Southern Puffer

Southern Puffer, Sphoeroides nephelus

The Southern Puffer, Sphoeroides nephelus, whose common Spanish name is botete fruta, is a member of the Puffer or Tetraodontidae Family, known collectively as botetes in Mexico. Globally, there are 23 species in the genus Sphoeroides, of which 13 are found in Mexican waters, eight in the Atlantic and five in the Pacific.

The Southern Puffers have thick, oblong, and inflatable bodies. They are dark brown and covered with darker and lighter spots and blotches, many having pale tan rings and semicircles. They transition to light brown ventrally. They have large dark splotches along their lower sides, variable dark slashes on their lower cheek, a dark bar between their eyes, and a dark pectoral fin base. Breeding males are covered with small bright orange or red spots. Their head is blunt with a small terminal mouth and four fused teeth that form a strong beak. Their anal fin has a short base and six rays. They have a single dorsal fin with a short base and seven rays. They have no pelvic fins, fin spines or scales.

The Southern Puffers are found in coastal and estuarine habitats in shallow protected waters at depths up to 60 feet and have an affinity for mangroves and seagrasses. They reach a maximum length of 25.0 cm (9.8 inches). They are active during the day and settle into sandy bottoms at night. They have the ability to survive in a wide range of salinities (5 ppm to 45 ppm). They are normally solitary individuals but are known to form loose aggregations around man-made structures. They are exceedingly well camouflaged. They are also capable of inflating their abdomen with water when frightened or disturbed. They produce and accumulate toxins such as Tetrodotoxin and Saxitoxin in their skin, gonads, and liver to deter predator attacks. They feed on shellfish, crustaceans, and small fish. Reproduction is oviparous with external fertilization. Eggs are laid demersal and attach themselves to rock and coral surfaces; they hatch quickly and larvae are pelagic. They are an exceedingly rare and poorly studied species and very limited is known about their behavioral patterns.

In Mexican waters the Southern Puffers are found in all waters of the Atlantic being most abundant in the eastern half of the Gulf of Mexico.

Due to its color variations and prickle differences, the Southern Puffer is frequently misidentified. In Mexican waters there are six similarly looking puffers: the Bandtail Puffer, Sphoeroides spengleri, the Blunthead Puffer, Sphoeroides pachygaster, the Checkered Puffer, Sphoeroides testudineus, the Least Puffer, Sphoeroides parvus, the Marbled Puffer, Sphoeroides dorsalis, and the Northern Puffer, Sphoeroides maculatus, but none of these have the markings of the fish photographed below.

The Southern Puffers are caught in abundance by recreational anglers. They are known to contain Tetrodotoxin and Saxitoxin, therefore should not be consumed as they are reputed to be highly poisonous, even fatal, if eaten. From a conservation perspective, they are currently considered of Least Concern, with widely distributed and abundant populations. In some parts of their range, their populations have decreased significantly which has been attributed to loss of habitat due to coastal development and pollution.

Southern Puffer, Sphoeroides nephelus. Fish caught from coastal waters off Key West, Florida, March 2017. Length: 22.0 cm (8.7 inches). Catch, photo, and identification courtesy of Dean Kimberly, Atlanta, GA.