[Federal Register: November 7, 2002 (Volume 67, Number 216)]
[Proposed Rules]               
[Page 67803-67818]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AF67

Endangered and Threatened Wildlife and Plants; Withdrawal of 
Proposed Rule To Remove the Northern Populations of the Tidewater Goby 
From the List of Endangered and Threatened Wildlife

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule; withdrawal.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), withdraw the 
proposed rule, published in the Federal Register on June 24, 1999, to 
remove the northern populations of tidewater goby (Eucyclogobius 
newberryi) from the list of endangered and threatened wildlife and the 
concurrent proposal to keep listed as endangered a distinct population 
segment (DPS) of tidewater goby in Orange and San Diego Counties, CA. 
The tidewater goby will remain listed throughout its range as an 
endangered species under the Endangered Species Act of 1973, as amended 
(Act). Our withdrawal is based on comments and additional information 
received from the public, the scientific community, industry, other 
concerned governmental agencies, and other parties interested in the 
proposed delisting rule. We are convinced by the information provided 
by the scientific community that our assessment of the importance of 
new tidewater goby populations and the recolonization ability of the 
tidewater goby in the proposed delisting rule were premature. We agree 
with a number of the commenters that it is prudent to wait and assess 
the persistence of these populations for a longer period of time. 
Withdrawing the delisting proposal for the northern populations of the 
tidewater goby makes the retention of a southern California DPS as 
endangered unnecessary, and therefore, we also withdraw our proposal to 
retain as listed a southern California DPS.

DATES: This action is made on December 9, 2002.

ADDRESSES: The supporting record for this withdrawal is available for 
inspection, by appointment, during normal business hours at our Ventura 
Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, CA 

FOR FURTHER INFORMATION CONTACT: Carl Benz at the above address 
(telephone: 805-644-1766).



    The tidewater goby (Eucyclogobius newberryi) is the only member of 
the genus Eucyclogobius in the family Gobiidae. The species was first 
described as Gobius newberryi by Girard in 1857. Gill (1862) studied 
Girard's specimens and created the genus Eucyclogobius for this fish 
species. The majority of scientists have accepted this classification 
(e.g., Bailey et al. 1970, Miller and Lea 1972, Hubbs et al. 1979, 
Eschmeyer et al. 1983, Robins et al. 1991). A few older works and 
Ginsburg (1945) placed the tidewater goby and the eight related eastern 
Pacific species into the genus Lepidogobius. This classification 
included the currently recognized genera Lepidogobius, Clevelandia, 
Ilypnus, Quietula, and Eucycloglobius.
    Crabtree's (1985) allozyme (enzyme) work on tidewater gobies from 
12 localities throughout the range identified fixed allelic (genetic) 
differences at the extreme northern and southern ends of the range, 
with the more centrally distributed populations more similar to one 
another. The results suggest a low level of gene movement between 
populations in the northern, central and southern parts of the range. 
However, the sites Crabtree sampled were widely separated 
geographically, and his results may not indicate gene flow on more 
local levels, as noted by Lafferty et al. (1999, cited in proposed 
delisting as in prep.).
    More recently, David Jacobs (Department of Organismic Biology, 
Ecology and Evolution, University of California, Los Angeles, in litt., 
1998; Dawson et al. 2001) conducted an analysis of mitochondrial DNA 
(mtDNA) from tidewater goby populations ranging from Humboldt to San 
Diego Counties. Results suggested that San Diego tidewater gobies 
(i.e., the southernmost tidewater goby populations) began diverging 
from the remainder of tidewater gobies more than 100,000 years ago and 
are therefore genetically distinct from individuals across the rest of 
the range.
    The tidewater goby is a small elongate fish seldom exceeding 50 
millimeters (mm), about 2 inches (in), standard length. This goby is 
characterized by large, dusky pectoral fins and a ventral sucker-like 
disk formed by the complete fusion of the pelvic fins. It is nearly 
transparent, with a mottled brownish upper surface, and often with 
spots or bars on dusky dorsal and anal fins. The mouth is large and 
oblique with the upper jaw extending nearly to the rear edge of the 
eye. The eyes are widely spaced. The tidewater goby is a short-lived 
species, apparently having an annual life cycle (Eschmeyer et al. 1983, 
Irwin and Soltz 1984, Swift et al. 1997).
    The tidewater goby is endemic to California and restricted to 
coastal brackish water habitats. This species historically ranged from 
Tillas Slough (mouth of the Smith River, Del Norte County) near the 
Oregon border to Agua Hedionda Lagoon (northern San Diego County). 
Within this range, shallow brackish water habitats occur in two 
relatively distinct situations: (1) The upper edge of tidal bays, such 
as Tomales, Bolinas, and San Francisco Bays near the entrance of 
freshwater tributaries, and (2) the coastal lagoons formed at the 
mouths of small to large coastal rivers, streams, or seasonally wet 
canyons along the coast of California. Overall, the tidewater goby 
occupies a very small portion of the California coast (probably less 
than 5 percent) (C. Swift, Emeritus, Section of Fishes, Natural History 
Museum of Los Angeles County, CA, in litt. 1999).
    Tidewater gobies can tolerate a wide range of salinities (from 0 to 
60 parts per thousand (ppt)) and are frequently found throughout 
lagoons (Swift et al. 1989, 1997; Worcester 1992; Worcester and Lea 
1996). However, tidewater gobies are often found in waters of low 
salinities (about 10 ppt) in the uppermost brackish zone of larger 
estuaries and coastal lagoons. In some cases, tidewater gobies may also 
be found in habitats that are essentially fresh with little or no tidal 

[[Page 67804]]

(e.g., San Mateo Creek, Arroyo Laguna) (D. Holland, University of 
Southwestern Louisiana, Lafayette, in litt. 1999). Few well documented 
records of this species are known from marine environments outside of 
coastal lagoons and estuaries, but specimens have been collected from 
salinities up to 42 ppt (Swift et al. 1989) and 55 ppt (Swift and 
Holland 1998 as cited in D. Holland, in litt. 1999). Ocean seawater 
salinity is about 32 ppt. This goby can tolerate salinities up to 60 
ppt for varying time periods (Swift et al. 1989, Worcester and Lea 
    Tidewater gobies usually are collected from water depths of less 
than 1 meter (m) (3 feet (ft)) and many localities are no deeper than 
this (Wang 1982, Irwin and Soltz 1984, Swenson 1995). They have been 
found, however, at water depths greater than 1 m (3 ft) (Worcester 
1992, Lafferty and Altstatt 1995, Swift et al. 1997, Smith 1998). The 
lack of collections of tidewater gobies from depths greater than 1 m (3 
ft) in lagoons and estuaries with deeper water may be due to the 
inadequacy of the sampling methods used, rather than the absence of 
tidewater gobies (Worcester 1992, Smith 1998).
    Tidewater gobies may be preyed upon by native species, such as 
steelhead (Oncorhynchus mykiss) (Swift et al. 1989), and are documented 
prey items of prickly sculpin (Cottus asper), staghorn sculpin 
(Leptocottus armatus), and starry flounder (Platichthys californicus) 
(Swift et al. 1997). However, tidewater gobies were found in stomachs 
of only 6 percent of nearly 120 of the latter three species examined 
and comprised less that 20 percent by volume of the prey. Predation by 
the Sacramento perch (Archoplites interruptus) and tule perch 
(Hysterocarpus traski) may have prevented tidewater gobies from 
inhabiting the Sacramento-San Joaquin River delta (Swift et al. 1989). 
Nonnative predators, such as striped bass (Morone saxatilis), may have 
also contributed to the absence of tidewater gobies in the San 
Francisco Bay area (Swift et al. 1989, 1990). Although direct 
documentation of this is lacking, Shapalov and Taft (1954) and Wang 
(1982) noted predation by striped bass on tidewater goby.
    Tidewater gobies may also be preyed upon by nonnative species other 
than striped bass, such as the African clawed frog (Xenopus laevis) 
(Lafferty and Page 1997), shimofuri goby (Tridentiger bifasciatus) 
(Swenson and Matern 1995), chameleon goby (Tridentiger trigonocephalus) 
(D. Holland, in litt. 1999), yellowfin goby (Acanthogobius flavimanus) 
(Wang 1984), centrarchid fish (Swift et al. 1989, 1997), mosquitofish 
(Gambusia affinis) (D. Holland, in litt. 1999), and rainwater killifish 
(Lucania parva) (C. Swift, in litt. 1999). Chameleon and yellowfin 
gobies may also compete with tidewater gobies. Some of these fish, such 
as sunfish and black bass (Centrarchidae) are relatively widespread (M. 
Capelli, University of California, Santa Barbara, in litt. 1999). 
Predation and competition by nonnative species is further discussed in 
Factors C and E of the Summary of Factors Affecting the Species below.

Distinct Population Segments

    Prior to publishing the proposed rule to delist the northern 
populations of the tidewater goby, we analyzed tidewater goby 
populations based on the joint National Marine Fisheries Service and 
U.S. Fish and Wildlife Service Policy Regarding the Recognition of 
Distinct Vertebrate Populations (61 FR 4722). Concurrently with the 
proposed delisting of the northern tidewater goby populations, we 
proposed a distinct population segment for the southern California 
portion of the tidewater goby range.
    When determining whether a distinct vertebrate population segment 
could be treated as threatened or endangered under the Act, we consider 
three elements: discreteness, significance, and conservation status in 
relation to the standards for listing. Discreteness refers to the 
isolation of a population from other members of the species and is 
based on two criteria: (1) Marked separation from other populations of 
the same taxon resulting from physical, physiological, ecological, or 
behavioral factors, including genetic discontinuity, or (2) populations 
delimited by international boundaries. Significance is determined by 
the importance or contribution, or both, of a discrete population to 
the species throughout its range. The policy (61 FR 4722) lists four 
examples of factors that may be used to determine significance:
    (1) Persistence of the discrete population segment in an ecological 
setting unusual or unique for the taxon;
    (2) Evidence that loss of the discrete population segment would 
result in a significant gap in the range of the taxon;
    (3) Evidence that the discrete population segment represents the 
only known surviving natural occurrence of a taxon that may be more 
abundant elsewhere as an introduced population outside its historic 
range; and
    (4) Evidence that the discrete population segment differs markedly 
from other populations of the taxon in genetic characteristics.

If we determine that a population segment is both discrete and 
significant, we evaluate it for endangered or threatened status based 
on the Act's standards.
    For the tidewater goby, we determined that the southern California 
portion of the range met the discreteness criterion based on (1) 
allozyme and mtDNA differences between the northern and southern 
portions of the tidewater goby range (Crabtree 1985; D. Jacobs, in 
litt. 1998) and (2) the geographic distance between the southern 
California tidewater gobies and the closest extant populations to the 
north (129 kilometers (km), 80 miles (mi)). Further, we determined that 
the southern California portion of the range was significant because it 
constitutes the most genetically divergent tidewater goby group (D. 
Jacobs, in litt. 1998). Its loss would result both in loss of a 
genetically unique tidewater goby group and in a reduction in range of 
tidewater gobies of approximately 129 km (80 mi). Upon analyzing the 
status of the tidewater goby in southern California, based on the Act's 
standards, we determined that it was appropriate to propose that the 
southern portion of the range remain listed as an endangered distinct 
population segment. Some of our rationale regarding status of the 
southern California populations is discussed further below in the 
Summary of Factors Affecting the Species. Our rationale for withdrawing 
the proposal to retain as listed a southern California DPS of tidewater 
goby is discussed below in the Summary of Comments and Recommendations 
and in the Finding and Withdrawal section.

