The black jack lives both in solitude and in schools of up to 30 individuals.
Like several other jacks, black jack are able to coordinate these aggregations over coral reefs based on the release of dimethylsulfoniopropionate (DMSP) from the reef.
DMSP is a naturally occurring chemical produced by marine algae and to a lesser extent corals and their symbiotic zooxanthellae.
In the Atlantic the species has also been video-recorded schooling with the almaco jack, Seriola rivoliana, and the greater amberjack, Seriola dumerili.
The diet of the species has been reported on two occasions; once from Easter Island in the south Pacific, where the diet consisted mainly of fish and crustaceans including stomatopods and isopods; and from Brazil, where a variety of fish, crustaceans and molluscs were taken.
There is also some suggestion that in Brazil the species may be competing for food with the red snapper, Lutjanus campechanus, with both having almost identical diets.
The black jack is also known to follow spinner dolphins to feed off their excrements.
The life history of the species has been determined in  part from the waters of Jamaica.
Here the Male:Female sex ratios have been reported as 1:0.55, indicating males are nearly twice as common than females.
 The black jack reaches sexual maturity at 34.6 cm in females and 38.2 cm in males.
The timing of spawning is poorly known, with occurrences recorded in February, April, May and July to September.
The reproductive behaviour and early life history of the species is entirely unknown.
Analysis of black jack catches suggest the average length of the fish is 50 cm for males and 48 cm for females.
The black jack lives both in solitude and in schools of up to 30 individuals. Like several other jacks, black jack are able to coordinate these aggregations over coral reefs based on the release of dimethylsulfoniopropionate (DMSP) from the reef. DMSP is a naturally occurring chemical produced by marine algae and to a lesser extent corals and their symbiotic zooxanthellae. In the Atlantic the species has also been video-recorded schooling with the almaco jack, Seriola rivoliana, and the greater amberjack, Seriola dumerili. The diet of the species has been reported on two occasions; once from Easter Island in the south Pacific, where the diet consisted mainly of fish and crustaceans including stomatopods and isopods; and from Brazil, where a variety of fish, crustaceans and molluscs were taken. There is also some suggestion that in Brazil the species may be competing for food with the red snapper, Lutjanus campechanus, with both having almost identical diets. The black jack is also known to follow spinner dolphins to feed off their excrements. The life history of the species has been determined in  part from the waters of Jamaica. Here the Male:Female sex ratios have been reported as 1:0.55, indicating males are nearly twice as common than females.  The black jack reaches sexual maturity at 34.6 cm in females and 38.2 cm in males. The timing of spawning is poorly known, with occurrences recorded in February, April, May and July to September. The reproductive behaviour and early life history of the species is entirely unknown. Analysis of black jack catches suggest the average length of the fish is 50 cm for males and 48 cm for females.
Caranx lugubris