Tuna - Frigate

Max length : 65.0 cm FL male/unsexed; common length : 60.0 cm TL male/unsexed; max. published weight: 1.7 kg; max. reported age: 5 years

Family	Scombridae
Description	Mackerels, tunas, bonitos
Environment	Brackish & Marine
Etymology	Latin, scomber = mackerel.
Genus	15
No. of Species	54
Order	Perciformes
Class	Actinopterygii
Reproductive Guild	Nonguarders
Distribution	Tropical and subtropical seas. Body elongate and fusiform, moderately compressed in some genera. Snout pointed, premaxilla beaklike, free from nasal bones which are separated by the ethmoid bone; mouth large; teeth in jaws strong, moderate, or weak; no true canines; palate and tongue may bear teeth. The 2 dorsal fins separate and depressible into grooves with 5-12 finlets behind second dorsal and anal fins; first dorsal fin with 9-27 rays, origin well behind the head. Pectoral fins high on body. Pelvic fins moderate or small with 6 fin rays, placed below the pectoral fins. Caudal fin deeply forked with supporting caudal rays completely covering hypural plate. At least 2 small keels on each side of caudal fin base, a larger keel in between on caudal peduncle in more advanced species. Lateral line simple. Vertebrae 31-66. Body covered with small to moderate scales or a scaly corselet developed (area behind head and around pectoral fins covered with large thick scales) and rest of body naked or covered with tiny scales. Gill membranes not united to isthmus. Thunnus and close relatives with a specialized vascular system for heat exchange; the evolution of this and related adaptations for endothermy are discussed in Block et al. 1993 (Ref. 11221). Primarily swift, epipelagic predators; some species occur in coastal waters, others far from shore. Mackerels (Scomber and Rastrelliger) filter plankton with their long gill rakers. Spanish mackerels, bonitos and tunas feed on larger prey, including small fishes, crustaceans and squids. The main predators of smaller scombrids are other predacious fishes, particularly large tunas and billfises. Dioecious and most display little or no sexual dimorphism in structure or color pattern. Females of many species attain larger sizes than maels. Batch spawning of most species takes place in tropical and subtropical waters, frequently inshore. Eggs are pelagic and hatch into planktonic larvae. Among the most important of commercial and sport fishes. [Thunninae=ISSCAAP 36; Scombrinae=ISSCAAP 37]. Also Ref. 50681. According to the recent phylogenies (Ref. 58009), two subfamilies can be recognized: - Gasterochismatinae with one species Gasterochisma melampus. - Scombrinae: divided currently in four tribes (Ref. 58010), only Scombrini are supported by molecular data; more research is needed for Scomberomorini, Sardini, and Thunnini.

Epipelagic in neritic and oceanic waters. Feeds on small fish, squids, planktonic crustaceans (megalops), and stomatopod larvae. Because of their abundance, they are considered an important element of the food web, particularly as forage for other species of commercial interest. Preyed upon by larger fishes, including other tunas

Dorsal spines (total): 10 - 12; Dorsal soft rays (total): 10-13; Anal spines: 0; Anal soft rays: 10 - 14. Back bluish, turning to deep purple or almost black on the head. A pattern of 15 or more narrow, oblique to nearly horizontal, dark wavy lines in scaleless area above lateral line. Belly white. Pectoral and pelvic fins purple, their inner sides black. Body robust, elongate and rounded. Teeth small and conical, in a single series. Pectoral fins short, but reaching past vertical line from anterior margin of scaleless area above corselet. A large single-pointed flap (interpelvic process) between pelvic fins. Body naked except for the corselet, which is well developed and narrow in its posterior part (no more than 5 scales wide under second dorsal-fin origin). A strong central keel on each side of caudal-fin base between 2 smaller keels

In correlation with temperature and other environmental changes, the spawning season varies with areas, but in some places it may even extend throughout the year.

Summary of Distribution: Atlantic, Indian and Pacific (Western Central). Eastern Pacific population recognized as subspecies Auxis thazard brachydorax. Many authors have used the name Auxis thazard as including Auxis rochei in the belief that there was only a single worldwide species of Auxis. Highly migratory species
Note: Distribution range colors indicate degree of suitability of habitat which can be interpreted as probabilities of occurrence (fishbase.org)