Inhabits seagrass beds and algal mats in very shallow, protected waters. Prefers fully saline water.

Gobiosoma robustum is a small, unscaled goby that is somewhat variable in coloration. The body typically bears several irregular, interconnected dark bands with pale spots that give a chain-like appearance. A distinctive series of dark dots and dashes occur along the mid-side (Robbins et al. 1986). The resemblance of these markings to a visual representation of Morse code gives the animal its common name. The outer row of teeth is enlarged in the upper and lower jaws (GRI undated). The body depth is typically 16-23% of standard length (Hoese and Moore 1977).Dawson (1966) notes the species typically possesses 9-11 anal rays, 11-13 second dorsal rays, and 15-17 pectoral rays. Robbins et al. (1986) cite the most common count as: 12 dorsal rays; 10 anal fin rays; 16-17 pectoral fin rays. The first dorsal typically has a spine count of VII and a pelvic spine and ray count of I, 5 (GRI undated).

Western Atlantic: Cape Canaveral in northeastern Florida to Keys in USA and the entire Gulf of Mexico. Reported from Jamaica (Ref. 27228).

Gulf of Mexico

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Atlantic and Gulf coasts from Massachusetts to Yucatan, Mexico (Lee et al. 1980). Northeastern Florida to the Florida Keys, and the entire Gulf of Mexico (Robins and Ray 1986). Evidently, occurrence north of Florida is sporatic.

Gobiosoma robustum is a subtropical western Atlantic species reported in Florida from Cape Canaveral to the Florida Keys, and throughout the Gulf of Mexico. Accounts from the Bahamas and Jamaica are likely erroneous (GRI undated). The published northern distributional limit of this species is somewhat south of the northernmost limits of the Indian River Lagoon system, although it is common in the India River Lagoon from Cape Canaveral south.

Western Atlantic.

Maximum size: 50 mm TL

5.0 cm TL (male/unsexed; (Ref. 7251)); max. reported age: 1 years (Ref. 12193)

Length: 5 cm

Brown-Peterson et al. (1993) report a size range for Gobiosoma robustum of 11.3-45.2 mm SL, and a median size of 22.4 mm SL. Robbins et al. (1986) give a maximum total length of the species as 50 mm.The maximum reported age for the species is one year (Froese and Pauly 2008).

Type for Gobiosoma robustum
Catalog Number: USNM 92802
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Fishes
Year Collected: 1927
Locality: Corpus Christi, Texas, United States, Gulf of Mexico, Atlantic

Code gobies co-occur throughout their range with a very large number of other small, very similar gobiid fishes. Positive differentiation among these typically requires close examination and comparison of ray and scale counts and body part measurements by experienced biologists. Ray counts and size measurements overlap to a great degree with some co-occurring species such as Gobiosoma bosci, and microhabitat of the various species may be helpful in making identifications (e.g., see Dawson 1966).

demersal; brackish; marine

Depth range based on 1 specimen in 1 taxon.

Environmental ranges
  Depth range (m): 1 - 1
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Habitat Type: Marine

Comments: Abundant in moderate to high salinity, especially on sandy bottoms with covering vegetation such as mangrove roots or grasses (Thalassia) (Lee et al. 1980). Seagrass beds and algal mats, in very shallow, protected waters; prefers fully saline waters (Robins and Ray 1986).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Gobiosoma robustum preys on several small invertebrate species, including shrimp, gammaridean amphipods, and caprellid amphipods. (Caine 1983). Competitors: Schofield (2003) experimentally demonstrated that G. robustum was able to competitively displace clown gobies (Microgobius gulosus), forcing them out of structured (artificial seagrass) habitat and into bare sand. The results of this study suggest that habitat selection of these two species is modified in areas where they co-occur. Predators: Llanso et al. (1998) note that red drum (Scaenops ocellatus) often prey on Gobiosoma robustum, while McMichael and Peters (1989) report G. robustum is a component in the diet of spotted seatrout (Cynoscion nebulosus).Laboratory experiments by Schofield (2005) reveal that G. robustum remained susceptible to predation by toadfish (Opsanus beta) regardless of the presence or absence of structurally complex seagrass in which to seek refuge. Parasites: Hutton and Sogandares-Bernal (1960) list Diphterostomum americanum (Platyhelminthes: Digenea) as a known parasite of code gobies in Florida. Habitats: Code gobies are cryptic benthic fishes commonly encountered within seagrass meadows and algal mats of shallow, protected waters (Robbins et al. 1986, Froese and Pauly 2008). The species is demersal but non-burrowing, as compared, for example, to the co-occurring burrowing goby Microgobius gulosus (Schofield 2005). Hoese and Moore (1977) indicate Thalassia testudinum as the preferred seagrass habitat. They appear to be less sensitive than canopy-dwelling species to declines in seagrass cover (Matheson et al. 1999, Fourqurean and Robblee 1999). Less commonly, code gobies can be found in mangrove habitats (Lorenz 1999).Patrick and Palavage (1994) list G. robustum as a pollution-tolerant species.

Gobiosoma robustum (Gobies and blennies) preys on:
Nauplii2
Nauplii1
Foraminifera
Nematoda
Polychaeta
Harpacticoida
Pycnogonidae
Acartia tonsa
Elasmopus levis
Lembos rectangularis
Acunmindeutopus naglei
Synchelidium
Ampithoe longimana
Cymadusa compta
Batea catharinensis
Listriella barnardi
Lysianopsis alba
Caprella penantis
Brachiodontes exustus
Bivalvia
Crepidula fornicata
Crepidula convexa
Argopecten irradians
Chione cancellata
meiofauna
Amphipoda
Pinixia floridana
Neopanope texana
Paracerces caudata
Erichsionella
Edotia triloba

Based on studies in:
USA: Florida (Estuarine)

This list may not be complete but is based on published studies.

Gobiosoma robustum (Gobies and blennies) is prey of:
Lophodytes cucullatus
Tringa melanoleuca
Catoptrophorus semipalmatus
sediment POC

Based on studies in:
USA: Florida (Estuarine)

This list may not be complete but is based on published studies.

Tolan et al. (1997) list Gobiosoma robustum as among the top five most abundant fish in a seasonal seargass study from Redfish Bay, TX. Llanso et al. (1998) report G. robustum as one of two benthic rank dominant fish from Double Branch Bay, Upper Tampa Bay, FL. Florida Bay trawl collections conducted in 1984-1985 reveal a density of 4.5 individuals/ha, and collections made a decade later yielded 7.5 individuals/ha (Thayer et al. 1999). Sampling within seagrass beds themselves yields a considerably higher mean density of 1-4 individuals per square meter (Matheson et al. 1999).

Reproduction in Gobiosoma robustum is sexual, and the sexes are separate. As with most gobies, G. robustum is a demersal spawning species in which breeding males and females both care for the eggs [from generalized family info on: http://reefkeeping.com/issues/2002-09/hcs3/index.php - confirm this with Breder 1942[. (Smith 1997).Garcia et al. (1988) notes that spawning occurs throughout the year in a population from a lagoon in Campeche, Mexico, with maximal spawning occurring in the cold, dry season when salinity levels become elevated.

Details regarding embryologic development are lacking. Eggs are elliptical, around 1.5 mm long and 0.5 mm wide (Coleman et al 1991).

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Not Evaluated