page_title: Bluefin trevally
section_title: Habitat
hierarchical_section_title: Bluefin trevally / Habitat
caption_attribution_description: A Caranx melampygus, commonly known as the bluefin trevally.
context_page_description: The bluefin trevally, Caranx melampygus, is a species of large, widely distributed marine fish classified in the jack family, Carangidae. The bluefin trevally is distributed throughout the tropical waters of the Indian and Pacific Oceans, ranging from Eastern Africa in the west to Central America in the east, including Japan in the north and Australia in the south. The species grows to a maximum known length of 117 cm and a weight of 43.5 kg, however is rare above 80 cm. Bluefin trevally are easily recognised by their electric blue fins, tapered snout and numerous blue and black spots on their sides. Juveniles lack these obvious colours, and must be identified by more detailed anatomical features such as fin ray and scute counts. The bluefin trevally inhabits both inshore environments such as bays, lagoons and shallow reefs, as well as deeper offshore reefs, atolls and bomboras. Juveniles prefer shallower, protected waters, even entering estuaries for short periods in some locations.
  The bluefin trevally is a strong predatory fish, with a diet dominated by fish and supplemented by cephalopods and crustaceans as an adult.
context_section_description: The bluefin trevally occurs in a wide range of inshore and offshore marine settings throughout its range, including estuarine waters. The species is known to move throughout the water column; however is most often observed in a demersal setting, swimming not far from the seabed. In the inshore environment, the species is present in almost all settings including bays, harbours, coral and rocky reefs, lagoons, sand flats and seagrass meadows.
  Juveniles and subadults are more common in these settings, and prefer these more protected environments, where they live in water to a minimum of around 2 m depth. Adults tend to prefer more exposed, deeper settings such as outer reef slopes, outlying atolls and bomboras, often near drop offs, with the species reported from depths up to 183 m. Adults often enter shallower channels, reefs and lagoons to feed at certain periods during the day. The bluefin trevally displays some habitat partitioning with giant trevally, Caranx ignobilis, tending to be more common outside the major bays than their relatives.
  Juvenile and subadult bluefin trevally have been recorded in estuaries in several locations, and generally occupy large, open estuaries up to the middle reaches of the system. These estuaries are often lined by mudflats and mangroves, however the species rarely enters these shallow waters. Individuals of between 40 and 170 mm have been recorded in South African estuaries, where they are the least tolerant carangid to the brackish and freshwater conditions of these systems. Bluefin trevally can tolerate salinities of between 6.0 and 35 ‰, and only occupy clear, low turbidity waters. There is evidence the species is only resident in these estuaries for short periods. The species is also absent from coastal lakes that many other carangids are known from.
caption: A lone bluefin trevally patrolling a coral reef, one of the species most common habitats
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