Threadfin Jack

Threadfin jack is classified under the Carangoides genus and forms one of several fishes commonly referred to as jacks or trevallies, belonging to Perciformes order of fishes.

Species-defining features for this fish include its long, threadlike fin rays that appear on both its anal and pectoral fins; over time these rays shorten as it grows older.

Early Life and Education

Jacks (Carangidae), are a diverse marine fish family found throughout tropical Atlantic and Pacific oceans. These fish species can be distinguished from one another by laterally compressed bodies with rows of large scales along their sides near the head and tailfin, smaller scales producing a smooth appearance, deep forked tails and laterally compressed bodies.

Threadfin jacks belong to the Caranx genus of fishes that exhibit protandrous hermaphroditism; thus changing from male to female at different ages21. They display silvery blue above and silvery white below with golden to yellow reflections; first dorsal, pelvic and anal fins are grey while their second set are hyaline; they also possess black spots on soft dorsal ray bases and an operculum with small black spots at different ages22.

Personal Life

Threadfin jack is a coastal pelagic species with an average maximum length of 67 cm (2 feet 2 inches). They are opportunistic predators that prey upon benthic and pelagic fish species as well as squid, crustaceans, and other invertebrates. Threadfin jacks are fairly abundant across their range; often caught using hook and line, gill nets, or various artisanal traps; often sold fresh or salted at markets.

The threadfin jack, also referred to as the thread pompano, is a species of coastal marine fish belonging to the Carangidae family that inhabits tropical waters of the eastern Pacific Ocean from Baja California in the north to Ecuador and Galapagos Islands in the south. It has an elongated body with deep compression that appears silvery in color; an angular head profile; small dark spots located between dorsal and anal fin rays and small dark blotches between dorsal/anal fin ray bases and small dark blotches between its dorsal/anal fin ray bases that distinguishes it from its relatives in terms of appearance and other characteristics.

Net Worth

Threadfin jack is an economically important fish species, harvested both open ocean and nearshore waters by hook and line as well as in gill nets or various artisanal traps. Considered good to excellent table fare, threadfin jack is generally sold fresh or salted for marketing. Unfortunately, its population dynamics, movement patterns, habitat use or reproduction remain poorly studied with little known of its population dynamics, reproduction rates or diet/reproduction cycles. Opportunistic predators that prey upon benthic/pelagic fishes along with crustaceans/invertebates; threadfin jack has currently been classified as Least Concern and populations seem stable across their range.