Bigeye Tuna

Dasyrhynchus Infestation 2. Parasitic infestations (protozoa, worms, etc.)

Hexostoma sibi Disease. Parasitic infestations (protozoa, worms, etc.)

Metazoan Infection 1. Parasitic infestations (protozoa, worms, etc.)

Dinurus Infestation. Parasitic infestations (protozoa, worms, etc.)

Caligus Infestation 7. Parasitic infestations (protozoa, worms, etc.)

Hexostoma thynni Disease. Parasitic infestations (protozoa, worms, etc.)

Pseudocycnus Disease. Parasitic infestations (protozoa, worms, etc.)

Koellikerioides Infestation 6. Parasitic infestations (protozoa, worms, etc.)

Kudoa Infestation 3. Parasitic infestations (protozoa, worms, etc.)

Areotestis Infection. Parasitic infestations (protozoa, worms, etc.)

Univietellodidymocytis Infestation 2. Parasitic infestations (protozoa, worms, etc.)

Orbitonematobothrium Infection. Parasitic infestations (protozoa, worms, etc.)

Neonematobothrioideis Infection. Parasitic infestations (protozoa, worms, etc.)

Köllikeria Infestation 8. Parasitic infestations (protozoa, worms, etc.)

Köllikeria Infestation 7. Parasitic infestations (protozoa, worms, etc.)

Köllikeria Infestation 5. Parasitic infestations (protozoa, worms, etc.)

Koellikerioides Infestation 4. Parasitic infestations (protozoa, worms, etc.)

Sphyriocephalus Infestation 1. Parasitic infestations (protozoa, worms, etc.)

Tristomella Infestation 1. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation 1. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation 2. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation 7. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation 8. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation 9. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation 10. Parasitic infestations (protozoa, worms, etc.)

Didymocystoides Infestation 4. Parasitic infestations (protozoa, worms, etc.)

Nematobothrium Disease. Parasitic infestations (protozoa, worms, etc.)

Opisthorchinematobothrium Infestation 2. Parasitic infestations (protozoa, worms, etc.)

Univietellodidymocytis Infestation. Parasitic infestations (protozoa, worms, etc.)

Are multiple spawners that may spawn every 1 or 2 days over several months (Ref. 30330). They spawn over periods of the full moon (Ref. 6390). Spawn throughout the year in tropical waters (Ref. 6390).

Oceanodromous. Migrating within oceans typically between spawning and different feeding areas, as tunas do. Migrations should be cyclical and predictable and cover more than 100 km.

Dorsal spines (total): 13 - 14; Dorsal soft rays (total): 14 - 15; Analspines: 0; Analsoft rays: 14; Vertebrae: 39

Temperature and thermocline depth seem to be the main environmental factors governing the vertical and horizontal distribution of this species (Ref. 168). Bigeye tuna are more tolerant of lower temperatures and lower dissolved oxygen concentration than are other tunas and tend to occupy deeper waters (Ref. 30326). For example, during the day, adult bigeye tuna inhabit the thermocline zone at about 150-250 m in tropical waters where temperatures descend to almost 10°C, provided dissolved oxygen concentration is more than 1 mg per l (Ref. 28952, 30327). The tuna make occassional short ascents to 100 m or shallower (Ref. 6390).Young bigeye tuna have not been reported outside tropical waters (Ref. 30326). In Australia, bigeye tuna smaller than 20 kg may form surface-dwelling schools of similar sized fish with other species such as yellowfin tuna and skipjack tuna (Katsuwonus pelamis). Schools of only bigeye tuna are less common (Ref. 30328). In tropical waters, young bigeye tuna are often caught 50-100 m below floating objects such as logs and fish aggregating devices (Ref. 30326). Adults tend to be solitary (Ref. 6390). Behavioural studies in Hawaiian waters using ultrasonic tags (Ref. 30329) found that the distribution of adult bigeye tuna was closely correlated with the 15°C isotherm during the day (Ref. 6390). Like yellowfin tuna, bigeye tuna move into the warmer surface waters (within 50 m of the surface) at night. Feed during the day and at night. In Hawaii, more abundant in late fall through late spring.

Koellikerioides Infestation 2. Parasitic infestations (protozoa, worms, etc.)