Previous Federal Action

    We first classified the tidewater goby as a Category 2 candidate 
species in 1982 (47 FR 58454). Category 2 candidate species were 
species for which information then in our possession indicated that 
proposing to list the species as endangered or threatened was possibly 
appropriate, but for which substantial data on biological vulnerability 
and threats were not currently known or on file to support proposed 
rules. We reclassified the tidewater goby as a Category 1 species in 
1991 (56 FR 58804). Category 1 candidate species were species for which 
we had sufficient information on biological vulnerability and threats 
to support preparation of listing proposals. On October 24, 1990, we 
received a petition to list the tidewater goby as endangered. Our 
finding (signed March 22, 1991) that the requested action might be 
warranted was published in a proposal to list the tidewater goby as

[[Page 67805]]

endangered on December 11, 1992 (57 FR 58770). We determined endangered 
status for the tidewater goby throughout its entire range on February 
4, 1994 (59 FR 5494). At that time, we found that critical habitat was 
not determinable because we lacked sufficient information to perform 
the economic analysis.
    On June 24, 1999, we proposed to remove all of the tidewater goby 
populations north of Orange County, CA (64 FR 33816) from protection 
under the Act. Because we felt the southern portion of the range met 
the definition of a DPS and was subject to continuing threats, we 
concurrently proposed that it be retained as an endangered DPS when the 
northern portion of the range was delisted. We invited public comments 
and suggestions to this proposal in three comment periods. The first 
comment period ended August 23, 1999. Late in that comment period, we 
received new information on the potential marine dispersal of tidewater 
gobies, with additional information provided after the comment period 
closed. On February 15, 2000, we reopened the comment period (65 FR 
7483) from February 15 to March 31, 2000, to request additional review 
of our proposal and to solicit the interpretations of appropriate and 
independent specialists and the public on the new information. On 
January 3, 2001 (66 FR 345), we reopened the comment period for a 
second time. We requested additional public and peer review comment 
from January 3 to February 2, 2001, on: (1) Our assertion that the 
original listing rule exaggerated the risk of extinction by 
overestimating the rate of local population extinction; (2) any 
information either supporting or contradicting the information in the 
proposed delisting rule that suggested the tidewater goby was not, in 
1994 when it was listed, nor was currently, in danger of extinction due 
to a high rate of local extinctions; and (3) any new information that 
suggested a reasonable causal link between any of the threats, or 
combination of threats, and a high risk of extinction of the tidewater 
    In addition to our proposal to delist the tidewater goby and the 
three public comment periods during 1999 to 2001, we designated 
critical habitat for the tidewater goby in 2000. The Natural Resources 
Defense Council, Inc., filed a lawsuit on September 18, 1998, in the 
United States District Court for the Central District of California, 
against the Service for our failure to designate critical habitat for 
the tidewater goby. The court ordered, on April 5, 1999, that we 
``publish a proposed critical habitat designation for the tidewater 
goby in 120 days' (Natural Resources Defense Council, Inc. v. U.S. 
Department of the Interior et al., CV 98-7596, C.D. Cal.). We proposed 
critical habitat for the tidewater goby on August 3, 1999 (64 FR 
42250). The final rule designating critical habitat for the tidewater 
goby was published on November 20, 2000 (65 FR 69693). It includes 10 
coastal stream segments in Orange and San Diego Counties, CA, totaling 
about 14.5 linear km (9 linear miles) of streams, including the stream 
channels and their associated wetlands, floodplains, and estuaries.

Tidewater Goby Proposed Delisting

    In our proposed rule to delist the northern populations of the 
tidewater goby, we identified three major reasons for our proposed 
action: (1) There are more populations in the north than were known at 
the time of listing, (2) threats to those populations are less severe 
than previously believed, and (3) the tidewater goby has a greater 
ability than was known to recolonize sites from which it is temporarily 
absent. We believed that a number of populations had been recolonized 
following the end of the drought of the late 1980s and early 1990s and 
that the original listing of the tidewater goby was in error (66 FR 
345). Commenters seriously disagreed with all three premises, but the 
most compelling information and arguments addressed premises 1 and 3. 
These commenters included a number of scientists with extensive 
experience with tidewater goby. The commenters' opinions and analyses 
and additional information received during the comment periods form the 
basis of this withdrawal. They are discussed in detail below in the 
Summary of Comments and Recommendations and the Summary of Factors 
Affecting the Species.

Summary of Comments and Recommendations

    We received a total of 45 written responses from individuals, 
agencies, or other entities during three public comment periods: June 
24 to August 23, 1999 (64 FR 33816), February 15 to March 31, 2000 (65 
FR 7483), and January 3 to February 2, 2001 (66 FR 345). Of those 45 
written responses, 38 opposed delisting; two supported delisting all 
northern and southern populations; one supported delisting the northern 
populations; three requested the Service first delist all populations 
of the tidewater goby before proposing, if warranted, establishment of 
a southern distinct population segment; and, one commenter provided new 
information on the collection of two tidewater gobies near Diablo Cove, 
south of Morro Bay, CA. Several commenters submitted multiple 

Peer Review

    During the second and third comment periods, we requested peer 
review from independent scientists in compliance with our peer review 
policy (59 FR 34270; July 1, 1994). During the second comment period, 
one peer reviewer responded and supported the delisting. During the 
third comment period, we asked two fish biologists familiar with fish 
ecology, genetics, and the evolution of fish to review the proposed 
tidewater goby delisting and the designation of a southern California 
DPS. Both reviewers recommended that we keep the species listed as 
endangered and provided suggestions for our future review of this 
species' population dynamics and population genetics. One concluded 
that the tidewater goby data used and our interpretations were 
insufficient to support the delisting. Their responses are included in 
the totals above, and their specific comments are addressed below along 
with the public comments.
    We grouped comments of a similar nature into a single issue for 
response. Where applicable, we have revised this notice based on 
factual information provided by the commenters.

Issue 1: Procedural and Legal Compliance

    The following comments and responses deal with compliance with the 
Act and other laws, regulations, and policies, and the public 
involvement in the delisting process.
    Comment 1: One commenter felt that we had improperly proposed the 
tidewater goby DPS in the south. The commenter felt that the species 
must be delisted before a DPS may be designated. In addition, the 
commenter felt we violated the notice provisions of the Administrative 
Procedure Act (APA) by failing to give adequate notice of the listing 
of a DPS, suggesting that the proposal to retain the southern 
California portion of the range as a DPS was not adequately noticed for 
public comment.
    Our Response: We believe we followed proper procedure in proposing 
the southern California tidewater goby DPS. Typical rulemaking 
procedures dictate that we propose an action, provide the public an 
opportunity to comment on the proposed action, and then make a final 
determination. The public was given the opportunity to comment on the 
proposed actions during three separate comment periods. Based on 
comments received from the public and from peer reviewers, we

[[Page 67806]]

have decided to withdraw the proposal to delist the northern 
populations of the tidewater goby and the concurrent proposal to retain 
the southern populations as a DPS.
    Comment 2: One commenter referred to the designation of critical 
habitat for the tidewater goby and felt we violated section 4 of the 
Act by preceding a listing determination with a critical habitat 
designation. The commenter felt the outcome of this proposed delisting 
rule was predetermined by the critical habitat designation, violating 
the APA and the Endangered Species Act.
    Our Response: The critical habitat designation the commenter refers 
to (65 FR 69693) is not a designation of critical habitat for a 
southern California DPS of the tidewater goby. The critical habitat 
designation is for the tidewater goby throughout its range. At the time 
of the designation, we believed the only areas essential to the 
conservation of the tidewater goby were in southern California. 
Therefore, we only designated critical habitat in southern California. 
We issued this designation of critical habitat as the result of a court 
    Comment 3: One commenter felt the proposed action was based on 
unpublished data which was not made available to the public for review.
    Our Response: The commenter did not identify specific data that he 
felt were not available for public review. The proposed action was the 
subject of three public comment periods. All the supporting 
documentation, including comments received, were available for 
inspection at the Ventura Fish and Wildlife Office.
    Comment 4: One commenter stated that we must establish objective 
recovery criteria before a species can be delisted. Several commenters 
suggested that we ignored the draft tidewater goby recovery plan in the 
formulation of the delisting proposal and that, in so doing, we 
contradicted the recommendations and recovery criteria of the draft 
plan. Others recommended retaining the endangered status of the 
tidewater goby and focusing our efforts on finalizing and implementing 
the draft tidewater goby recovery plan.
    Our Response: Species can be delisted for any one of three reasons: 
(1) The species is extinct; (2) the species has recovered; or (3) the 
original data for listing, or the interpretation of those data, are in 
error (50 CFR 424.11(d)). In the first and third cases, we would not 
necessarily have recovery criteria by which to gauge delisting. Our 
delisting proposal for the tidewater goby was published because we felt 
that the original data or their interpretation were in error (see also 
the notice reopening the comment period for the third time, 66 FR 345).
    We wish to clarify that, while a preliminary draft recovery plan 
for the tidewater goby has been circulated among tidewater goby 
experts, we have not approved a draft recovery plan. The preliminary 
draft plan was never published and made available to the public for 
comment. Because they have not yet been published in an official draft 
recovery plan available for public comment, the recommendations and 
recovery criteria in the preliminary draft recovery plan are not our 
official guidance. We agree that the most appropriate course of action, 
given our withdrawal of this proposed delisting, is to proceed with the 
recovery planning process for the tidewater goby.
    Comment 5: One commenter felt that monitoring for the tidewater 
goby is required if it is delisted.
    Our Response: According to the Act, monitoring is required for a 
delisted species only if the species was delisted due to recovery. We 
had proposed delisting of the northern populations of the tidewater 
goby based on new information, not recovery. Furthermore, we have 
decided to withdrawal the proposal to delist the northern populations.
    Comment 6: One commenter suggested that the proposed delisting rule 
violates both the APA and the fifth amendment of the U.S. Constitution, 
by selectively imposing the regulatory burdens of the Endangered 
Species Act on certain landowners, without legal or scientific 
    Our Response: We believe we were in compliance with the APA (see 
also responses to comments 1 through 3) throughout this rulemaking 
process. Furthermore, the regulations governing listing and delisting 
(50 CFR 424.11(b)) state that listing and delisting of a species as 
threatened or endangered are made ``solely (emphasis added) on the 
basis of the best available scientific and commercial information 
regarding a species' status, without reference to possible economic or 
other impacts of such a determination.''
    Had we decided to finalize the proposal to retain a southern DPS as 
listed, the regulatory situation for landowners in southern California 
would not have changed because tidewater goby was already listed as 
endangered in southern California. However, we are withdrawing the 
proposal to retain a southern California DPS as listed, along with the 
withdrawal of the proposal to delist the northern populations.

Issue 2: Data Adequacy, Data Interpretation and Biological Concerns

    The following comments and responses deal with issues related to 
the adequacy of the scientific information used for proposing the 
delisting and establishing the southern California distinct vertebrate 
population segment. We received comments that challenged our assessment 
of the available information at the time we proposed delisting the 
northern populations of the tidewater goby, and we received comments 
that introduced new information on the species. Comments were received 
on issues such as: the genetics of the northern and southern portions 
of the tidewater goby's range (including the determination that 
southern California constitutes a DPS), the number of known tidewater 
goby populations and its relevance, metapopulation theory and 
population dynamics, natural recolonization by marine dispersal of 
tidewater goby larvae, salinity tolerance, and alternative 
interpretations of the data.

