior proposal because the
                                                 official comment and should include                     Air Plan Approval; Tennessee:                          Agency views this as a noncontroversial
                                                 discussion of all points you wish to                    Reasonable Measures Required                           submittal and anticipates no adverse
                                                 make. EPA will generally not consider                                                                          comments. A detailed rationale for the
                                                                                                         AGENCY:  Environmental Protection
                                                 comments or comment contents located                                                                           approval is set forth in the direct final
                                                                                                         Agency.
                                                 outside of the primary submission (i.e.                                                                        rule. If no adverse comments are
                                                                                                         ACTION: Proposed rule.
                                                 on the web, cloud, or other file sharing                                                                       received in response to this rule, no
                                                 system). For additional submission                      SUMMARY:    The Environmental Protection               further activity is contemplated. If EPA
                                                 methods, please contact the person                      Agency (EPA) is proposing to approve a                 receives adverse comments, the direct
                                                 identified in the FOR FURTHER                           State Implementation Plan (SIP)                        final rule will be withdrawn and all
                                                 INFORMATION CONTACT section. For the                    revision submitted by the State of                     public comments received will be
                                                 full EPA public comment policy,                         Tennessee, through the Tennessee                       addressed in a subsequent final rule
                                                 information about CBI or multimedia                     Department of Environment and                          based on this proposed rule. EPA will
                                                 submissions, and general guidance on                    Conservation (TDEC), on March 25,                      not institute a second comment period
                                                 making effective comments, please visit                 1999. The SIP submittal includes a                     on this document. Any parties
                                                 http://www2.epa.gov/dockets/                            change to the TDEC regulation                          interested in commenting on this
                                                 commenting-epa-dockets.                                 ‘‘Reasonable Measures Required.’’ EPA                  document should do so at this time.
                                                 FOR FURTHER INFORMATION CONTACT: Matt                   is proposing to approve this SIP revision                Dated: March 15, 2017.
                                                 Rau, Environmental Engineer, Control                    because it is consistent with the Clean
                                                                                                                                                                V. Anne Heard,
                                                 Strategies Section, Air Programs Branch                 Air Act and federal regulations
                                                 (AR–18J), Environmental Protection                      governing SIPs.                                        Acting Regional Administrator, Region 4.
                                                 Agency, Region 5, 77 West Jackson                                                                              [FR Doc. 2017–06878 Filed 4–6–17; 8:45 am]
                                                                                                         DATES: Written comments must be
                                                 Boulevard, Chicago, Illinois 60604,                     received on or before May 8, 2017.                     BILLING CODE 6560–50–P
                                                 (312) 886–6524, rau.matthew@epa.gov.                    ADDRESSES: Submit your comments,
                                                 SUPPLEMENTARY INFORMATION: In the                       identified by Docket ID No. EPA–R04–
                                                 Final Rules section of this Federal                     OAR–2016–0575 at http://                               DEPARTMENT OF THE INTERIOR
                                                 Register, EPA is approving the State’s                  www.regulations.gov. Follow the online
                                                 SIP submittal as a direct final rule                    instructions for submitting comments.                  Fish and Wildlife Service
                                                 without prior proposal because the                      Once submitted, comments cannot be
                                                 Agency views this as a noncontroversial                 edited or removed from Regulations.gov.                50 CFR Part 17
                                                 submittal and anticipates no adverse                    EPA may publish any comment received                   [Docket No. FWS–R2–ES–2015–0148;
                                                 comments. A detailed rationale for the                  to its public docket. Do not submit                    4500030113]
                                                 approval is set forth in the direct final               electronically any information you
                                                 rule. If no adverse comments are                        consider to be Confidential Business                   RIN 1018–BA86
                                                 received in response to this rule, no                   Information (CBI) or other information
                                                                                                                                                                Endangered and Threatened Wildlife
                                                 further activity is contemplated. If EPA                whose disclosure is restricted by statute.
                                                                                                                                                                and Plants; Threatened Species Status
                                                 receives adverse comments, the direct                   Multimedia submissions (audio, video,
                                                                                                                                                                for the Headwater Chub and Roundtail
                                                 final rule will be withdrawn and all                    etc.) must be accompanied by a written
                                                                                                                                                                Chub Distinct Population Segment
                                                 public comments received will be                        comment. The written comment is
                                                 addressed in a subsequent final rule                    considered the official comment and                    AGENCY:   Fish and Wildlife Service,
                                                 based on this proposed rule. EPA will                   should include discussion of all points                Interior.
                                                 not institute a second comment period.                  you wish to make. EPA will generally                   ACTION: Proposed rule; withdrawal.
                                                 Any parties interested in commenting                    not consider comments or comment
                                                 on this action should do so at this time.               contents located outside of the primary                SUMMARY:   We, the U.S. Fish and
                                                 Please note that if EPA receives adverse                submission (i.e., on the web, cloud, or                Wildlife Service (Service), withdraw the
                                                 comment on an amendment, paragraph,                     other file sharing system). For                        proposed rule to list the headwater chub
                                                 or section of this rule and if that                     additional submission methods, the full                (Gila nigra) and a distinct population
nlaroche on DSK30NT082PROD with PROPOSALS




                                                 provision may be severed from the                       EPA public comment policy,                             segment (DPS) of the roundtail chub
                                                 remainder of the rule, EPA may adopt                    information about CBI or multimedia                    (Gila robusta) from the lower Colorado
                                                 as final those provisions of the rule that              submissions, and general guidance on                   River basin as threatened species under
                                                 are not the subject of an adverse                       making effective comments, please visit                the Endangered Species Act (Act). This
                                                 comment. For additional information,                    http://www2.epa.gov/dockets/                           withdrawal is based on a thorough
                                                 see the direct final rule which is located              commenting-epa-dockets.                                review of the best scientific and
                                                 in the Rules section of this Federal                    FOR FURTHER INFORMATION CONTACT: D.                    commercial data available, which
                                                 Register.                                               Brad Akers, Air Regulatory Management                  indicate that the headwater chub and


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                                                 16982                      Federal Register / Vol. 82, No. 66 / Friday, April 7, 2017 / Proposed Rules

