Chasmodes saburrae Jordan and Gilbert, 1882
Family: Blenniidae
Common names: Florida Blenny
Chasmodes saburrae image
Chasmodes saburrae  

Species Description: The Florida blenny, Chasmodes saburrae, is a small fish displaying a brown mottled or spotted pattern (Robins & Ray 1986). Like many other blenniids, C. saburrae has a continuous dorsal fin with no separation between the spinous and soft fin rays, which average 6 and 19, respectively. Other fin ray counts are as follows: pectoral, 11-13; caudal, 10-13; and anal, 18-19 (Williams 1983). The mouth is large with prominent lip flaps, and contains 10-14 large and 1-10 small upper pharyngeal teeth, along with 5-6 small lower pharyngeal teeth immediately in front of 6 larger canines. The number of mandibular teeth increases with body size. The head slopes steeply toward the mouth, bears at least six mandibular pores and no cirri. The Florida blenny exhibits sexual dimorphism, and descriptive characters of both sexes are detailed below.

Potentially Misidentified Species: The genus Chasmodes contains three species: C. saburrae; the striped blenny, C. bosquianus; and the stretchjaw blenny, C. longimaxilla. While all three species are present in the southeast United States, their ranges rarely overlap. Most of Florida is dominated by C. saburrae, coinciding with C. bosquianus in the northeastern region of the state and both C. bosquianus and C. longimaxilla in northwestern Florida (Robins & Ray 1986, Williams 1983). All species are very similar in appearance, with subtle distinguishing characteristics evident upon close inspection or through dissection. The striped blenny has only four mandibular pores, four canines, a more gradual slope to the head, and more prominent lip flaps than those of C. saburrae (Robins & Ray 1986, Williams 1983). In addition, the two species differ in the number of gill rakers present, averaging 9-13 and 12-14 for C. saburrae and C. bosquianus, respectively (Williams 1983). The remaining species, C. longimaxilla, typically exhibits fewer teeth and a longer maxillary, or upper jaw, than either the Florida or striped blenny (Williams 1983).

IRL Distribution: The Florida blenny is found throughout the IRL in all of the habitats described above. However, most specimens are located in seagrass beds and among oyster reefs.

Age, Size, Lifespan: The maximum age and lifespan for C. saburrae is unknown. However, Peters (1981) documented a developmental period of approximately three weeks from hatched egg to juvenile during laboratory studies. Growth and mortality rates vary with food availability, environmental conditions and other factors. The maximum reported size for the Florida blenny is 10 cm (Robins & Ray 1986), but most specimens collected are between 2 and 6 cm (Carr & Adams 1973).

Abundance: Though common, the Florida blenny is mostly solitary. Therefore, large populations are rarely seen. No abundance data have been published for C. saburrae in the IRL, but populations living among oyster reefs in southwest Florida average 1 to 3 individuals per square meter (Tolley et al. 2006).

Reproduction: The Florida blenny is sexually dimorphic, and sex is determined primarily upon examination of the anal spine (Smith-Vaniz 1980). In females, the first spine is greatly reduced; whereas, males in courtship display enlarged spines with associated fleshy structures and longitudinal folds of skin. Coloration, body length and jaw length are secondary sexual characteristics of C. saburrae (Williams 1983). Females and immature or non-territorial males are variously mottled. Territorial males often display a series of light longitudinal lines over a darker olive or mottled background, an iridescent blue spot on the membrane between the first and second dorsal spines, with an orange streak running from the spot to the tenth dorsal spine. In addition, these males have orange membranes on the chest and gills, can grow at least twice as long as females, and exhibit a longer jaw. Reproductive individuals have been reported to spawn throughout the day, with one male fertilizing the eggs of several females. After fertilization occurs, all the females of a single male mate deposit eggs on one of several surfaces, such as: empty shells of C. virginica or A. rigida, holes in rocks, sponges, or inside discarded cans (Peters 1981). The parental male then guards the clutches for about three weeks until hatching. Presence of nests in the field has indicated that spawning begins in early March and lasts through October (Peters 1981). The spawning process is continuous, and females lay eggs every one to two weeks throughout the season, spawning at least 2,600 eggs over a lifetime (Peters 1981).

Embryology / Larval Development: Clutch size is determined by the number of contributing females, the guarding ability of the male, and the surface chosen. Peters (1981) found that oyster shells held an average of 1,000 to 2,000 eggs, whereas a single can housed about 11,000. Eggs range from 0.7 to 0.9 mm in diameter, are bright yellow at deposition, and turn orange and then pale yellow with age. At 27°C, eggs hatch in six days, releasing larvae about 3.7 mm in length. Some newly-hatched individuals carry a yolk sac, which is quickly absorbed. Larvae then feed on zooplankton until settling to the benthos after about 21 days. Newly settled juveniles are approximately 6 mm long, and have developed fins and pigmentation.