General Comments

    Comment 7: A number of commenters suggested that (1) additional 
data or analyses are needed on some aspects of tidewater goby biology 
or threats (e.g., 4 years of population data, encompassing only one 
dry-wet climate cycle, were collected since the listing), (2) we had 
misinterpreted or omitted existing scientific data (e.g., 
misinterpretation of stringency of habitat requirements), (3) we failed 
to provide data, citations, or references to support numerous 
statements, (4) we relied on unpublished and unreviewed sources, and 
(5) we had ignored the professional opinions of tidewater goby experts. 
Most suggested that the entire species should remain listed. One 
commenter felt that the entire species should be delisted, in part 
because of Congress's charge that we list species ``sparingly.''
    Our Response: We agree that additional data and analysis would be 
valuable, that there are alternate interpretations of the available 
data, and that additional supporting documentation (i.e., references) 
would have strengthened our proposal. The arguments the commenters 
presented regarding the need for additional analysis, their 
presentation of alternative interpretations, and their call for 
additional documentation and reliance on published or peer reviewed 
sources have led us to withdraw the proposed rule to delist the 
northern populations of the tidewater goby. Withdrawing the proposed 
delisting makes retention of a southern DPS as

[[Page 67807]]

endangered unnecessary; therefore, we are also withdrawing the proposal 
to retain as listed the southern California portion of the range as an 
endangered DPS. Details of the commenters' arguments are presented 
throughout the remainder of the Summary of Comments and Recommendations 
and in the Summary of Factors Affecting the Species.
    Comment 8: One peer reviewer felt that the information presented in 
our proposal to delist the tidewater goby populations north of Orange 
and San Diego Counties was thorough and well documented and that the 
conclusion to delist the northern populations appears justified.
    Our Response: The bulk of the argument we received during the 
comment periods and the valid concerns raised regarding the meaning of 
the increased population levels identified indicates that withdrawing 
the proposal is appropriate at this time. Our reasoning is provided 
throughout the remainder of the Summary of Comments and Recommendations 
and in the Summary of Factors Affecting the Species.

Genetic Data and DPS Determination

    Comment 9: A number of commenters questioned the adequacy of the 
available genetic data, suggesting that (1) Crabtree's (1985) allozyme 
work had various limitations, including geographically sporadic 
sampling and low sample sizes, and is not a thorough population genetic 
analysis, (2) at the time of the proposed delisting rule, the mtDNA 
analysis was incomplete, preliminary, and had not yet been published or 
peer reviewed, (3) the sample sizes of the mtDNA analysis were small 
(based on 2 to 4 fish per population), and (4) more study would be 
warranted. They were concerned that the best available genetic data for 
tidewater goby did not provide a credible scientific foundation for 
determining that the southern portion of the range constitutes a DPS. 
They suggested more study would allow analysis of larger sample sizes, 
additional tidewater goby populations and different genetic markers. 
One commenter was concerned by the use of mtDNA, which is maternally 
inherited; he advocated the use of biparentally inherited or paternally 
inherited markers. He also commented extensively on the use of mtDNA 
variation in these sorts of decision-making processes.
    Our Response: We are required to use the best available scientific 
and commercial data in making our decisions. We used the best genetic 
data that were available at the time of the proposed delisting rule. We 
have relied upon comments from scientists and the public to help us 
evaluate the sufficiency of these data, and based on their comments, we 
have decided to withdraw the proposal to delist the northern 
populations of the tidewater goby and the proposal to retain a southern 
California DPS.
    Comment 10: A number of commenters questioned our interpretation of 
the recent genetic data of Jacobs (cited as D. Jacobs, in litt. 1998 in 
the proposed delisting). These commenters suggested that the data do 
not support a simple bifurcation into northern and southern portions of 
the range. The commenters felt we did not consider the differentiation 
Jacobs identified within the northern portion of the range, which 
suggests there are also genetically isolated units on a more local 
level. One commenter indicated that the tidewater goby is the ``most 
genetically subdivided vertebrate with marine dispersal on the West 
Coast'' and that its local genetic subdivision exceeds that which has 
been used to differentiate steelhead DPSs along coastal California. He 
felt the genetic evidence supports division of the tidewater goby's 
northern populations into four or five distinct populations segments. 
Another commenter suggested that Crabtree's (1985) older results also 
indicated significant levels of genetic differentiation in tidewater 
    Our Response: In our proposal to delist the northern portion of the 
tidewater goby range and retain the listing of the southern portion as 
a DPS, we did not include an attempt to identify all possible distinct 
population segments. We felt, at the time of the proposal, that the 
threats to the northern portion of the tidewater goby range did not 
warrant its continued listing and that genetic differences exhibited by 
tidewater gobies between the northern and southern portions of the 
range were large enough, along with the geographic gap in the range, to 
allow its distinction as a DPS. We did not intend to imply that the 
tidewater gobies in the northern portion of the range were genetically 
uniform. We understand that more complete genetic data have been 
published recently that underscore genetic differences within the 
northern portion of the range. Based on comments questioning our 
interpretation of the population data and our assumptions regarding 
recolonization we have decided to withdraw the proposal.
    Comment 11: One commenter asked whether it is adequate to use only 
molecular genetics data to designate a tidewater goby DPS. He felt 
that, while Jacobs mtDNA data (cited as D. Jacobs, in litt. 1998 in the 
proposed delisting) showed different haplotypes in the north than in 
the south, they give no indication that the divergence is of 
evolutionary significance. He suggested we have no actual evidence that 
the data reflect meaningful adaptive differentiation or the populations 
are ``evolutionarily significant,'' noting that such judgements are 
subjective. He felt the data do not warrant a DPS determination and, 
instead of a DPS, he suggested the southern populations could simply be 
considered a management unit. Such a management unit could then be the 
subject of a management plan to maintain existing southern tidewater 
goby populations, precluding the need to list the tidewater goby.
    Our Response: While we would like to have specific data reflecting 
adaptive differentiation and evolutionary significance of various 
portions of the tidewater goby range, we can only use information 
available when making our decisions. Based on our DPS policy, published 
on February 7, 1996 (61 FR 4722), we must evaluate whether the segment 
under consideration is discrete and significant. Genetic data can be 
used for either determination. However, genetic data are only one kind 
of data that are typically used; we also evaluate physical, 
physiological, ecological, or behavioral factors in making a 
determination. In the case of the tidewater goby, we used the best 
available genetic data (in this case, mtDNA data), along with 
information on the geographic distribution of the species (i.e., we 
identified a 126 km (80 mi) geographic gap between the southern 
California tidewater gobies and the next closest extant population) to 
determine whether the southern portion of the range might constitute a 
DPS. However, given the comments of many scientists on the sufficiency 
of the available data and on our interpretation of them, we have 
decided to withdraw the proposal to delist the northern portion of the 
range and the proposal to retain as listed a southern California DPS. 
Because the species will remain listed, we cannot consider the southern 
portion of the range as a management unit that might preclude listing.
    Comment 12: Several commenters suggested it was inappropriate to 
propose southern California as a DPS. One felt that, because all 
tidewater goby populations are characterized by some degree of 
reproductive isolation and because extensive natural gaps in its 
distribution occur, each population can

[[Page 67808]]

be viewed as discrete and significant under our DPS policy. 
Identification of only southern California as discrete and significant 
is inherently subjective and arbitrary. Another felt that we 
recognized, de facto, a second DPS comprised of the remaining northern 
populations from Los Angeles County to Oregon. A northern DPS is 
defined by default, with no specific reference to population structure, 
population dynamics, or genetic differences with this northern DPS. 
They suggested we created, by definition, a limited range and number of 
southern tidewater goby populations to support our conclusion that the 
southern DPS is endangered. Conversely, we created, again by 
definition, a northern tidewater goby population that is not endangered 
because of its much larger range and number of populations.
    Our Response: We acknowledge that the proposed establishment of a 
southern DPS would create an area of multiple populations in the north 
that could be treated as a DPS. We believe our proposal was in 
compliance with our DPS policy (61 FR 4722). However, based on the 
arguments of numerous scientific commenters, we have decided to 
withdraw the proposal to delist the northern populations of the 
tidewater goby. This decision makes it unnecessary to pursue further 
the retention of an endangered DPS in southern California; therefore, 
we are withdrawing that proposal as well.

Number of Tidewater Goby Locations

    Comment 13: A number of commenters noted that one of the main 
reasons for the proposed delisting was that tidewater gobies actually 
occur in more locations than known at the time of listing. One 
commenter stated that it was not uncommon to discover new populations 
once a species is listed because focused, systematic surveys are 
conducted. Most who commented on the discovery of new populations were 
concerned that we merely counted the number of extant tidewater goby 
populations, failing to evaluate the size, trend, threats, and 
viability of newly documented populations. They felt we considered all 
populations equally important, rather than evaluating whether the 
populations are small and marginal or large and likely to persist over 
longer time periods. Several commenters felt many of the recently 
documented tidewater goby populations were small and vulnerable to 
extirpation. One commenter considers only about 50 tidewater goby 
populations likely to persist for the long term. Others attempted 
similar calculations or noted they could not understand (or disagreed 
with) our estimates of the number of extant populations and what 
percentage of tidewater goby populations had been extirpated (i.e., our 
estimates were inconsistent with their data or knowledge of the 
tidewater goby's status). One commenter noted we had not attempted to 
take into account the possibility that un-sampled populations had been 
extirpated. One commenter noted that, although many ``new populations'' 
occur in a series of small estuaries in a mostly undeveloped area of 
Santa Barbara County and probably have a fairly high probability of 
persistence, this is not likely to be the general case in California 
where many tidewater goby populations are more isolated.
    Our Response: We agree that not all populations contribute equally 
to the long-term persistence of a species. We relied heavily on the 
documentation of new populations as a rationale for our delisting 
proposal. One of the major reasons we have decided to withdraw this 
proposal is the convincing case made by numerous commenters that 
further information is needed to evaluate new locations.
    Comment 14: One comment letter, received during the third comment 
period in early 2001, noted that a number of the ``new'' populations 
had not been surveyed for years and that some of those that were 
surveyed no longer contained tidewater goby populations. Consequently, 
they were concerned we are relying on outdated population data.
    Our Response: At the time of the proposed delisting rule, we used 
the best available information to evaluate the presence or absence of 
new populations. Clearly, as time goes by, the situation can change. As 
noted above, we agree that further evaluation of the new locations is 

Metapopulation Theory and Population Dynamics

    Comment 15: Several commenters were concerned that the proposed 
delisting rule did not consider current understanding about 
metapopulation or ``source-sink'' dynamics in evaluating the likelihood 
of tidewater goby persistence. The long-term persistence of a 
metapopulation is complex, depending on specific habitat conditions, 
the spatial arrangement of habitats, environmental fluctuations, local 
population dynamics, dispersal probabilities, and other factors, many 
of which are site-specific. A number of commenters expressed their 
opinions that tidewater goby populations likely exhibit ``source-sink'' 
dynamics, where not all local populations contribute to the overall 
persistence of the metapopulation. They suggested that larger 
populations contribute individuals to smaller sites that are not, by 
themselves, sustainable. One commenter estimated that less than 50 
percent of tidewater goby populations can be considered ``sources,'' 
and 30 to 50 percent are either extirpated or ``sinks.'' Another stated 
that the additional twenty or so populations we reported since the 1994 
listing are probably intermittent populations that could be sinks for 
the species as a whole, suggesting that the extinction risk is higher 
than we indicated in the proposed delisting rule. One commenter 
presented a very preliminary metapopulation viability analysis.
    Our Response: Given the comments we received, we agree that we did 
not fully evaluate (1) metapopulation dynamics in the long-term 
persistence of local populations of tidewater gobies and (2) whether or 
not some local populations might behave as ``sinks'' for tidewater 
gobies from other populations. We agree with the commenters that such 
considerations are important in evaluating the likelihood of 
persistence of the tidewater goby. Comments on this topic contributed 
to our decision to withdraw the proposed delisting.
    Comment 16: One peer reviewer noted that true metapopulations are 
exceedingly rare in nature and that other spatially structured models 
may be more appropriate for the tidewater goby. He would not advise 
using a ``true'' metapopulation model.
    Our Response: We cannot evaluate whether the other commenters were 
referring to ``true'' metapopulations or whether they were using the 
terms more loosely, as often occurs. We agree that tidewater goby 
dynamics should probably be evaluated using the most appropriate of the 
more complex models that deal with population dynamics.