                                                 the roundtail chub DPS are not discrete                 these species, please refer to the October             Rinne 1969; Holden and Stalnaker 1970;
                                                 taxonomic entities and do not meet the                  7, 2015, proposed listing rule (80 FR                  Rinne 1976; Smith et al. 1977; DeMarais
                                                 definition of a species under the Act.                  60754).                                                1986; Rosenfeld and Wilkinson 1989;
                                                 These fish are now recognized as a part                                                                        Dowling and DeMarais 1993; Douglas et
                                                                                                         Background
                                                 of a single taxonomic species—the                                                                              al. 1998; Minckley and DeMarais 2000;
                                                 roundtail chub (Gila robusta). Because                     At the time we published our                        Gerber et al. 2001). As noted by nearly
                                                 the entities previously proposed for                    proposed rule (October 7, 2015; 80 FR                  all researchers investigating the
                                                 listing are no longer recognized as                     60754), the Committee on Names of                      systematics of Gila spp., the taxonomic
                                                 species, as defined by the Act, we have                 Fishes, a joint committee of the                       situation is complicated and
                                                 determined that they are not listable                   American Fisheries Society and                         problematic (Holden and Stalnaker
                                                 entities and we are withdrawing our                     American Society of Ichthyologists and                 1970; Minckley 1973; Minckley and
                                                 proposed rule to add them to the List of                Herpetologists (the Societies) (Page et al.            DeMarais 2000; Gerber et al. 2001;
                                                 Endangered and Threatened Wildlife.                     2013, p. 71), considered headwater chub                Schönhuth et al. 2014) due to various
                                                    Section 4(b)(6) of the Act and                       and roundtail chub to be separate                      factors including multiple independent
                                                 implementing regulations at 50 CFR                      species. As a consortium of fisheries                  hybridization events over time (Rinne
                                                 424.17 provide that the Service must,                   scientists, the American Fisheries                     1976; DeMarais 1986; Rosenfeld and
                                                 within 1 year of a proposed rule to list,               Society is the recognized and accepted                 Wilkinson 1989; DeMarais et al. 1992;
                                                 delist, or reclassify species, or to                    scientific authority on fish taxonomy.                 Dowling and DeMarais 1993; Minckley
                                                 designate or revise critical habitat,                   Accordingly, our proposed rule assessed                and DeMarais 2000; Gerber et al. 2001;
                                                 withdraw the proposal if the available                  the headwater chub and roundtail chub                  Schwemm 2006; Schönhuth et al. 2014;
                                                 evidence does not justify the proposed                  as separate species. However,                          Brandenburg et al. 2015,) potential past
                                                 action. The document withdrawing the                    commenters on our proposed rule raised                 introgression (the transfer of genetic
                                                 rule must set forth the basis upon which                questions during the public comment                    information from one species to another
                                                 the proposed rule has been found not to                 period regarding the taxonomic                         as a result of hybridization between
                                                 be supported by available evidence.                     distinctness of the headwater and                      them and repeated backcrossing)
                                                 Once withdrawn, the action may not be                   roundtail chubs, as related to the Gila                (DeMarais et al. 1992; Minckley and
                                                 re-proposed unless sufficient new                       chub (Gila intermedia). At that time,                  DeMarais 2000), recent divergence
                                                 information is available.                               some scientists knowledgeable about the                within the three fish (Schwemm 2006).
                                                 FOR FURTHER INFORMATION CONTACT:                        fish contended that the three entities                 Further, the original assignment to
                                                                                                         were not separate species (Carter et al.               species was based on the assumption
                                                 Steve Spangle, Field Supervisor, U.S.
                                                                                                         2016 in press; Copus et al. 2016). For                 that the three fish do not overlap
                                                 Fish and Wildlife Service, Arizona
                                                                                                         this reason, the Arizona Game and Fish                 geographically (parapatry), which we
                                                 Ecological Services Office, 9828 North
                                                                                                         Department requested that the Societies                recognize now is not an accurate
                                                 31st Ave., #C3, Phoenix, AZ 85051–
                                                                                                         evaluate the most recent literature                    assumption. Additionally, in some
                                                 2517; telephone 602–242–0210. Persons
                                                                                                         associated with roundtail chub,                        instances when the same fish was
                                                 who use a telecommunications device
                                                                                                         headwater chub, and Gila chub                          identified based on morphology
                                                 for the deaf (TDD) may call the Federal
                                                                                                         taxonomy. In their final report to the                 (physical characteristics) it was
                                                 Relay Services at 800–877–8339.
                                                                                                         Arizona Game and Fish Department, the                  identified as one species and when
                                                 SUPPLEMENTARY INFORMATION:                                                                                     identified based on genetic analysis it
                                                                                                         Societies panel concluded that ‘‘no
                                                 Previous Federal Action                                 morphological or genetic data define                   was identified as a different species
                                                                                                         populations of Gila in the lower                       (Dowling et al. 2015, pp. 14–15). Recent
                                                    On October 7, 2015 (80 FR 60754), we                                                                        and ongoing genetic and morphologic
                                                 published a proposed rule to list the                   Colorado River basin (which, as defined
                                                                                                         by the Service, includes the Little                    analyses of chubs in the Gila River basin
                                                 headwater chub and the lower Colorado                                                                          continue to yield conflicting results
                                                 River basin roundtail chub DPS                          Colorado River, Bill Williams River,
                                                                                                         Gila River, Verde River, and Salt River                (DeMarais et al. 1992; Schwemm 2006;
                                                 (roundtail chub DPS) as threatened                                                                             Dowling et al. 2008 and 2015;
                                                 species under the Act (16 U.S.C. 1531 et                drainages) as members of more than one
                                                                                                         species’’ and ‘‘that the data available                Schönhuth et al. 2014; Marsh et al.
                                                 seq.). On August 15, 2016 (81 FR                                                                               2016, all entire).
                                                 54018), we announced a 6-month                          support recognition of only one species
                                                 extension on the final listing                          of Gila, the roundtail chub, Gila                      History
                                                 determination that the Act allows when                  robusta’’ (Page et al. 2016, p. 1). These
                                                                                                                                                                  Gila robusta (roundtail chub) was first
                                                 there is substantial disagreement                       three fish are now considered by the
                                                                                                                                                                described by Baird and Girard (1853, p.
                                                 regarding the sufficiency or accuracy of                Societies to be a single species,
                                                                                                                                                                365–369) from specimens collected in
                                                 the available data, and reopened the                    roundtail chub (Gila robusta) because
                                                                                                                                                                1851 from the Zuni River (tributary to
                                                 comment period on the proposed                          data do not support recognition of three               Little Colorado River). Gila nigra
                                                 listings for 30 days. During this                       species.                                               (headwater chub; formerly known as G.
                                                 comment period we received new                          Taxonomy                                               robusta graham or G. grahami) was first
                                                 information. On November 1, 2016 (81                                                                           described as a subspecies (G. robusta
                                                 FR 75801), we reopened the comment                      Introduction                                           graham) from Ash Creek in the San
                                                 period on the proposed listings for an                    The taxonomic history of the genus                   Carlos River in east-central Arizona in
                                                 additional 45 days to provide the public                Gila in the Colorado River basin has                   1874 (Cope and Yarrow 1875, p. 663),
nlaroche on DSK30NT082PROD with PROPOSALS




