Endangered and Threatened Wildlife and Plants; Designation of Revised Critical Habitat for the Tidewater Goby, 64996-65060 [2011-26301]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 202 (Wednesday, October 19, 2011)]
[Proposed Rules]
[Pages 64996-65060]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-26301]



[[Page 64995]]

Vol. 76

Wednesday,

No. 202

October 19, 2011

Part II





Department of the Interior





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 Fish and Wildlife Service





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50 CFR Part 17





 Endangered and Threatened Wildlife and Plants; Designation of Revised 
Critical Habitat for the Tidewater Goby; Proposed Rule

Federal Register / Vol. 76 , No. 202 / Wednesday, October 19, 2011 / 
Proposed Rules

[[Page 64996]]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2011-0085; MO 92210-0-0009]
RIN 1018-AX39


Endangered and Threatened Wildlife and Plants; Designation of 
Revised Critical Habitat for the Tidewater Goby

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
revise critical habitat for the tidewater goby (Eucyclogobius 
newberryi) under the Endangered Species Act of 1973, as amended (Act). 
In total, approximately 12,157 acres (4,920 hectares) are being 
proposed for designation as critical habitat. The proposed revised 
critical habitat is located in Del Norte, Humboldt, Mendocino, Sonoma, 
Marin, San Mateo, Santa Cruz, Monterey, San Luis Obispo, Santa Barbara, 
Ventura, Los Angeles, Orange, and San Diego Counties, California.

DATES: We will accept comments received or postmarked on or before 
December 19, 2011. We must receive requests for public hearings, in 
writing, at one of the addresses shown in the FOR FURTHER INFORMATION 
CONTACT section by December 5, 2011.

ADDRESSES: You may submit comments by one of the following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal: https://www.regulations.gov. In the Enter Keyword or ID box, enter Docket No. 
FWS-R8-ES-2011-0085, which is the docket number for this rulemaking.
    (2) By hard copy: Submit by U.S. mail or hand-delivery to: Public 
Comments Processing, Attn: FWS-R8-ES-2011-0085; Division of Policy and 
Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax 
Drive, MS 2042-PDM; Arlington, VA 22203.
    We will post all comments on https://www.regulations.gov. This 
generally means that we will post any personal information you provide 
us (see the Public Comments section below for more information).

FOR FURTHER INFORMATION CONTACT: For general information, and 
information about the proposed designation in Santa Cruz, Monterey, San 
Luis Obispo, Santa Barbara, Ventura, and Los Angeles Counties, contact 
Diane K. Noda, Field Supervisor, U.S. Fish and Wildlife Service, 
Ventura Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, 
CA 93003; telephone 805-644-1766; facsimile 805-644-3958.
    For information about the proposed designation in Del Norte, 
Humboldt, and Mendocino Counties, contact Nancy Finley, Field 
Supervisor, Arcata Fish and Wildlife Office, 1655 Heindon Road, Arcata, 
CA 95521 (telephone 707-822-7201; facsimile 707-822-8411).
    For information about the proposed designation in Sonoma, Marin, 
and San Mateo Counties, contact Susan Moore, Field Supervisor, 
Sacramento Fish and Wildlife Office, U.S. Fish and Wildlife Service, 
2800 Cottage Way, Suite W-2605, Sacramento, CA 95825 (telephone 916-
414-6600; facsimile 916-414-6712).
    For information about the proposed designation in Orange and San 
Diego Counties, contact Jim Bartel, Field Supervisor, Carlsbad Fish and 
Wildlife Service Office, 6010 Hidden Valley Road, Suite 101, Carlsbad, 
CA 92011 (telephone 760-431-9440; facsimile 760-431-5901).
    If you use a telecommunications device for the deaf (TDD), call the 
Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Public Comments

    We intend that any final action resulting from this proposed rule 
will be based on the best scientific and commercial data available, and 
be as accurate and as effective as possible. Therefore, we request 
comments or information from other concerned government agencies, the 
scientific community, industry, or any other interested party 
concerning this proposed revised rule. We particularly seek comments 
concerning:
    (1) The reasons why we should or should not designate habitat as 
``critical habitat'' under section 4 of the Act (16 U.S.C. 1531 et 
seq.), including whether there are threats to the species from human 
activity, the degree of which can be expected to increase due to the 
designation, and whether that increase in threat outweighs the benefit 
of designation such that the designation of critical habitat may not be 
prudent.
    (2) Specific information on:
    (a) The amount and distribution of tidewater goby habitat;
    (b) Which areas that are within the geographical area occupied at 
the time of listing (or are currently occupied) contain features 
essential to the conservation of the species, should be included in the 
designation and why;
    (c) Special management considerations or protection that may be 
needed for the physical or biological features essential to the 
conservation of the species in areas we are proposing, including 
managing for the potential effects of climate change; and
    (d) What areas outside the geographical area occupied at the time 
of listing that should be included in the designation because they are 
essential for the conservation of the species and why.
    (3) Land use designations and current or planned activities in the 
subject areas and their possible impacts on proposed critical habitat.
    (4) Information on the projected and reasonably likely impacts of 
climate change on the tidewater goby, the features essential to its 
conservation and the areas proposed as critical habitat.
    (5) Any probable economic, national security, environmental, 
cultural, or other relevant impacts of designating any area that may be 
included in the final designation; in particular, any impacts on small 
entities, and the benefits of including or excluding areas that exhibit 
these impacts.
    (6) Any information on potential threats to habitat and the 
feasibility of reintroduction or introduction of the tidewater goby to: 
Walker Creek, Bolinas Lagoon, Pomponio Creek, Waddell Creek, Salinas 
River, Arroyo del Cruz, Oso Flaco Lake, Arroyo Sequit, Zuma Creek, 
Aliso Creek, or any other areas identified for reintroduction or 
introduction in the recovery plan for the tidewater goby (Service 
2005), and the reasons why we should or should not designate these or 
other unoccupied areas as critical habitat for the tidewater goby.
    (7) Specifically with reference to those State Park lands under the 
jurisdiction of the California Department of Parks and Recreation 
(CDPR) that are proposed for designation, information on any areas 
covered by conservation or management plans that we should consider for 
exclusion from the designation under section 4(b)(2) of the Act.
    (8) Any additional proposed critical habitat areas covered by 
conservation or management plans that we should consider for exclusion 
from the designation under section 4(b)(2) of the Act. We specifically 
request any information on any operative or draft habitat conservation 
plans for the tidewater goby that have been prepared under section 
10(a)(1)(B) of the Act, or any other management or other conservation 
plan or agreement that benefits the tidewater goby or its primary 
constituent elements.
    (9) Any information concerning tribal lands or trust resources that 
may be

[[Page 64997]]

impacted by this proposed revision to critical habitat.
    (10) Whether our exemption under section 4(a)(3)(B) of the Act of 
Department of Defense land at Vandenberg Air Force Base (VAFB) in Santa 
Barbara County, and Marine Corps Base (MCB) Camp Pendleton in San Diego 
County, is or is not appropriate, and why.
    (11) Whether we could improve or modify our approach to designating 
critical habitat in any way to provide for greater public participation 
and understanding, or to better accommodate public concerns and 
comments.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section. We request 
that you send comments only by the methods described in the ADDRESSES 
section. We will post your entire comment--including your personal 
identifying information--on https://www.regulations.gov. You may request 
at the top of your document that we withhold personal information such 
as your street address, phone number, or email address from public 
review; however, we cannot guarantee that we will be able to do so.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on https://www.regulations.gov, or by 
appointment, during normal business hours, at the U.S. Fish and 
Wildlife Service, Ventura Fish and Wildlife Office (see FOR FURTHER 
INFORMATION CONTACT).