Natural Recolonization

    Comment 17: Our delisting proposal relied heavily on our conclusion 
that the tidewater goby has a greater ability than previously thought 
to recolonize habitat from which it is temporarily absent. We felt that 
such ability was associated with an increased likelihood the species 
would persist. Many commenters disagreed with this interpretation, 
suggesting strongly that we had overestimated the tidewater goby's 
potential for recolonization. A number stated that (1) the tidewater 
goby's ability to recolonize habitats is limited, (2) it is not known 
to occur beyond 10 km (6 mi) from source populations, (3) the tidewater 
goby has

[[Page 67809]]

a weak swimming ability for long distances and against the currents of 
an estuarine system, and (4) because of prevailing currents, 
recolonization is most likely to occur to the south rather than the 
north. Many noted recolonization is much less likely in areas where 
populations are more widely separated, have geographic barriers, or 
where there is no nearby population to the north, as occurs in a number 
of areas. One commenter suggested that delisting the northern 
populations of tidewater goby is particularly problematic given the 
apparent one-way movement southward, going with the prevailing 
southerly ocean currents. In one study cited by a commenter, a high 
rate of extinction appeared to be related to a low rate of 
recolonization from outside sources. Another commenter noted that just 
because some recolonization occurs does not mean recolonization rates 
are sufficient to maintain a tidewater goby metapopulation. In 
contrast, one commenter suggested that some, perhaps many, of the new 
populations discovered following the drought were due to recolonization 
from adjacent areas where tidewater gobies remained, although he 
thought it would occur over a relatively short distance and might not 
always be possible (e.g., if a lagoon mouth does not open).
    Our Response: Of the 45 total responses from commenters, 20 were 
identified with tidewater goby experts (multiple responses from some 
commenters) and a majority of these indicated that we overestimated the 
likelihood of natural recolonization of tidewater goby over any 
substantial distance. We are convinced by the commenters' arguments 
that additional time is needed to assess whether natural recolonization 
is as frequent as we assumed in the proposed delisting rule. Our 
delisting proposal relied heavily on our conclusion that recolonization 
was more frequent than previously thought. One of the major reasons we 
have decided to withdraw the proposal is the commenters' convincing 
case that an alternative interpretation may be more appropriate.
    Comment 18: One commenter suggested that we consider tidewater goby 
recolonization in the context of a long-term tidewater goby recovery 
plan. One peer reviewer strongly recommended additional study to 
document if natural recolonization is actually occurring between 
localities where the tidewater goby exists. The peer reviewer and one 
commenter noted the delisting rule presented no alternatives to natural 
recolonization to explain presence/absence data. One alternative to our 
recolonization hypothesis is that local populations periodically 
experience very low abundances under very unfavorable environmental 
conditions, and then, when conditions become favorable, repopulate 
through local reproduction (rather than from recolonization from 
another locality). Repopulation through local reproduction, along with 
little migration, could lead to losses of genetic diversity in local 
populations through bottleneck effects. The peer reviewer suggested 
approaches to evaluate whether this local reproduction hypothesis is 
    Our Response: We agree that further study would be beneficial and 
that such a study would be appropriate as part of a tidewater goby 
recovery plan. In addition, we have added a brief discussion of 
susceptibility of small populations to extirpation from random 
demographic, environmental and/or genetic events to Factor E of the 
Summary of Factors Affecting the Species.
    Comment 19: We stated that a lack of collection efforts at 
appropriate times may explain the absence of well authenticated records 
of the tidewater goby from marine environments outside of enclosed 
coastal lagoons and estuaries. If such collections had been made, we 
implied, tidewater gobies might have been found, providing evidence of 
marine movements consistent with natural recolonization. One commenter 
stated that this argument selectively employs absence of evidence. 
Another noted that some survey work has actually been done by Larry 
Allen of California State University, Northridge, and by James Allen, 
of Marine Environmental Consultants. The commenter noted that, based on 
their negative survey results, it is clear that marine incursions by 
tidewater gobies are very rare and involve very few fish.
    Our Response: As noted above, there are other equally plausible 
interpretations of the data. Accordingly, we have reconsidered our 
rationale regarding recolonization.
    Comment 20: Several commenters noted that a new research paper was 
published, since the time of the proposed delisting, that bears on the 
issue of recolonization as well as metapopulation dynamics.
    Our Response: An unpublished draft of this manuscript was used in 
the preparation of the proposed delisting rule, cited as Lafferty et 
al. in prep. The work has now been published and is cited in this 
notice as Lafferty et al. 1999.

Salinity Tolerance

    Comment 21: In the proposed delisting rule, we reasoned that the 
tidewater goby's tolerance of relatively high salinities indicated 
their potential for successful marine dispersal and recolonization of 
unoccupied habitat. Many commenters strongly disagreed with our 
interpretation. One peer reviewer noted that demonstrating laboratory 
survival in high salinities is not equivalent to showing migration 
through high salinity habitats is likely. He suggested that it is 
necessary to show documented movement of tidewater gobies from one 
estuary to another, either directly through tag and recapture studies, 
or indirectly through targeted genetic studies to show that 
recolonization occurs. Commenters noted that tidewater gobies prefer 
low salinities, that the species is most widespread and abundant in low 
salinity conditions, and that the species is much more restricted in 
saltier systems. Some gave site-specific examples to support their 
assertions. For example, Devereux Lagoon, which becomes hypersaline, no 
longer supports tidewater goby. In addition, the proposed delisting did 
not discuss long-term effects of high salinity on reproductive 
behavior, feeding or successful rearing of juveniles.
    Our Response: As noted above, the commenters arguments regarding 
the likelihood of recolonization are compelling, and we are convinced 
that additional information is necessary to determine whether natural 
recolonization is as frequent as we assumed in the proposed delisting 
rule. We also agree that tolerance to high salinity does not 
necessarily indicate that natural recolonization occurs or is likely. 
Our proposed delisting relied heavily on our conclusion that 
recolonization was more frequent than previously thought. One of the 
major reasons we have decided to withdraw the proposal is the 
commenters' convincing case that an alternative conclusion may be more 

Morro Bay Collection

    Comment 22: We reopened the comment period for the first time in 
response to new information that putative tidewater goby larvae had 
been collected in Morro Bay. The new information came from sampling 
done by Tenera Associates (G. McLaughlin, U.S. Fish and Wildlife 
Service, in litt. undated; Tenera, in litt. undated). We asked the 
public to provide input on how the collection might influence our 
interpretation of the frequency of marine dispersal by tidewater 
gobies. A

[[Page 67810]]

number of commenters responded, and none felt that the collection 
should change our interpretation of the tidewater goby's recolonization 
potential. One commenter suggested that, even if new information 
indicated substantial numbers of tidewater gobies were found in 
nearshore marine waters, it does not change the fact that their 
colonization of new habitats is an uncommon event that occurs close to 
the source population. Several noted that the collection was made 
within Morro Bay and not in the open water, where there were also 
sampling stations. One commenter stated that the appearance of 
tidewater goby larvae in Morro Bay does not indicate the species has 
recovered. In addition, several noted that the species identification 
was not certain. In fact, later genetic analysis showed the specimens 
were not tidewater gobies.
    Our Response: Genetic data, mentioned by commenters, indicate that 
the specimens collected during sampling by Tenera Associates were not, 
in fact, tidewater gobies. Since the specimens were not tidewater 
gobies, the new collection data are not relevant to the frequency of 
marine dispersal by tidewater gobies. As noted above, we find that the 
commenters arguments regarding the potential for tidewater goby 
recolonization provide a convincing case for more study. One of the 
major reasons we have decided to withdraw the proposal is the 
commenters' arguments that the proposed rule overstated the 
recolonization ability of the tidewater goby merit consideration.

Issue 3: Threats to the Tidewater Goby

    The following comments and responses are related to our evaluation 
of threats to the tidewater goby. Some comments provided new 
information; where applicable, this new information was incorporated 
into this withdrawal notice.
    Comment 23: Several commenters objected to our characterization of 
the tidewater goby's status relative to environmental regulations, 
coastal development, and habitat loss and modification north of Orange 
and San Diego Counties. They pointed out that we offered no evidence to 
support our contention that environmental regulations have appreciably 
reduced the potential for substantial habitat loss and modification. 
Rather, we inferred the conclusion from the relatively small number of 
known population extirpations since the implementation of major 
environmental programs in the early 1970s. In fact, the commenters 
note, the other environmental regulatory mechanisms are most effective 
in conjunction with the Act, and some local agencies have already 
discounted the significance of potential effects to the tidewater goby 
based on the proposed delisting.
    Our Response: We are required to use the best available scientific 
and commercial data in making our decisions. We are unaware of any 
studies demonstrating the adequacy or inadequacy of environmental 
regulations enacted since the 1970's. We agree that documentation of 
this would be useful. See additional discussion in Factor D below in 
the Summary of Factors Affecting the Species.
    Comment 24: Several commenters felt that we did not adequately, or 
accurately, assess the current and future threats to the tidewater 
goby, including the threat to tidewater goby populations from coastal 
and upstream development projects, the threat of predation and 
competition by nonnative species, and the cumulative effects of threats 
in combination. One of these commenters noted that smaller wetlands, 
which can be ``stepping stones'' between larger tidewater goby 
habitats, are vulnerable to random events such as drought. On the other 
hand, larger wetlands tend to be susceptible to human activities.
    Our Response: We agree that further analysis of the impacts of 
coastal and upstream development projects, the threat of predation and 
competition by nonnative species, and the cumulative effects of threats 
in combination is needed (see also comment 25 below).
    Comment 25: A number of commenters stated that we were inconsistent 
in our evaluation of the northern versus southern portions of the 
tidewater goby range, suggesting that northern and southern populations 
of tidewater goby face the same threats from development, bridge and 
highway maintenance projects, dredging projects, artificial breaching, 
and inadequate regulatory mechanisms. Several commenters questioned our 
speculation that tidewater goby biology may differ in the southern 
portion of the range, a speculation used, in part, as a rationale for 
north-south distinctions in the rule. One commenter noted that we had 
failed to identify any substantive differences in population 
demographics, habitat variation, and response to disturbance between 
northern and southern tidewater gobies.
    Our Response: We have addressed threats to the tidewater goby 
range-wide in the Summary of Factors Affecting the Species below. To 
the extent that threats remain, it appears that the distinctions 
between threats to the northern and southern portions of the tidewater 
goby range may be less pronounced than we previously believed. 
Furthermore, there currently appears to be little evidence that 
northern and southern tidewater gobies differ in biology.
    Comment 26: One commenter supporting the proposed delisting of 
tidewater goby asked whether tidewater gobies in the northern part of 
the range are threatened or endangered with extinction. He stated that 
whether or not the local populations in the northern range have limited 
gene flow among them does not address the basic question of whether the 
species, as a whole, is endangered. He suggested that new data obtained 
by Dr. Jacobs (presumably since the delisting proposal was published) 
only reveal insights to the genetic structure of the species' 
    Our Response: We agree that Dr. Jacobs's data do not address the 
status of the tidewater goby in the north. As discussed below in the 
Summary of Factors Affecting the Species and in the other comments and 
responses in this section, we believe it is prudent to withdraw the 
proposal to delist the northern populations. Our decision is based 
primarily on scientific comments received during the three comment 
periods questioning the conclusions we drew based on the population 
increases. Specifically, the commenters felt we overemphasized the 
importance of the discovery of new tidewater goby populations and 
overstated the recolonization ability of the tidewater goby. The 
alternate interpretations of the data presented by the commenters have 
led us to believe that additional time is necessary to fully understand 
the dynamic of tidewater goby populations.
    Comment 27: One commenter suggested that one wet-dry climate cycle 
is insufficient to evaluate the resiliency of tidewater goby 
    Our Response: We agree that data from one wet and dry cycle is 
subject to multiple interpretations--none of which is conclusive. We 
discuss the effects of drought in Factor E of the Summary of Factors 
Affecting the Species.