                                                 additional time to review and consider                  changed over time, especially for the                  but not returned to full species status
                                                 the proposed rulemakings in light of                    three forms (roundtail, headwater, and                 (G. robusta) until proposed so by
                                                 this new information. As a result of the                Gila chub) found in the Gila River basin.              Minckley and DeMarais (2000, p.
                                                 6-month extension, the deadline to                      These forms have been variously                        entire). The Societies accepted Gila
                                                 finalize, modify, or withdraw the                       classified as full species, assigned as                nigra as a full species (Nelson et al.
                                                 proposed rule is April 7, 2017.                         different species, subspecies of Gila                  2004, p. 71), as did the New Mexico
                                                    For a description of additional                      robusta, or as part of a ‘‘Gila robusta                Department of Game, Fish (Carman
                                                 previous Federal actions concerning                     complex’’ (Miller 1945; Holden 1968;                   2006, p. 3), Arizona Game, and Fish


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                                                                            Federal Register / Vol. 82, No. 66 / Friday, April 7, 2017 / Proposed Rules                                           16983

                                                 Department (AGFD 2006, p. 3) and                        254) indicate that G. nigra is physically              as separate non-overlapping (allopatric)
                                                 continued to recognize G. robusta as a                  different from G. intermedia even                      morphological species. In addition,
                                                 distinct species. Therefore, based on the               though they appear physically more                     some populations assigned to species
                                                 best available commercial and scientific                similar to one another than either is to               based on genetics appeared to conflict
                                                 data the Service accepted both Gila                     G. robusta. In addition, Copus et al.                  with the species level-assignment based
                                                 robusta and Gila nigra as full species as               (2016, p. 13) did not find physical                    on morphology (Dowling et al. 2008, p.
                                                 documented in our 12-month findings                     characteristics in the Minckley and                    27).
                                                 (May 3, 2006; 71 FR 26007 and July 7,                   DeMarais (2000, pp. 254–255)
                                                                                                                                                                Speciation
                                                 2009; 74 FR 32352). In their 2013                       classification key to reliably
                                                 publication of Common and Scientific                    differentiate G. robusta, G. nigra, and G.                Minckley and DeMarais (2000, p. 253)
                                                 Names of Fishes from the United States,                 intermedia from one another. Copus et                  describe three different taxonomic
                                                 Canada, and Mexico, the Societies                       al. (2016 p. 16) concluded that there was              options for chubs in the Gila River
                                                 continued to list both Gila robusta and                 no morphological basis for taxonomic                   basin: a single species with many
                                                 Gila nigra as distinct species (Page et al.             distinctions within the Gila spp.                      different forms or stages (polymorphic
                                                 2013, p. 71). A summary of the historic                 complex.                                               species), a species containing multiple
                                                 and current nomenclature from Rinne                                                                            subspecies, or three full species. They
                                                                                                         Genetics                                               acknowledge that none of these
                                                 (1976, entire), Sublette et al. (1990,
                                                 entire), and Minckley and DeMarais                         Multiple genetic analysis studies have              taxonomic options is biologically
                                                 (2000, entire) is summarized in Voeltz                  been conducted that reveal differences                 justified without knowing if these fish
                                                 (2002, pp. 8) and Copus et al. (2016, pp.               between different chub populations, but                naturally occur in the same geographic
                                                 1&6). The Gila chub (Gila intermedia) is                have been unable to identify differences               area (sympatry, indicating an initial
                                                 currently listed as an endangered                       between G. robusta, G. nigra, and G.                   interbreeding population that split), or
                                                 species (November 2, 2005; 70 FR                        intermedia (DeMarais et al. 1992, pp.                  occur immediately adjacent to each
                                                 66664).                                                 2748–2749; Schwemm 2006, p. 29;                        other but not significantly overlapping
                                                    These entities were originally                       Dowling et al. 2008, p. 2, and 2015, p.                (parapatry, indicating there is no barrier
                                                 classified based on the streams in which                13; Copus et al. 2016, pp. 14–15; Marsh                to gene flow). They further acknowledge
                                                 they were found (Minckley and                           et al, 2016, p.58). Mitochondrial DNA                  that a persistent narrow interaction zone
                                                 DeMarais 2000, p. 252), under the                       analysis (Schönhuth et al. 2014, p. 223)              (parapatry, indicating there is no barrier
                                                 assumption that G. robusta and G. nigra                 indicates that G. robusta, G. nigra, and               to gene flow) of morphologically
                                                 either did not overlap (allopatric, no                  G. intermedia belong to one clade (a                   distinguishable G. robusta, G.
