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Species Name: 
Abudefduf saxatilis Linnaeus, 1758

Common Name(s):
Seargeant Major, Sargento (Portuguese), Asan (Malay), Badret (Marshallese), Pesce Damigella (Italian), Petaca Rayada (Spanish), Pintano (Spanish), Castagnole (French), Castanheta (Portuguese), Chauffet Soleil (French)

Synonymy:
Abudefduf ascensionis (Fowler 1919)
Apogon quinquevittatus (Blyth 1958)
Chaetodon marginatus (Bloch 1787)
Chaetodon mauritii (Bloch 1787) )
Chaetodon sargoides (Lacepede 1802)
Chaetodon saxatilis (Linnaeus 1758)
Glyphisodon biniar (Montrouzier 1857)
Glyphisodon moucharra (Lacepede 1802)
Glyphisodon rahti (Cuvier)
Sparus fasciatus (Gronow)

Species Description:
Abudefduf saxatilis is a member of the pomacentridae family that includes both the damselfishes and anemonefishes. This family is abundant in the tropical and warm temperate waters of the world. The Seargeant major is a small, laterally compressed rounded fish. There is a single nostril on either side of the snout distinguishing it from the butterflyfishes and angelfishes. It has a small, oblique terminal mouth. The upper part of the body is yellowish with 5 vertical black bars. Sometimes a faint sixth bar can be present. There is a black spot at the upper base of the pectoral fin (Randall 1996).

A. saxatilis is often observed on shallow reefs in large feeding aggregations of up to a few hundred individuals (Randall 1996). This fish uses different color phases for camouflage. The light phase is visible from below when the sergeant major is swimming over the reef, while the dark phase allows the fish to hide in the reef in response to danger. When males guard the red or purple patches of eggs in their nests they become dark bluish (Randall 1996).

Potentially Misidentified Species:
Abudefduf sexfasciatus (LacŽp�de 1801)
Abudefduf septemfasciatus (Cuvier)
Abudefduf vaigiensis (Quoy and Gaimard 1825)

II.  HABITAT AND DISTRIBUTION 

Regional Occurrence:
Abudefduf saxatilis is abundant in reef and rocky environments in the Atlantic ocean (Molina et al. 2006). Populations have been recorded in the western Atlantic ocean from as far north as Canada to Uruguay in South America at depths ranging from 0 to 20 m. A. saxatilis is abundant on Caribbean reefs (Randall 1996) and on the tropical coast of western Africa to Angola where they form large feeding aggregations of up to a few hundred individuals. Juveniles are found in tide pools or in protected areas schooling close to caves and shipwrecks. Adults are most common on shallow reefs.

IRL Distribution:
Juveniles of Abudefduf saxatilis were recorded as one of the ten most abundant species of fish occurring in the surveys in the Indian River Lagoon (Lindemen and Snyder 1999).

III. LIFE HISTORY AND POPULATION BIOLOGY

Age, Size, Lifespan:
Abudefduf saxatilis grows to a maximum length of approximately 23 cm and can weigh up to 0.2 kg. Males and females reach maturity at 10 cm and 8 cm, respectively.

Abundance:
Abudefduf saxatilis is abundant on tropical reefs and has been observed to rapidly increase its population size in areas of recreational disturbance where artificial food sources are created by fish feeding and habitat disturbances (Medieros et al. 2007).

Reproduction:
Sergeant majors are oviparous. Males prepare nests for egg masses on rocks, reef outcrops, shipwrecks, and pilings. Spawning times vary depending upon region. For example, Caribbean populations do not appear to exhibit a lunar spawning pattern. Females in this region have been observed to spawn at various times throughout the month (Foster 2004). During courtship males actively chase females in the early hours of the day and spawning takes place in the morning hours. Approximately 200,000 salmon or red colored, oval shaped eggs measuring 0.5 to 0.9 mm in diameter are released in discrete, densely packed monolayers that adhere to the substratum (Robertson et al. 1993). Once fertilized the eggs turn greenish (with 96 hours). The male guards the eggs until they hatch usually within 4-5 days after fertilization in the hour following sunset (Robertson et al. 1993, Foster 2004).

Embryology:
Abudefduf saxatilis larvae have a reduced pelagic stage lasting 18-27 days and a post larval pelagic stage lasting 55 days (Molina et al. 2006). The egg and larval development of laboratory-reared A. saxatilis has been exhaustively described by Alshuth et al. (1998). This study identified pigmentation, pelvic fin size, and the pectoral fin rays as the most useful characteristics for identifying the larvae of A. saxatilis from the yellowtail damselfish Microspathodon chrysurus and beaugregory Stegastes leucostictus. The sergeant major larva has a smaller and less pigmented fin and more heavily pigmented dorsal and pelvic fins.