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of critical habitat for the tidewater goby in this 
proposed rule. This proposed rule incorporates new information on 
tidewater goby genetics and distribution that was not available when we 
completed our 2008 final critical habitat designation (73 FR 5920; 
January 31, 2008). A summary of topics that are relevant to this 
proposed critical habitat designation is provided below. For more 
information on tidewater goby taxonomy, biology, and ecology, please 
refer to: the final listing rule published in the Federal Register on 
February 4, 1994 (59 FR 5494); the first and second rules proposing 
critical habitat published in the Federal Register on August 3, 1999 
(64 FR 42250) and November 28, 2006 (71 FR 68914), respectively; and 
the subsequent final critical habitat designations published in the 
Federal Register on November 20, 2000 (65 FR 69693) and January 31, 
2008 (73 FR 5920). Additionally, more species information can be found 
in the Recovery Plan for the Tidewater Goby (Recovery Plan) (Service 
2005), and in the Tidewater Goby 5-year review (Service 2007).

Species Description and Genetic/Morphological Characteristics

    The tidewater goby is a small, elongate, grey-brown fish rarely 
exceeding 2 inches (in) (5 centimeters (cm)) in length. This species 
possesses large pectoral fins, with the pelvic or ventral fins joined 
to each other beginning below the chest and belly and from below the 
gill cover back to just anterior of the anus. Male tidewater goby are 
nearly transparent with a mottled brown upper surface. Female tidewater 
goby develop darker colors, often black, on the body and dorsal and 
anal fins. Tidewater goby are short-lived species; the lifespan of most 
individuals appears to be about 1 year (Irwin and Soltz 1984, p. 26; 
Swift et al. 1989, p. 4; M. Hellmair, pers. comm. 2010).
    Various genetic markers demonstrate that pronounced differences 
exist in the genetic structure of the tidewater goby, and that 
tidewater goby populations in some locations are genetically distinct. 
A study of mitochondrial DNA and cytochrome b (molecular material used 
in genetic studies) sequences from tidewater goby that were collected 
at 31 locations throughout the species' geographic range has identified 
six major phylogeographic units (Dawson et al. 2001, p. 1171). These 
six regional units are the basis for the recovery units in the Recovery 
Plan (Service 2005), and include the following areas: (1) Tillas Slough 
(Smith River) in Del Norte County to Lagoon Creek in Mendocino County 
(North Coast (NC) Unit); (2) Salmon Creek in Sonoma County to Bennett's 
Slough in Monterey County (Greater Bay (GB) Unit); (3) Arroyo del Oso 
to Morro Bay in San Luis Obispo County (Central Coast (CC) Unit); (4) 
San Luis Obispo Creek in San Luis Obispo County to Rincon Creek in 
Santa Barbara County (Conception (CO) Unit); (5) Ventura River in 
Ventura County to Topanga Creek in Los Angeles County (Los Angeles-
Ventura (LV) Unit); and (6) San Pedro Harbor in Los Angeles County to 
Los Pe[ntilde]asquitos Lagoon in San Diego County (South Coast (SC) 
Unit).
    A more recent study to gather genetic distribution data for the 
tidewater goby used a panel of novel microsatellite loci (repeating 
sequences of DNA) assessed in a first-order (unbound strands of DNA) 
survey across its range (Earl et al. 2010, p. 104). More specifically, 
Earl et al. (2010, p. 103) described 19 taxon-specific microsatellite 
loci, and assessed genetic variation across the tidewater goby's range 
relative to genetic subdivision. The study concluded: (1) Populations 
of tidewater goby in northern San Diego County form a highly divergent 
clade (a genetically related group) with reduced genetic variation that 
appears to merit status as a separate species; (2) populations along 
the mid-coast of California are subdivided into regional groups, which 
are more similar to each other than different, contrary to conclusions 
from previous mitochondrial sequence-based studies (Dawson et al. 2001, 
p. 1176); and (3) that tidewater goby dispersal during the Pleistocene/
Holocene sea-level rise (approximately 7,000 years ago), followed by 
increased isolation during the Holocene, formed a star phylogeny 
(recent population formed from a common ancestor) with geographic 
separation in the northernmost populations and some local 
differentiation (Earl et al. 2010, p. 103). Genetic diversity among 
populations within a species may be important to long-term persistence 
because it represents the raw material for adapting to differing local 
conditions and environmental stochasticity (Frankham 2005, p. 754).
    The conclusion that the North Coast populations of the tidewater 
goby formed as a result of a single recent episode of colonization of 
newly formed habitats is supported by McCraney and Kinziger (2009, p. 
30). They compared genetic variation of 13 naturally and artificially 
fragmented populations of the tidewater goby in northern California, 
including eight Humboldt Bay populations and five coastal lagoon 
populations, and reached similar conclusions to Earl et al. (2010, p. 
113). McCraney et al. (2010, p. 3325) also concluded that natural and 
artificial habitat fragmentation caused marked divergence among the 
tidewater goby in the North Coast populations. Their study showed that 
Humboldt Bay populations, due to isolation by man-made barriers, 
exhibited very high levels of genetic differentiation between 
populations, extremely low levels of genetic diversity within 
populations, and no migration among populations. They concluded that 
this pattern makes the Humboldt Bay populations of tidewater goby 
vulnerable to extirpation (McCraney and Kinziger 2009, p. 37). In 
contrast, the study found that while coastal lagoon populations also 
exhibited very high levels of genetic differentiation between 
populations, these populations displayed substantial

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levels of genetic diversity within populations indicating occasional 
migration among lagoons (McCraney and Kinziger 2009, p. 32). 
Populations in all coastal lagoons, with the exception of Lake Earl in 
Del Norte County, appear to be stable and genetically healthy (McCraney 
and Kinziger 2009, p. iii). The Lake Earl population exhibited reduced 
levels of genetic diversity in comparison to similar coastal lagoon 
populations (McCraney and Kinziger 2009, p. 34). The reduced genetic 
diversity detected within Lake Earl is likely due to repeated 
population bottlenecks (reduced genetic diversity due to reduced 
population size) resulting from regular artificial breaching of the 
lagoon mouth (McCraney and Kinziger 2009, p. 34).
    The conclusions from these studies are:
    (1) The tidewater goby exhibits considerable genetic diversity 
across its range.
    (2) The species can be divided into six phylogeographic units based 
upon genetic similarities and differences.
    (3) The tidewater goby to the south of the gap between Los Angeles 
and Orange Counties is probably a distinct species from populations to 
the north based on its divergent genetic makeup.
    (4) Natural and anthropogenic barriers have contributed to genetic 
differentiation among populations.
    (5) Although genetic differences occur between populations north of 
Los Angeles County, they are not as divergent as those populations 
found south of Los Angeles County.

