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

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.

atened 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

pecies 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

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

losely 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)

males, 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

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

rts 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

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

east 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

t 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.)

es 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

r 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

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,

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

acles 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

d 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

ulation 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

duction 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

idewater 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

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

ty (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

t 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

n 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

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)

e, 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

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

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

ewater 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

idewater 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

stem 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)

nia 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

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

rt 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

agoon) 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

n 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

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

le

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

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

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

n 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)

s, 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

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

n 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

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

ersions 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

al 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

tions. 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

e 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

her 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.

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

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).......

- 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