Issue 4: Site-Specific Comments

    The following comments and responses involve site-specific issues. 
Most site-specific issues were incorporated into the withdrawal, as 
appropriate. Two are addressed specifically below.
    Comment 28: The Marine Corps Base, Camp Pendleton, provided 
comments that the proposed southern DPS exists in its entirety on Camp 
Pendleton and that it is not endangered. They provided specific 
information to support this contention, including an increase in

[[Page 67811]]

tidewater goby populations from three to eight and expansion or 
recolonization of all available tidewater goby habitat. They felt that 
(1) considering the southern DPS to be endangered is inconsistent with 
our 1995 Biological Opinion for Riparian and Estuarine/Beach Ecosystems 
on Camp Pendleton which set a recovery goal of six tidewater goby 
populations in six of the eight estuaries on the base, (2) we failed to 
consider and evaluate Camp Pendleton's natural resource management 
plans and efforts, and (3) the proposed southern DPS should be viewed 
as viable and self-sustaining, and not nearing extinction.
    Our Response: There were 13 historic locations of tidewater goby in 
Orange and San Diego counties, of which 8 are intermittently extant on 
Camp Pendleton. All eight localities are relatively pristine coastal 
wetlands and are all crossed or just downstream of Interstate 5 and the 
coastal railway. They are, from north to south, San Mateo Creek, San 
Onofre Creek, Las Flores Creek, Hidden Creek, Aliso Creek, French 
Creek, Cockleburr Creek, and the Santa Margarita River.
    Currently all locations are occupied on Camp Pendleton except 
French Creek and the Santa Margarita River. As recently as 1991, the 
number of occupied tidewater goby localities was only three (Swift and 
Holland 1998, D. Holland, in litt. 1999). Based on survey information, 
San Onofre Lagoon and Los Flores have been consistently occupied since 
1987 (Camp Pendleton INRMP, 2001).
    In 1995, the Service issued a programmatic biological opinion on 
the ``Programmatic Activities and Conservation Plans in Riparian and 
Estuarine/Beach Ecosystems on Marine Corps Base, Camp Pendleton,'' 
including an Estuarine/Beach Ecosystems Conservation Plan (U.S. Fish 
and Wildlife Service, Biological Opinion 1-6-95-F 02, 1995). The 
reasonable and prudent measures of the biological opinion require the 
Marines to adopt and implement the Estuarine/Beach Ecosystem 
Conservation Plan.
    The Estuarine/Beach Ecosystem Conservation Plan is structured to 
minimize the effects to listed species resulting from potential impacts 
associated with ongoing and future training, maintenance, recreation, 
and construction activities. The Marines have the authority to carry 
out the measures in the plan, and because the terms and conditions are 
mandatory, there are assurances that the Conservation Plan will be 
implemented. While the Conservation Plan focuses primarily on avian 
species and does address the tidewater goby generally, it does not 
contain specific biological objectives, recovery criteria, or recovery 
goals for the tidewater goby. While an internal draft recovery plan for 
the tidewater goby had been informally released in 1996, we have not 
formalized and published a draft or final recovery plan for the species 
that establishes recovery criteria and goals for delisting.
    In 2001, Camp Pendleton completed an Integrated Natural Resource 
Management Plan (INRMP) for the Base that addresses the tidewater goby. 
However, the INRMP, does not provide conservation and management 
measures for the tidewater goby beyond those indicated in the 
Conservation Plan.
    In addition, other conditions related to the recent drought 
conditions in southern California and the presence of non-native 
predators have threatened tidewater goby populations. For example, 
Hidden Creek appears to have perennial water flow but may become so 
hypersaline in a severe drought as to be unsuitable for any fish 
species (Swift and Holland 1998). Aliso Creek, French Creek, and 
Cockleburr Creek are all relatively ephemeral and have not supported 
tidewater gobies in times of drought. The Santa Margarita River seemed 
to contain a large stable population until 1991, but tidewater gobies 
disappeared in 1991, shortly after the nonnative yellowfin goby became 
abundant in the estuary.
    Overall, taking into consideration the measures in the Conservation 
Plan for the tidewater goby, the continued threats to the species and 
its habitat, and the species' intermittent occupancy in the drainages 
on Camp Pendleton as discussed above, we believe that the populations 
of tidewater goby on Camp Pendleton still require the protection 
afforded it under the Act.
    Comment 29: The proposed delisting rule overstates the impact of 
the Foothill (South) Transportation Corridor.
    Our Response: The proposed ``CP alignment'' of the Foothill 
Transportation Corridor South (FTCS), if constructed, has the potential 
to negatively impact the tidewater goby, specifically in San Mateo and 
San Onofre Creeks (Michael Brandman and Associates 1998). The lagoons 
at the mouth of San Mateo and San Onofre Creeks are occupied by 
tidewater gobies, and these two lagoons are capable of supporting large 
tidewater goby populations from several thousand to approximately 
70,000 tidewater gobies (Swift and Holland 1998). These two 
populations, along with Las Flores Creek, are the largest and most 
persistent in the region and are thought to serve as source populations 
for dispersal into the ephemeral estuaries and streams in the area. 
Thus, these populations are important to the recovery of the tidewater 
    A preliminary investigation of the impacts to tidewater gobies from 
the CP alignment found that adverse impacts would be less than 
significant after mitigation (Michael Brandman and Associates 1998). 
However, mitigation proposals have not been included as part of the 
project description, and the alternatives for this project are still 
being developed for an Environmental Impact Statement. Absent complete 
mitigation being incorporated into the project, the FTCS CP alignment 
may have both short-term and long-term impacts to tidewater gobies in 
the San Mateo Creek and San Onofre Creek drainage and accompanying 
watershed (Michael Brandman and Associates 1998). Short-term impacts 
could include mortality and temporary loss of habitat for breeding, 
feeding, and sheltering due to blockage or diversion of water flow, 
increased siltation from the required earthen cut and fill, and the 
disturbance of low oxygen sediments. Long-term impacts could include: 
the alteration of the hydrologic regime, primarily in changes to flow 
regimes, temperature patterns, and sediment movement characteristics of 
the streams; loss of habitat for breeding, feeding, and sheltering due 
to siltation; and deterioration in water quality of the streams from 
the input of heavy metals and other contaminants. These types of 
changes to the abiotic elements of a stream are often associated with 
corresponding changes to the ichthyofauna (fish species assemblage 
within a region). Generally, this kind of disturbance results in an 
increase of exotic fish species to the detriment of the indigenous 
(native) ichthyofauna (Moyle and Light 1996). Currently, projects in 
coastal streams are regulated by the California Environmental Quality 
Act (CEQA), the State of California's streambed alteration permit 
program, the Army Corps of Engineers 404 permits and California's 
delegated authorities under the Clean Water Act which regulates 
stormwater runoff from highways and during construction. While such 
effects as are enumerated are possible, they may be remediated in whole 
or in part by these regulatory controls prior to project approval and 

Summary of Factors Affecting the Species

    Section 4(a)(1) of the Act and regulations implementing the listing 
provisions of the Act (50 CFR part 424)

[[Page 67812]]

set forth the procedures for adding species to the Federal list of 
threatened and endangered species. We must consider the five factors 
described in section 4(a)(1) of the Act when determining whether any 
species is an endangered or threatened species. These factors and their 
application to our decision to withdraw the proposal to delist the 
tidewater goby are described below:
    A. The present or threatened destruction, modification, or 
curtailment of its habitat or range.
    Coastal development and habitat modification/loss. The final rule 
listing the tidewater goby indicated that coastal development projects 
that result in the loss of coastal saltmarsh habitat were the major 
threat adversely affecting the tidewater goby. Our delisting proposal, 
on the other hand, stated that north of Orange and San Diego Counties 
such projects, including dredging of waterways for navigation and 
harbors and road construction that severed the connections of marshes 
with the Pacific Ocean, were responsible for historical loss of 
tidewater goby populations. Having reevaluated the number of tidewater 
goby extirpations resulting from coastal development and habitat 
modification and loss, we stated that the potential for the significant 
habitat loss and modification that occurred historically has been 
substantially reduced in the northern portion of the tidewater goby 
range. We postulated that this was largely due to the implementation of 
key environmental regulation required by the Clean Water Act, Coastal 
Zone Management Act, and related California environmental statutes. We 
cited only five permanent extirpations resulting from destruction or 
modification of habitat since the initial promulgation of environmental 
regulations in the early 1970s.
    In Orange and San Diego Counties, we identified several recent 
human activities that may have adversely affected the tidewater goby. 
We specifically discussed activities at San Onofre Creek Lagoon and San 
Mateo Creek Lagoon. We thought both of these locations might be 
important sources of dispersing tidewater gobies, appearing to be two 
of the three most stable populations in the area. We felt that 
population losses or reductions of the San Onofre and San Mateo 
tidewater goby populations were very serious and illustrated ongoing 
adverse impacts of earthmoving activities in and around creeks and 
lagoons in the southern portion of the tidewater goby range.
    As noted above in the Summary of Comments and Recommendations, 
several commenters objected to our characterization of the tidewater 
goby's status relative to coastal development and habitat loss and 
modification north of Orange and San Diego Counties. They state that we 
inferred that environmental regulations have substantially reduced the 
potential for habitat loss and modification from the relatively small 
number of known population extirpations since the implementation of 
major environmental programs in the early 1970s (J. Buse, Environmental 
Defense Center, in litt. 1999, M. Capelli, in litt. 1999). Review of 
pending development projects within the California Coastal Zone 
indicates that development pressure continues (M. Capelli, in litt. 
1999) and economic signs point to dramatic human population increases 
in California in the near future, greatly increasing infrastructure 
needs that could impact coastal watersheds and drainages (Swift, 
Emeritus, Section of Fishes, Natural History Museum of Los Angeles 
County, California, in litt. 2001). Some counties, such as San Luis 
Obispo, are expected to expand by 175 percent by 2010, potentially 
having significant impacts on tidewater goby habitat (S. Christie, 
Environmental Center of San Luis Obispo, in litt. 1999). Human-made 
impacts, combined with the effects of drought, could lead to a 
situation in which a marginal tidewater goby population may not recover 
from the drought as we would predict based on their life history 
(Hight, California Department of Fish and Game, in litt. 2001). The 
tidewater goby's estuarine and coastal lagoon habitats are potentially 
the most highly altered aquatic environments in the state. They are 
threatened by the impacts from coastal development projects and urban 
development, and these threats are likely to continue into the near 
future. Research has shown a pronounced trend toward extirpation when a 
cyclic species encounters drastic anthropogenic disturbance (M. 
Marchetti, California State University, Chico, in litt. 2001).
    Water diversions and groundwater overdrafting. The final listing 
rule stated that upstream water diversions and groundwater overdrafting 
may adversely affect the tidewater goby by altering downstream flows. 
This alteration would diminish the extent of marsh habitats that 
historically occurred at the mouths of most rivers and creeks and 
potentially affect the species' breeding and foraging activities. The 
rule further suggested that alterations of flows upstream of coastal 
lagoons resulting in changes in downstream salinity regimes might 
affect the tidewater goby due to its presumed narrow salinity 
tolerances. The delisting proposal, on the other hand, noted that the 
San Antonio Creek in Santa Barbara County, which was used as an example 
of the adverse effects of groundwater overdrafting, was occupied by 
tidewater gobies in 1995 (but C. Swift, in litt. 1999 suggests the 
proposed delisting rule was in error and should have referred to Santa 
Rosa Creek).
    Scientists who commented on the proposed delisting pointed out that 
extirpation is not the only effect we ought to be concerned about. 
Effects short of complete extirpation should be considered as well. For 
example, population size and stability are important considerations, as 
is the combination of human influences and natural perturbations (M. 
Capelli, in litt. 1999). In fact, the final listing rule also noted 
that negative impacts of water diversions and alterations of flows may 
extend to breeding and foraging activities.
    The delisting proposal also included a lengthy discussion of the 
salinity tolerances of tidewater gobies, suggesting that the tidewater 
goby appears tolerant of a broad range of salinity conditions and 
implying, therefore, that salinity changes due to upstream flow 
alterations would not have adverse effects on the tidewater gobies. 
Some scientists commenting on the proposed delisting suggested that we 
confused salinity tolerance with the natural preference of tidewater 
gobies for mildly brackish water (M. Capelli, in litt. 1999, T. Frink, 
American Fisheries Society, in litt. 1999, R. Swenson, The Nature 
Conservancy, in litt. 1999). Most researchers have found that the 
species is most widespread and abundant in low salinity conditions, and 
much more restricted in saltier systems (T. Frink, in litt. 1999; R. 
Swenson, in litt. 1999). The proposed delisting rule cites only simple 
extreme saline water experiments; one commenter questioned the long-
term effects of saline conditions on critical reproductive behavior, 
feeding, or the successful rearing of juveniles (M. Capelli, in litt. 
1999). Furthermore, the response to salinity of benthic invertebrates 
on which tidewater gobies feed may also be critical in evaluating the 
long-term response of tidewater gobies to high salinities (T. Frink, in 
litt. 1999; R. Swenson, in litt. 1999).
    Channelization. The final listing rule noted that channelization of 
rivers inhabited by the tidewater goby threatens the species because of 
the scouring effects of high winter flows in the restricted channels 
and the lack of protective habitat. The delisting