Metapopulation Dynamics

    Local populations of tidewater goby are best characterized as 
metapopulations (Lafferty et al. 1999a, p. 1448). A metapopulation is 
defined as a population made up of a group of subpopulations 
interconnected through patterns of gene flow, extinction, and 
recolonization, and at least somewhat geographically isolated from 
other populations (Meffe and Carrol 1994, p. 189). Local tidewater goby 
populations are frequently isolated from other local populations by 
extensive areas of unsuitable habitat. They occupy coastal lagoons and 
estuaries that in most cases are separated by the open ocean. Very few 
tidewater goby have ever been captured in the marine environment (Swift 
et al. 1989, p. 7), which suggests that this species rarely occurs in 
the open ocean. Studies of the tidewater goby suggest that some 
populations persist on a consistent basis, while other populations 
appear to experience intermittent extirpations (local extinctions) 
(Lafferty et al. 1999a, p. 1452). These extirpations may result from 
one or a series of factors, such as the drying up of some small streams 
during prolonged droughts (Lafferty et al. 1999a, p. 1451). Some of the 
areas where the tidewater goby has been extirpated apparently have been 
recolonized by nearby (within 6 miles (mi) (10 kilometers (km))) 
populations (Lafferty et al. 1999a, p. 1451). These recolonization 
events suggest that tidewater goby populations exhibit a metapopulation 
dynamic where some populations survive or remain viable by continually 
exchanging individuals and recolonizations after occasional 
extirpations (Doak and Mills 1994, p. 619).
    Lafferty et al. (1999b, p. 618) monitored the post-flood 
persistence of several tidewater goby populations in Santa Barbara and 
Los Angeles Counties after the heavy winter floods of 1995. All of the 
monitored populations persisted after the floods, and no significant 
changes in population sizes were noted (Lafferty et al. 1999b, p. 621). 
However, tidewater goby apparently colonized Ca[ntilde]ada Honda in 
Santa Barbara County after one flood event (Lafferty et al. 1999b, p. 
621). This suggests that flooding may sometimes have a positive effect 
by contributing to recolonization of habitats where a tidewater goby 
population has become extirpated.
    The largest wetland habitats where the tidewater goby has been 
known to occur are not necessarily the most secure, as evidenced by the 
fact that the Santa Margarita River in San Diego County and the San 
Francisco Bay have lost their populations of tidewater goby. Today, the 
most stable locations with the largest tidewater goby populations 
consist of lagoons and estuaries of intermediate sizes (5 to 125 ac (2 
to 50 ha)) that have remained relatively unaffected by human activities 
(Service 2005, p. 12). Many of the locations where tidewater goby are 
consistently present are likely to be ``source'' populations, which 
probably provide the colonists for locations where tidewater goby are 
intermittently extirpated.
    Historical records and survey results for several areas occupied by 
tidewater goby are available (Swift et al. 1989, pp. 18-19; Swift et 
al. 1994, pp. 8-16). These documents suggest that the persistence of 
tidewater goby populations is related to habitat size, configuration, 
location, and proximity to human development. In general, the most 
stable and persistent tidewater goby populations occur in lagoons and 
estuaries that are more than 2.47 ac (1 ha) in size, and that have 
remained relatively unaffected by human activities (Lafferty et al. 
1999a, pp. 1450-1453). We note, however, that some systems that are 
affected or altered by human activities also have relatively large and 
stable populations, for example, Humboldt Bay in Humboldt County, Pismo 
Creek in San Luis Obispo County, Santa Ynez River in Santa Barbara 
County, and the Santa Clara River in Ventura County. Also, some 
habitats less than 2.47 ac (1 ha) in size have tidewater goby 
populations that persist on a regular basis, such as Ca[ntilde]ada del 
Agua Caliente in Santa Barbara County (Swift et al. 1997, p. 3). The 
best available information suggests that the lagoons and estuaries with 
persistent tidewater goby populations are likely the source of core 
populations that provide individuals that colonize adjacent smaller 
locations with intermittent populations (Lafferty et al. 1999a, p. 
1452).

Distribution

    The known geographic range of the tidewater goby is limited to the 
coast of California (Eschmeyer et al. 1983, p. 262; Swift et al. 1989, 
p. 12). The species historically occurred from locations 3 mi (5 km) 
south of the California-Oregon border (Tillas Slough in Del Norte 
County) to 44 mi (71 km) north of the United States-Mexico border (Agua 
Hedionda Lagoon in San Diego County). The available documentation 
(e.g., Eschmeyer et al. 1983, p. 262; Swift et al. 1989, p. 12) 
suggests that the northernmost extent of the current geographic range 
has not changed over time. Tidewater goby historically occurred in Agua 
Hedionda Lagoon, but do not currently. The species' southernmost known 
currently occupied locality is the San Luis Rey River, 5 mi (8 km) 
north of Agua Hedionda Lagoon. Although the northernmost and 
southernmost extent of the tidewater goby's range has not changed, its 
overall distribution has become patchy and fragmented along the coast.
    The tidewater goby appears to be naturally absent from several long 
(50 to 135 mi (80 to 217 km)) stretches of coastline lacking lagoons or 
estuaries, where steep topography or swift currents may prevent the 
tidewater goby from dispersing between adjacent locations (Swift et al. 
1989, p. 13; Earl et al. 2010, p. 104). One such gap occurs between the 
Eel River in Humboldt County and the Ten Mile River in Mendocino 
County. A second gap exists between Davis Lake in Mendocino County and 
Salmon Creek in Sonoma County. Another large natural gap

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occurs between the Salinas River in Monterey County and Arroyo del Oso 
in San Luis Obispo County. Habitat loss and other anthropogenic-related 
factors have resulted in the tidewater goby's absence from several 
locations where it historically occurred; their recent disappearance 
from some of these locations has created additional gaps in the 
species' geographic distribution (Capelli 1997, p. 7). Such locations 
include San Francisco Bay in San Francisco and Alameda Counties, and 
Redwood Creek and Freshwater Lagoon in Humboldt County.
    Swift et al. (1989, p. 13) reported that, as of 1984, tidewater 
goby occurred or had been known to occur at 87 locations, including 
those at the extreme northern and southern end of the species' 
historical geographic range. An assessment of the species' distribution 
in 1993, using records that were limited to the area between the 
Monterey Peninsula in Monterey County and the United States-Mexico 
border, found the tidewater goby occurring at four additional sites 
since 1984 (Swift et al. 1993, p. 129). Other locations have been 
identified since 1993, and to date the tidewater goby has been 
documented at 135 locations within its historical range. Of these 135 
locations, 23 (17 percent) are no longer occupied by the tidewater 
goby. Therefore, 112 locations are currently occupied (Service 2005, p. 
6).