                                                 gene flow) or there was only a narrow                   grouping that includes a common                        intermedia, and G. nigra has been
                                                 overlap (parapatric; limited interaction                ancestor and all its descendants, living               confirmed, but note that in no instance
                                                 and opportunity for gene flow)                          and extinct, of that ancestor).                        was any two of the three caught at the
                                                 (Minckley and DeMarais 2000 pp. 252–                    Schönhuth et al. (2014, p. 223)                       same locality (allopatric, no gene flow;
                                                 254). Because hybridization between G.                  hypothesized that this could reflect                   p. 251). However, they also
                                                 robusta and G. intermedia indicates that                hybridization or incomplete lineage                    acknowledge that hybridization
                                                 these fish must co-occur in some                        sorting (when the lineage of a specific                (between G. robusta and G. intermedia,
                                                 streams (Minckley and DeMarais 2000,                    gene is not the same as the lineage of the             resulting in G. nigra) in the past must
                                                 entire), we conclude that Minckley and                  species, obscuring the true species                    have occurred in some places and not
                                                 DeMarais’s (2000) assumption they did                   relationship).                                         others, thereby demonstrating
                                                 not overlap was unfounded. Further,                        However, when nuclear DNA (rather                   occurrence in the same geographic area
                                                 other studies have found that fish                      than mitochondrial DNA) was analyzed,                  (sympatry) (p. 253). They conversely
                                                 designated as G. robusta, G. nigra, and                 a broader grouping was identified that                 hypothesized that the current minimal
                                                 G. intermedia overlap geographically or                 included G. seminude and G. elegans,                   overlap in an area where species are
                                                 occur adjacent to one another (Dowling                  but when mitochondrial and nuclear                     adjacent (parapatry, indicating there is
                                                 and Marsh 2009, p. 1; Marsh et al. 2016,                DNA results are combined G. robusta, G.                no barrier to gene flow) may thus reflect
                                                 p. 57; Brandenburg et al. 2015, p. 18).                 nigra, and G. intermedia were in one                   an ancestral ecological segregation area
                                                                                                         grouping (Schönhuth et al. 2014, p.                   (sympatry, indicating an initial
                                                 Morphology                                              223). Preliminary studies by Chafin et                 interbreeding population that split due
                                                    The approach for classifying G.                      al. (2016) indicate evolutionary                       to the use of different habitats and
                                                 robusta, G. nigra, and G. intermedia                    independent lineages for G. robusta, G.                resources) that promoted persistence in
                                                 developed by Minckley and DeMarais                      nigra, and G. intermedia, and that the                 the ever-increasing aridity of the
                                                 (2000, pp. 254–255) presumes there is                   hybrid origin of G. nigra is not                       Southwest (p. 253).
                                                 little intraspecific variation (differences             supported. Studies by Marsh et al.                        In Fossil Creek, G. nigra and G.
                                                 within a species) in the morphologic                    (2016, entire) point to genetic variation              robusta appear to be sympatric,
                                                 and meristic (counting quantitative                     between populations of G. robusta and                  including hybrids between G. robusta
                                                 characteristics such as fins)                           G. nigra, and demonstrate evidence that                and G. nigra (Marsh et al. 2016, p. 57).
                                                 characteristics used to distinguish these               distinct ecological differences between                Brandenburg et al. (2015, p. 18)
                                                 three taxa. However, the three purported                some populations are now thought to                    concluded that the morphological
                                                 species overlap in physical                             exist. Minckley and DeMarais (2000,                    assessment of Gila spp. in New Mexico
                                                 characteristics, and many fish have                     entire) supported recognition of three                 confirmed that the three fish were found
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                                                 intermediate physical characteristics.                  species, but acknowledged that most                    in the same geographic area (sympatric)
                                                 Those characteristics that do not overlap               genetic variation was within                           in almost all cases, contradicting
                                                 are separated by very small margins,                    populations for G. robusta, and was                    Minckley and DeMarais’ results (2000,
                                                 making species-level identification of                  among populations for G. intermedia                    p. 251) as well as other previous
                                                 individual fish problematic, even when                  and G. nigra. Minckley and DeMarais                    literature suggesting that these Gila spp.
                                                 the geographic origin of the species is                 (2000, p. 253) also indicated that these               are occurring in separate non-
                                                 known (Brandenburg 2015, entire).                       three fishes share genetic features (that              overlapping geographical areas
                                                 Minckley and DeMarais (2000, pp. 253–                   had been studied so far) while behaving                (allopatric) through their ranges (Rinne