[[Page 67813]]

proposal stated that, with the exception of Waddell Creek, Santa Cruz 
County, we were unable to identify population extirpation due to 
channelization and that in Waddell Creek, tidewater gobies were 
reestablished in 1991.
    Some scientists who commented on the proposed delisting disagreed 
with both our characterization of the threat from channelization and 
our characterization of the situation at Waddell Creek. The effect of 
channelization is not limited to the increased probability of tidewater 
gobies being swept into marine environments and to lack of refugia but 
also includes direct loss of habitat area and increased rate of urban 
runoff (M. Capelli, in litt. 1999). Additionally, the significance of 
reestablishment in Waddell Creek is questionable because it has not 
been demonstrated that tidewater gobies were extirpated there or 
whether instead they were depressed to the point of not being 
detectable (M. Capelli, in litt. 1999) and because they likely have 
been eliminated again from the lagoon (C. Swift, in litt. 1999). 
Finally, one scientist pointed out that, even if tidewater gobies had 
recolonized, it is not appropriate to extrapolate that finding to all 
localities (M. Capelli, in litt. 1999).
    Cattle and feral pigs. The final listing rule identified cattle 
grazing and feral pig activity as threats to the tidewater goby, 
stating that these activities have resulted in increased sedimentation 
of coastal lagoons and riparian habitats, removal of vegetative cover, 
increased ambient water temperatures, and elimination of plunge pools 
and collapsed undercut banks used by tidewater gobies. The proposed 
delisting rule, on the other hand, argued that many lagoons receiving 
agricultural and sewage effluents are occupied by tidewater gobies and 
they are the most abundant fish species present (e.g., in Santa Barbara 
County lagoons (Ambrose et al. 1993)). Tidewater gobies were also found 
in high numbers in areas with low levels of dissolved oxygen (0.2-1.7 
mg/l) (Worcester 1992, Swift et al. 1997). We concluded, therefore, 
that the tidewater goby appears to be tolerant of agricultural and 
sewage effluents as well as a wide range of dissolved oxygen levels.
    Commenters noted that sedimentation and erosion has also been 
caused by vineyard conversions in some areas (P. Ashley, in litt. 1999; 
S. Christie, in litt. 1999). Scientists who commented on the proposal 
stated that our analysis is insufficient because we have not assessed 
how many populations persist when subject to siltation and topsoil 
runoff (D. Holland, in litt. 1999). Presence of tidewater gobies in a 
particular situation does not mean that tidewater gobies are doing well 
(P. Ashley, biologist, in litt. 1999; C. Swift, in litt. 1999). They 
believe that despite tidewater gobies being present, and even abundant, 
siltation and topsoil runoff and waste discharge may still influence 
tidewater goby declines and future viability of tidewater gobies and 
may be important because of other potential effects (e.g., effects of 
waste discharges on tidewater goby food supply) (M. Capelli, in litt. 
    Numbers of populations/resiliency/recolonization. In the final 
listing rule, we stated that extirpated localities had left remaining 
tidewater goby populations so widely separated that we felt 
recolonization was unlikely. Many lagoons inhabited by tidewater gobies 
were small and widely separated. According to Swift et al. (1990), only 
eight extant localities, all north of San Francisco Bay, contained 
populations considered both large enough and free enough from habitat 
degradation to be safe for the immediate future. The remaining lagoons 
were so small or modified that tidewater goby populations were 
restricted in distribution and vulnerable to elimination (Swift et al. 
1989, 1990).
    In the proposed delisting rule, we stated that new information and 
analyses showed that the tidewater goby is very well adapted to the 
climatically dynamic system in which it evolved and that intermittent 
occupancy of some sites was a normal aspect of the species biology 
(Swift et al. 1994, 1997; Lafferty et al. 1999 (cited in proposed 
delisting as in prep.)). We noted that at the end of the 1987-1992 
drought at least 14 populations thought to be extirpated were found to 
be extant. In addition to these 14 sites, following a return to normal 
or above average rainfall, tidewater gobies were found in approximately 
20 other sites. Our interpretation of this information was that 
recolonization is possible, and in fact, is a normal process following 
habitat variation due to climatic fluctuation (Swift et al. 1994, 1997; 
Lafferty et al. 1999 (cited in proposed delisting as in prep.)). We 
determined that the continued survival of tidewater goby populations, 
after the drought of the late 1980s and early 1990s, indicated we were 
incorrect in concluding that most tidewater goby populations were 
extremely vulnerable to extirpation. However, based on the comments we 
received, we believe it is appropriate to review our interpretations of 
(1) the meaning of additional tidewater goby locations, and (2) the 
likelihood of tidewater gobies recolonizing temporarily unoccupied 
sites. These two premises were fundamental to our rationale to propose 
delisting the northern populations of the tidewater goby; each is 
discussed briefly below.
    The commenters' arguments that a simple enumeration of locations 
where tidewater gobies have been identified is not sufficient to 
evaluate the vulnerability of this species have merit. Information on 
population sizes, trends and/or viabilities is needed to accurately 
assess whether the species or individual populations are likely to 
persist (M. Capelli, in litt. 1999; D. Holland, in litt. 1999; J. 
Smith, San Jose State University, San Jose, California, in litt. 1999; 
C. Swift, in litt. 2001). A number of scientists noted that not all 
local tidewater goby populations contribute equally to the overall 
persistence of the species. The additional populations reported since 
the 1994 listing are likely to be sink populations, smaller sites that 
receive individuals from larger sites, and are not by themselves 
sustainable (C. Swift, in litt. 1999; R. Swenson, The Nature 
Conservancy, in litt. 2001). Therefore, evaluating the vulnerability of 
the tidewater goby will likely require an understanding of the 
interaction among populations or a demonstration of their persistence 
or repeat recolonization (i.e., metapopulation structure, source-sink 
dynamics, other spatial structure) (R. Ambrose, University of 
California, Los Angeles, in litt. 1999; C. Swift, in litt. 1999, 2001; 
R. Swenson, in litt. 2001). As noted by Richard Ambrose (in litt. 
1999), the long-term persistence of a metapopulation depends on 
numerous factors, including specific habitat conditions, the spatial 
arrangement of habitats, environmental fluctuations, local population 
dynamics, dispersal probabilities, and other site-specific factors. In 
the proposed delisting, we did not evaluate the likelihood of tidewater 
goby persistence in terms of this complexity, and we feel that it is 
worthy of further consideration.
    A second reason we proposed to delist the northern populations of 
the tidewater goby was because we felt that the tidewater goby's 
ability to recolonize temporarily unoccupied habitat was greater than 
we had previously thought. We felt that such ability was associated 
with an increased likelihood that the species would persist. As 
evidence that recolonization occurred, we noted the reappearance of 
tidewater gobies after cessation of the drought and tidewater goby 
salinity tolerance. However, recolonization is not the only possible 
explanation for the reappearance of tidewater gobies after the drought 

[[Page 67814]]