Temperature: The Florida blenny is found in warm coastal waters, and though isolated individuals have been reported as far north as South Carolina, most thriving populations are restricted to more subtropical locations (Williams 1983). Surface water temperatures in shallow coastal areas can vary widely between seasons, and specimens have been collected from waters ranging between 14 and 33°C (Carr & Adams 1973, Kuhlmann 1994). Larvae of C. saburrae have been successfully cultured at temperatures of 21.4-27.7°C (Peters 1981).

Salinity: As a primarily estuarine species, C. saburrae has been reported in a wide range of salinities. Populations in the Everglades National Park experience salinities as low as 5.5 psu (Williams 1983), while those in east central areas of Florida Bay have been found in waters up to 44 psu (Sogard et al. 1987). Larvae of the Florida blenny have been cultured successfully at both 26 and 35 psu, depending on the salinity of the egg collection site (Peters 1981).

Trophic Mode: The Florida blenny is omnivorous, but its specific dietary preferences appear to vary with age (Carr & Adams 1973). Amphipods are a common prey item, and are consumed by all size classes (Carr & Adams 1973, Reid 1954). However, feeding behaviors change with growth and alter other food choices of the blenny. Smaller fish are more carnivorous and consume prey from the water column, including copepods and pelagic amphipods. As the blennies grow, they begin to feed on or near the benthos, adding detritus and plant material to their diets (Carr & Adams 1973). Other less abundant prey items determined from gut content analyses include: shrimps, tanaid crustaceans, polychaete worms, pelecypod mollusks, xanthid crabs, fish embryos and isopods (Carr & Adams 1973, Reid 1954).

Predators: Little information exists concerning predators of C. saburrae. However, it is likely that the hiding behavior of adults and juveniles among bivalve shells reduces predation risk. Still, blennies may be consumed by larger fishes and invertebrates, and pelagic larvae are possible prey for a host of organisms. Although the male parent guards each clutch, predatory snails, small crabs and other fishes could prey on fertilized eggs before hatching occurs.

Associated Species: As inhabitants of a variety of coastal ecosystems, Florida blennies are associated with several organisms common to mangroves, seagrass beds, oyster reefs and rocky intertidal zones. As mentioned above, C. saburrae is closely associated with the eastern oyster, C. virginica and the stiff penshell, A. rigida, through its reproductive processes (Kuhlmann 1994, 1997; Peters 1981). For lists of other organisms found throughout the ecosystems in which C. saburrae occurs, please refer to the Habitats of the IRL page.

Carr, WES & CA Adams. 1973. Food habits of juvenile marine fishes occupying seagrass beds in the estuarine zone near Crystal River, Florida. Trans. Amer. Fish. Soc. 102: 511-540.

Kuhlmann, ML. 1994. Indirect effects of a predatory gastropod in a seagrass community. J. Exp. Mar. Biol. Ecol. 183: 163-178.

Kuhlmann, ML. 1997. Regulation of fish reproduction by a predatory gastropod: an experimental investigation of indirect effects in a seagrass community. J. Exp. Mar. Biol. Ecol. 218: 199-214.

Peters, KM. 1981. Reproductive biology and developmental osteology of the Florida blenny, Chasmodes saburrae (Perciformes: Blenniidae). Northeast Gulf Sci. 4: 79-98.

Reid, GK. 1954. An ecological study of the Gulf of Mexico fishes in the vicinity of Cedar Key, Florida. Bull Mar. Sci. 4: 1-94.

Robins, CR & GC Ray. 1986. A field guide to Atlantic coast fishes of North America. Houghton Mifflin Co. New York. USA. 354 pp.

Sogard, SM, Powell, GVN & JG Holmquist. 1987. Epibenthic fish communities on Florida Bay banks: relations with physical parameters and seagrass cover. Mar. Ecol. Prog. Ser. 40: 25-39.

Smith-Vaniz, WF. 1976. The saber-toothed blennies, tribe Nemophini (Pisces: Blenniidae). Acad. Nat. Sci. Philadelphia. Monog. 19: vii + 196 pp.

Tolley, SG, Volety, AK, Savarese, M, Walls, LD, Linardich, C & EM Everham III. 2006. Impacts of salinity and freshwater inflow on oyster-reef communities in Southwest Florida. Aquat. Living Resour. 19: 371-387.

Williams, JT. 1983. Taxonomy and ecology of the genus Chasmodes (Pisces: Blenniidae) with a discussion of its zoogeography. Bull. Florida State Mus. Biol. Sci. 29: 65-100.