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                                                 16984                      Federal Register / Vol. 82, No. 66 / Friday, April 7, 2017 / Proposed Rules

                                                 1969, p. entire; DeMarais 1986, p. entire;              scientific organizations; interested                   seminuda and G. elegans, but when
                                                 Minckley and DeMarais 2000, p. 253). In                 groups; and other interested parties.                  mitochondrial and nuclear DNA results
                                                 Fossil Creek, they found that G. nigra                    In accordance with our peer review                   were combined, G. robusta, G. nigra,
                                                 and G. robusta are locally in the same                  policy published in the Federal Register               and G. intermedia were alone in one
                                                 geographic area (sympatric) and have                    on July 1, 1994 (59 FR 34270), we                      grouping. While Marsh et al. (2016,
                                                 hybridized (Marsh et al. 2016, p. 57).                  solicited independent opinions from at                 entire) concluded there are two similar
                                                 Marsh et al. (2016, p. 58) concluded                    least three knowledgeable individuals                  but genetically distinguishable species
                                                 there are two morphologically similar,                  who have expertise with these fish, who                in the creek they studied, their findings
                                                 but genetically distinguishable, chub in                possess a current knowledge of the                     differ somewhat from Schwemm (2006)
                                                 Fossil Creek, G. robusta and G. nigra.                  geographic region where the fish occurs,               and Dowling et al. (2008 and 2015,
                                                                                                         and/or are familiar with the principles                entire), who were unable to
                                                 Conservation Implications                               of conservation biology.                               conclusively identify distinct species
                                                   Dowling et al. (2015, pp. 14–15)                        We reviewed all comments received                    using genetic markers across a much
                                                 reasoned that the lack of diagnostic                    from peer reviewers and the public for                 wider range. Further, the Societies
                                                 molecular characteristics does not                      substantive issues and new information                 conducted a review of the literature and
                                                 inform the status of these three fish, but              regarding the proposed listing of G.                   found no evidence to support three
                                                 rather highlights the role that local                   nigra and the G. robusta DPS.                          species. The Service has reviewed the
                                                 evolution has played in shaping                         Substantive comments pertaining to the                 best available scientific and commercial
                                                 patterns of variation in these taxa and                 taxonomy of these fish received during                 data and also found a lack of sufficient
                                                 the importance of accounting for this                   the comment period are addressed                       evidence to support more than one
                                                 variation when managing the complex.                    below. We also received several                        species.
                                                 Most, if not all, scientists agree that                 comments from both the public and                         (2) Comment: Recognized authorities
                                                 conservation actions for these chubs                    peer reviewers concerning threats to                   on the taxonomy and ecology of these
                                                 must be directed at the population level                these fish; however, because our                       fish recognized these fish as separate
                                                 and must include consideration of the                   withdrawal is due to taxonomic revision                species based on morphological
                                                 complex as a whole (Dowling et al.                      such comments are outside the scope of                 diagnostics.
                                                 2008, pp. 30–31; Dowling and DeMarais                   this withdrawal.                                          Response: Minckley and DeMarais
                                                 1993, p. 445; Gerber et al. 2001, p. 2037;                                                                     (2000), Miller et al. (2005), and
                                                                                                         Peer Review Comments
                                                 Schwemm et al. 2006, pp. 32–33). The                                                                           Minckley and Marsh (2009) report
                                                 Arizona Game and Fish Department                           (1) Comment: One peer reviewed                      identification of three species using a
                                                 recognizes the importance of conserving                 stated that there are no recent (since                 diagnostic morphological key. However,
                                                 the currently recognized roundtail chub                 2000) publications in the peer-reviewed                additional reports were unable to
                                                 population rangewide (including the                     literature that provide evidence that                  reliably identify these three fish to
                                                 formerly known headwater chub and                       Gila intermedia, G. nigra, and G. robusta              species using the same diagnostic key
                                                 Gila chub) and is committed to the                      are other than separate and distinct                   (Carter et al. 2016, p. 2 and 20, in press;
                                                 conservation agreements and practices                   species. The peer reviewer further stated              Brandenburg 2015, entire; Copus et al.
                                                 that have been in place since 2006                      that there are articles that study the                 2016, p. 13). Further, Minckley and
                                                 (AGFD 2017, entire; AGFD 2006, entire).                 genetics or morphology of these fish                   DeMarais (2000, pp. 253–254) stated
                                                                                                         without questioning its taxonomy,                      that G. nigra is morphologically separate
                                                 Public Comments                                         specifically Schönhuth et al. 2014,                   from G. intermedia, but that G. nigra
                                                    In our October 7, 2015 proposed rule                 Schönhuth et al. 2012, and Marsh et al.               and G. intermedia appear
                                                 (80 FR 60754), we requested that all                    in press.                                              morphologically more similar to one
                                                 interested parties submit comments or                      Response: Multiple studies since 2000               another than either is to G. robusta. In
                                                 information concerning the proposed                     provide information on the genetic                     addition to issues surrounding
                                                 listings during a 60 day comment                        analysis for these fish, including                     morphological identification, multiple
                                                 period, ending December 7, 2015. We                     Schwemm 2006, Dowling et al. 2008                      genetic analysis studies have found
                                                 particularly sought comments                            and 2015, and Copus et al. 2016. While                 population-level differences, but have
                                                 concerning genetics and taxonomy. In                    these studies may not have questioned                  been unable to identify genetic markers
                                                 our August 15, 2016, 6-month extension                  the taxonomic classification, they also                that have the ability to distinguish
                                                 document (81 FR 54018), we reopened                     have not been able to identify genetic                 among G. robusta, G. nigra, and G.
                                                 the comment period on the proposed                      markers that have the ability to                       intermedia (DeMarais 1992, pp. 2748–
                                                 rule for 30 days, ending September 14,                  distinguish among G. robusta, G. nigra,                2749; Schwemm 2006, p. 29; Dowling et
                                                 2016, and we again requested comments                   and G. intermedia. Schönhuth et al.                   al. 2008, p. 2, and 2015, p. 13; Copus
                                                 and information regarding genetics and                  (2008, p. 213; 2014, p. 223), using                    et al. 2016, pp. 14–15). There are also
                                                 morphology that would aid in resolving                  mitochondrial and nuclear DNA                          the findings of Schönhuth et al. (2014),
                                                 the ongoing taxonomic issues regarding                  sequencing, found that G. robusta, G.                  Schönhuth et al. (2012) as described in
                                                 classification of these fish. On                        nigra, and G. intermedia were well                     Response to Comment 1.
                                                 November 1, 2016 (81 FR 75801, we                       supported as having a common                              (3) Comment: Conclusions are mainly
                                                 announced an additional 45-day                          ancestor. Using mitochondrial DNA,                     based on two ‘‘gray literature’’ reports
                                                 comment period, ending December 16,                     Schönhuth et al. (2008, p. 213; 2014, p.              that have not undergone peer review
                                                 2016, on the October 7, 2015 proposed                   223) found that G. robusta, G. nigra, and              (Copus et al. 2016) or were not available
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                                                 rule.                                                   G. intermedia were in one grouping that                for public consideration (Carter et al.
                                                    We provided notification of these                    included a common ancestor and all the                 2016, in press).
                                                 publications and their comment periods                  descendants (living and extinct) of that                  Response: Section 4(b)(1)(A) of the
                                                 through email, letters, and news releases               ancestor (clade), and this could reflect               Act requires the Service to make listing
                                                 faxed and/or mailed to the appropriate                  incomplete lineage sorting or                          or delisting decisions based on the best
                                                 Federal, State, and local agencies;                     hybridization. However, when nuclear                   scientific and commercial data
                                                 county governments; elected officials;                  DNA was analyzed, a broader grouping                   available. Further, our Policy on
                                                 media outlets; local jurisdictions;                     was identified that included G.                        Information Standards under the Act