M. Capelli, in litt. 1999; T. Turner, University of New Mexico, in 
litt. 2001). In addition, salinity tolerance, particularly as 
determined in laboratory experiments, does not necessarily indicate 
that tidewater gobies will travel through the marine environment to 
recolonize temporarily unoccupied sites (M. Capelli, in litt. 1999; T. 
Frink, in litt. 1999; R. Swenson, in litt. 1999; T. Turner, in litt. 
2001). We believe, based on the evidence presented by the commenters, 
that the tidewater goby's potential for recolonization may be lower 
than we believed at the time of the proposed delisting rule (see also 
comments 15 to 20 above). Information presented by the commenters 
suggests the tidewater goby's ability to recolonize is very limited, 
perhaps no more than 10 km (6 mi) (T. Frink, in litt. 1999; R. Swenson, 
in litt. 1999; Swift et al. 1997 as cited in D. Holland, in litt. 1999; 
Lafferty et al. 1999; C. Swift, in litt. 1999). Recolonization appears 
to be much less likely where populations are more widely separated, 
have geographic barriers, or where there is no nearby population to the 
north (T. Frink, in litt. 1999; R. Swenson, in litt. 1999). Given this 
possible interpretation, we feel the tidewater goby may be more 
vulnerable than we thought at the time of the delisting proposal. We 
believe it is prudent to evaluate its vulnerability in more detail 
before delisting any portion of the species.
    Artificial lagoon breaching. Although not discussed in the final 
listing rule, the proposed delisting also discussed artificial lagoon 
breaching during the dry season as a potential threat to the tidewater 
goby. We considered significant decreases in water level, exposure of 
tidewater goby breeding burrows and bottom habitat, and increased 
salinity resulting from breaching as possible threats to the tidewater 
goby from breaching during the dry season. However, we noted, in the 
northern portion of the tidewater goby range, the species continues to 
persist at numerous locations where unseasonable breaching has occurred 
(Lafferty 1995, Swenson 1995, Lafferty and Alstatt 1995, Heasly et al. 
1997; D. W. Alley, in litt. 1998). Because we had no records of 
breaching-related extirpations, we concluded that breaching does not 
pose a significant threat to the northern populations of the species. 
In the southern portion of the range, we were aware of adverse effects 
on tidewater goby from an artificial breaching at San Onofre Creek 
    The argument we presented in the proposed delisting rule with 
respect to unseasonable breaching was couched entirely in terms of 
extirpation (M. Capelli, in litt. 1999; D. Holland, in litt. 1999; K. 
Lafferty, U.S. Geological Survey and University of California, Santa 
Barbara, in litt. 1999). Commenters noted a significant threat to 
tidewater goby populations via loss of individuals, a significant 
portion of a population, and/or changes in the quality or quantity of 
habitat may well occur during breaching (M. Capelli, in litt. 1999; D. 
Holland, in litt. 1999; K. Lafferty, in litt. 1999). Commenters opined 
that repeated disturbance from breaching events could also jeopardize 
food supplies for tidewater gobies in lagoon habitats (Swenson 1999 as 
cited in R. Swenson, in litt. 1999). Although breaching can reduce 
population densities and alter hydrology in ways that may be 
detrimental to tidewater gobies, several populations manage to persist 
with regular breaching and it is not possible, given the information 
available, to determine when and where breaching will lead to 
extirpation (K. Lafferty, in litt. 1999).
    One reason we proposed delisting the northern populations of 
tidewater goby was that we felt threats to the populations were less 
severe than we believed at the time of listing. Some commenters 
provided information suggesting that there is cause for concern about 
the impacts of coastal development, habitat modification and loss, 
water diversions, channelization, cattle and pigs, and artificial 
lagoon breaching on tidewater goby populations throughout its range. As 
noted below in Factors C and E, such impacts may also exacerbate 
threats from other sources (e.g., predation by non-native fish). In 
light of these considerations, we believe the prudent course of action 
is to withdraw the proposed delisting.
    B. Overutilization for commercial, recreational, scientific, or 
educational purposes. Overutilization is not known to be applicable; 
there is no change in this factor since the delisting proposal in 1999.
    C. Disease or predation. Disease was not identified as a threat in 
the final listing rule or the delisting proposal, nor is it known to be 
a threat at this time.
    Trematodes. The proposed delisting rule noted that the digenean 
trematode (a flatworm or fluke) Cryptocotyle lingua could have been a 
factor in the apparent population decline of tidewater gobies in 
Pescadero Lagoon in 1992 and 1993 (Swenson 1995). The trematode species 
also had been reported from Corcoran (Rodeo) Lagoon in Santa Cruz 
County (Swift et al. 1989), where we felt it did not affect tidewater 
goby populations. In fact, there has been no appropriate investigation 
to determine whether trematodes are a significant source of mortality 
in tidewater gobies. However, they are known to be an important 
mortality source in other fish species. For example, trematodes can 
cause up to a 30-fold increase in killifish mortality (Lafferty and 
Morris 1996 as cited in K. Lafferty, in litt. 1999).
    Nonnative predators. The final listing rule stated that introduced 
predators, especially centrarchid fish, may have contributed to the 
elimination of the tidewater goby from several localities in California 
(Swift et al. 1989). We noted that the present day absence of the 
tidewater goby from the Sacramento-San Joaquin River delta and San 
Francisco Bay area may well be explained by the presence of introduced 
predators such as striped bass and native predators including 
Sacramento perch (Swift et al. 1989, 1990) (see also Background 
section). At that time, two recent disappearances of tidewater gobies 
were also likely due to the presence of exotic largemouth bass 
(Micropterous salmoides) and green sunfish (Lepomis cyanellus), in Old 
Creek of San Luis Obispo County and San Onofre Creek of San Diego 
County, respectively (Swift et al. 1989). Additionally, we were 
concerned that direct predation on adults, larvae, or eggs by other 
nonnative predators, such as crayfish (Cambarus spp.) and mosquitofish, 
might threaten the tidewater goby.
    In the delisting proposal, we asserted that tidewater goby 
populations north of Orange and San Diego Counties were not 
particularly vulnerable to these introduced fish. Centrarchid fish were 
known, at the time, to exist at many sites inhabited by large 
populations of tidewater gobies (e.g., Santa Clara River, Las Pulgas 
Creek, San Mateo Creek). The threat of tidewater goby extirpation 
throughout its habitat as a result of predation by these nonnatives was 
thought to be minimal because (1) tidewater goby populations were large 
and able to repopulate from adjacent streams and (2) tidewater gobies 
have a wider range of salinity tolerance than the nonnative fish do. 
Although nonnative fish consume tidewater gobies, we felt the predation 
was not a serious threat. We also noted that tidewater gobies occur in 
large numbers in at least one location (Santa Clara River) occupied by 
African clawed frogs, which also feed on tidewater gobies. We implied 
that the co-occurrence of both African frogs and nonnative fish with 
tidewater gobies meant that predation was not a threat.
    In contrast, we felt that nonnative predation could be a threat to 
tidewater gobies in Orange and San Diego

[[Page 67815]]

Counties when combined with other factors such as habitat disturbance. 
We noted that nonnative predators could prevent or contribute to 
significant reductions in dispersal and recolonization of sites in 
southern California. Nonnative fish were thought to have played a role 
in population losses or declines in San Onofre Creek and the Santa 
Margarita River. In addition, yellowfin goby was, by that time, 
established in most lagoons inhabited by tidewater gobies in Orange and 
San Diego Counties. We received no comments that allay our concerns 
that ongoing impacts continue to endanger the tidewater goby in 
southern California.
    Based on comments and new information we received, it appears that 
nonnative predators are likely to be a threat to tidewater gobies 
throughout their range. We implied in the proposed delisting that the 
presence of tidewater gobies with nonnative species (i.e., co-
occurrence) indicated that predation by nonnatives was not a threat. In 
fact, co-occurrence does not necessarily suggest that long-term co-
existence is likely (K. Lafferty, in litt. 1999; C. Swift, in litt. 
1999). Although direct evidence that introductions of nonnatives led to 
extirpations of tidewater gobies is lacking, tidewater gobies did 
disappear from several localities soon after centrarchid fish were 
introduced (Swift et al. 1989, 1994; Rathbun et al. 1991). Commenters 
noted specific examples of situations where predation by nonnatives may 
have negatively affected tidewater goby populations (M. Capelli, in 
litt. 1999; D. Holland, in litt. 1999; C. Swift, in litt. 1999). In the 
Santa Ynez River system, tidewater gobies accounted for 61 percent of 
the prey volume of 55 percent (10 of 18) of the juvenile largemouth 
bass sampled (Swift et al. 1997, M. Capelli, in litt. 1999). The 
decline and subsequent recovery of the tidewater goby population in Las 
Pulgas Creek closely tracked the absence of green sunfish from the 
lagoon in this system (Swift and Holland 1998 as cited in D. Holland, 
in litt. 1999). The elimination of tidewater gobies from the Santa 
Margarita may have been due to the combined influence of nonnative 
species and decreasing habitat available for the tidewater goby (Swift 
and Holland 1998 as cited in D. Holland, in litt. 1999). Largemouth 
bass in Old Creek of San Luis Obispo County are likely responsible for 
the elimination and prevention of re-establishment of tidewater gobies 
there (D. Holland, in litt. 1999). The evidence suggests that nonnative 
fish are often introduced to tidewater goby habitats, prey on tidewater 
gobies, and in some documented cases, may lead to the extirpation of 
tidewater gobies. This evidence, though indirect, suggests that some 
nonnative predators can have negative impacts on tidewater gobies, 
including extirpation (K. Lafferty, in litt. 1999). In addition, 
predation by nonnatives may have negative effects short of extirpation, 
reducing tidewater goby population sizes and, thereby, rendering 
populations more vulnerable over the long-term to extirpation as a 
result of natural perturbations of habitat conditions at the site (M. 
Capelli, in litt. 1999).
    Some commenters believed that tidewater gobies may have limited 
ability to repopulate from adjacent streams. We suggested that the 
ability to repopulate, along with sufficiently large population sizes, 
made predation by nonnatives a minimal threat. The commenters 
questioned how many tidewater goby populations might be considered 
large and how population fluctuations might affect vulnerability (D. 
Holland, in litt. 1999, see also comments 13 and 15). In addition, as 
noted elsewhere (see comments 17 to 22 and Factor A), the dispersal 
ability of tidewater gobies may be very limited, making repopulation of 
extirpated sites problematic (D. Holland, in litt. 1999).
    Our argument that tidewater gobies are not threatened by nonnatives 
because tidewater gobies have a wider salinity tolerance was not 
supported by scientists commenting on the proposal. The commenters 
assert that many of the species known or thought to prey on tidewater 
goby have a wide range of salinity tolerance, including striped bass, 
chameleon gobies, yellowfin gobies and shimfuri gobies (D. Holland, in 
litt. 1999). Additionally, some commenters asserted that the habitat of 
the tidewater goby may be essentially freshwater for part, or even 
much, of the year (Swift and Holland 1998 as cited in D. Holland, in 
litt. 1999), making tidewater gobies vulnerable even to nonnative 
species with limited salinity tolerance, including largemouth bass, 
green sunfish, African clawed frogs, and others (M. Capelli, in litt. 
1999; D. Holland, in litt. 1999).
    Finally, commenters speculated that ranges of current nonnative 
species may expand (e.g., African clawed frog, yellowfin goby), and new 
nonnative species (e.g., Chinese mitten crabs (Eriocheir sinensis)) may 
become a problem in the future. Some establishment and movement of 
nonnatives may be facilitated by water redistribution plans (D. 
Holland, in litt. 1999).
    We received comments to the effect that there is cause for concern 
about the impacts of nonnative species on tidewater gobies (M. Capelli, 
in litt. 1999; D. Holland, in litt. 1999; K. Lafferty, in litt. 1999; 
C. Swift, in litt. 1999). The commenters surmise that if nonnative 
species are not responsible for tidewater goby declines by themselves, 
they may be important in concert with factors such as drought, habitat 
loss or alteration, and natural or anthropogenically induced 
fluctuations in population size (M. Capelli, in litt. 1999; D. Holland, 
in litt. 1999).
    D. The inadequacy of existing regulatory mechanisms. A number of 
existing State, local, and Federal regulatory requirements provide some 
protection to the tidewater goby. Section 10 of the Rivers and Harbors 
Act, section 404 of the Clean Water Act, the National Environmental 
Policy Act (NEPA), the California Environmental Quality Act (CEQA), the 
California Coastal Act, the California Department of Fish and Game's 
streambed alteration permit program, and the State Water Resources 
Control Board's stormwater control program all provide some level of 
protection for the goby and its habitat. At the time of the original 
listing, however, we concluded that the existing regulatory mechanisms 
were inadequate to protect the tidewater goby.
    In the proposed delisting rule, we changed our position, stating 
that there is little evidence to support the conclusion that existing 
regulatory mechanisms inadequately protect the tidewater goby or are 
contributing to substantial or widespread population decline and loss 
in the northern portion of the species' range. We stated that (1) 
review and permitting of projects under sections 10 and 404 was 
unlikely to allow the extent of destruction and modification of habitat 
that occurred prior to their implementation, (2) measures included in 
section 404 permits because of the presence of other listed and 
sensitive species (e.g., California red-legged frog (Rana aurora 
draytonii), steelhead trout (Oncorhynchus mykiss), unarmored threespine 
stickleback (Gasterosteus aculeatus williamsoni)) provide protection of 
tidewater goby habitat, (3) a review of the Environmental Protection 
Agency's (EPA's) AQUIRE on-line database found no contaminant data 
directly relating to tidewater goby, and (4) in the current regulatory 
environment, little evidence exists to support the conclusion that 
water diversions, groundwater overdrafting, and modifications in 
salinity regimes, or the discharge of effluents are posing a