Habitat

    The lagoons, estuaries, backwater marshes, and freshwater 
tributaries that tidewater goby occupy are dynamic environments subject 
to considerable fluctuations on a seasonal and annual basis. Typically, 
a sandbar forms in the late spring as flow into a lagoon declines 
enough to allow the ocean surf to build up sand at the mouth of the 
lagoon. Winter rains and increased stream flows may bring in 
considerable sediment and dramatically affect the bottom profile and 
substrate composition of a lagoon or estuary. Fine mud and clay either 
move through the lagoon or estuary, or settle out in the backwater 
marshes, while heavier sand is left behind. High flows associated with 
winter rains can scour out the lagoon bottom to a lower level, 
especially after breaching the mouth sandbar, with sand building up 
again after flows decline. These dynamic processes result in wetland 
habitats that, over time, move both up or down coast, and inland or 
coastward.
    The horizontal extent of the lentic (pond-like) wetland habitat 
associated with a particular tidewater goby locality varies, and is 
affected in part, by local precipitation patterns and topography. In 
coastal areas where the topography is steep and precipitation 
relatively low, such as areas adjacent to the Santa Ynez Mountains in 
Santa Barbara County, the habitats occupied by tidewater goby may be a 
few acres in size, only extend a few hundred feet inland from the 
ocean, with backwater marshes small or absent. In other coastal 
settings where topography is less steep and precipitation is more 
abundant, surface streams are larger, coastal lagoons or estuaries may 
be hundreds of acres in size and extend many miles inland, and may 
include extensive backwater marshes (Lake Earl in Del Norte County and 
Ten Mile River in Mendocino County). Some locations occupied by the 
tidewater goby, for example, Bennett's Slough in Monterey County, 
receive water from upstream areas on a year-round basis. Such locations 
tend to possess wetland habitats that are larger and can extend inland 
for several miles. Other occupied locations do not possess stream 
channels or tributaries that provide a considerable amount of water 
throughout the summer or fall months. Such locations, such as Little 
Pico Creek in San Luis Obispo County, tend to possess wetland habitats 
that extend only a short distance inland.

Reproduction

    The tidewater goby has been observed to spawn in every month of the 
year except December (Swenson 1999, p. 107). Reproduction tends to peak 
in late April or May to July, and can continue into November depending 
on seasonal temperature and rainfall. Swenson (1995, p. 31) has 
documented the spawning activities of adult fish or the presence of egg 
clutches at water temperatures between 48 and 77 degrees Fahrenheit (F) 
(9 and 25 degrees Celsius (C)). Spawning tidewater goby have been 
observed in water salinities between 2 and 27 parts per thousand (ppt) 
(Swenson 1999, p. 31).

Threats

    The final listing rule for the tidewater goby published in 1994 (59 
FR 5494; February 4, 1994) and the 5-year review (Service 2007) states 
that this species is threatened, or potentially threatened, by: (1) 
Coastal development projects that result in the loss or alteration of 
coastal wetland habitat; (2) water diversions and alterations of water 
flows upstream of coastal lagoons and estuaries that negatively impact 
the species' breeding and foraging activities; (3) groundwater 
overdrafting; (4) channelization of the rivers where the species 
occurs; (5) discharge of agricultural and sewage effluents; (6) cattle 
grazing and feral pig activity that results in increased sedimentation 
of coastal lagoons and riparian habitats, removal of vegetative cover, 
increased ambient water temperatures, and elimination of plunge pools 
and undercut banks utilized by the tidewater goby; (7) introduced 
species that prey on the tidewater goby (e.g., bass (Micropterus spp.) 
and crayfish (Cambaris spp.)); (8) inadequacy of existing regulatory 
mechanisms; (9) drought conditions that result in the deterioration of 
coastal and riparian habitats; and (10) competition with introduced 
species, such as the yellowfin goby (Acanthogobius flavimanus) and 
chameleon goby (Tridentiger trigonocephalus).

Previous Federal Actions

    On April 15, 2009, Natural Resources Defense Council (NRDC) filed a 
lawsuit in the U.S. District Court for the Northern District of 
California challenging a portion of the January 31, 2008, final rule 
that designated 44 critical habitat units in Del Norte, Humboldt, 
Mendocino, Sonoma, Marin, San Mateo, Santa Cruz, Monterey, San Luis 
Obispo, Santa Barbara, Ventura, Los Angeles, Orange, and San Diego 
Counties, California (73 FR 5920, January 31, 2008). In a consent 
decree dated December 11, 2009, the U.S. District Court: (1) Stated 
that the 44 critical habitat units should remain in effect, (2) stated 
that the final rule designating critical habitat was remanded in its 
entirety for reconsideration, and (3) directed the Service to 
promulgate a revised critical habitat rule that considers the entire 
geographic range of the tidewater goby and any currently unoccupied 
tidewater goby habitat. The consent decree requires that the Service 
submit proposed and final revised rules to the Federal Register no 
later than October 7, 2011, and November 27, 2012, respectively. For 
additional information on previous Federal actions please refer to the 
1994 listing rule (59 FR 5494; February 4, 1994), and previous critical 
habitat designation (73 FR 5920; January 31, 2008).

Critical Habitat

Background

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species and

[[Page 65000]]

