[Federal Register Volume 64, Number 121 (Thursday, June 24, 1999)]
[Proposed Rules]
[Pages 33816-33825]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-16030]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AF67


Endangered and Threatened Wildlife and Plants; 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.

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SUMMARY: The Fish and Wildlife Service, pursuant to the Endangered 
Species Act of 1973, as amended (Act), proposes to remove the northern 
populations of the tidewater goby (Eucyclogobius newberryi) from the 
list of endangered and threatened wildlife. The species is now 
classified as endangered throughout its entire range. We have 
determined that north of Orange County there are more populations than 
were known at the time of the listing, that the threats to those 
populations are less severe than previously believed, and that the 
tidewater goby has a greater ability than was known in 1994 to 
recolonize habitats from which it is temporarily absent. This proposal 
would remove the northern populations of the tidewater goby from 
protection under the Act.
    The Orange and San Diego counties population of tidewater goby, 
which constitutes a distinct population segment, is genetically 
distinct, is comprised of gobies from only six localities, and 
continues to be threatened by habitat loss and degradation, predation 
by non-native species, and extreme weather and streamflow conditions. 
Therefore, this distinct population segment will be retained as an 
endangered species on the List of Endangered and Threatened Wildlife.

DATES: We must receive comments from all interested parties by August 
23, 1999. We must receive public hearing requests by August 9, 1999.

ADDRESSES: Send written comments and other materials concerning this 
proposal to Ms. Diane Noda, Field Supervisor, Ventura Fish and Wildlife 
Office, 2493 Portola Road, Suite B, Ventura, California 93003. You may 
inspect comments and materials received, by appointment, during normal 
business hours at the above address.

FOR FURTHER INFORMATION CONTACT: Carl Benz at the above address; 
telephone 805/644-1766, facsimile 805/644-3958.

SUPPLEMENTARY INFORMATION:

Background

    The tidewater goby was first described in 1857 by Girard as Gobius 
newberryi. Gill (1862) erected the genus Eucyclogobius for this 
distinctive species. The majority of scientists has accepted this 
classification (e.g., Bailey et al. 1970, Miller and Lea 1972, Hubbs et 
al. 1979, Robins et al. 1991, Eschmeyer et al. 1983). No other species 
has been described in this genus. A few older works and Ginsburg (1945) 
placed the tidewater goby and the eight related eastern Pacific species 
into the genus Lepidogobius. This classification includes the currently 
recognized genera Lepidogobius, Clevelandia, Ilypnus, Quietula, and 
Eucyclogobius. Birdsong et al. (1988) coined the informal Chasmichthys 
species group, recognizing the phyletic relationship of the eastern 
Pacific group with species in the northwestern Pacific.
    Crabtree's (1985) allozyme work on tidewater gobies from 12 
localities throughout the range shows fixed allelic differences at the 
extreme northern (Lake Earl, Humboldt Bay) and southern (Canada de Agua 
Caliente, Winchester Canyon, and San Onofre Lagoon) ends of the range. 
The northern and southern populations are genetically distinct from 
each other and from the central populations sampled. The more centrally 
distributed populations are relatively similar to each other (Brush 
Creek, Estero Americano, Corcoran Lagoon, Arroyo de Corral, Morro Bay, 
Santa Ynez River, and Jalama Creek). Crabtree's results indicate that 
there is a low level of gene flow (movement of individuals) between the 
populations sampled in the northern, central, and southern parts of the 
range. However, Lafferty et al. (in prep.) point out that Crabtree's 
sites were widely distributed geographically, and may not be

[[Page 33817]]