[[Page 67816]]

significant threat to the tidewater goby. In contrast, we felt that 
existing regulatory mechanisms failed to protect tidewater gobies in 
the southern portion of the range. We were concerned because the small 
number of extant tidewater goby populations in Orange and San Diego 
Counties would make the loss of any one population a greater cause for 
concern than in the northern portion of the range.
    Several commenters expressed concern over our changed perspective 
about the northern range. They stated that we presented no evidence to 
support the contention that environmental regulations have 
substantially reduced the potential for the substantial habitat loss 
and modification that occurred historically, instead inferring the 
conclusion from the relatively small number of known population 
extirpations since the implementation of major environmental programs 
in the early 1970s (J. Buse, in litt. 1999). Commenters also claimed 
that our assertion that tidewater goby will be protected by measures 
for other listed and sensitive species assumes that the species have 
substantially the same requirements, have the same timing of life 
history stages, or share the same habitats (J. Buse, in litt. 1999; M. 
Capelli, in litt. 1999; T. Frink, in litt. 1999; D. Holland, in litt. 
1999; S. Manion, Resource Conservation District of the Santa Monica 
Mountains, in litt. 1999; J. Smith, in litt. 1999; R. Swenson, in litt. 
1999; A. Wetzler and M. Gold, in litt. 1999). This may not be the case; 
in fact, there is not complete overlap in the distribution of these 
species and the tidewater goby (e.g., J. Buse, in litt. 1999; D. 
Holland, in litt. 1999; R. Swenson, in litt. 1999). For example, 
steelhead and unarmored threespine stickleback are not found in all 
locations where tidewater gobies occur (J. Buse, in litt. 1999; R. 
Swenson, in litt. 1999). Similarly, the range of the California red-
legged frog only extends to the vicinity of Point Reyes National 
Seashore, leaving tidewater gobies north of that area no protection 
from those regulations protecting the frog (D. Holland, in litt. 1999).
    Several comments also suggested that regulatory agencies (e.g., 
Corps, California Coastal Commission) and some local governments have 
only become aware of the tidewater goby since it was listed and that 
the Act has, in fact, protected populations of the tidewater goby (J. 
Buse, in litt. 1999; M. Capelli, in litt. 1999). We agree that listing 
the goby under the Endangered Species Act has provided focused 
protection to this species and that, if the tidewater goby remains 
listed, proposed and future project proponents and agencies will be 
more likely to specifically consider the tidewater goby in their 
planning. That benefit notwithstanding, we have not changed our view 
that review and permitting of projects under sections 10 and 404 as 
well as other state and local programs is unlikely to allow the extent 
of destruction and modification of habitat that occurred prior to the 
    Finally, several comments took issue with our interpretation of the 
results of our search of EPA's AQUIRE database. They indicated that a 
vast body of literature documents the effects of effluents, runoff and 
contaminants on aquatic organisms and habitats. Even if species-
specific data about effects to the goby are lacking, this body of 
literature suggests effluents, runoff, and contaminants could be a 
threat to the tidewater goby (D. Holland, in litt. 1999), to the extent 
that they remain even after the prevention and remediation measures 
required by various local, State, and Federal regulations.
    We continue to believe that existing State, local, and Federal 
regulatory mechanisms provide substantial protections to the tidewater 
goby. We recognize that these existing mechanisms may not address all 
the threats to the goby discussed in this notice, and are not in 
themselves sufficient basis to delist the species.
    E. Other natural or manmade factors affecting their continued 
    Drought. In the final listing rule, we stated that the most 
significant natural factor adversely affecting the tidewater goby was 
drought and the resultant deterioration of coastal and riparian 
habitats. At the time, California had recently experienced five 
consecutive years of lower than average rainfall. We felt that these 
drought conditions, when combined with human-induced water reductions, 
degraded coastal and riparian ecosystems and created extremely 
stressful conditions for aquatic species. Formerly large tidewater goby 
populations declined in numbers at this time because of the reduced 
availability of suitable lagoon habitats (e.g., San Simeon Creek, Pico 
Creek). Other tidewater goby populations disappeared when lagoons dried 
(e.g., Santa Rosa Creek).
    The proposed delisting rule reported that, since the end of the 
drought, 14 sites believed to be extirpated had been recolonized. The 
survival and recovery of these populations following the drought 
alleviated the concern that drought exacerbated by human-induced water 
reductions would result in significant permanent population decline and 
loss. In southern California, however, we stated that the loss of many 
of the larger tidewater goby populations had made recolonization of 
smaller intermittent lagoons much more unlikely. Therefore, we 
concluded that extended droughts, along with other physical alterations 
to the lagoons, threatened the southern California portion of the 
tidewater goby range.
    Periodic droughts are a historical feature of California, which has 
been repeatedly subject to prolonged droughts (M. Capelli, in litt. 
1999; T. Frink, in litt. 1999; D. Holland, in litt. 1999; R. Swenson, 
in litt. 1999). We have documentation in the final listing rule and the 
proposed delisting rule of the dramatic effects drought can have on the 
tidewater goby. It is not unexpected that species respond to climatic 
fluctuations, booming when conditions are favorable and declining 
sharply when conditions are adverse (T. Frink, in litt. 1999; R. 
Swenson, in litt. 1999; W. Watson, fisheries biologist, in litt. 2000; 
M. Marchetti, in litt. 2001). Such natural population fluctuations 
assume a different character when considered in conjunction with other 
threats to the species, such as coastal development projects, 
freshwater diversions, pollution, siltation, urban development, and 
introduced species. A large body of scientific research has 
demonstrated that when a cyclic species encounters drastic 
anthropogenic disturbance, there is pronounced threat of extirpation 
(M. Marchetti, in litt. 2001). When coupled with the other human-
related modifications to the habitat of the tidewater goby, these 
droughts increase in significance, and will undoubtedly be repeated in 
the future (M. Capelli, in litt. 1999; D. Holland, in litt. 1999). In 
addition, because the tidewater goby has life history characteristics 
that make it vulnerable to extirpation (e.g., short lifespan, 
preference for still water and low-salinity habitats that have a 
limited distribution, and lack of marine dispersal in all but wet 
years), there may be little buffer for the species when drought returns 
(Swenson, in litt. 1999). Finally, widely dispersed populations of 
tidewater gobies occur in the northern portion of the range as well as 
in the southern portion (M. Capelli, in litt. 1999). We argued in the 
proposed delisting rule that tidewater gobies in the southern portion 
of the range were threatened by extended droughts because many of the 
larger tidewater goby populations had been lost, making recolonization 
of smaller intermittent lagoons much more unlikely. Because it appears 
that recolonization may not occur over anything but short distances

[[Page 67817]]

(i.e., 10 km (6 mi)) (see comments 17 to 22 and Factor A above) and 
because populations in the northern portion of the range appear to be 
widely separated, we believe we need to reevaluate our assertion that 
only southern tidewater goby populations are threatened by drought.
    We have reconsidered our analysis of the tidewater goby's status 
with respect to drought. When evaluating the status of a species which 
fluctuates widely in response to climatic conditions, we should 
consider a time period which includes the full range of climatic 
variation. In proposing to delist the tidewater goby, we considered 
only one drought cycle. Drought can have dramatic negative effects on 
tidewater goby, at least decreasing goby populations to very low levels 
(perhaps to the point where they are undetectable) and at most 
extirpating populations (see final listing rule and delisting 
proposal). Because future droughts in California are a certainty, we 
know that tidewater gobies will be subject to the negative effects of 
drought again. We need to consider the potential magnitude and 
importance of these drought events on long-term persistence of the 
tidewater goby prior to delisting any portion of the range of the 
    Flooding. In the final listing rule we indicated that events such 
as river flooding and heavy rainfall have reportedly destroyed 
tidewater goby burrows and washed tidewater gobies out to sea. While 
the tidewater goby was undoubtedly subjected to natural flood events 
before major human alteration of drainage basins, urbanization and 
channelization increased the frequency, and perhaps the intensity, of 
the events. Increased isolation of tidewater goby populations through 
extirpation of intervening populations reduces the likelihood of 
successful recolonization after a population is lost in a flood event.
    In the proposed delisting rule, we changed our position, stating 
that flood events have been shown to have no significant adverse effect 
on tidewater goby populations. Instead, we felt the flushing action of 
floods was probably the primary mechanism for colonization of other 
habitats along the coast (Lafferty et al. 1996, Swift et al. 1997). In 
southern California, however, we observed that the historic extirpation 
of many tidewater goby populations has left the remaining populations 
more isolated. Thus, tidewater gobies must travel greater distances and 
from smaller source populations, making natural recolonization much 
more uncertain and difficult. We implied that, on balance, this 
isolation made flooding more detrimental in southern California than it 
was in northern California.
    As has been mentioned above, we may have overestimated the 
tidewater goby's potential for recolonization. If the tidewater goby's 
ability to recolonize sites is actually highly restricted (i.e., no 
more than 10 km (6 mi) (T. Frink, in litt. 1999; R. Swenson, in litt. 
1999; Swift et al. 1997 as cited in D. Holland, in litt. 1999), the 
degree of isolation of tidewater goby populations in northern 
California is greater than we estimated at the time of the delisting 
    Competition with nonnative species. In the final listing rule we 
stated that competition with introduced species is a potential threat 
to the tidewater goby. At the time, no problems had been reported, but 
we were concerned that the spread of the introduced yellowfin goby and 
chameleon goby might have a detrimental effect of the tidewater goby. 
In the proposed delisting rule, we stated that no documented 
extirpation or population decline can be directly attributed to these 
or other introduced competing species. However, as noted by Holland (in 
litt. 1999), direct evidence of extirpation or population decline 
through competition is rarely forthcoming, especially without focused 
surveys. Further research may clarify the impact of competition on 
tidewater goby.
    Population size. Tidewater goby populations are known to fluctuate 
in size within and between years (Swift et al. 1989, Holland 1992, 
Swift and Holland 1998 as cited in D. Holland, in litt. 1999). 
Populations that are continuously small, or that fluctuate to small 
size (as tidewater goby populations tend to do), are more susceptible 
to extirpation from random demographic, environmental, and genetic 
events than larger populations are. Demographic events that may put 
small populations at risk involve chance variation in age, sex ratios, 
and other population characteristics, which can change birth and death 
rates (Shaffer 1981, 1987; Lande 1988; Meffe and Carroll 1997; Primack 
1998). Small, isolated populations are also vulnerable to genetic drift 
(random changes in gene frequencies) and inbreeding (mating between 
close relatives). Genetic drift and inbreeding may lead to reductions 
in the ability of individuals to survive and reproduce (i.e., 
reductions in fitness) in small populations. In addition, reduced 
genetic variation in small populations may decrease the potential for 
persistence in the face of long-term environmental change (Shaffer 
1981, 1987; Primack 1998).

Finding and Withdrawal

    We proposed to delist the northern portion of the tidewater goby 
range because we felt the original listing was in error. Specifically, 
we believed that new evidence showed that (1) there were more 
populations in the northern portion of the range at the time of the 
delisting proposal than at the time of the listing, (2) the threats to 
those populations were less severe than previously believed, and (3) 
the tidewater goby has a greater ability to recolonize than was known 
at the time of the listing. We received 45 responses from individuals, 
agencies or other parties. Thirty-eight of the responses opposed our 
proposal to remove the northern populations of the tidewater goby from 
the list of endangered and threatened wildlife. Most commenters did not 
agree that the original listing was in error. Further, our specific 
conclusions in the proposal were not corroborated by the comments we 
received during the three comment periods. In particular, the 
commenters, including many tidewater goby scientific researchers, 
suggested that we overemphasized the importance of the discovery of new 
tidewater goby populations, that we minimized the severity of the 
threats in the northern portion of the range, and that we overstated 
the recolonization ability of the tidewater goby. After review of the 
information presented, we find the commenters' arguments with respect 
to the goby's ability to recolonize compelling and believe that it is 
prudent to withdraw the proposed delisting. Withdrawing the delisting 
proposal for the northern populations of the tidewater goby makes the 
establishment of an endangered southern California DPS unnecessary. We 
will focus instead on proceeding with the recovery planning process 
that will both guide conservation activities for the species and make 
explicit under what criteria the tidewater goby should be considered 
for delisting.
    We conclude, therefore, based on our review of the best information 
currently available, including these comments and the recommendations 
of two scientific peer reviewers, and for the reasons discussed 
throughout this withdrawal notice, that the tidewater goby should 
remain listed as an endangered species throughout its range. We 
withdraw our June 24, 1999, proposal to remove the northern populations 
of tidewater goby from the list of endangered and threatened wildlife 
and the concurrent proposal to establish an endangered distinct 
population segment of tidewater goby in Orange and San Diego

[[Page 67818]]

Counties, CA (64 FR 33816).

References Cited

    A complete list of all references we cited, as well as others, is 
available on request from our Ventura Fish and Wildlife Office (see 
ADDRESSES section).

    Dated: November 1, 2002.
Steve Williams,
Director, Fish and Wildlife Service.
[FR Doc. 02-28282 Filed 11-6-02; 8:45 am]