Invasion History

First Non-native North American Tidal Record: 1994
First Non-native West Coast Tidal Record: 1994
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Tridentiger barbatus (Shokihaze Goby) is native to the marine and brackish waters of the northwest Pacific, including the coasts of Japan, Korea. China, Taiwan, and Vietnam (Greiner 2002; Froese and Pauly 2014). This goby is considered a near-threatened species in Japan where it occurs mainly in upper estuaries.

North American Invasion History:

Invasion History on the West Coast:

Tridentiger barbatus (Shokihaze Goby) was first caught in North America in Denverton Slough,off Suisun Bay in the inner San Francisco Bay estuary in 1994 (Greiner 2002; USGS Nonindigenous Aquatic Species Program 2014). It rapidly became widespread and common in the San Francisco Bay system ranging from the lower Sacramento and San Joaquin Rivers to San Pablo Bay, and 0.2-28.8 PSU salinity (Greiner 2002). In Montezuma Slough, Suisun Marsh (1-7 PSU, 10-22 C) in 2013-2015, T. barbatus was ~2% of the catch in minnow traps, compared to 10% for T. bifasciatus (Young et al. 2017). “One shokihaze goby was found on 22 August 2001 at the John E. Skinner Delta Fish Protective Facility” (J. Morinaka, CDFG, personal communication). This facility is located at the northern end of the California Aqueduct, near Tracy California (Greiner 2002). We have not found reports of this fish in southern California reservoirs.


Tridentiger barbatus (Shokihaze Goby; Bearded Goby) is a coastal marine and estuarine fish. It has the typical features of the family Gobiidae, including the two pelvic fins united to form a conical sucking disk, an (anterior) spiny and (posterior) soft dorsal fin, and eyes near the top of the head. The dorsal fins have seven spines and ten rays, respectively, which are separated by a gap. The anal fin has ten rays. This goby is relatively fat, with a wide flat head. There is a fringe of short barbels on the ventral margin of behind the eye, on the lower jaw, and on the preoperculum, resembling a short beard. The lateral line is not noticeable. Colors are highly variable, with six diffuse dark-brown bands over a light-brown background. The dark bands fade ventrally. There are usually two black spots at the upper and lowers bases of the caudal fin. This fish reaches a maximum length of 112 mm (Greiner 2002; Froese and Pauly 2018).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Chordata
Subphylum:   Vertebrata
Superclass:   Osteichthyes
Class:   Actinopterygii
Subclass:   Neopterygii
Infraclass:   Teleostei
Superorder:   Acanthopterygii
Order:   Perciformes
Suborder:   Gobioidei
Family:   Gobiidae
Genus:   Tridentiger
Species:   barbatus


Traiaenophorichthys barbatus (Günther, 1861)
Traiaenopogon barbatus (Bleeker, 1874)

Potentially Misidentified Species

Tridentiger bifasciatus
Tridentiger bifasciatus (Shimofuri Goby), introduced to the San Francisco estuary, was formerly considered conspecific with T. trigonocephalus. It differs in patterns of coloration, the size of sensory canals on the head, and the structure of pectoral fin rays. The Shimofuri Goby does not tolerate marine salinities (Matern and Fleming 1995).

Tridentiger trigonocephalus
Tridentiger trigonocephalus (Chameleon Goby), introduced to San Franicsco Bay, and southern California is stenohaline-marine (Cohen and Carlton 1995; Matern et al. 1995).



Tridentiger barbatus (Shokihaze Goby) is a coastal marine and estuarine fish. In Ariake Sound, Japan spawning takes place in May through September. Male fish select large empty hinged oyster shells (Crassostrea ariakensis) as nests for the females to lay their eggs. The males then clean and guard the eggs and nest. Females can lay between 2,610 to 23,365 eggs. The eggs are ellipsoid and attached to the shells. Eggs take about 4 days to hatch at 25 C. The planktonic larvae are about 3 mm long at hatching and settle at ~15-17 mm. The fish mature after one year, and some may survive to their third year (Dotu 1957).

Tridentiger barbatus ranges from cold-temperate to tropical climates in brackish and marine coastal waters. They have been collected at temperatures of from 7 to 28 C (Greiner 2002; Yagi et al. 2011; Inui et al. 2014; Froese and Pauly 2018). In the Ariake Sea, Japan juvenile fish are largely restricted to the upper regions of estuaries (Yagi et al. 2011). In the San Francisco estuary, T. barbatus has ranged well into tidal fresh water in the Delta (Greiner 2002). The salinity requirements for spawning are unknown, but we have not found reports of spawning populations in nontidal freshwater. Reported foods of this fish are annelids, crustaceans, and small fishes (Dotu 1957).


