Bar jack

ciguatera cases are attributed to the species, with most cases reported on the island of St. Thomas

Carangoides bartholomaei,^[13] with the best identifier being gill raker counts.^[14] The entire body has been observed to change colour to a blackish colour when the fish is feeding near the bottom.^[15]

tropical and subtropical waters of the western Atlantic Ocean, and is a common species throughout most of its range.^[8] The northernmost limit of its range is New Jersey in the northern United States, with its range extending south along the continental coast to Venezuela. It inhabits a number of offshore islands and archipelagos including Bermuda, as well as the West Indies.^[10] The bar jack is most abundant in the Gulf of Mexico, the West Indies and Caribbean, but in the Gulf of Mexico is limited to offshore waters. There have been reliable reports of the species from Rio de Janeiro in Brazil and far offshore at Saint Helena in the south central Atlantic,^[16] which would extend the species southern limit significantly if correct.^[8]

coral reefs to depths of around 60 ft (18 m). Tagging studies demonstrate the species is highly mobile, not lingering over one particular reef patch for very long, often moving between reefs over large expanses of sand.^[17] Bar jack often venture into lagoons from seaward reefs, preferring to move over the sandy substrate while in these shallow waters, often forming shoals alongside barracudas, stingrays and sharks. Unlike most fish live on both the lagoon and reef, there is no particular age partitioning, with both juveniles and adults entering the lagoon to forage.^[18] Records of bar jack taken from Saint Helena came from seamounts in waters deeper than 100 m (330 ft), indicating they live in more offshore pelagic waters also.^[16] Juveniles are often found under floating sargassum mats, using the algae for protection. They also inhabit areas around docks and pilings. Juveniles can be caught using a sabiki rig.^[15]

dolphinfish, mackerels, marlins and various seabirds.^[10]

gastropods, nematodes and benthic algae as well as a range of crustaceans.^[20]

body weight, and during the periods of decline to 0.5–2%, with the annual intake being 1000–1500% of the body weight.^[21] In a 1993 paper, Troy Baird reported a foraging association between bar jacks and puddingwife wrasse, Halichoeres radiatus, in which a jack followed a single wrasse while it foraged for food. These associations were initiated by both jacks and wrasse, with apparently little pilfering of uncovered items, suggesting a beneficial relationship to both parties.^[20] While foraging with the wrasse, the jack increases its prey detection levels, which is useful for a species which is more adept at pelagic hunting, allowing it to be more efficient at this less common mode of food gathering.^[20]

flexion occurs at 4–5 mm. The larval stage of the bar jack has been extensively described by Richards (2006).^[24] Larvae appear between April and October in the Gulf Stream current, and grow the fastest during their first three years of life.^[25]