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                                                                            Federal Register / Vol. 82, No. 66 / Friday, April 7, 2017 / Proposed Rules                                           16985

                                                 (July 1, 1994; 59 FR 34271), the                        Office (see FOR FURTHER INFORMATION                    obtain a complete list of references cited
                                                 Information Quality Act (section 515 of                 CONTACT).   The Service has reviewed the               on the Internet at http://
                                                 the Treasury and General Government                     best available scientific and commercial               www.regulations.gov and upon request
                                                 Appropriations Act for Fiscal Year 2001                 data and found a lack of sufficient                    from the Arizona Ecological Services
                                                 (Pub. L. 106–554; H.R. 5658)), and our                  evidence to support more than one                      Office (see FOR FURTHER INFORMATION
                                                 associated Information Quality                          species.                                               CONTACT). In regards to the
                                                 Guidelines (https://www.fws.gov/                           (5) Comment: This taxonomic dispute                 mitochondrial DNA and phylogenetic
                                                 informationquality), provide criteria                   is not simply an academic exercise of                  analysis, Copus et al.’s findings are
                                                 and, guidance, and establish procedures                 whether to lump or split taxa, because                 consistent with Schönhuth et al.’s
                                                 to ensure that our decisions are based                  the decision has enormous implications                 (2014) and Schönhuth et al.’s (2012)
                                                 on the best scientific data available.                  for the conservation of imperiled                      mitochondrial DNA and phylogenetic
                                                 They require us, to the extent consistent               species. Multiple experts recommended                  analysis. In addition, multiple genetic
                                                 with the Act and with the use of the best               that the roundtail chub complex,                       analysis studies have been conducted
                                                 scientific data available, to use primary               however it is constituted, be managed as               that indicate population-level
                                                 and original sources of information as                  separate populations or managed as a                   differences, but do not identify genetic
                                                 the basis for our determinations.                       complex.                                               markers that have the ability to
                                                 Primary or original information sources                    Response: The Service recognizes that               distinguish among G. robusta, G. nigra,
                                                 are those that are closest to the subject               multiple experts agree that conservation               and G. intermedia (DeMarais 1992, pp.
                                                 being studied, as opposed to those that                 actions must be directed at the                        2748–2749; Schwemm 2006, p. 29;
                                                 cite, comment on, or build upon                         population level and must include                      Dowling et al. 2008, p. 2, and 2015, p.
                                                 primary sources. The Act and our                        consideration of the complex as a whole                13).
                                                 regulations do not require us to use only               (Dowling et al. 2008, pp. 30–31;                          In regards to morphological diagnostic
                                                 peer-reviewed literature, but instead                   Dowling and DeMarais 1993, p. 445;                     errors due to using preserved
                                                 they require us to use the ‘‘best                       Gerber et al. 2001, p. 2037; Schwemm                   specimens, Copus et al. (2016) did use
                                                 scientific and commercial data                          2006, pp. 32–33). However, the Service                 preserved specimens. However, they
                                                 available.’’ We use information from                    must adhere to the Act and its                         also analyzed fresh material and
                                                 many different sources, including                       implementing regulations, which define                 concluded that no single diagnostic
                                                 articles in peer-reviewed journals,                     a ‘‘species’’ as any species or subspecies             character can be used for species
                                                 scientific status surveys and studies                   of fish, wildlife, or plant, and any                   identification, and with considerable
                                                 completed by qualified individuals,                     distinct population segment of any                     overlap among species in every
                                                 Master’s thesis research that has been                  vertebrate species which interbreeds                   morphological character, no suite of
                                                 reviewed but not published in a journal,                when mature (16 U.S.C. 1532(16) and 50                 characters can distinguish species
                                                 other unpublished governmental and                      CFR 424.02). The best available                        unambiguously (Copus et al. 2016, p.
                                                 nongovernmental reports, reports                        scientific and commercial data as                      13). Brandenburg et al. (2015, entire)
                                                 prepared by industry, personal                          discussed above in the Taxonomy                        also reported overlap in the meristic and
                                                 communication about management or                       section, support recognition of only one               morphometric characteristics, records of
                                                 other relevant topics, conservation plans               species, Gila robusta. The Service’s                   many individual fish with intermediate
                                                 developed by States and counties,                       withdrawal of our proposed rule to list                physical characteristics, and even those
                                                 biological assessments, other                           the headwater and roundtail chub based                 characters that do not overlap are
                                                 unpublished materials, experts’                         on new taxonomic classification does                   separated by very small margins making
                                                 opinions or personal knowledge, and                     not diminish the conservation efforts of               species-level identification of individual
                                                 other sources. For these reasons, we                    our partners to conserve this species                  fish problematic, even when the
                                                 think it is appropriate to include review               and habitat, nor does our decision affect              geographic origin of the species is
                                                 of Copus et al. (2016) and Carter et al.                the State’s ability to conserve this                   known.
                                                 (2016, in press), as well as other                      species under its own authority. The
                                                                                                         Arizona Game and Fish Department                       Public Comments
                                                 sources, within our review.
                                                    (4) Comment: Several authors                         recognizes the importance of conserving                  (7) Comment: Multiple commenters
                                                 presented data and conclusions that                     the currently recognized roundtail chub                requested various listing alternatives
                                                 conflicted with the previously cited                    population rangewide (including the                    under the Act including: List G. robusta
                                                 Carter et al. (2016, in press) and Copus                formerly known headwater chub and                      as threatened and encompass all
                                                 et al. (2016) reports pertaining to                     Gila chub) and is committed to the                     populations of the chub complex within
                                                 morphological identification, DNA                       conservation agreements and practices                  the Gila basin requiring a revision of the
                                                 analysis, and ecological equivalency to                 that have been in place since 2006                     recovery plan, list G. robusta and G.
                                                 a subset of the Joint Committee                         (AGFD 2017, entire; AGFD 2006, entire).                nigra as threatened and retain the
                                                 convened in April 2016, to specifically                    (6) Comment: Multiple commenters                    current endangered species status of G.
                                                 address the taxonomy of the roundtail                   raised concerns with Copus et al. (2016)               intermedia, list G. robusta as threatened
                                                 chub complex.                                           methods and conclusions, particularly                  and retain the current endangered
                                                    Response: We were present at the                     small sample size, lack of key analytical              species status of G. intermedia, or other
                                                 April 2016 Joint Committee webinar,                     and laboratory steps, the study’s DNA                  combinations.
                                                 and experts beyond Carter and Copus,                    sequence data filtering and analyses that                Response: The Service must adhere to
                                                 such as Brandenburg, Schwemm,                           failed to follow best practices for                    the Act and its implementing
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                                                 Dowling, O’Neill, and Chafin, also                      phylogenetic analysis, and specimen                    regulations, which define a ‘‘species’’ as
                                                 provided information based on research                  shrinkage associated with duration of                  any species or subspecies of fish,
                                                 they either had previously conducted or                 preservation impacting morphological                   wildlife, or plant, and any distinct
                                                 are currently conducting on Gila. A                     diagnostics.                                           population segment of any vertebrate
                                                 complete list of references cited may be                   Response: The Service did not rely                  species which interbreeds when mature
                                                 obtained on the Internet at http://                     solely on Copus et al. 2016. We                        (16 U.S.C. 1532(16) and 50 CFR 424.02),
                                                 www.regulations.gov and upon request                    considered the best available                          and based on our review, the best
                                                 from the Arizona Ecological Services                    commercial and scientific data; you may                available scientific and commercial data


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                                                 16986                      Federal Register / Vol. 82, No. 66 / Friday, April 7, 2017 / Proposed Rules