    (b) Which may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
an endangered or threatened species to the point at which the measures 
provided pursuant to the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management such as research, census, law 
enforcement, habitat acquisition and maintenance, propagation, live 
trapping, and transplantation, and, in the extraordinary case where 
population pressures within a given ecosystem cannot be otherwise 
relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that Federal agencies ensure, in consultation 
with the Service, that any action they authorize, fund, or carry out is 
not likely to result in the destruction or adverse modification of 
critical habitat. The designation of critical habitat does not affect 
land ownership or establish a refuge, wilderness, reserve, preserve, or 
other conservation area. Such designation does not allow the government 
or public to access private lands. Such designation does not require 
implementation of restoration, recovery, or enhancement measures by 
non-Federal landowners. Where a landowner seeks or requests Federal 
agency funding or authorization for an action that may affect a listed 
species or critical habitat, the consultation requirements of section 
7(a)(2) would apply, but even in the event of a destruction or adverse 
modification finding, the obligation of the Federal action agency and 
the landowner is not to restore or recover the species, but to 
implement reasonable and prudent alternatives to avoid destruction or 
adverse modification of critical habitat.
    For inclusion in a critical habitat designation, the habitat within 
the geographical area occupied by the species at the time it was listed 
must contain the physical or biological features which are essential to 
the conservation of the species and which may require special 
management considerations or protection. Critical habitat designations 
identify, to the extent known using the best scientific and commercial 
data available, those physical or biological features that are 
essential to the conservation of the species (such as space, food, 
cover, and protected habitat), focusing on the principal biological or 
physical constituent elements (primary constituent elements (PCEs)) 
within an area that are essential to the conservation of the species 
(such as roost sites, nesting grounds, seasonal wetlands, water 
quality, tide, soil type). Primary constituent elements are the 
elements of physical or biological features that provide for a species' 
life-history processes and are essential to the conservation of the 
species.
    Under the Act, we can designate critical habitat in areas outside 
the geographical area occupied by the species at the time it is listed, 
upon a determination that such areas are essential for the conservation 
of the species. We designate critical habitat in areas outside the 
geographical area occupied by a species only when a designation limited 
to its range would be inadequate to ensure the conservation of the 
species. When the best available scientific data do not demonstrate 
that the conservation needs of the species require such additional 
areas, we will not designate critical habitat in areas outside the 
geographical area occupied by the species. An area currently occupied 
by the species but that was outside the geographical area occupied by 
the species at the time of listing may, however, be essential for the 
conservation of the species and may be included in the critical habitat 
designation.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific and commercial data available. 
Further, our Policy on Information Standards under the Endangered 
Species Act (published in the Federal Register on July 1, 1994 (59 FR 
34271)), the Information Quality Act (section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658)), and our associated Information Quality 
Guidelines, provide criteria, establish procedures, and provide 
guidance to ensure that our decisions are based on the best scientific 
data available. They require our biologists, to the extent consistent 
with the Act and with the use of the best scientific data available, to 
use primary and original sources of information as the basis for 
recommendations to designate critical habitat.
    When we determine which areas should be designated as critical 
habitat, our primary source of information is generally the information 
developed during the listing process for the species. Additional 
information sources may include the recovery plan for the species, 
articles in peer-reviewed journals, conservation plans developed by 
States and counties, scientific status surveys and studies, biological 
assessments, or other unpublished materials, expert opinion, or 
personal knowledge.
    Habitat is dynamic, and species (or habitats) may naturally shift 
within an area, or from one area to another, over time. Climate change 
will be a particular challenge for biodiversity because the addition of 
stressors associated with climate change to current stressors may push 
species beyond their ability to survive (Lovejoy and Hannah 2005, pp. 
325-326). The synergistic implications of climate change and habitat 
fragmentation are the most threatening facet of climate change for 
biodiversity (Lovejoy and Hannah 2005, p. 4), because species may not 
be able to migrate with shifting habitats. Current climate change 
predictions for terrestrial areas in the Northern Hemisphere generally 
indicate warmer air temperatures, more intense precipitation events, 
and increased summer continental drying, although predictions vary for 
any given specific location (Field et al. 1999, pp. 1-3; Hayhoe et al. 
2004, p. 12422; Cayan et al. 2005, p. 6; Intergovernmental Panel on 
Climate Change (IPCC) 2007, p. 11; Cayan et al. 2009, p. xi). Climate 
change may lead to increased frequency and duration of severe storms 
and droughts (McLaughlin et al. 2002, p. 6074; Cook et al. 2004, p. 
1015; Golladay et al. 2004, p. 504).
    Furthermore, these predictions also point to a future of warmer 
oceans and melting glaciers and icecaps, all of which are expected to 
raise mean sea levels, leading to the inundation and displacement of 
many estuaries and lagoons. A rise in sea level will most dramatically 
affect those estuaries that have been confined by surrounding 
development that prohibits their boundaries from naturally shifting in 
response to inundation. Projections for sea-level rise by the year 2100 
vary from 0.59 to 6.2 ft (0.18 to 1.9 m) (Raper and Braithwaite 2006, 
p. 311, IPCC 2007, p. 11; Rahmstorf 2007, p. 368; Herberger et al. 
2009, p. 8; Vermeer and Rahmstorf 2009, p. 21530). Paleoclimatic data 
suggest that the rate of future melting of the Greenland and Antarctic 
ice sheets and related sea level rise could be faster than currently 
projected (Overpeck et al. 2006, p. 1747). Park et al. (1989, pp. 1-52) 
projected that of the salt marshes along the coast of the contiguous 
United

[[Page 65001]]

States, 30 percent would be lost with a 1.6-ft (0.5-m) sea level rise, 
46 percent with a 3.3-ft (1-m) sea level rise, 52 percent with a 6.6-ft 
(2-m) sea level rise, and 65 percent with a 9.8-ft (3-m) sea level 
rise.
    We cannot project directly to California the percentage of salt 
marsh habitat that would be lost based upon the estimates of Park et 
al. (1989, p. 1-52), who focused on the east coast and Gulf coast of 
the United States; however, we can anticipate that with a projected sea 
level rise of up to almost 6.6 ft (2 m), much of the marshlands and 
estuaries in the state will be lost by 2100. In addition to the 
inundation and displacement of estuaries/lagoons, there would be shifts 
in the quality of the habitats in affected coastal regions. Prior to 
being inundated, coastal watersheds would become saline due to 
saltwater intrusion into the surface and groundwater. However, 
predictions of climatic conditions for smaller sub-regions, such as 
California, remain less certain. The full effects of these changes on 
aquatic organisms, such as the tidewater goby, are not well known. 
Thus, the information currently available on the effects of global 
climate change is not sufficiently precise to determine what additional 
areas, if any, may be appropriate to include in the revised critical 
habitat for this species to address the effects of climate change.
    Additionally, we recognize that critical habitat designated at a 
particular point in time may not include all of the habitat areas that 
we may later determine are necessary for the recovery of the species. 
For these reasons, a critical habitat designation does not signal that 
habitat outside the designated area is unimportant or may not be 
required for recovery of the species. Areas that are important to the 
conservation of the tidewater goby, both inside and outside the 
critical habitat designation, will continue to be subject to: (1) 
Conservation actions implemented under section 7(a)(1) of the Act, (2) 
regulatory protections afforded by the requirement in section 7(a)(2) 
of the Act for Federal agencies to ensure that their actions are not 
likely to jeopardize the continued existence of any endangered or 
threatened species, and (3) the prohibitions of section 9 of the Act if 
actions occurring in these areas may result in take of the species. 
Federally funded or permitted projects affecting listed species outside 
their designated critical habitat areas may still result in jeopardy 
findings in some cases. These protections and conservation tools will 
continue to contribute to recovery of this species. Similarly, critical 
habitat designations made on the basis of the best available 
information at the time of designation will not control the direction 
and substance of future recovery plans, habitat conservation plans 
(HCPs), or other species conservation planning efforts if new 
information available at the time of these planning efforts calls for a 
different outcome.

