The jolthead porgy (Calamus bajonado) is an ocean-going species of fish in the family Sparidae. In Bermuda, it is known as the blue bone porgy, in the United States, it is also known by the Spanish name bojanado, in Jamaica, it is one of the species known by the name, porgi grunt.
The Jolthead porgy usually has 12 rays on the dorsal fin, 10 on the anal fin. They have 15 pectoral rays, though they can sometimes vary from 14 to 16. The lateral line can have from 50 to 57 scales. It differs from similar poriges it that most members of the genus has 45–49 scales on their lateral lines. It also differs from Calamus pennatula in that it has more pectoral rays. Jolthead porgies have a blue line under each eye, and their mouths are rimmed in orange. The fish's overall color is a brassy silver with occasional blue/green iridescence, making it one of the dullest-colored member of its genus.
The largest recorded Jolthead porgy was 76 cm, while they commonly grow up to 54 cm. Though they normally grow to around 8 lb, The heaviest weighed 23.36 lb.
Known only from the western Atlantic Ocean, Jolthead porgies are found from Rhode Island and Bermuda south to Brazil. They are abundant in the northern Gulf of Mexico and the West Indies. They have been collected from beds of seagrass, and commonly swim in clear, shallow water up to 150 feet, (though there have been reports of them as deep as 180 and 200 m) where they are normally solitary, but sometimes appear in schools near reefs. They are thought to spawn in July and August.
There is some debate over the Jolthead porgy's diet. Some sources consider it omnivorous, while others state at its eats mainly other animals such as sea urchins (especially of the genus Diadema), mollusks and crustaceans.
Considered to be an excellent food fish, Jolt head porgies can easily be caught with a hook and line on the bottom and by means of fish traps. They are considered to be a game fish and are of minor commercial importance, though there have been reports of ciguatera poisoning due to red tide associated with them.