Crustaceans, Annelids, Fishes; Squid

Trophic Status:




General HabitatGrass BedNone
General HabitatTidal Fresh MarshNone
General HabitatUnstructured BottomNone
General HabitatSalt-brackish marshNone
General HabitatOyster ReefNone
Salinity RangeLimnetic0-0.5 PSU
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone
Vertical HabitatNektonicNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)7.6Minimum field temperature, San Francisco Bay CA (Greiner 2002)
Maximum Temperature (ºC)28Maximum field temperature, Ariake Sound, Japan (Dotu 1957)
Minimum Salinity (‰)0.2Minimum field salinity, San Francisco Bay CA (Greiner 2002)
Maximum Salinity (‰)28Maximum field salinity, San Francisco Bay CA (Greiner 2002)
Minimum Length (mm)53Female, Male 56 mm (Japan, Dotu 1957)
Maximum Length (mm)121Greiner 2002
Broad Temperature RangeNoneCold Temperate-Warm Temperate
Broad Salinity RangeNoneTidal Limnetic-Euhaline

General Impacts

No impacts have been reported for Tridentiger barbatus (Shokihaze Goby) in California. The major concern would be a potential spread to southern California reservoirs, and estuaries inhabited by the endangered Tidewater Goby (Greiner 2002). However, unlike the T. bifasciatus, the Shokihaze Goby is not known to reproduce in nontidal freshwater, so dispersal through the aqueduct and reservoir system is less likely.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NWP-4a None 0 Native Estab
NWP-3a None 0 Native Estab
NWP-3b None 0 Native Estab
NWP-2 None 0 Native Estab
NEP-V Northern California to Mid Channel Islands 1994 Def Estab
P090 San Francisco Bay 1994 Def Estab
EAS-I None 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Precht, William F. Hickerson, Emma L.; Schmah, George P.; Aronson, Richard B. (2014) The invasive coral Tubastraea coccinea (Lesson, 1829): Implications for natural habitats in the Gulf of Mexico and the Florida Keys, Gulf of Mexico Science 2014: 55-59

Anderson, Dean P. ·Pepper, Margaret A. Traver, Shelby s- Michaels, Trevor A. · Sullivan, Kevin · Ramsey, David S. L. (2022) Confirming the broadscale eradication success of nutrias (Myocastor coypus) from the Delmarva Peninsula, USA, Biological Invasions <missing volume>: Published online
Biol Invasions

Florida Museum of Natural History 2009-2022 Collections Databases (University of Florida Invertebrate Zoology Collection); (University of Florida Ichthyology Collection); .

Froese, R.; Pauly, D. (Editors). 2002-2024 FishBase.(World Wide Web electronic publication).. <missing URL>

Greiner, Thomas (2002) Records of the shokihaze, Tridentiger barbatus, newly introduced into the San Francisco estuary., California Fish and Game 88(2): 68-74

Kajihara, Hiroshi; Sun, Shi-Chun; , Chernyshev, Alexei V.; Chen, Hai-Xia; Ito, Katsutoshi; Asakawa, Manabu; Maslakova, Svetlana A.;Norenburg; Jon L. Strand, Malin; Sundberg, Per: Iwata, Fumio (2013) Taxonomic Identity of a Tetrodotoxin-Accumulating Ribbon-worm Cephalothrix simula (Nemertea: Palaeonemertea): A Species Artificially Introduced from the Pacific to Europe, Zoological Science 30(11): 985-997

Ladysmith Historical Society 2018 Oyster Industry in Ladysmith BC. <missing URL>

Massé, Cécile; Jourde, Jérôme; Fichet, Denis; Sauriau, Pierre-Guy; Dartois, Manon; Ghillebaert, François; Dancie, Chloé (2022) Northern range expansion of the Asian mussel Arcuatula senhousia (Benson, 1842) along the French Atlantic coasts, BioInvasions Records 11: Published online

Matern, Scott A.; Fleming, Kevin J. (1995) Invasion of a third Asian goby, Tridentiger bifasciatus, into California., California Fish and Game 81(2): 71-76

Matern, Scott A.; Moyle, Peter; Pierce, Leslie C. (2002) Native and alien fishes in a California estuarine marsh: twenty-one years of changing assemblages, Transactions of the American Fisheries Society 131: 797-816

Moyle, Peter B. (2000) A list of freshwater, anadromous, and euryhaline fishes of California., California Fish and Game 86(4): 244-258

Sturtevant, Rochelle; Lower, El; Bartos, Austin; Elgin, Ashley (2021) A review and secondary analysis of competition-related Impacts of nonindigenous aquatic plants in the Laurentian Great Lakes, Plants 10(406): Published online

USGS Nonindigenous Aquatic Species Program 2003-2024 Nonindigenous Aquatic Species Database.