indicative of gene flow on more local levels.
    Recently, David Jacobs (University of California, Los Angeles, 
Department of Organismic Biology, Ecology and Evolution, in litt., 
1998) initiated an analysis of mitochondrial genetic material from 
tidewater goby populations ranging from Humboldt to San Diego counties. 
Preliminary results indicate the San Diego gobies separated from other 
gobies along the coast long ago. These southernmost populations likely 
began diverging from the remainder of the gobies in excess of 100,000 
years ago. Furthermore, gobies from the Point Conception area are more 
closely related to gobies from Humboldt County than they are to the 
gobies analyzed in San Diego County.
    The tidewater goby (Eucyclogobius newberryi) is a small, elongate, 
grey-brown fish with dusky fins not exceeding 50 millimeters (mm) (2 
inches (in.)) standard length (SL). The tidewater goby is a short-lived 
species, apparently having an annual life cycle (Irwin and Soltz 1984, 
Swift et al. 1997). At the time of the listing, the species was 
believed to have more stringent habitat requirements and to be less 
likely to disperse successfully than recent research indicates (see 
below). These factors, coupled with the short life span of the 
tidewater goby, were believed to make most tidewater goby populations 
vulnerable to extirpation by human activities. At the time of the 
listing, we believed that approximately 50 percent of the documented 
populations had been extirpated. However, in spite of the many factors 
affecting coastal wetlands, recent survey data demonstrate a less than 
25 percent permanent loss of the known tidewater goby populations 
(Ambrose et al. 1993; Swift et al. 1994; Lafferty et al. 1996; C. 
Chamberlain, U.S. Fish and Wildlife Service, Arcata, California, in 
litt. 1997; Lafferty 1997; Swift et al. 1997).
    The tidewater goby inhabits coastal brackish water habitats 
entirely within California. Within the range of the tidewater goby, 
these conditions 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 most of the length of California. Few 
well authenticated records of this species are known from marine 
environments outside of enclosed coastal lagoons and estuaries (Swift 
et al. 1989). This may be due to the lack of collection efforts at 
appropriate times (i.e., following storm events or breachings when 
gobies are flushed from the estuaries and lagoons). Historically, the 
species ranged from Tillas Slough (mouth of the Smith River, Del Norte 
County) near the Oregon border to Agua Hedionda Lagoon (northern San 
Diego County).
    The tidewater goby is often found in waters of relatively low 
salinities (around 10 parts per thousand (ppt)) in the uppermost 
brackish zone of larger estuaries and coastal lagoons. However, the 
fish can tolerate a wide range of salinities (Swift et al. 1989, 1997; 
Worcester 1992; K. R. Worcester, California Department of Fish and Game 
(CDFG), in litt. 1996; Worcester and Lea 1996), and is frequently found 
throughout lagoons. Tidewater gobies regularly range upstream into 
fresh water, and downstream into water of up to 28 ppt salinity 
(Worcester 1992, Swenson 1995), although specimens have been collected 
at salinities as high as 42 ppt (Swift et al. 1989). The species' 
tolerance of high salinities (up to 60 ppt for varying time periods) 
likely enables it to withstand the marine environment, allowing it to 
colonize or re-establish in lagoons and estuaries following flood 
events (Swift et al. 1989; K. R. Worcester, in litt. 1996; Worcester 
and Lea 1996; Lafferty et al. in prep.).
    Tidewater gobies are usually collected in water less than 1 meter 
(m) (3 feet (ft)) deep; many localities have little or no area deeper 
than this (Wang 1982, Irwin and Soltz 1984, Swift et al. 1989, Swenson 
1995). However, it has been found in waters over 1 m in depth 
(Worcester 1992, Lafferty and Altstatt 1995, Swift et al. 1997, Smith 
1998). In lagoons and estuaries with deeper water, the failure to 
collect gobies may be due to the inadequacy of the sampling methods, 
rather than the lack of gobies (Worcester 1992, Lafferty 1997, Smith 
1998).
    Tidewater gobies often migrate upstream into tributaries up to 2.0 
kilometers (km) (1.2 mile (mi)) from the estuary. However, in San 
Antonio Creek and the Santa Ynez River, Santa Barbara County, tidewater 
gobies are often collected 5 to 8 km (3 to 5 mi) upstream of the tidal 
or lagoonal areas, sometimes in beaver impounded sections of streams 
(Swift et al. 1989). The fish move upstream in summer and fall, as sub-
adults and adults. There is little evidence of reproduction in these 
upper areas (Swift et al. 1997).
    Populations originally inhabiting tidal areas, such as those found 
in San Francisco Bay, rarely were studied before they disappeared, and 
none remain to adequately study their use of truly tidal conditions. 
Several of the lagoonal habitats have been converted by human 
activities into tidal harbors and bays, such as Humboldt Bay, Elkhorn 
Slough, Morro Bay and Santa Margarita River, among others (Swift et al. 
1989, 1993). Populations recently present in these artificially created 
tidal situations, such as Elkhorn Slough, Morro Bay, and Santa 
Margarita River, have disappeared in the last 5 to 10 years. The only 
remaining tidal system with tidewater gobies is Humboldt Bay (Swift et 
al. 1989; C. Chamberlain, in litt. 1997).
    The life history of tidewater gobies is keyed to the annual cycles 
of the coastal lagoons and estuaries (Swift et al. 1989, 1994; Swenson 
1994, 1995). Water in estuaries, lagoons and bays is at its lowest 
salinity during the winter and spring as a result of precipitation and 
runoff. During this time, high runoffs cause the sandbars at the mouths 
of the lagoons to breach, allowing mixing of the relatively fresh 
estuarine and lagoon waters with seawater. This annual building and 
breaching of the sandbars is part of the normal dynamics of the systems 
in which the tidewater goby has evolved (e.g., Zedler 1982, Lafferty 
and Alstatt 1995, Heasly et al. 1997). The time of sandbar closure 
varies greatly between systems and years, and typically occurs from 
spring to late summer. Later in the year, occasional waves washing over 
the sandbars can introduce some sea water, but good mixing often keeps 
the lagoon water at a few parts per thousand salinity or less. Summer 
salinity in the lagoon depends upon the amount of freshwater inflow at 
the time of sandbar formation (Zedler 1982, Heasly et al. 1997).
    Males begin digging breeding burrows 75-100 mm (3-4 in.) deep, 
usually in relatively unconsolidated, clean, coarse sand averaging 0.5 
mm (0.02 in.) in diameter, in April or May (Swift et al. 1989; Swenson 
1994, 1995). Swenson (1995) has shown that tidewater gobies prefer this 
substrate in the laboratory, but also found tidewater gobies digging 
breeding burrows in mud in the wild (Swenson 1994). Inter-burrow 
distances range from about 5 to 275 centimeters (cm) (2 to 110 in.) 
(Swenson 1995). Females lay about 100-1000 eggs per clutch, averaging 
400 eggs/clutch, with clutch size depending on the size of both the 
female and the male. Females can lay more than one clutch of eggs over 
their lifespan, with captive females spawning 6-12 times (Swenson 
1995). Wild females may spawn less frequently due to fluctuations in 
food supply and other environmental conditions, but the species clearly 
has a high reproductive potential, enabling populations to recover 
quickly under suitable conditions. Male gobies remain in the

[[Page 33818]]

burrow to guard the eggs that are attached to sand grains in the walls 
of the burrow. Males also spawn more than once per season (Swenson 
1995), and although they can have more than one clutch in their burrow, 
presumably from different females (Swift et al. 1989), Swenson (1995) 
found that males accepted only one female per brood period. Males 
frequently go for at least a few weeks without feeding, and this 
probably contributes to a mid-summer mortality often noted in 
populations (Swift et al. 1989; Swenson 1994, 1995).
    Reproduction peaks during spring to mid-summer, late April or May 
to July, and can continue into November or December depending on the 
seasonal temperature and rainfall. Reproduction sometimes increases 
slightly in the fall (Swift et al. 1989; Camm Swift, Department of 
Biology, Loyola Marymount University, pers. comm., 1995). Reproduction 
takes place from 15-20 degrees Celsius (60-65 degrees 
Fahrenheit (F)) and at salinities of 0-25 ppt (Swift et al. 1989; 
Swenson 1994, 1995). Typically, winter rains and cold weather interrupt 
spawning, but in some warm years reproduction may occur all year 
(Goldberg 1977, Wang 1984). Goldberg (1977) showed by histological 
analysis that females have the potential to lay eggs all year in 
southern California, but this rarely has been documented. Length-
frequency data from southern and central California (Swift et al. 1989; 
Swenson 1994, 1995) and analysis of otoliths from central California 
populations (Swift et al. 1997) indicate that tidewater gobies are an 
annual species and typically live one year or less.
    Tidewater goby eggs hatch in 7-10 days at temperatures of 15-18 
degrees C (60-65 degrees F). The newly hatched larvae are 4-7 mm (0.2 
in) in length and are planktonic for one to a few days. Once they reach 
8-18 mm (0.3-0.8 in.) in length they become substrate oriented. All 
larger size classes are substrate oriented and, although little habitat 
segregation by size has been noted (Swift et al. 1989, Swenson 1995), 
Worcester (1992) did find that larval gobies in Pico Creek Lagoon 
tended to use the deeper portion of the lagoon. Individuals collected 
in marshes appear to be larger (43-45 mm (1.7-1.8 in.) SL) than those 
collected in open areas of lagoons (32-35 mm (1.3-1.4 in.) SL) (Swenson 
1995).
    Studies of the tidewater goby's feeding habits suggest that it is a 
generalist. At all sizes examined, tidewater gobies feed on small 
invertebrates, usually mysids, amphipods, ostracods, snails, and 
aquatic insect larvae, particularly dipterans (Irwin and Soltz 1984; 
Swift et al. 1989; Swenson 1994, 1995). The food items of the smallest 
tidewater gobies (4-8 mm (0.2-0.3 in.)) have not been examined, but 
these gobies, like many other early stage larval fishes, probably feed 
on unicellular phytoplankton or zooplankton (Swenson and McCray 1996).
    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 than 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 San Francisco Bay delta (Swift et al. 1989), although 
direct documentation to support this hypothesis is lacking.
    Tidewater gobies also are preyed upon by non-native African clawed 
frogs (Xenopus laevis) (Lafferty and Page 1997), although this is 
probably not a significant source of mortality due to the limited 
distribution of this frog species in tidewater goby habitats. The frogs 
are killed by the higher salinities that occur when the lagoons are 
breached (Glenn Greenwald, U.S. Fish and Wildlife Service, pers. obs.). 
Several non-native fish species also prey on tidewater gobies. The 
shimofuri goby (Tridentiger bifasciatus), which has become established 
in the San Francisco Bay region (Matern and Fleming 1995), may compete 
with the smaller tidewater goby, based on dietary overlap (Swenson 
1995) and foraging and reproductive behavioral observations in 
captivity. Shimofuri gobies have been observed to eat juvenile 
tidewater gobies in captivity, but usually were unable to catch 
subadult and adult tidewater gobies (Swenson and Matern 1995). Evidence 
of predation or competition in the wild is lacking (Swenson 1998). 
Competition with yellowfin (Acanthogobius flavimanus) and chameleon 
(Tridentiger trigonocephalus) gobies has also been hypothesized. 
Although Wang (1984) found that yellowfin gobies do prey on tidewater 
gobies, no data were presented indicating the extent of such 
interactions, nor has there been any further documentation of such 
competitive or predatory interactions with either species. Shapovalov 
and Taft (1954) documented the non-native striped bass (Morone 
saxatilis) preying on tidewater gobies in Waddell Creek Lagoon, but 
stated that striped bass were found only infrequently in the areas 
inhabited by the goby. Sunfishes and black bass (Centrarchidae) have 
been introduced in or near coastal lagoons and may prey heavily on 
tidewater gobies under some conditions. Predation by young-of-the-year 
largemouth bass (Micropterus salmoides) on tidewater gobies was 
documented in one system (Santa Ynez River), where tidewater gobies 
accounted for 61 percent of the prey volume of 55 percent (10 of 18) of 
the juvenile bass sampled (Swift et al. 1997). Although tidewater 
gobies disappeared soon after centrarchids were introduced at several 
localities, direct evidence that the introductions led to the 
extirpations is lacking (Swift et al. 1989, 1994; Rathbun et al. 1991; 
Dan Holland, Department of Biology, Southwestern Louisiana State 
University, Monroe, LA, pers. comm. 1991). In at least one location, 
tidewater gobies have re-established naturally (see below).
    Lafferty et al. (1996) monitored post-flood persistence of 17 
tidewater goby populations in Santa Barbara and Los Angeles counties 
during and after the heavy winter flows of 1995. All 17 populations 
persisted after the high flows, and no significant changes in 
population sizes were detected. In addition, gobies apparently 
colonized Canada Honda, approximately 10 km (6 mi) from the closest 
known population, during or after the flooding (Swift et al. 1997). 
Lafferty et al. (in prep.) estimated the extirpation and recolonization 
rates for 37 populations in southern California, based on over 250 
presence-absence records. They found higher recolonization rates than 
expected, and suggested that there is more gene flow among populations 
within geographic clusters (northern California, San Francisco Bay, 
Santa Cruz, San Luis Obispo and south) than previously believed to 
exist. They also found an association between tidewater goby presence 
and wet years. This information suggests that flooding may contribute 
to recolonization of sites from which gobies have temporarily 
disappeared.
    Lagoons in which tidewater gobies are found range in size from a 
few square meters (yards) (less than 0.10 hectares (ha) (0.25 acres 
(ac)) of surface area to about 800 ha (2000 ac). Most lagoons with 
tidewater goby populations are in the range of 0.5-5 ha (1.25-12.5 ac). 
Surveys of tidewater goby localities and historical records indicate 
that size,