Physical or Biological Features

    In accordance with section 3(5)(A)(i) and 4(b)(1)(A) of the Act and 
regulations at 50 CFR 424.12, in determining which areas within the 
geographical area occupied by the species at the time of listing to 
designate as critical habitat, we consider the physical or biological 
features essential to the conservation of the species and which may 
require special management considerations or protection. These include, 
but are not limited to:
    (1) Space for individual and population growth and for normal 
behavior;
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, or rearing (or development) 
of offspring; and
    (5) Habitats that are protected from disturbance or are 
representative of the historical, geographical, and ecological 
distributions of a species.
    We derive the specific physical or biological features required for 
tidewater goby from studies of this species' habitat, ecology, and life 
history as described below. Additional information can be found in the 
final listing rule published in the Federal Register on February 4, 
1994 (59 FR 5494), the Tidewater Goby 5-Year Review (Service 2007), and 
the Recovery Plan (Service 2005). Based on our current knowledge of the 
life history, biology, ecology, and the habitat requirements of the 
species, we have determined that the tidewater goby requires the 
following physical or biological features:

Space for Individual and Population Growth and for Normal Behavior

Saline Aquatic Habitat
    The tidewater goby occurs in lagoons, estuaries, and backwater 
marshes that are adjacent to the Pacific Ocean (Wang 1982, p. 14; Irwin 
and Soltz 1984, p. 27; Swift et al. 1989, p. 1; Swenson 1993, p. 3; 
Moyle 2002, p. 431). The tidewater goby is most commonly found in 
waters with relatively low salinities (less than 10 to 12 parts per 
thousand (ppt)) (Swift et al. 1989, p. 7). This species can, however, 
tolerate a wide range of salinities, and is frequently found in coastal 
habitats with higher salinity levels (Swift et al. 1989, p. 7; 
Worcester 1992, p. 106; Swift et al. 1997, pp. 15-22); it has been 
collected in salinities as high as 42 ppt by Swift et al. (1989, p. 7) 
and at 63 ppt in McDaniel Slough, Arcata Bay, Humboldt County (G. 
Goldsmith pers. comm. 2011). The species' tolerance of high salinities 
likely enables it to withstand some exposure to the marine environment, 
allowing it to recolonize nearby lagoons and estuaries following flood 
events. However, tidewater goby have only rarely been captured in the 
marine environment (Swift et al. 1989, p. 7), and they appear to enter 
the ocean only when flushed out of lagoons, estuaries, and river mouths 
by storm events or human-caused breaches of sand bars.
Freshwater Habitat
    The tidewater goby also occurs in freshwater streams up-gradient 
and tributary to brackish habitats; the salinity of these freshwater 
streams is typically less than 0.5 ppt. The available documentation 
demonstrates that, in some areas, tidewater goby can occur 1.6 to 7.3 
mi (2.6 to 11.7 km) upstream from the ocean environment (Irwin and 
Soltz 1984, p. 27; Swift et al. 1997, p. 20; Chamberlain and Goldsmith 
2006, p. 1). Within a 2-hour period, hundreds of tidewater goby have 
been observed to move upstream of a fixed location into areas in the 
Santa Ynez River 3.2 mi (5.1 km) from the ocean in Santa Barbara County 
(Swift et al. 1997, p. 20). The fact that this many individuals were 
observed to move through an area suggests that freshwater tributaries 
in some riverine systems provide important habitat for individual and 
population growth.
    We have reviewed a variety of documents to determine how far 
tidewater goby have been detected upstream from the ocean. Chamberlain 
and Goldsmith (2006, p. 1) found tidewater goby 1.6 to 2.0 mi (2.6 to 
3.3 km) upstream from the ocean in the Ten Mile River in Mendocino 
County, Swift et al. (1997, p. 18) found tidewater goby 4.6 mi (7.3 km) 
upstream from the ocean in the San Antonio River in Santa Barbara 
County, Swift et al. (1997, p. 20) found tidewater goby at various 
distances from 3.9 to 7.3 mi (6.2 to 11.7 km) upstream from the ocean 
in the Santa Ynez River in Santa Barbara County, and Holland (1992, p. 
9) found tidewater goby 3 mi (5 km) upstream from the ocean in the 
Santa Margarita River in San Diego County. Collectively, these data 
suggest the average distance tidewater goby have been detected

[[Page 65002]]

upstream from the ocean in medium to large rivers is approximately 3.8 
mi (6.1 km). Other than a high stream gradient, the reasons for the 
variation in upstream movement between one locality and another have 
not been determined; salinity could be an important factor. Upstream 
salinity levels may vary with time of year, tidal cycles, storm events, 
and topography. However, Swift et al. (1997, p. 26) indicate that 
stream gradient and lack of barriers (e.g., beaver dams, sills) are 
more important factors than salinity to upstream dispersal.
Sandbars
    Many of the locations occupied by the tidewater goby closely 
correspond to stream drainages. Under natural conditions these stream 
drainages and the marine environment collectively act to produce 
sandbars that form a barrier between the ocean and the lagoon, estuary, 
backwater marsh, and freshwater stream system (Habel and Armstrong 
1977, p. 39). These sandbars tend to be present during the late spring, 
summer, and fall seasons. The presence of a sandbar can create a lower 
salinity level (5 to 10 ppt) in the area inshore from the sandbar 
(Carpelan 1967, p. 324) than would otherwise exist if there were no 
sandbar. The tidewater goby is more commonly associated with these 
lower salinity levels than with the salinity levels that occur in the 
ocean or an estuary without a sandbar (about 35 ppt). The formation of 
a sandbar also creates more habitat for aquatic organisms because water 
becomes ponded behind the sandbar. Artificial breaching of a sandbar 
tends to result in a rapid decrease in water levels, and increases the 
likelihood that adult tidewater goby, their nests, and their fry could 
become stranded and die, or become concentrated and subject to greater 
levels of predation pressure by birds or other predators.
    In Humboldt Bay and the Eel River estuary in Humboldt County, a 
large amount of salt and brackish marsh habitat was eliminated through 
the construction of levees and drainage channels. As a result, several 
of the locations occupied by tidewater goby do not contain natural 
sandbars between the ocean and habitat where the species is present. 
Instead, manmade water control structures such as tidegates and 
culverts, exist between tidal waters and the locations where tidewater 
goby occur. These tidegates have been in place for decades, and in some 
cases they provide habitat conditions similar to those created by the 
presence of a seasonal sandbar. In fact, most of the occupied tidewater 
goby habitat in the Humboldt Bay-Eel River estuaries are above 
tidegates.
    Therefore, lagoons and estuaries with relatively low salinities for 
suitable breeding conditions, upstream freshwater habitat for refuge, 
and sandbars, which creates larger areas of suitable habitat with lower 
salinities, are essential to the conservation of the species.