                                                 support recognition of only one species,                result of hybridization between the                    well as the Service review, of the best
                                                 Gila robusta. As the headwater chub                     other two taxa, so we would expect the                 available scientific and commercial data
                                                 and roundtail chub DPS no longer meet                   greatest morphological overlap from that               did not result in a species-level
                                                 the definition of a ‘‘species’’ under the               species with the other two taxa. The                   differentiation between G. robusta and
                                                 Act, we must withdraw our proposed                      question then becomes, is G. nigra                     G. intermedia, or among G. robusta, G.
                                                 rule to list them as threatened species.                continuing to differentiate from                       intermedia, and G. nigra.
                                                   (8) Comment: Multiple commenters                      ancestral G. robusta? When in sympatry,                  (11) Comment: One commenter
                                                 stated that there is a great amount of                  G. nigra and G. robusta are becoming                   recommend that we proceed with an
                                                 morphological overlap among counts                      increasingly reproductively isolated                   amended recovery plan to list the status
                                                 and measures for these chub taxa and                    from one another (Desert Fishes Council                of this species as threatened under the
                                                 that this has long been recognized. If a                meeting, Dowling et al. 2016).                         Act. The listing of this species is
                                                 taxonomic key is not 100 percent                           Response: We recognize that multiple                necessary even if all populations of G.
                                                 correct, that does not necessarily mean                 studies have indicated that                            intermedia and G. nigra are subsumed
                                                 that these are not taxa that are                        hybridization has occurred among G.                    into G. robusta.
                                                 biologically distinct at the specific level.            intermedia and G. robusta resulting in                   Response: An assessment of the entire
                                                 A test of the key would require the a                   G. nigra and that continuing evolution                 range of the new taxonomic group of
                                                 priori identification of each individual                may occur (Schwemm 2006; Dowling et                    roundtail chub is planned. We are
                                                 to species. Rather than dismiss the                     al. 2008, entire). However, there has                  initiating a status review of the new
                                                 species’ taxonomic status, biologists                   also been information presented                        taxonomic entity in 2 to 4 years.
                                                 should be working to make a better key                  showing no evidence of the hybrid                      Following that review, we will take
                                                 that can be used in the field for the                   origin of G. nigra, and that G.                        action as appropriate.
                                                 effective identification and management                 intermedia and G. nigra evolved                        Determinations
                                                 of the species.                                         separately in non-overlapping areas
                                                    Response: We recognize that                          (parapatry) (Chafin 2016, entire). In                     An entity may only be listed under
                                                 diagnostic keys do not produce correct                  addition, past research (Dowling et al.                the Act if that entity meets the Act’s
                                                 results all the time, whether due to                    2008, 2015; Schwemm 2006) indicate                     definition of a species. The recent report
                                                 human error or morphological                            that there is more variation among                     by the Societies indicates that neither
                                                 similarities among purported species.                   populations and unique genetics within                 the headwater chub nor the roundtail
                                                 However, Copus et al. (2016, p. 13)                     specific populations (streams).                        chub can be considered species, as
                                                 concluded that, based on genetic                           (10) Comment: If only G. robusta and                defined by the Act. Under section 3 of
                                                 analysis, no single diagnostic character                G. intermedia are evaluated, there is no               the Act (16 U.S.C. 1532(16)) and
                                                 can be used for species identification,                 question that they would be considered                 associated implementing regulations at
                                                 and with considerable overlap among                     distinct morphological species.                        50 CFR 424.02, a ‘‘species’’ is defined to
                                                 species in every morphological                             Response: Carter et al. (2016, in press)            include any species or subspecies of
                                                 character, no suite of characters can                   found that the physical characteristics                fish, wildlife, or plant, and any distinct
                                                 distinguish species unambiguously.                      did not reliably differentiate among G.                population segment of any vertebrate
                                                 Brandenburg et al. (2015, entire) also                  robusta, G. intermedia, and G. nigra. In               species which interbreeds when mature.
                                                 reported overlap in the meristic and                    addition, Brandenburg et al. (2015, pp.                The Act’s implementing regulations at
                                                 morphometric characteristics, and there                 8–9) found physically similarity of the                50 CFR 424.11(a) and the Service
                                                 are many individual fish whose                          three species, as numerous individuals                 Director’s November 25, 1992,
                                                 morphology resides on an intermediate                   exhibited intermediate characters along                ‘‘Taxonomy and the Endangered Species
                                                 spectrum, and even those characters                     the species gradient. The discriminant                 Act’’ Memorandum (Memo) provide
                                                 that do not overlap are separated by                    function analysis (a statistical analysis              additional guidance on how to consider
                                                 very small margins, making species-                     tool to determine which variables                      taxonomic information when assessing a
                                                 level identification of individual fish                 discriminate between two or more                       species for listing under the Act. The
                                                 problematic, even if the geographic                     naturally occurring groups) classified                 regulations at 50 CFR 424.11(a) state,
                                                 origin of the species is known. In                      only 16 percent (n = 42) of G.                         ‘‘In determining whether a particular
                                                 regards to a priori identification of fish,             intermedia (the fewest) while the                      taxon or population is a species for the
                                                 assignment to species has been based on                 majority of the samples were classified                purposes of the Act, the Secretary [of
                                                 the stream in which the fish occurs                     as G. robusta (53.2 percent, n = 140),                 the Interior] shall rely on standard
                                                 (Minckley and DeMarais 2000, p. 252),                   which indicates that the ability to                    taxonomic distinction and the biological
                                                 so the identification of the fish that                  classify these fish correctly to G.                    expertise of the Department [of the
                                                 occurs in each stream is assumed to be                  intermedia or G. robusta based on                      Interior] and the scientific community
                                                 known. Consequently, there exists the                   physical characteristics was low. Due to               concerning the relevant taxonomic
                                                 ability to compare findings from the                    the complex genetic makeup and                         group.’’ The Director’s Memo specifies
                                                 diagnostic key to the fish within a                     observable characteristics or traits (i.e.,            that the Service is ‘‘required to exercise
                                                 particular stream. An updated key may                   physical appearance, behavior, or                      a degree of scientific judgment regarding
                                                 be prudent; however, the Service must                   physiology) of these species, there are                the acceptance of taxonomic
                                                 use the best available scientific and                   some stream locations where we do not                  interpretations, particularly when more
                                                 commercial data available, and we have                  know where the geographic overlap of                   than one possible interpretation is
                                                 concluded from our review that the data                 headwater, roundtail, and, in some                     available. The Memo further states,
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                                                 currently support only one species, Gila                cases Gila chub, begins and ends,                      ‘‘When informed taxonomic opinion is
                                                 robusta. Further, given the overlap in                  because of the plasticity of observable                not unanimous, we evaluate available
                                                 diagnostic characteristics, the                         characteristics or traits of these fish                published and unpublished information
                                                 development of a valid key seems                        within individual streams. Our review                  and come to our own adequately
                                                 unlikely.                                               of the data does indicate that there are               documented conclusion regarding the
                                                    (9) Comment: Multiple commenters                     differences in observable characteristics              validity of taxa.’’
                                                 stated that it has long been                            or traits between the fish in different                   The Act requires that we finalize,
                                                 hypothesized that G. nigra formed as the                streams, but the Societies’ review, as                 modify, or withdraw the proposed rule


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                                                                            Federal Register / Vol. 82, No. 66 / Friday, April 7, 2017 / Proposed Rules                                            16987

