EnMuuiered Species Pacts
The tidewater goby is
an endangered species.
Endangered species are
plants and animals that are
in immediate danger of
becoming extinct.
Threatened species are plants
and animals whose population
numbers are so low that they
may become endangered in the
near future.
The U.S. Environmental
Protection Agency's (EPA)
Endangered Species Protection
Program (ESPP) will help
ensure that pesticide use does
not jeopardize the survival of
listed species.
Tidewater Goby
Description and Ecology
Eucycl^jofniis newimryi
Status Endangered, listed February 4, 1994.
Critical Habitat Designated November 20, 2000
Appearance The tidewater goby is a small fish, rarely
more than 2 inches in length. It has large pectoral fins (face-
framing when viewed from the front). The pelvic fins are
fused, forming a "sucker-like disc" below the chest and belly.
The two dorsal fins are close to one another. The upper 1/4
to 1/3 of the forward dorsal fin bears a transparent, white,
or yellowish triangular area which distinguishes the tidewater
goby. Overall, this elongate fish appears nearly transparent;
the males are grey-brown mottled, while the females may
also develop black or dark coloring on the body, dorsal fin and
anal fin. The scales of this fish are so small and embedded
that they are visible only with magnification.
Range Populations of the tidewater goby are described
as being "discontinuously distributed" along most of the
California Coast. The northern most population is found in
Tillas Slough at the mouth of the Smith River in Del Norte
County. The southern most population is located in Agua
Hedionda Lagoon in San Diego County. Tidewater gobies
are still found spread across their original range and yet
within that range, at the time of the Recovery Plan (2005),
17% of the populations were extirpated and 41-52% of
the populations so small and degraded that their long-term
survival appears uncertain. Gaps in distribution along the
coast may be natural, due to steep coastlines, or due to the
extirpation of populations. Because the tidewater goby is
adapted to a narrow range of salinity tolerance, the marine
environment limits genetic exchange between populations and
recolonization of habitat following extirpations.
Habitat Tidewater gobies are nearly unique among Pacific
coast fish in that they inhabit the fresh-saltwater interface
where salinity is less than 10 to 12 parts per thousand. This
occurs both at the upper edge of tidal bays (such as Tomales,
Bolinas, and San Francisco Bays) near the entrance of fresh-
water tributaries and in coastal lagoons formed at the mouths
of coastal rivers, streams, and seasonally wet canyons. These
habitats provide the relatively shallow, and still, but not stag-
nant, water that tidewater gobies prefer. Yet, such areas are
also subject to seasonal variations. Spring floods can scour
lagoons, breaking open (breaching) the sandbar barriers es-
tablished the previous season, and flushing tidewater gobies
into an unfavorable marine environment. Sediments settle
out variously, mud in the backwaters, soft sand across the
lagoon. These deeper, backwater habitats offer safe harbor
for tidewater gobies during the spring floods. Aquatic vegeta-
tion such as sago pond weed and widgeon grass are typical of
tidewater goby habitat. They provide shelter for young gobies
and substrate for the vertebrates used as food by the gobies.
Half grown and adult tidewater gobies may migrate upstream
from the estuaries into tributaries, a distance of 0.5 miles to
3-5 miles. Such upstream locations appear to also be used for
Reproduction and Life Cycle Reproduction can
occur year round, but appears to peak in April-May, after the
lagoons close to the ocean, and again later in summer. Males
dig burrows in clean, coarse sand at least 3-4 inches from
one another. Females compete with one another for access to
these burrows, where they will deposit a clutch of 300-500
eggs about 1 inch below the burrow entrance. The male goby
then remains in the burrow with the eggs until they hatch
9-11 days later. For a couple of days the young hang out in
midwater, before becoming "benthic" (settling to the bottom
to live and feed). Tidewater gobies have several strategies
for capturing prey such as chironomid midge larvae, mysid
shrimp, ostracods, and amphipods. They pluck them from
the water or the substrate surface, or sift sediment in their
mouths. In turn, they are prey for young steelhead, staghorn
sculpin, tule, and Sacramento perch, nonnative fish such as
bass and shimofuri gobies, and many birds such as egrets,
herons, mergansers, grebes, and loons. Tidewater gobies only
live about a year.
Recovery Plan The U.S. Fish and Wildlife Service
Eucj/clocjoUus -Kmimryi
Office of Pesticide Programs (7507P)
February 2010

Tidemvter Qoby
(FWS) developed a recovery plan for the tidewater goby in
2005. Recovery plans outline reasonable actions that FWS
believes are required to recover or protect listed species.
FWS prepares recovery plans, sometimes with the assistance
of recovery teams, contractors, state agencies, and others.
Recovery plans do not necessarily represent the views nor the
official positions or approvals of any individuals or agencies,
other than FWS, involved in the plan formulation. Approved
recovery plans are subject to modification as dictated by new
findings, changes in species'status, and the completion of
recovery tasks.
Tidewater Goby Information Sources
Primary Reference Beacham, Walton, Castronova,
Frank F,, and Sessine, Suzanne (eds.), 2001. Beacham's
Guide to the Endangered Species of North America, Gale
Group, New York. Vol. 2, pp. 1090-1092.
Listing Notice U.S. Fish and Wildlife Service, 1994.
Federal Register 59 No. 24, pp. 5494-5499, February 4, 1994.
Critical Habitat Designation u.s. Fish and wildlife
Service, 2000. Federal Register 65 No. 224, pp. 69693-
69717, November 20, 2000. http://ecos.fws.gov/docs/fed-
Recovery Plan U.S. Fish and Wildlife Service, 2005.
Recovery Plan for the Tidewater Goby, (Eucyclogobius new-
berryi). U.S. Fish and Wildlife Service, Pacific Region, Port-
land, Oregon.vi + 199 pp.
h ttp: //ecos .fws.go v/docs/reco very_plan/051207, pdf
Tidewatergoby kaMtat, Tillas Sfaugh., Vet Norte County CatifbrtUa.
Pkofo courtesy of Bradford, Norman, wtAM>.arsc(rMutiwg. org
Gravid female tidewater goby /  2007 Bradford, Norma.k
Tidewater gobiesjr&m near the mouth of Lake Totoum.
 2007 Bradford Norman, AKS Consulting