Southern Puffer, Sphoeroides nephelus

Southern Puffer, Sphoeroides nephelus. Fish caught off the Sanibel Island Pier, Sanibel Island, Florida, March 2017. Length: 11.2 cm (4.4 inches). Catch, photograph and identification courtesy of Marc Eberlein, Grand Rapids, Michigan.

Southern Puffer, Sphoeroides nephelus. Fish caught from coastal waters off Clearwater, Florida, March 2012. Length: 13 cm (5.1 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Southern Puffer, Sphoeroides nephelus. Fish caught from coastal waters off Tampa, Florida, May 2018. Length: 18 cm (7.1 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

Southern Puffer, Sphoeroides nephelus. Fish caught off the Dunedin Causeway, Dunedin, Florida, March 2016. Length: 20 cm (7.9 inches). Catch, photograph and identification courtesy of Ryan Crutchfield, Tampa, Florida.

Southern Puffer, Sphoeroides nephelus. Fish caught from coastal waters off Key West, Florida, March 2017. Length: 22 cm (8.7 inches). Catch, photograph, and identification courtesy of Dean Kimberly, Atlanta, Georgia.

Southern Puffer, Sphoeroides nephelus. Fish caught from coastal waters off Key Largo, Florida, March 2017. Length: 22 cm (8.7 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

The Southern Puffer, Sphoeroides nephelus, is a member of the Puffer or Tetraodontidae Family, and is known in Mexico as botete fruta or simply just botete. Globally, there are twenty-three species in the genus Sphoeroides, of which thirteen are found in Mexican waters, eight in the Atlantic and five in the Pacific Ocean.

The Southern Puffer has a thick, oblong, and inflatable body. 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 4 fused teeth that form a strong beak. Their anal fin has 6 rays and a short base; and, their dorsal fin has 7 rays and a short base. They do not have pelvic fins, fin spines or scales.

The Southern Puffer is found in coastal and estuarine habitats in shallow protected waters at depths up to 18 m (60 feet) and have an affinity for mangroves and seagrasses. They reach a maximum length 25.0 cm (9.8 inches) in length. 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 are reported to accumulate toxins including the potent neurotoxins saxitoxin and tetrodotoxin 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. The Southern Puffer is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Southern Puffer is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the Caribbean and are 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 6 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 above.

From a conservation perspective the Southern Puffer is currently considered to be of Least Concern with stable, widely distributed 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. They are a frequent by-catch of recreational anglers being very very accessible via hook and line. They are a “catch and release.” Note: Like many Puffers, the Southern Puffer is reputed to be highly poisonous, even fatal, if eaten, due to the presence of the potent neurotoxins saxitoxin and/or tetrodotoxin, which is found in their skin, viscera, and gonads and is believed to protect them from predation by larger fish.