[[Page 33819]]

configuration, location, and access by humans are all related to 
persistence of populations of this species (Swift et al. 1989, 1994). 
Watered surface areas smaller than about 2 ha (5 ac) generally have 
histories of extinction, extirpation, or population reduction to very 
low levels, although some as small as 0.35 ha (0.86 ac) have been 
identified as having permanent tidewater goby populations (Swift et al. 
1997, Lafferty 1997, Heasly et al. 1997). As evidenced by the Canada 
Honda colonization (Swift et al. 1997), even relatively long distances 
are not obstacles to colonization or re-establishment. Many of the 
small lagoons with histories of intermittent populations are within 1-2 
km (0.6-1.2 mi) of larger lagoons that can act as sources of colonizing 
gobies.
    The largest localities have not proved to be the best for the 
species, as evidenced by the loss of tidewater gobies from San 
Francisco and Morro bays and the Santa Margarita River estuary. Today, 
the most stable and largest populations are in lagoons and estuaries of 
intermediate sizes, 2-50 ha (5-125 ac) that have remained relatively 
unaffected by human activities, although some systems that are heavily 
affected or altered also have large, stable populations (e.g., Santa 
Clara River, Ventura County; Santa Ynez River, Santa Barbara County; 
Pismo Creek, San Luis Obispo County). In many cases these probably have 
provided the colonists for the smaller ephemeral sites (Swift et al. 
1997, Lafferty et al. in prep.).

Distinct Population Segments

    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, published 
in the Federal Register on February 7, 1996 (61 FR 4722). We consider 
three elements in determining whether a vertebrate population segment 
could be treated as threatened or endangered under the Act: 
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. We determine significance either by the 
importance or contribution, or both, of a discrete population to the 
species throughout its range. The policy 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 surviving natural occurrence of the 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 its genetic characteristics.
    If we determine that a population segment is discrete and 
significant, we evaluate it for endangered or threatened status based 
on the Act's standards.
    The previously discussed electrophoretic and mitochondrial DNA 
analysis indicates the Orange and San Diego counties population is 
genetically discontinuous from other coastal populations of tidewater 
gobies. Furthermore, the significant distance (129 km, 80 mi) between 
the Orange and San Diego counties population and the closest extant 
population physically isolates these gobies from those populations to 
the north. Therefore, we conclude the Orange and San Diego counties 
population of tidewater gobies is discrete in accordance with our 
distinct vertebrate populations policy.
    Genetic investigations (e.g., Jacobs in litt., 1998) indicate that 
tidewater gobies are made up of four geographically distinct 
populations in California. Of these four, the southernmost, in Orange 
and San Diego counties, constitutes the most genetically divergent 
population. The genetic data reveal differences in the southern 
population that are consistent with interspecific boundaries in other 
species, and suggest divergence of the southern population from the 
rest of the populations over 100,000 years ago. This coincides with the 
fact that the southern population is the most geographically isolated, 
being 129 km (80 mi) from the nearest extant population. Loss of the 
Orange and San Diego counties population of tidewater gobies would 
result in a loss of a genetically unique tidewater goby population, and 
a reduction in range of tidewater gobies by approximately 129 km (80 
mi). We therefore conclude that the Orange and San Diego counties 
population is significant in accordance with our distinct vertebrate 
populations policy. This population constitutes a distinct population 
segment, and we have evaluated it for endangered or threatened status 
based on the Act's standards.