                                                 within 12 months. The Act provides for                  species as valid from various works, we                not able to identify genetic markers
                                                 one 6-month extension for scientific                    made little or no judgment on authors’                 distinguishing between the three fish.
                                                 uncertainty, which we have used. As                     species concepts. Taxa of uncertain                    Finally, Schönhuth et al. (2014, p. 223)
                                                 such, we are required to make a                         status were dealt with on a case-by-case               found that G. robusta, G. nigra, and G.
                                                 decision regarding the entities’                        basis.’’ Based on the Societies’ expertise             intermedia were in one grouping that
                                                 eligibility for listing at this time. In                and their internal guidance (stated                    included a common ancestor and all the
                                                 addition, section 4(b)(1)(A) of the Act                 above) on making such decisions, we                    descendants (living and extinct) of that
                                                 requires the Service to make listing or                 conclude that the preponderance of                     ancestor (clade), and hypothesized this
                                                 delisting decisions based on the best                   evidence before them was clear and                     could reflect incomplete lineage sorting
                                                 scientific and commercial data                          decisive enough to make a taxonomic                    or hybridization, but this was not
                                                 available. Further, our Policy on                       change.                                                studied.
                                                 Information Standards under the Act                        After reviewing the best available
                                                 (July 1, 1994; 59 FR 34271), the                                                                                  For the purposes of our
                                                                                                         scientific and commercial information
                                                 Information Quality Act (section 515 of                 (as described above in the Taxonomy                    determination, we accept the ‘‘single
                                                 the Treasury and General Government                     section and summarized below) and                      species’’ finding by the Societies
                                                 Appropriations Act for Fiscal Year 2001                 applying statutory and regulatory                      described above and, consequently,
                                                 (Pub. L. 106–554; H.R. 5658)), and our                  guidance, we determined that the                       withdraw the proposed rule to list the
                                                 associated Information Quality                          Societies’ report considered the best                  headwater chub (Gila nigra) and a DPS
                                                 Guidelines (https://www.fws.gov/                        commercial and scientific data                         of the roundtail chub (Gila robusta)
                                                 informationquality), provide criteria,                  available. We agree with the conclusion                from the lower Colorado River basin as
                                                 guidance, and establish procedures to                   that available data support recognition                threatened species under the Act. This
                                                 ensure that our decisions are based on                  of only one species, Gila robusta. Our                 withdrawal is based on a thorough
                                                 the best scientific data available. They                determination is based on various                      review of the best scientific and
                                                 require us, to the extent consistent with               factors, including the method of original              commercial data available, which
                                                 the Act and with the use of the best                    assignment to species, hybridization                   indicate that the headwater chub and
                                                 scientific data available, to use primary               events, conflicting identification of                  the DPS of the roundtail chub are not
                                                 and original sources of information as                  species based on morphology versus                     discrete taxonomic entities and do not
                                                 the basis for recommendations. Primary                  genetics, evolutionary history,                        meet the definition of species under the
                                                 or original information sources are those               morphological identification                           Act. These fish are now recognized as a
                                                 that are closest to the subject being                   limitations, and lack of genetic markers               single taxonomic species—the roundtail
                                                 studied, as opposed to those that cite,                 to identify species. We lack confidence                chub (Gila robusta). Because the entities
                                                 comment on, or build upon primary                       in the initial species assignments to G.               previously proposed for listing are no
                                                 sources. The Act and our regulations do                 robusta, G. nigra, and G. intermedia due               longer recognized as species, as defined
                                                 not require us to use only peer-reviewed                to the scientific methods used (fish were
                                                 literature, but instead they require us to                                                                     by the Act, we have determined that
                                                                                                         assigned to a species based on the                     they are not listable entities, and we are
                                                 use the ‘‘best scientific and commercial                stream in which they occurred, the
                                                 data available.’’ We use information                                                                           withdrawing our proposed rule to list.
                                                                                                         erroneous assumption that these fish
                                                 from many different sources, including                  did not overlap geographically, and the                Future Actions
                                                 articles in peer-reviewed journals,                     absence of genetic or morphological
                                                 scientific status surveys and studies                   diagnostic information). Minckley and                    Following the publication of this
                                                 completed by qualified individuals,                     DeMarais (2000, entire) based their                    withdrawal, we intend to reevaluate the
                                                 Master’s thesis research that has been                  diagnostic key on the assumption that                  status of the Gila chub (currently listed
                                                 reviewed but not published in a journal,                none of these species occurs in the same               as endangered) in the near future and
                                                 other unpublished governmental and                      locality; however, they acknowledge                    initiate a range-wide species status
                                                 nongovernmental reports, reports                        hybridization among G. robusta and G.                  assessment (SSA) of the newly-
                                                 prepared by industry, personal                          intermedia. Further, other studies have                recognized roundtail chub (Gila
                                                 communication about management or                       found that fish designated as G. robusta,              robusta).
                                                 other relevant topics, conservation plans               G. nigra, and G. intermedia overlap
                                                 developed by States and counties,                       geographically or occur adjacent to one                References Cited
                                                 biological assessments, other                           another (Dowling and Marsh 2009, p. 1;                   A complete list of references cited in
                                                 unpublished materials, experts’                         Marsh et al. 2016, p. 57; Brandenburg et
                                                 opinions or personal knowledge, and                                                                            this document is available on the
                                                                                                         al. 2015, p. 18). In addition, some                    Internet at http://www.regulations.gov
                                                 other sources.                                          populations appeared to conflict
                                                                                                                                                                and upon request from the Arizona
                                                    We conducted a similar internal                      genetically with the species-level
                                                                                                                                                                Ecological Services Office (see FOR
                                                 review of the information presented by                  assignment based on morphology
                                                                                                                                                                FURTHER INFORMATION CONTACT).
                                                 and available to the Societies in their                 (Dowling et al. 2015, pp. 14–15).
                                                 review. Our review primarily focused                    Multiple scientists (as described above)               Authors
                                                 on Marsh et al. (2016), Carter et al.                   found Minckley and DeMarais’s (2000,
                                                 (2016, in press), Copus et al. (2016),                  entire) key for identification of G.                     The primary authors of this document
                                                 Minckley and DeMarais (2000), and                       robusta, G. nigra, and G. intermedia to                are the staff members of the Arizona
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                                                 Chafin et al. (2015), as well as other                  not reliably differentiate among these                 Ecological Services Office.
                                                 literature as discussed above in the                    three fish. In Fossil Creek, Marsh et al.
                                                                                                                                                                Authority
                                                 Taxonomy section. In their most recent                  (2016, entire) concluded there are two
                                                 publication of Common and Scientific                    morphologically similar, but genetically                  The authority for this action is section
                                                 Names of Fishes (Page et al. 2013, p. 8),               distinguishable chub. However, there                   4(b)(6)(B)(ii) of the Endangered Species
                                                 the Societies state the following                       are several genetic analysis studies                   Act of 1973, as amended (16 U.S.C. 1531
                                                 regarding the common process of their                   indicating population-level differences                et seq.)
                                                 naming committee: ‘‘In accepting                        among these fish, but the studies were


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                                                 16988                      Federal Register / Vol. 82, No. 66 / Friday, April 7, 2017 / Proposed Rules

                                                   Dated: March 21, 2017.
                                                 James W. Kurth,
                                                 Acting Director, U.S. Fish and Wildlife
                                                 Service.
                                                 [FR Doc. 2017–06995 Filed 4–6–17; 8:45 am]
                                                 BILLING CODE 4333–15–P
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Document Created: 2017-04-06 23:49:42
Document Modified: 2017-04-06 23:49:42
CategoryRegulatory Information
CollectionFederal Register
sudoc ClassAE 2.7:
GS 4.107:
AE 2.106:
PublisherOffice of the Federal Register, National Archives and Records Administration
SectionProposed Rules
ActionProposed rule; withdrawal.
ContactSteve Spangle, Field Supervisor, U.S. Fish and Wildlife Service, Arizona Ecological Services Office, 9828 North 31st Ave., #C3, Phoenix, AZ 85051-2517; telephone 602-242-0210. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Relay Services at 800-877-8339.
FR Citation82 FR 16981 
RIN Number1018-BA86

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