This large species is distinguished by the following characters: robust, fusiform body, slightly compressed from side to side; total gill rakers on first gill arch 23-31; dorsal fins separated only by a narrow interspace, the second followed by 8-10 finlets; anal fin followed by 7-10 finlets; pectoral fins moderately long (22 to 31% of fork length) in large specimens (over 110 cm FL), but very long (as long as in Thunnus alalunga) in smaller specimens; 2 flaps (interpelvic process) between pelvic fins; very small scales on body; corselet of larger and thicker scales developed, but not very distinct; caudal peduncle very slender, with a strong lateral keel between 2 smaller keels; ventral surface of liver striated; swimbladder present. Colour of back metallic dark blue, lower sides and belly whitish; a lateral iridescent blue band runs along sides in live specimens; first dorsal fin deep yellow, second dorsal and anal fins light yellow, finlets bright yellow edged with black (Ref. 9684).

Sphyriocephalus Disease. Parasitic infestations (protozoa, worms, etc.)

Brachiella Infestation. Parasitic infestations (protozoa, worms, etc.)

Caligus Infestation 17. Parasitic infestations (protozoa, worms, etc.)

Caligus Infestation 18. Parasitic infestations (protozoa, worms, etc.)

Euryphorous Infestation 1. Parasitic infestations (protozoa, worms, etc.)

Euryphorous Infestation 2. Parasitic infestations (protozoa, worms, etc.)

Hexostoma Disease. Parasitic infestations (protozoa, worms, etc.)

Didymosulcus Infestation 3. Parasitic infestations (protozoa, worms, etc.)

Didymozoon Infestation 2. Parasitic infestations (protozoa, worms, etc.)

Caballerocotyla Infestation 4. Parasitic infestations (protozoa, worms, etc.)

Caballerocotyla Infestation 8. Parasitic infestations (protozoa, worms, etc.)

Caballerocotyla Infestation 9. Parasitic infestations (protozoa, worms, etc.)

Capsala Infestation 3. Parasitic infestations (protozoa, worms, etc.)

Hexostoma grossum Disease. Parasitic infestations (protozoa, worms, etc.)

Nasicola Infestation 2. Parasitic infestations (protozoa, worms, etc.)

Koellikerioides Infestation 3. Parasitic infestations (protozoa, worms, etc.)

Didymocystoides Infestation 7. Parasitic infestations (protozoa, worms, etc.)

Didymocystoides Infestation 5. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation 23. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation 20. Parasitic infestations (protozoa, worms, etc.)

Didymocystis Infestation18. Parasitic infestations (protozoa, worms, etc.)

Dermatodidymocystis Infestation. Parasitic infestations (protozoa, worms, etc.)

Dermatodidymocystis vivipira Infection. Parasitic infestations (protozoa, worms, etc.)

Dermatodidymocystis indicus Infection. Parasitic infestations (protozoa, worms, etc.)

Cardicola Infestation 1. Parasitic infestations (protozoa, worms, etc.)

Botulus Infection. Parasitic infestations (protozoa, worms, etc.)

Tristomella Infestation 3. Parasitic infestations (protozoa, worms, etc.)

Sibitrema Infection. Parasitic infestations (protozoa, worms, etc.)

Neohexostoma Infestation 3. Parasitic infestations (protozoa, worms, etc.)

Hexostoma acutum Disease. Parasitic infestations (protozoa, worms, etc.)

Occur in areas where water temperatures range from 13°-29°C, but the optimum is between 17° and 22°C. Variation in occurrence is closely related to seasonal and climatic changes in surface temperature and thermocline. Juveniles and small adults school at the surface in mono-species groups or mixed with other tunas, may be associated with floating objects. Adults stay in deeper waters (Ref. 5377). Eggs and larvae are pelagic (Ref. 6390). Feed on a wide variety of fishes, cephalopods and crustaceans during the day and at night (Ref. 9340). Meat is highly prized and processed into sashimi in Japan. Marketed mainly canned or frozen (Ref. 9684), but also sold fresh (Ref. 9340).

fisheries: highly commercial; gamefish: yes; price category: very high; price reliability: reliable: based on ex-vessel price for this species