Previous Federal Actions

    We first classified the tidewater goby as a category 2 species in 
1982 (47 FR 58454). We reclassified it as a category 1 candidate in 
1991 (56 FR 58804) based on status and threat information in Swift et 
al. (1989). Category 2 applied to taxa for which information we 
possessed indicated that proposing to list as endangered or threatened 
was possibly appropriate, but for which conclusive data on biological 
vulnerability and threats were not currently available to support a 
listing proposal. Category 1 species, now referred to as candidate 
species, applies to taxa for which we have on file substantial 
information on biological vulnerability and threats to support a 
proposal to list as threatened or endangered. On October 24, 1990, we 
received a petition from Dr. Camm Swift, Associate Curator of Fishes at 
the Los Angeles Museum of Natural History, to list the tidewater goby 
as endangered. We published a finding that the requested action may be 
warranted on March 22, 1991. We published a proposal to list the 
tidewater goby as an endangered species on December 11, 1992 (57 FR 
58770). On March 7, 1994, we listed tidewater goby as a federally 
endangered species (59 FR 5494). No critical habitat was designated.
    Federal involvement with the tidewater goby following listing has 
included consultations under section 7 of the Act, permitting of 
breaching and other activities in lagoons through the section 404 
process by the U.S. Army Corps of Engineers (ACOE), and funding and 
conducting research and surveys. Measures to reduce impacts to 
tidewater goby habitat and reduce or eliminate the potential for take 
of individuals have included adjusting the timing of projects to avoid 
disruption to breeding activities, the use of silt fencing to reduce 
sediment loads and as barricades around project sites, installing 
coffer dams above and below project sites and removal and translocation 
of animals found within the exclosures prior to necessary dewatering of 
project sites, minimization of project area, and requiring qualified 
biologists to oversee all activities.

Tidewater Goby Status Review

    At the time of listing (1994), California had recently experienced 
5 years of drought conditions (1987-1991), and we believed that most 
populations throughout the species' range were threatened by one or 
more factors, including modification and loss

[[Page 33820]]

of habitat as a result of coastal development, channelization of 
habitat, diversion and alteration of water flows, groundwater 
overdrafting, discharge of agricultural and sewage effluents, 
introduction of exotic fish species (particularly centrarchid species), 
and increased sedimentation due to cattle grazing and feral pig 
activity (59 FR 5494). We have assembled and evaluated new information 
regarding habitat status, habitat requirements of the goby, critical 
life history needs, dispersal processes and goby population status 
during drought and wet years. In the remainder of this section and in 
the Summary of Factors Affecting this Species, we review this new 
information and reassess the threats to the tidewater goby.
    At the time of listing, we believed that the number of extant 
tidewater goby populations was 46, with 87 known historically. Since 
the listing, 4 populations once believed permanently extirpated have 
been rediscovered, 2 populations have been re-established artificially 
(Waddell Creek, Malibu Creek), records for at least 15 populations 
indicate that they are naturally intermittent, 11 populations believed 
extinct due to drought conditions have re-established naturally, and 20 
new populations have been found. At present the number of extant 
populations is believed to be about 85, and the number of historical 
populations about 110.
    In the early 1990s, the number of tidewater goby populations 
believed to be extinct caused concern, especially considering the high 
proportion believed lost in the southern third of the species' range. 
The final rule for the listing of the tidewater goby stated that 74 
percent of the populations in coastal lagoons south of Morro Bay had 
been extirpated, with only 3 populations remaining south of Ventura 
County. We now know of 6 populations south of Ventura County, and only 
about 20 percent of populations south of Morro Bay are currently 
considered extirpated. Range-wide, of the 25 populations currently 
considered permanently extirpated, 19 were extirpated prior to 1970, 
before regulations protecting the environment were promulgated. The six 
more recent population extirpations are discussed in the appropriate 
sections below.

Summary of Factors Affecting the Species

    Section 4 of the Endangered Species Act and regulations (50 CFR 
Part 424) promulgated to implement the listing provisions of the Act, 
set forth the procedures for listing, reclassifying, and delisting 
species on Federal lists. A species may be determined to be an 
endangered or threatened species due to one or more of the five factors 
described in section 4(a)(1). A species may be delisted, according to 
section 4 regulations (50 CFR Part 424.11(d)), if the best scientific 
and commercial data available substantiate that the species is neither 
endangered nor threatened because of (1) extinction, (2) recovery, or 
(3) original data for classification of the species were in error.
    In the case of the tidewater goby, a significant number of 
populations previously believed extirpated have recolonized naturally, 
and a significant number of populations previously believed to be in 
decline have stabilized or increased in size since the listing. 
Therefore, we reevaluated all of the factors believed to be threatening 
the existence of the tidewater goby. We found that some of our 
interpretations of the data available when the species was listed were 
in error, and we also found that new information exists which supports 
interpretations of status and threats that differ from those presented 
in the final listing rule. After a thorough review of all available 
information, including considerable new information, we have determined 
that, north of Orange and San Diego counties, the tidewater goby is not 
endangered or threatened with endangerment. In this part of the range 
we now know that there are more populations than were known at the time 
of the listing, that the threats to those populations are less severe 
than previously believed, and that the tidewater goby has a marked 
ability to recolonize habitats from which it is temporarily absent. The 
1994 final rule identified several threats to the tidewater goby, 
including coastal development, upstream water diversions and alteration 
of flows, groundwater overdrafting, discharge of agricultural and 
sewage effluents, channelization, cattle grazing, feral pig activity, 
predation by introduced fish species, inadequacy of existing regulatory 
mechanisms, drought, flood events and competition with introduced 
species. A reanalysis of these threats follows.
    The remaining tidewater gobies in Orange and San Diego counties, 
which constitute a distinct population segment, are limited to the U.S. 
Marine Corps Base, Camp Pendleton. Threats to these southernmost 
tidewater goby populations differ from those found elsewhere on the 
California coast or, due to the small number of populations or other 
factors, threats that are minor to the northern populations of gobies 
are greatly exacerbated in the south. Urban development, although 
possibly impacting recovery areas, is not an overriding threat on Camp 
Pendleton. Nevertheless, habitat loss and degradation have occurred 
frequently and continue to threaten this population segment, as do 
predation by and competition with introduced species. These factors are 
discussed below for both the populations north of Orange and San Diego 
counties and the population within Orange and San Diego counties.

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

    Populations North of Orange and San Diego Counties. Coastal 
development projects that result in the loss of coastal saltmarsh 
habitat were identified in the final rule as the major threat adversely 
affecting the tidewater goby. Such projects probably were the most 
significant threat responsible for the historical loss of tidewater 
goby populations. Projects included dredging of waterways for 
navigation and harbors and road construction that severed the 
connections of marshes with the Pacific Ocean. Reevaluation of the 
number of extirpations resulting from coastal development and habitat 
modification and loss shows that the potential for the substantial 
habitat loss and modification that occurred historically has been 
reduced substantially. This is due largely to the implementation of key 
environmental regulations required by the Clean Water Act, Coastal Zone 
Management Act and related California environmental statutes. For 
example, only five permanent extirpations resulting from destruction or 
modification of habitat have occurred since the initial promulgation of 
environmental regulations during the early 1970s (two due to 
construction of golf courses, one due to installment of culverts that 
altered natural lagoon dynamics, one due to placement of riprap cutting 
off ocean access, and one due to water appropriations). Thus, in the 
northern part of the species' range (i.e., north of Orange and San 
Diego counties) there is insufficient evidence to suggest that 
destruction and modification of habitat from coastal development are 
occurring at levels that constitute a substantial threat to the 
continued existence of the northern populations of tidewater gobies.
    We stated in the final rule that upstream water diversions and 
groundwater overdrafting may adversely affect the tidewater goby by 
altering downstream flows, thereby diminishing the extent of marsh 
habitats that occurred historically at the mouths of

