Knobbed Porgy

Knobbed Porgy, Calamus nodosus

 The Knobbed Porgy, Calamus nodosus, whose common Spanish name is mojarrón pecoso is a member of the Porgy or Sparidae Family, known collectively as plumas in Mexico. Globally, there are thirteen species in the genus Calamus, nine of which are found in Mexican waters, eight in the Atlantic and one in the Pacific.

The Knobbed Porgies are characterized by their “porgy-like” laterally compressed relatively deep bodies, which have a depth that is 46 to 50% of standard length. They have an overall pinkish silvery coloration with a bluish cast. Their snout and cheeks have yellow to bronze spots. They have blue streaks under their eyes and a blue spot at the base of their pectoral fins. Their head is deep with a very steep upper profile, a projecting or humped forehead (in mature adults), and a well-developed bony knob above the rear nostril (after which they are named). They have a large mouth with thick heavy lips. They are equipped with molar teeth on the sides of each jaw and equal-sized canines at the front of each jaw that are used to crush hard shell prey. Their anal fin has a short base with 3 spines and 10 or 11 rays; their caudal fin is forked; their dorsal fin is low with 12 or 13 spines and 11 to 13 rays; and their pectoral fins are long and reach past the anal fin origin. Their body is covered with scales.

The Knobbed Porgies are a common coastal species and are abundant throughout most of their range; they are found over hard bottoms, within ledges and caves, within coral reefs and associated gravel, and in grass and sand areas along the outer continental shelf at depths up to 300 feet. They reach a maximum length of 54 cm (21 inches), but on average measure around 35 cm (14 inches) and can weigh up to 2.6 kg (5.7 pounds). They are bottom dwellers that feed primarily on invertebrates including barnacles, crabs, mollusks, polychaetes, sea stars, and sea urchins. They are protogynous hermaphrodites with all fish starting out as females and changing to males at midlife. Each female releases thousands of eggs which are fertilized externally by males and become pelagic. They are generally long-lived (up to seventeen years) and slow growing.

In Mexican waters the Knobbed Porgy are found in all waters of the Atlantic with the exception that they are absent from along the east coast of the Yucatán.

The Knobbed Porgy is very similar in shape to the seven other Porgies found in Mexican waters of the Atlantic, however, it is the only one with numerous small spots on its face.

The Knobbed Porgies are considered an excellent food fish and are targeted by both commercial and recreational fishermen. They are caught primarily by hook and line, longlines, bottom trawls, and fish traps. They are caught alongside other reef fish, such as the Gray Triggerfish, Red Porgy, Atlantic Red Snapper, and Red Porgy. From a conservation perspective they are currently considered of Least Concern and unregulated in most parts of their range (except for coastal waters of the southeast United States). It is generally believed that their commercial and recreational landings as well as their body length have decreased over the last 10 years, although these findings have been poorly documented. They are subject to habitat destruction and overfishing in some parts of their range.

Knobbed Porgy, Calamus nodosus. Fish caught from the Florida Middle Grounds, March 2015. Length: 41 cm (16 inches). Catch, photo and identification courtesy of George Brinkman, Guelph, Ontario, Canada.