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

Diet
    The tidewater goby feeds mainly on macroinvertebrates such as mysid 
shrimp, gammarid amphipods, ostracods, and aquatic insects such as 
chironomid midge larvae (Irwin and Soltz 1984, pp. 21-23; Swift et al. 
1989, p. 6; Swenson 1995, p. 87). The diets of adult and juvenile 
tidewater goby tend to include the same relative abundance of different 
invertebrate species (Swenson and McCray 1996, p. 962).
Water Depth, Velocity, and Temperature
    The tidewater goby is most commonly collected in water less than 6 
feet (ft) (2 meters (m)) deep (Wang 1982, pp. 4-5; Worchester 1992, p. 
53). However, tidewater goby were recently collected in Big Lagoon in 
Humboldt County during the breeding season at a water depth of 15 ft 
(4.6 m) (Goldsmith 2006a, p. 1). Whether use of these deeper waters is 
confined to this locality or is more widespread will require additional 
sampling at various depths and locations. The tidewater goby tends to 
avoid currents and concentrate in slack-water areas; this suggests they 
are less likely to occur in areas with a steep gradient or 
microhabitats with a substantial current. At Pescadero Creek in San 
Mateo County, tidewater goby were absent from portions of the flowing 
creek that had a surface velocity of 0.15 m per second (0.49 ft per 
second), and were instead more densely concentrated in nearby eddies 
with lower water velocities (Swenson 1993, p. 3).
    Backwater marshes, including lateral sloughs, are likely to be 
important to the tidewater goby for multiple reasons. Flood waters with 
increased water velocities can have a negative effect on the tidewater 
goby (Irwin and Soltz 1984, p. 27), and backwater marshes may provide 
important refuges that reduce the likelihood that tidewater goby will 
be flushed out of the lagoons or estuaries and into the marine 
environment during heavy winter floods (Lafferty et al. 1999a, p. 619). 
Evidence that increased flows can eliminate tidewater goby from a 
locality is suggested by the extirpation of tidewater goby from Waddell 
Creek in Santa Cruz County following a flood event in the winter of 
1972-73 (Nelson as cited in Swift 1990, p. 2); this creek had been 
channelized and no longer afforded protection from high flows during 
flood events. Likewise, the channelization and elimination of habitat 
lateral to the main stream channel upstream of San Onofre Lagoon in San 
Diego County probably led to the flushing and extirpation of tidewater 
goby from this locality during a storm in 1993 (Swift et al. 1994, pp. 
22-23). The importance of backwater marshes is also highlighted by the 
fact that tidewater goby in these habitats can achieve a greater size 
than in adjacent lagoons and creeks (Swenson 1993, pp. 6-7).
    Therefore, lagoons and estuaries with a variety of aquatic 
macroinvertebrates providing food for tidewater goby as well as 
backwater marshes, including lateral sloughs, which are used as refuge 
during storm events and sandbar breaches, are essential to the 
conservation of the species.

Cover or Shelter

    A variety of native and nonnative fish species and fish-eating bird 
species, such as egrets (Egretta spp.) and herons (e.g., great blue 
herons (Ardea herodias)), prey on tidewater goby. A species' ability to 
persist when it is subject to predation pressure frequently depends on 
the presence of escape cover or shelter, heterogeneous features that 
provide a greater level of structure to make it more likely to avoid 
predation (Crowder and Cooper 1982, p. 1802; Gilinsky 1984, p. 455). At 
locations where the tidewater goby occurs, submerged and emergent 
aquatic vegetation can create habitat heterogeneity and structure to 
provide a greater degree of cover from predators than would exist 
without it. Stable lagoons often possess dense aquatic vegetation, 
including sago pondweed (Potamogeton pectinatus) or widgeon grass 
(e.g., Ruppia maritima and R. cirrhosa). At some locations, juvenile 
tidewater goby are more prevalent in areas with at least some 
submergent vegetation compared to areas with little or no vegetation 
(Wang 1984, p. 16; Swenson 1994, p. 6; Trihey & Associates, Inc. 1996, 
p. 11). The presence of submerged or emergent vegetation appears to 
reduce the likelihood that tidewater goby will be preyed upon. Aquatic 
vegetation also may provide some degree of shelter or refuge during 
flash flood events (Lafferty et al. 1999b, p. 621) by lowering water 
velocity compared to unvegetated areas. Such refuges would

[[Page 65003]]

be especially important to fish species, such as tidewater goby, that 
are not strong swimmers. Therefore, lagoons and estuaries with 
submerged and emerged vegetation, which provide protection from 
predators and provide refuge during flood events, are essential to the 
conservation of the species.

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

    The eggs of the tidewater goby are laid in burrows excavated by 
male fish. Burrows most commonly occur in areas with relatively 
unconsolidated, clean, coarse sand (Swift et al. 1989, p. 8), and in 
silt or mud (Wang 1982, p. 6). Swenson (1995, p. 148) demonstrated that 
tidewater goby prefer a sandy substrate in the laboratory. Male 
tidewater goby remain in the burrow to guard the eggs attached to the 
burrow ceiling and walls, and care for the embryos for approximately 9 
to 11 days until they hatch. They rarely, if ever, emerge from the 
burrow to feed (Swift et al. 1989, p. 4). The tidewater goby larvae 
occupy the water column after the eggs hatch (Wang 1982, p. 15), then 
move to the bottom substrate as they mature. Worcester (1992, pp. 77-
79) found that larval tidewater goby in Pico Creek Lagoon in San Luis 
Obispo County tended to use the deeper portion of the lagoon at a depth 
of 29 in (73 cm), which is considerably deeper than the depth level of 
17 in (42 cm) where they were not detected. Therefore, lagoons and 
estuaries with relatively unconsolidated, clean, coarse sand, and silt 
or mud, which provide for breeding, are essential to the conservation 
of the species.

Habitats Protected From Disturbance or Representative of the 
Historical, Geographical, and Ecological Distributions of the Species

    The majority of lagoons, estuaries, and coastal streams that 
currently support the tidewater goby have experienced some level of 
disturbance. These range in size from approximately 31.5 square feet (3 
m\2\) of surface area to about 2,000 acres (ac) (800 hectares (ha)). 
Most lagoons and estuaries that support tidewater goby range from about 
1.25 to 12.5 ac (0.5 to 5 ha). Surveys of tidewater goby locations and 
historic records indicate that size, configuration, location, and 
access by humans are all factors in the persistence of populations of 
this species (Swift et al. 1989, p. 15; Swift et al. 1994, pp. 26-27). 
Lagoons and estuaries smaller than about 5 ac (2 ha) generally exhibit 
patterns of extirpation or population reduction and subsequent 
recolonization to very low levels. Many of the records for smaller 
locations, less than about 1 ac (0.4 ha), include one or a few large 
individuals with no evidence of reproduction. These small locations are 
also often within a mile or so of another locality from which 
recolonization could occur following catastrophic events, such as 
drought or artificial breaching of the lagoon.
    The largest locations are not necessarily the most secure, such as 
the San Francisco Bay or the Santa Margarita River, which have lost 
their populations of tidewater goby. However, an exception is Lake 
Tolowa, Del Norte County, which is several thousand acres in size and 
has had a continuous presence of tidewater goby. The most stable or 
largest populations today are in locations of intermediate sizes, which 
range from 5 to 125 ac (2 to 50 ha). In many cases, the tidewater goby 
populations in these intermediate sized locations likely serve as 
source populations for the smaller ephemeral sites (Lafferty et al. 
1999b, p. 1452). Therefore, lagoons and estuaries that range in size 
from small to large are important for maintaining the metapopulation 
dynamics and are essential to the conservation of the species.
Primary Constituent Elements for Tidewater Goby
    Under the Act and its implementing regulations, we are required to 
identify the physical or biological features essential to the 
conservation of tidewater goby in areas within the geographical area 
occupied by the species at the time of listing, focusing on the 
features' primary constituent elements. We consider primary constituent 
elements to be the elements of the physical or biological features that 
provide for a species' life-history processes and, under the 
appropriate circumstances, are essential to the conservation of the 
species.
    Based on our current knowledge of the physical or biological 
features and habitat characteristics required to sustain the species' 
life-history processes, we determine that the primary constituent 
element (and its components) specific to tidewater goby are:
    (1) Persistent, shallow (in the range of approximately 0.3 to 6.6 
ft (0.1 to 2 m)), still-to-slow-moving, lagoons, estuaries, and coastal 
streams ranging in salinity from 0.5 ppt to about 12 ppt, which 
provides adequate space for normal behavior and individual and 
population growth that contain:
    (a) Substrates (e.g., sand, silt, mud) suitable for the 
construction of burrows for reproduction;
    (b) Submerged and emergent aquatic vegetation, such as Potamogeton 
pectinatus, Ruppia maritima, Typha latifolia, and Scirpus spp., that 
provides protection from predators and high flow events; or
    (c) Presence of a sandbar(s) across the mouth of a lagoon or 
estuary during the late spring, summer, and fall that closes or 
partially closes the lagoon or estuary, thereby providing relatively 
stable water levels and salinity.