[[Page 33821]]

most rivers and creeks and potentially affecting the species' breeding 
and foraging activities. The final rule also 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. Supporting these arguments at the time of 
the listing, the population in San Antonio Creek, Santa Barbara County, 
was believed to have been extirpated due to groundwater overdrafting. 
However, gobies are not currently extirpated from this location; they 
were found there in 1995.
    Tidewater gobies have been collected from waters ranging from 0 to 
42 ppt salinity (Swift et al. 1989, Lafferty and Alstatt 1995). During 
the late 1980s and early 1990s, Worcester (1992) conducted an 
investigation of habitat use in Pico Creek lagoon, and observed large 
numbers of tidewater gobies using the lower portion of the lagoon where 
high salinities (up to 27 ppt) were documented. Since the listing, 
Swenson (1995) and Swift et al. (1997) have reported capturing gobies 
in waters up to 28 ppt and 32 ppt salinity, respectively. Two salinity 
tolerance experiments discussed in Swift et al. (1989) indicate that 
tidewater gobies can withstand a wide range of salinities, from 0-40 
ppt for up to 25 days with 20 percent or less mortality, even when 
moved directly from low salinity environments into high. A third 
experiment allowed salinities to increase through evaporation for 53 
days. At a final salinity of 25 ppt, 75 percent of the tidewater gobies 
survived, while 59 percent of those held in water reaching a final 
salinity of 62 ppt survived. In the early 1990s, while tidewater gobies 
were held at the Granite Canyon Fish Culture Facility, a salinity 
tolerance test was conducted in hypersaline water (45-54 ppt) for 6 
months, with no mortality. In addition, tidewater gobies were 
maintained in fresh water and salinities of 10-15 ppt, 20 ppt, and 
normal sea water (about 33 ppt salinity). Reproduction took place in 
all four regimes. Some of the laboratory bred tidewater gobies spawned 
when they matured (K. R. Worcester, in litt. 1996; Worcester and Lea 
1996). Based on these studies, the goby appears tolerant of a broad 
range of salinity conditions.
    Channelization was identified as a threat in ``most'' of the 
habitats occupied by the species due to the scouring effects of high 
winter flows in the restricted channels and the lack of protective 
habitat. However, with the exception of the extirpation of the Waddell 
Creek, Santa Cruz County, population during the winter of 1972-73 
attributed to channelization, further review of causes of extirpations 
since 1970 has not been able to identify population extirpation due to 
this threat. Moreover, tidewater gobies were re-established in Waddell 
Creek in 1991 and have persisted there through 1997 (Smith 1998).
    Siltation from topsoil runoff and the increased sedimentation and 
habitat degradation associated with cattle grazing and feral pig 
activity were also identified as threats to the tidewater goby. Many 
tidewater goby populations exist in habitats where such agricultural 
effluent and runoff and wastewater effluent occur, and the final rule 
identified the resulting algal blooms and deoxygenation as possible 
factors in the further degradation of tidewater goby habitats. During 
the 1950s, sewage effluents high in ammonia were discharged into the 
Salinas River and are believed to have been a factor in the apparent 
extirpation of that tidewater goby population (Jerry J. Smith, Ph.D., 
San Jose State University, pers. comm. 1998). However, in many lagoons 
receiving agricultural and sewage effluents, tidewater gobies are the 
most abundant fish species present, as found during surveys of lagoons 
in Santa Barbara County (Ambrose et al. 1993). Field observations made 
during tidewater goby surveys have found extremely low levels of 
dissolved oxygen (0.2-1.7 mg/l) (Worcester1992, Swift et al. 1997) and 
elevated temperatures (greater than 30 degrees C) where gobies were 
found in high numbers (C. Chamberlain, pers. comm. 1996; E. Ballard, 
U.S. Fish and Wildlife Service, Sacramento, California, personal 
observation 1997). Based on those observations, the tidewater goby 
appears to be tolerant of agricultural and sewage effluents, and of a 
wide range of dissolved oxygen levels and temperatures.
    We suggested in the final rule that only 6 to 8 of the 46 remaining 
populations were large enough and free enough from habitat degradation 
to be safe in the immediate future. The remaining lagoons were 
considered so small or modified that tidewater goby populations were 
thought to be restricted in distribution and vulnerable to extirpation. 
Of particular concern was the extirpation of smaller populations due to 
effects of drought exacerbated by upstream water diversions. The number 
of extirpated populations of gobies was believed to leave remaining 
populations so widely separated throughout most of the species' range 
that recolonization was unlikely. New information and analyses indicate 
that the tidewater goby is very well adapted to the climatically 
dynamic system within which it has evolved, and that the intermittent 
occupancy of some sites is a normal aspect of the species' biology 
(Swift et al. 1994, 1997; Lafferty et al. in prep.; J. Smith, pers. 
comm. 1998). Following the listing of the tidewater goby and the end of 
the 1987-1992 drought, at least 14 populations considered extirpated 
due to the drought and other causes were found to be extant. In some 
cases, these habitats were documented as being dry during the drought, 
with no gobies believed to be present in the drainages (e.g., Laguna 
and Moore creeks, Santa Cruz County; Arroyo del Puerto, San Luis Obispo 
County). Following a return to normal or above average rainfall, gobies 
were found not only in those 14 sites but also in approximately 20 
others from which they previously had not been found. These findings 
show that recolonization is possible and indicate that it is a normal 
process following habitat variation due to climatic fluctuations (Swift 
et al. 1994, 1997; Lafferty et al. in prep.; J. Smith, pers. comm. 
1998).
    In a number of cases, surveys that concluded that populations were 
extirpated from localities that did not go dry during the drought 
apparently were inadequate to determine presence or absence of the 
species. Periodic disappearances and re-appearances of the tidewater 
goby in various locations during the last 25 years (Lafferty 1997, 
Lafferty et al. in prep.) suggest that conclusions regarding presence/
absence based on standard survey methods may not be reliable. 
Researchers along the central California coast have observed periods 
when tidewater gobies cannot be found, but then later reappear (Rathbun 
et al. 1991; Swift et al. 1993, 1997; J. Smith, pers. comm. 1998). 
These observations may be the result of the gobies being temporarily 
absent from the sampled habitat or the population decreasing 
temporarily to a size not detectable by standard presence/absence 
methods (e.g., seine hauls). Regardless, the reappearance of tidewater 
gobies in localities where they previously were considered to be 
extirpated may be the result of earlier surveys being conducted during 
the windows of time when gobies temporarily were not observable (Smith 
1998; Norm Scott, Ph.D., U.S. Geological Survey, Biological Resources 
Division, San Simeon, pers. comm. 1997). The continued survival of 
tidewater goby populations, both large and small, following the long 
drought of the late 1980s and early 1990s suggests that the previous 
assessment that most of the

