Fish Identification Photos: Scalloped Hammerhead Shark, Sphyrna lewini: The Scalloped Hammerhead Shark is the most common of the hammerheads and has an overall brownish grey coloration and is white vertically. The Scalloped Hammerhead Shark is characterized by a broadly convex head, with four lobes on the front margin, that is 24-30 percent of the total length. The “blade” has five indentations, with the three in the middle being modest and the two on the outer edges notched deeper.

The Scalloped Hammerhead Shark has large first dorsal fins with rounded tips. The base of the anal fin is longer than the base of the second dorsal fin. The undersides of the pectoral fins are tipped in black. The Scalloped Hammerhead Shark reaches a maximum length of 12 feet and is normally found in the first 600 feet of the water column. It travels as individuals or in large schools.

The Scalloped Hammerhead Shark is found in all Mexican waters. The Scalloped Hammerhead Shark can be confused with the Great Hammerhead, Sphyrna mokarran (first dorsal fin very tall with a pointed tip, margin of head is straight), and the Smooth Hammerhead, Sphyrna zygaena (broadly convex head profile with no central indentation). The Scalloped Hammerhead Shark is sold commercially for food and its skin is sold for use in leather products. Reports of attacks on humans are exceedingly rare.

The Scalloped Hammerhead Shark is a member of the Sphyrnidae Family of global travelers found in all tropical seas which includes the Bonnethead Sharks, the Hammerhead Sharks, and the Scoop Head Sharks. They are characterized by strongly flattened front heads with side extensions that are axe, mallet, or spade shaped, with eyes on the outer edges. They have elongated rounded slender bodies with two dorsal fins, the first of which is high and pointed. They have five gill slits with the last one over the front of the pectoral fins. Their tails are crescent-shaped. Members of the Sphyrna genus have a small second dorsal fin that is very asymmetrical and a notched tail base.

There are eight species known globally, of which six frequent Mexican waters. They all feed on a variety of fishes, crabs, lobsters, octopi, shrimps, squid and snails.

Scalloped Hammerhead Shark, Sphyrna lewini: Igor Galvan with a Scalloped Hammerhead Shark, Bahia de los Angeles (L.A. Bay), Baja California, Mexico. Photo courtesy Russ Gale. Fish I.D. by Peter Langstraat. Scalloped Hammerhead Shark, Sphyrna lewini: Scalloped Hammerhead Shark concentration at El Bajo, near La Paz, Baja California Sur, Mexico. Photo courtesy Jonathan Roldan.