Special Management Considerations or Protection

    When designating critical habitat, we assess whether the specific 
areas within the geographical area occupied by the species at the time 
of listing contain features which are essential to the conservation of 
the species and which may require special management considerations or 
protection. Special management considerations or protection may be 
necessary to eliminate or reduce the magnitude of threats that affect 
the tidewater goby. Threats identified in the final listing rule for 
the tidewater goby include: (1) Coastal development projects that 
result in the loss or alteration of coastal wetland habitat; (2) water 
diversions and alterations of water flows upstream of coastal lagoons 
and estuaries that negatively impact the species' breeding and foraging 
habitat and activities; (3) groundwater overdrafting that results in 
reduction of flows and negatively impacts the species' breeding and 
foraging habitat and activities; (4) channelization of habitats where 
the species occurs that removes or reduces quality of habitat; (5) 
discharge of agricultural and sewage effluents; (6) cattle grazing and 
feral pig activity that result in increased sedimentation of coastal 
lagoons and riparian habitats, remove vegetative cover, increase 
ambient water temperatures, and eliminate plunge pools and collapsed 
undercut banks utilized by the tidewater goby; (7) introduced species 
that prey on the tidewater goby (e.g., bass, crayfish); (8) the 
inadequacy of existing regulatory mechanisms; (9) drought conditions 
that result in the deterioration of coastal and riparian habitats; and 
(10) competition with introduced species, such as the yellowfin goby 
and chameleon goby.
    For the purposes of this proposed rule, we have combined the 
``water diversions and alterations of water flows upstream of coastal 
lagoons and estuaries that negatively impact the species' breeding and 
foraging activities'' threats category with ``drought conditions'' and 
``groundwater overdrafting,'' along with the addition of

[[Page 65004]]

artificial breaching of sandbars, into one threat category, i.e., 
``water diversions, alterations of water flows, artificial sandbar 
breaching, and groundwater overdrafting that negatively impact the 
species' breeding and foraging activities.'' Similarly, we have 
combined the two threat categories of ``introduced species that prey on 
the tidewater goby (e.g., bass, crayfish)'' and ``competition with 
introduced species such as the yellowfin goby and chameleon goby'' into 
one category, i.e., ``introduced species that prey on, or compete with, 
the tidewater goby (e.g., yellowfin goby, bass, and crayfish).'' Where 
special management may be necessary, regulatory mechanisms may need to 
be added or amended by local, State, or Federal governmental entities 
if sufficient management is not achievable through voluntary 
mechanisms.
    The tidewater goby exhibits a pattern of occupancy and extirpation 
throughout its range. The species requires refugia under drought 
conditions and places to recolonize under wetter conditions; otherwise, 
the tidewater goby would be relegated to existing only within those few 
lagoons and estuaries large enough to support it during periods of 
drought. If the suitable localities that are occupied during periods of 
normal precipitation cease to function as tidewater goby habitat due to 
modification or destruction while the localities are unoccupied, the 
metapopulation dynamics may be disrupted and the species may not be 
able to respond by recolonizing unoccupied localities under favorable 
conditions. A more detailed discussion of threats to the tidewater goby 
can be found in the final listing rule (59 FR 5494, March 7, 1994), and 
the final Recovery Plan (Service 2005, pp. 16-19).
    We find that the components of the PCE present within all the areas 
we are proposing to designate as critical habitat may require special 
management considerations or protection due to threats to the tidewater 
goby or its habitat. Using current information provided in the Recovery 
Plan (Service 2005, Appendix E) and other information in our files, we 
have identified the components of the PCE that may require special 
management considerations or protection from known threats within each 
of the critical habitat units (see Critical Habitat Designation and 
Table 3 below for a unit-by-unit description). Some of the special 
management actions that may be needed for essential features of 
tidewater goby habitat are briefly summarized below.
    (1) Implement measures to avoid, minimize or mitigate direct and 
indirect loss and adverse modification of tidewater goby habitat due to 
dredging, draining, and filling of lagoons and estuaries. Additional 
management actions should be taken to restore historic locations and 
potential habitats as opportunities become available to eliminate, 
minimize, or mitigate the effects of existing structures and past 
activities that have destroyed or degraded tidewater goby habitat.
    (2) Measures should be developed and implemented to minimize the 
adverse effects due to channelization that can eliminate crucial 
backwater habitats or other flood refuges.
    (3) Implement measures, such as best management practices, for 
managing excessive sedimentation in tidewater goby habitat within 
current or enhanced parameters. Measures should prevent further 
increase in sedimentation in tidewater goby habitat due to cattle 
grazing, development, channel modification, recreational activity, and 
agricultural practices.
    (4) Implement measures to prevent further decrease in freshwater 
inflow, water depth, and surface area within tidewater goby habitat due 
to dams, water diversions and groundwater pumping.
    (5) Implement measures to avoid anthropogenic breaching of lagoons, 
for example, use of pumping and other water control structures to 
regulate water levels, to provide conditions during the summer and 
fall, when reproduction is at its highest and freshwater inflow is at 
its lowest.
    (6) Implement measures to prevent further degradation of water 
quality resulting from agricultural runoff and effluent, municipal run-
off, golf course runoff, sewage treatment effluent, cattle grazing, 
development, oil spills, oil field runoff, toxic waste, and gray water 
dumping. Also, measures should be implemented to prevent further 
degradation of the water quality due to dikes, tidal gates, and other 
impedances to the natural freshwater/saltwater interface that alter the 
salinity regime