[[Page 33822]]

populations are extremely vulnerable to extirpation is not valid.
    Although not discussed in the final listing rule, artificial lagoon 
breaching during the dry season has been suggested as a potential 
threat to tidewater gobies. No data exist to substantiate the severity 
of this threat (but see the adverse effects of artificial breaching San 
Onofre Creek lagoon, below). Significant decreases in water level, 
exposure of tidewater goby breeding burrows and bottom habitat, and 
increased salinity resulting from breaching during the dry season are 
factors that we considered as possible threats to the persistence of 
tidewater goby populations. However, in the northern part of its range, 
the species continues to persist at numerous locations (e.g., Pescadero 
Creek, San Mateo County; Pismo Creek, San Luis Obispo County; Santa 
Ynez and Arroyo Burro, Santa Barbara County; Santa Clara River, Ventura 
County) where unseasonal breaching occurred on a regular basis prior to 
the listing (Swenson 1995; Lafferty 1995; Lafferty and Alstatt 1995; 
Heasly et al. 1997; D. W. Alley, in litt. 1998). The lack of any 
records of breaching-related extirpations leads us to conclude that 
breaching does not pose a significant threat to the northern 
populations of the species.
    Orange and San Diego Counties Population. Of the 13 historic and 
current sites in Orange and San Diego counties, the two northernmost, 
Aliso and San Juan creeks in Orange County were lost in the 1980s and 
1960s (respectively). The three southernmost sites, San Luis Rey, Buena 
Vista, and Agua Hedionda were lost in the 1940s and 1950s. More 
recently, it appears that Santa Margarita River, which probably was 
habitat for a naturally intermittent population (see Lafferty 1997, 
Lafferty et al. in prep.), is now permanently unsuitable due to exotic 
species and hydrologic changes. Permanent population losses, such as 
those listed above, can seriously influence metapopulation dynamics in 
the region, leading to larger scale extinctions, by reducing 
opportunities for recolonization of suitable sites. Exacerbating this 
concern, recent human activities have further endangered the two 
largest goby populations in Orange and San Diego counties (San Onofre 
Creek Lagoon, San Mateo Creek Lagoon) which may be important sources of 
dispersing gobies that repopulate other areas when they are 
periodically lost.
    In October 1996, a survey conducted by Drs. Dan Holland and Camm 
Swift in the San Onofre Creek lagoon estimated the population of gobies 
at 12,265. On November 22, 1996, the lagoon was artificially breached 
and water immediately began draining from the lagoon into the ocean. 
The water level dropped 40 to 50 cm and the surface area of the lagoon 
decreased approximately 60 to 75 percent during the next 12 hours. 
During the night of November 22-23, 1996, the bar across the mouth of 
the lagoon reformed and water ceased to flow directly into the Pacific 
Ocean. On November 24, 1996, Drs. Holland and Swift resurveyed the 
lagoon and estimated the goby population at 5,345, a decrease of 6,920 
fish from their October 1996 survey (Swift and Holland 1998). Recent 
surveys confirm that tidewater gobies are still present in San Onofre 
Creek Lagoon but no precise population estimates are available.
    On February 24, 1998, repair work began on storm-damaged railroad 
trestles that traverse San Mateo Creek Lagoon. This work included 
dredging portions of the creek and lagoon, and filling fresh water 
marsh which function as goby refugia. The San Mateo goby population at 
this locality was estimated at approximately 70,000 in 1996 (Swift and 
Holland 1998). After the dredging and filling, several surveys were 
conducted and no gobies were detected, but they were found at Las 
Flores, Cockleburr, and Hidden lagoons. The trestle repair work coupled 
with the winter storms may have resulted in the extirpation of the goby 
at San Mateo Creek. The consequences of population losses or 
elimination of the San Mateo and San Onofre populations, which had 
appeared to be two of the three most stable in the area, are very 
serious because the effects could extend to other areas, contributing, 
for example, to long term or permanent extirpation of the remaining 
intermittent populations in the region (Hidden, Aliso, French and 
Cockleburr creeks).
    These examples described above illustrate serious adverse 
population responses to earthmoving activities in and around creeks and 
lagoons. The specific mechanism or mechanisms (e.g., changed 
hydrological regime, siltation, water quality) leading to population 
declines are not known, and it is also not known if gobies in the 
Orange and San Diego counties distinct population segment respond 
differently to environmental stresses than gobies to the north. 
Tidewater gobies from Orange and San Diego counties are genetically 
distinct and live in a very different physical and biotic environment 
from those in more northerly habitats. It is possible that in this part 
of the range, environmental stresses such as siltation or changed 
hydrology affect gobies more severely than the same stresses to the 
north. Or, environmental factors unique to southern California or 
combinations of factors of which we are now currently unaware may be 
leading to declines in disturbed areas occupied by Orange and San Diego 
counties populations. Whatever the mechanisms, the recent loss or 
serious reduction of the Santa Margarita River and San Onofre and San 
Mateo lagoon populations, all of which have experienced human-caused 
changes in hydrologic regime and earthmoving activities, suggests that, 
in this part of the range, this kind of disturbance has serious 
negative consequences for tidewater gobies. Depending on the 
alternative alignment selected, the proposed Foothill Transportation 
Corridor-South project could result in population effects similar to 
those described above.

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    Populations North of Orange and San Diego Counties. Overutilization 
is not known to be applicable; there is no change in this factor since 
the species was listed in 1994.
    Orange and San Diego Counties Population. Same as above.

C. Disease or Predation

    Populations North of Orange and San Diego Counties. Disease was not 
identified as a threat in the final listing rule, nor is it known to be 
a threat at this time. Swenson (1995) reported finding cysts, 
presumably of the digenean trematode (a flatworm or fluke (Cryptocotyle 
lingua), and felt that the fluke could have been a factor in the 
apparent population decline of tidewater gobies in Pescadero Lagoon in 
1992 and 1993. However, gobies have persisted in the lagoon and 
associated creek and marsh, at least through 1996 (J. Smith, pers. 
comm. 1998). The fluke species also has been reported from fish in 
Corcoran (Rodeo) Lagoon in Santa Cruz County (Swift et al. 1989), but 
there is no indication of consequences for the tidewater goby 
population there.
    A large number of exotic species that have been perceived as 
threats to the tidewater goby have been introduced into goby habitats. 
In the final rule, the introduction of striped bass into the San 
Francisco delta area was hypothesized to have caused the loss of 
tidewater gobies in that habitat. However, no historic data exist to 
test this hypothesis. As discussed in the background section, predation 
by and competition with the introduced yellowfin, chameleon, and 
shimofuri gobies exists. However, tidewater goby

