Sergeant Major

Sergeant Major, Abudefduf saxatilis

Sergeant Major, Abudefduf saxatilis, Juvenile. Fish caught from within the Sebastian Inlet, Micco, Florida, November 2020. Length: 7.5 cm (3.0 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

Sergeant Major, Abudefduf saxatilis. Fish caught from coastal waters off Puente Calinda, Cancun, Quintana Roo, January 2015. Length: 10.2 cm (4.0 inches). Catch, photograph and identification courtesy of Marc Eberlein, Grand Rapids, Michigan.

Sergeant Major, Abudefduf saxatilis. Fish caught from coastal waters off Key Largo, Florida, December 2013. Length: 11 cm (4.3 inches). Catch, photograph and identification courtesy of Ben Cantrell, Peoria, Illinois.

Sergeant Major, Abudefduf saxatilis. Fish caught off the Vidanta Grand Luxx Resort Pier, Playa del Carmen, Riviera Maya, Quintana Roo, February 2016. Length: 14.0 cm (5.5 inches). Catch and photograph courtesy of George Brinkman, Guelph, Ontario, Canada.

Sergeant Major, Abudefduf saxatilis. Fish caught from coastal waters off Sugarloaf Key, Florida, August 2014. Length: 19 cm (7.5 inches). Photograph courtesy of Dean Kimberly, Atlanta, Georgia.

Sergeant Major, Abudefduf saxatilis. Fish caught from coastal waters off Belize, April 2015. Length: 20 cm (7.9 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

The Sergeant Major, Abudefduf saxatilis, is a member of family Pomacentridae, the Damselfish or Pomacentridae Family, and is known in Mexico as petaca ratada. Globally, there are twenty-five species in the genus Abudefduf, of which four are found in Mexican waters, two in the Atlantic and two in the Pacific Ocean.

The Sergeant Major has a deep oval compressed body that has a depth that is 60% to 64% of standard length, thus similar in nature to freshwater bluegills. They are whitish to pale silver in color with a bright yellow back and five dark bars on their sides which are narrower than the interspaces. Their head has a steep profile and a small protrusible mouth that opens in the front with a single row of teeth. Their caudal fin is forked with broad and very symmetrical lobes. They have 2 anal spines with 10 to 13 rays and a single continuous dorsal fin with 13 spines and 12 or 13 rays. Their body is covered with rough scales. Their lateral line is incomplete and ends under the edge of the dorsal fin base.

The Sergeant Major is a non-migratory species found in shallow water over and within rocky reef structure buffeted by wave action at depths up to 43 m (140 feet). They reach a maximum of 23.0 cm (9.1 inches) in length. They are diurnal feeders consuming primarily algae, benthic invertebrates and plankton. Reproduction is oviparous with pairing of individuals; eggs are distributed demersal and adhere to the substrate due to their stickiness. While breeding, males turn a very dark metallic blue to attract females to the nesting site, then guard and aerate the eggs. The Sergeant Major 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 Sergeant Major is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the east coast of the Yucatán Peninsula in the Caribbean.

The Sergeant Major is not easily confused with any other species due to its barring pattern and yellow coloration, however, it is virtually identical to the Panamic Sergeant Major, Abudefduf troschelii (found only in the Pacific Ocean). It has a similar body profile as the Night Sergeant, Abudefduf taurus (lacks yellow coloration on back) and similar barring pattern as the Sheepshead, Archosargus probatocephalus (6 or 7 bars; lacks yellow collation on back).

From a conservation perspective the Sergeant Majors is currently considered to be of Least Concern with stable, widely distributed populations. They are rather small in stature but considered an excellent food fish. They are classic nibblers, thus difficult to catch by hook and line.