Alexandria pompano
Alectis alexandrina
Bluefin Trevally
Caranx melampygus
About
The bluefin trevally is a fast, sharp-nosed hunter. It patrols the same stretch of reef day after day, chasing down small reef fish along a route it seems to know by heart.
Also known as: black ulua, yellow fin jack, trevally, jack, blue-finned trevally, black-tipped trevally, bluefin kingfish, blue jack, blue-fin trevally, blue jack fish, bluefinned crevalle, bluefin jack, spotted trevally, blue ulua, blue trevally, kingfish, spotted trevally, blue-fin trevally, blue-finned trevally
- Length
- 60 cm · max 1.2 m
- Weight
- max 44 kg
- Depth
- up to 190 m
How to tell it apart
It looks much like other large jacks and trevallies, including the giant trevally. Look at the snout: the bluefin trevally's is noticeably more pointed than in other Caranx species.
Appearance
This is an oblong, flattened fish with a back that curves out a little more than its belly. This gives it a more pointed snout than other jacks in its genus. It has a strongly forked tail and long, sickle-shaped pectoral fins that reach past the length of its head. It grows up to 117 cm and 43,540 g, though fish over 80 cm are rare and 60 cm is more typical.
Habitat
It lives across the tropical and subtropical Indian and Pacific Oceans. Its range runs from the East African coast and Red Sea through South East Asia and the central Pacific to Hawaii and the eastern Pacific coast. It uses a wide range of inshore and offshore settings, including estuaries, and adults commonly patrol patch reefs and reef walls down to depths of 190 m.
Behaviour
Juveniles school, but adults become largely solitary and settle into a home range. By day they patrol back and forth along the same section of reef. At night they slow down and gather with other bluefin trevally from the area. They also form temporary schools to hunt together or to spawn.
Diet
It is a fast, mainly fish-eating predator, taking a wide variety of small reef fish along with some squid, octopus, and crustaceans such as shrimp and crabs. Juveniles feed much more on small crustaceans before shifting toward a fish-based diet as they grow.
Did you know?
Bluefin trevally can coordinate where to gather over a reef by picking up on a chemical, dimethylsulfoniopropionate, released by the reef's algae and corals.
Log it in Into the Blue
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