Sphoeroides nephelus (Goode & Bean, 1882)
Family: Tetraodontidae
Common names: Southern Puffer,  more...
Synonyms: Sphaeroides nephelus (Goode & Bean, 1882),  more...
Sphoeroides nephelus image
Sphoeroides nephelus  

Species Description: The southern puffer, Sphoeroides nephelus, has a brown body, paler below, adorned with a variety of darker and lighter spots and blotches and often pale tan rings and semicircles. Larger dark splotches along the lower sides are variable and dark slashes may occur on the lower cheek. A dark interorbital (between the eyes) bar and a distinctive dark spot at the axil of the pectoral fins are particularly useful in identifying specimens. mature, ripe males may be covered with small, bright red or orange spots (Shipps 1978). Hard spines are lacking and the usual ray count is: dorsal=7; anal=6; pectoral=14 (Hoese and Moore 1977 Robbins et al. 1986).

As with other puffers, the small mouth is comprised of 4 teeth fused together to form a strong beak. Individuals lack scales (Hinchcliff 2004).

Potentially Misidentified Species: The distributions of Sphoeroides nephelus and the northern puffer, S. maculatus, overlap along the northern half of Florida (including northern portions of the IRL). These congeners are similar in appearance, although southern puffers lack the dark spots and diffuse gray bars characteristic of the northern puffer (Robins et al. 1986). Ray counts, interorbital distance, and habitat and ecology also aid in differentiation of the two species. Adult S. nephelus remain inshore whereas adult S. maculatus typically are collected offshore, and usually only juveniles of the two species are collected together (Shipp and Yerger 1969).

Regional Occurrence: Sphoeroides nephelus occurs from northeast Florida south through much of the Caribbean and into the eastern half or the Gulf of Mexico (Shipp and Yerger 1969). Hoese and Moore (1977) extends the distribution to the Chandeleur Islands and off Yucatan. Robins et al. (1986) notes that the taxonomic status of populations reported from northern South America to Brazil is uncertain.

IRL Distribution: Southern puffers can be found throughout the IRL system.

Age, Size, Lifespan: Southern puffers commonly reach a length of 20 cm, although larger specimens up to 30 cm have been reported (Hoese and Moore 1977, Froese and Pauly 2008).

Abundance: Hoese and Moore (1977) note that this species is the common puffer in the northeastern Gulf of Mexico, and it is common along the east coast of Florida as well.

Reproduction: Reproduction is sexual; sexes are separate and fertilization is external. Springer and Woodburn (1960) reported Sphoeroides nephelus is a fall spawner, but Shipp and Yerger (1969) suggest more continuous spawning at least from spring through fall and possibly year-round within southern portions of the range.

Embryology: Developmental details are sparse for this species. Other tetraodontids lay demersal eggs that they attach to rock and coral surfaces and which hatch to release free-swimming larvae. Early development of southern puffers is likely similar.

Temperature: The distribution of southern puffers is restricted to the subtropics and tropics, suggesting a relatively narrow thermal tolerance for the species.

Salinity: Hoese (1960) indicates Sphoeroides nephelus is broadly euryhaline. The author collected individuals from Mesquite Bay at salinities ranging from 5.5 ppt to 45.3 ppt.

Trophic Mode: The diet of southern puffers consists primarily of crabs and molluscs which they crush and eat with their powerful fused teeth (Shipp and Yerger 1969). Some finfish are consumed as prey as well (Ship 1978, Froese and Pauly 2008).

Predators: The ability of puffers to take in water to inflate their body size is an important adaptation to minimize the risk of predation (Shipp 1978), although some predation certainly occurs.

Habitats: Sphoeroides nephelus is a primarily benthic inhabitant of bays, estuaries, and protected waters to a depth of 11 m, and is frequently encountered in and around seagrass beds (Sedberry and Carter 1993, Froese and Pauly 2008). The species may also occur in salt marshes (Nordlie 2003) and in protected reef environments. Sedberry and Carter (1993) note the presence in the rubble zone of a Belize a barrier reef lagoon they surveyed.

Activity Time: Southern puffers are primarily active by day, settling into sand bottoms to rest at night (author's personal observation).

Economic Importance: Between 2002 and 2004, 28 cases of puffer fish poisoning were linked to fish caught in the Indian River Lagoon. The suspected disease agent is the dinoflagellate Pyrodinium bahamense, a species that produces saxitoxins and is responsible for fatal cases of paralytic shellfish poisoning in the Pacific. Landsberg et al. (2006) reveal that the skin mucus of IRL southern puffers remained highly toxic even after a year in captivity and suggest that P. bahamense is an emerging human health threat in the Atlantic.

Abbot et al. (2008) monitored saxitoxin levels in three species of puffer all throughout Florida. These authors routinely found the highest toxin concentrations in southern puffer from the northern IRL. Bandtail puffer (S. spengleri) from the IRL also typically exhibited skin saxitoxin concentrations above reported toxicity thresholds, while checkered puffers (S. testudineus) from the IRL and elsewhere were largely non-toxic.

Abbott JP, Flewelling LJ, and JH Landsberg. 2008. Saxitoxin monitoring in three species of Florida puffer fish. Harmful Algae (in press at the time this species report was written).

Froese R and D Pauly (Eds). 2008. FishBase. World Wide Web electronic publication. Available online.

Hinchcliff G. 2004. Field Guide For the Rookery Bay National Estuarine Research Reserve. Available online.

Hoese HD. 1960. Biotic changes in a bay associated with the end of a drought. Limnology and Oceanography 5:326-336.

Hoese HD and RH Moore. 1977. Fishes of the Gulf of Mexico. Texas, Louisiana, and Adjacent Waters. Texas A&M University Press, College Station TX. 327 p.

Landsberg JH, Hall S, Johannessen JN, White KD, Conrad SM Abbott JP, Flewelling LJ, Richardson RW, Dickey RW, Jester ELE, Etheridge SM, Deeds JR, Van Dolah FM Leighfield TA, Zou Y, Beaudry CG, Benner RA, Rogers PL, Scott PS, Kawabata K, Wolny JL, and KA Steidinger. 2006. Saxitoxin puffer fish poisoning in the United States, with the first report of Pyrodinium bahamense as the putative toxin source. Environmental Health Perspectives, Vol. 114:1502-1507.

Nordlie FG. 2003. Fish communities of estuarine salt marshes of eastern North America, and comparisons with temperate estuaries of other continents. Reviews in Fish Biology and Fisheries 13:281-325.

Robins CR, Ray GC, and J Douglas. 1986. A Field Guide to Atlantic Coast Fishes. The Peterson Field Guide Series. Houghton Mifflin Co., Boston. 354 p.

Sedberry GR and J Carter. 1993. The Fish Community of a Shallow Tropical Lagoon in Belize, Central America. Estuaries 16:198-215. Shipp RL.1978. Tetraodontidae. In: Fischer W (ed.). FAO species identification sheets for fishery purposes. West Atlantic (Fishing Area 31). volume 5. FAO, Rome.

Shipp RL and RW Yerger. 1969. Status, characters, and distribution of the northern and southern puffers of the genus Sphoeroides Copeia 1969:425-433.

Sphoeroides nephelus image
Sphoeroides nephelus