[[Page 33823]]

populations north of Orange and San Diego counties are not particularly 
vulnerable to these introduced fish. The centrarchid species largemouth 
bass and green sunfish (Lepomis cyanellus) were identified in the final 
listing rule as having caused the loss of at least two populations. 
However, centrarchids are known to exist in many sites inhabited by 
large populations of tidewater gobies (e.g., Santa Clara River, Las 
Pulgas Creek, San Mateo Creek). Because of the range of salinity 
tolerances of the tidewater goby and the more limited salinity 
tolerances of many exotic species, and because tidewater goby 
populations are sufficiently large and can repopulate from adjacent 
streams, the threat of tidewater goby extirpation throughout its 
habitat as a result of predation by exotic species appears minimal. 
While exotic species forage on tidewater gobies, the current suite of 
exotic fishes are not likely a serious threat to populations north of 
Orange County at this time. Although African clawed frogs feed on 
tidewater gobies (Lafferty and Page 1997), gobies are found in large 
numbers in at least one habitat (Santa Clara River) occupied by the 
frogs.
    Orange and San Diego Counties Population. As described under Factor 
A, above, it is not known if tidewater gobies in Orange and San Diego 
counties respond differently to environmental stresses than gobies to 
the north. Exotic fishes are thought to have played an important role 
in population losses or declines in San Onofre Creek and the Santa 
Margarita River. The predatory yellowfin goby, native to the inshore 
marine waters of Japan and China, is established in most lagoons that 
have or had gobies in Orange and San Diego counties. This and other 
exotic species may or may not by themselves extirpate tidewater gobies 
in Orange and San Diego counties, but when combined with other factors, 
especially habitat disturbance (see Factor A, above), may pose a 
serious ongoing threat to the Orange and San Diego counties distinct 
population segment. In addition, only six populations remain and two of 
the formerly largest have been seriously imperiled recently by human 
activities (see Factor A, above). Therefore, threats such as exotic 
predators, that prevent or contribute to significant reductions in 
dispersal and recolonization of sites where gobies are temporarily 
absent, could lead to the extinction of the entire Orange and San Diego 
distinct population segment.

D. The Inadequacy of Existing Regulatory Mechanisms

    Populations North of Orange and San Diego Counties. Inadequacies of 
existing regulatory mechanisms were cited in the final listing rule as 
a factor leading to the listing. This factor undoubtably contributed to 
the loss of populations prior to the promulgation of environmental 
regulations circa 1970. Currently, the review and permitting of 
projects conducted by the ACOE under section 10 of the Rivers and 
Harbors Appropriation Act of 1899 and section 404 of the Clean Water 
Act (CWA) are unlikely to allow the extent of destruction and 
modification of tidewater goby habitat that occurred prior to the 
implementation of these regulations. Measures are often included as 
standard measures in section 404 permits because other listed and 
sensitive species (e.g., California red-legged frog (Rana aurora 
draytoni), steelhead trout (Oncorhynchus mykiss), unarmored threespine 
stickleback (Gasterosteus aculeatus williamsoni)) often occur in the 
same locations as tidewater gobies. Examples of these measures include 
eliminating or reducing siltation by silt fencing along project sites 
and access roads, preventing sensitive species from entering project 
areas, erecting coffer dams on either side of project sites, and timing 
project activities to reduce impacts during the breeding season. Little 
evidence exists to support the conclusion that existing regulatory 
mechanisms inadequately protect the species or are contributing to 
substantial or widespread population decline and loss in the northern 
portion of the species' range (see Factor A, above).
    Current regulations require that a project that may alter wetland 
habitat be reviewed by and permitted through the ACOE and the 
California Coastal Commission (CCC). During the review of projects, 
avoidance of impacts (i.e., the prevention of habitat degradation 
including that occupied by listed species) is the first consideration. 
If wetlands will be altered, mitigation and/or compensation are 
required (40 CFR Part 230, CCC 1994). Section 404 of the CWA and the 
subsequent guidelines (40 CFR Part 230) for implementing that act 
govern the discharge of materials into waters of the United States in 
such a manner as to avoid or minimize impacts to (in part) human health 
and welfare; aquatic life and wildlife; aquatic system diversity, and 
productivity and stability; and they prohibit violation of state water 
quality standards, Environmental Protection Agency toxic effluent 
standards, the Act, and the Marine Protection, Research and Sanctuaries 
Act. Projects within the California coastal zone come under the 
provisions of the Federal Coastal Zone Management Act of 1990, and must 
go through an environmental review process. As with projects falling 
under section 404 of the CWA, the priorities are to avoid impacts, to 
mitigate if impacts are unavoidable, and to provide compensation if 
mitigation is infeasible (CCC 1994).
    In most cases, current regulations generally do not require minimal 
freshwater inflows into lagoons and estuaries in California. However, 
in many cases, water inflows during the dry season probably are higher 
than occurred historically due to wastewater treatment plant discharge 
and urban and agricultural runoff. Although discharge of such effluents 
was identified as an adverse factor in the final listing rule, and the 
effects of such effluents have not been studied directly, many of the 
habitats where such dry season inflows occur (e.g., Santa Ynez Lagoon, 
Ventura Lagoon, Santa Clara Lagoon) support large populations of 
tidewater gobies. A review of the Environmental Protection Agency's on-
line database AQUIRE found no contaminant data directly relating to 
tidewater gobies. No published research has addressed contaminant 
concentrations or effects in the tidewater goby. 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 significant threat to the ongoing existence of 
the goby in the northern portion of its range, especially in today's 
regulatory environment. Of the five populations extirpated due to 
habitat destruction and modification since 1970, only the loss of the 
Upper Morro Bay population possibly can be attributed to water 
appropriation.
    Orange and San Diego Counties Population. Despite the fact that the 
previously cited regulatory mechanisms were in place, three of the 
largest populations of tidewater goby (e.g., Santa Margarita River, and 
San Onofre and San Mateo creeks) have been lost or nearly lost since 
1993. The populations in San Onofre and San Mateo creeks were lost or 
greatly diminished following single human-caused events occurring so 
rapidly that existing regulatory processes failed to protect the 
gobies. The small number (6) of extant populations in the Orange and 
San Diego counties distinct population segment makes the loss of any 
one population a greater cause for concern than in the northern portion 
of the

[[Page 33824]]

range. With fewer extant populations, the likelihood of recolonization 
of temporarily empty habitat is reduced, and the risk that all 
populations will be extirpated due to drought or human factors is 
greater.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

    Populations North of Orange and San Diego Counties. The 
deterioration of coastal and riparian habitats mostly resulting from 
drought was cited as the most significant natural factor adversely 
affecting the tidewater goby in the final rule. At the time of listing, 
California had experienced over 5 consecutive years of lower than 
average rainfall. The stressful conditions brought on by the drought 
were considered to be exacerbated by human-induced water reductions 
(i.e., diversions of water from streams, excessive groundwater 
withdrawals). The substantial increase in the numbers of populations 
apparently extirpated and in the rates of decline of other populations 
during the drought were the major impetus for listing the species. 
However, since the end of the drought, 14 sites from which tidewater 
gobies were believed to have been extirpated have been recolonized. The 
recovery of nearly all populations and recolonization after the 
prolonged drought demonstrated that recovery and recolonization of 
habitats following natural events is probably a normal process for this 
species. No information exists to indicate that the natural processes 
are being significantly compromised by current regulatory mechanisms, 
habitat use, or natural events. The survival and recovery of these 
populations following a prolonged drought has alleviated the concern 
that drought exacerbated by human-induced water reductions will result 
in significant permanent population decline and loss.
    The extent of habitat degradation and losses of the tidewater goby 
from weather related phenomena, cited as threats in the final listing 
rule, has been difficult to determine. However, flood events have been 
shown to have no significant adverse effect on tidewater goby 
populations. The flushing action of floods is probably the primary 
mechanism for colonization of other habitats along the coast (Lafferty 
et al. 1996, Swift et al. 1997).
    Competition with introduced species also was identified as a 
potential threat in the final listing rule. The competing species of 
concern were the yellowfin goby and the chameleon goby. The shimofuri 
goby is also found in some tidewater goby sites, exhibits dietary 
overlap with the tidewater goby (Swenson 1995), and has been documented 
to prey on tidewater gobies in the laboratory (Swenson and Matern 
1995). The significance of these interactions in the wild remains 
undocumented. To date no documented extirpation or population decline 
can be attributed directly to these or other introduced competing 
species. Lafferty and Page (1997) cite Brittan et al. (1970) and 
McGinnis (1984) as evidence that the introduction of the yellowfin goby 
into San Francisco Bay and the disappearance of tidewater gobies were 
correlated. However, Brittan et al. (1970) do not discuss the 
distribution of nor impacts on the tidewater goby. Lafferty and Page 
(1997) cited Hubbs and Miller (1965) as evidence that killifish also 
were involved in the loss of tidewater gobies from that region. 
However, Lafferty and Page (1997) note that yellowfin gobies, 
mosquitofish, and green sunfish coexist with tidewater gobies in at 
least one location, the Santa Clara River.
    Orange and San Diego Counties Population. Historically, natural 
events such as high storm flows washed many fish, including tidewater 
gobies, out of lagoons. These events ultimately may have benefitted 
many native fishes, including tidewater gobies. High flows likely 
reduced populations of predators, and gobies soon recolonized the 
lagoons from adjacent populations. Unfortunately, the extirpation of 
many historic tidewater goby populations from adjacent watersheds 
requires the gobies to travel greater distances and from smaller source 
populations. As a result, this natural recolonization is much more 
difficult and uncertain.
    Similarly, droughts may have temporarily reduced local tidewater 
goby populations, but they soon recovered during wet years. However, 
many of the larger tidewater goby populations in Orange and San Diego 
counties have already been lost, and therefore, recolonization of 
smaller intermittent lagoons following droughts appears much more 
unlikely. Extended droughts, coupled with other physical alterations to 
the lagoons threaten the tidewater goby in Orange and San Diego 
counties.

Effects of the Rule

    Finalization of this rule will change the portion of the range of 
the tidewater goby listed as endangered from ``Entire'' to ``Orange and 
San Diego counties'' in the List of Endangered and Threatened Wildlife. 
Therefore, taking, interstate commerce, import and export of tidewater 
gobies occurring outside of Orange and San Diego counties will no 
longer be prohibited under the Act. In addition, Federal agencies will 
no longer need to consult with the Service to ensure that any action 
authorized, funded, or carried out by them is not likely to jeopardize 
the continued existence of the tidewater goby outside of Orange and San 
Diego counties.
    The distinct population segment of the tidewater goby in Orange and 
San Diego counties will remain an endangered species on the List of 
Endangered and Threatened Wildlife. Federal agencies will need to 
continue to consult with the Service to ensure that any action 
authorized, funded, or carried out by them is not likely to jeopardize 
the continued existence of the Orange and San Diego counties population 
of tidewater goby.

Future Conservation Measures

    Section 4(g) of the Act requires that all species that have been 
delisted due to recovery be monitored for at least 5 years following 
delisting. The tidewater goby populations north of Orange and San Diego 
counties are proposed for delisting primarily because there have been 
additional discoveries of tidewater goby populations since the original 
listing and more complete information is now available. A monitoring 
plan is not required for species delisted due to errors in or 
insufficiency of the data on which the classification was based, but we 
strongly encourage those parties involved in conducting surveys and 
monitoring programs for tidewater gobies to continue their efforts and 
forward the information to us.

Public Comments Solicited

    We intend that any final action resulting from this proposal will 
be as accurate and as effective as possible. Therefore, we solicit 
comments or suggestions from the public, other concerned governmental 
agencies, the scientific community, industry, or any other interested 
party concerning this proposed rule. We particularly seek comments 
concerning:
    (1) Biological, commercial trade, or other relevant data concerning 
any threat (or lack thereof) to this species;
    (2) Additional information concerning the range, distribution, and 
population size of this species; and
    (3) Current or planned activities in the range of this species and 
their possible impacts on this species.
    The final decision on this proposal for the tidewater goby will 
take into consideration the comments and any additional information we 
receive, and such communications may lead to a final regulation that 
differs from this proposal.

[[Page 33825]]

    The Act provides for one or more public hearings on this proposal, 
if requested. Requests must be received within 45 days of the date of 
publication of this proposal. Such requests must be made in writing and 
addressed to the office listed in the ADDRESSES section (above).

Required Determinations

Paperwork Reduction Act

    This rule does not include any collections of information that 
require approval by OMB under the Paperwork Reduction Act.

National Environmental Policy Act

    We have determined that an Environmental Assessment or 
Environmental Impact Statement, as defined under the authority of the 
National Environmental Policy Act of 1969, need not be prepared in 
connection with regulations adopted pursuant to section 4(a) of the 
Endangered Species Act of 1973, as amended. We published a notice 
outlining our reasons for this determination in the Federal Register on 
October 25, 1983 (48 FR 49244).

References Cited

    A complete list of all references cited herein is available upon 
request from the Ventura Fish and Wildlife Office (see ADDRESSES 
section).

Authors

    The primary authors of this proposed rule are Ed Ballard and Grace 
McLaughlin, Ventura Fish and Wildlife Office (805/644-1766), and Paul 
Barrett, Carlsbad Fish and Wildlife Office (760/431-9440), U.S. Fish 
and Wildlife Service.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, Transportation.

Proposed Regulation Promulgation

    Accordingly, we propose to amend part 17, subchapter B of Chapter 
I, title 50 of the Code of Federal Regulations, as set forth below:

PART 17--[AMENDED]

    1. The authority citation for part 17 continues to read as follows:

    Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C. 
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.

    2. In Sec. 17.11(h), we propose to amend the table by revising the 
entry for ``goby, tidewater'' under FISHES to read as follows:


Sec. 17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
                        Species                                                    Vertebrate
--------------------------------------------------------                        population where                                  Critical     Special
                                                            Historic range       endangered or         Status      When listed    habitat       rules
           Common name                Scientific name                              threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                   *                  *                  *                  *                  *                  *                  *
              Fishes
 
                   *                  *                  *                  *                  *                  *                  *
Goby, tidewater..................  Eucyclogobius         U.S.A. (CA)........  Orange and San       E                       527           NA           NA
                                    newberryi.                                 Diego Counties
                                                                               (U.S.A.-CA).
 
                   *                  *                  *                  *                  *                  *                  *
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Dated: May 28, 1999.
Jamie Rappaport Clark,
Director, Fish and Wildlife Service.
[FR Doc. 99-16030 Filed 6-23-99; 8:45 am]
BILLING CODE 4310-55-P