Rare jack, with a deep, diamond-shaped silvery body, long filaments on the dorsal and anal fins and a black spot on the gill cover. It lives in coastal waters of the eastern Pacific, from the Gulf of California to Ecuador, and is hardly ever fished.
Also called: xaréu-de-fios, jurel chicuaca, jurel de hebra, Threadfin jack, Thread pompano
Eastern Pacific jack, from southern Baja California and the Gulf of California to Ecuador, with records also at the Revillagigedo, Galápagos and Malpelo islands. It is a coastal, midwater fish: FishBase describes it as benthopelagic, and STRI's regional survey gives a depth of 0 to 100 m. Adults are opportunistic predators, eating bottom and midwater fish, squid and crustaceans. It reaches 60 cm, and there is a report of a 66 cm fish caught near San José del Cabo, Mexico. No directed fishery is known and catch reports are rare; the fish is sold fresh, salted or dried, and FishBase lists it among the sport fish.
fun facts
In English it is threadfin jack or thread pompano, for the filaments on the dorsal and anal fins.
According to the author of a Mexican fish guide, it is one of the rarest jacks in the Mexican Pacific: he has seen it for sale only once, in the markets of the Los Cabos region.
Juvenile Alectis ciliaris also have very long filaments, which makes the two hard to tell apart.
how to recognize it
identification
Tall, diamond-shaped body, flattened on the sides, with an angular head profile; silvery to gray-silver. It has an elongated black spot at the upper corner of the gill cover and small dark spots between the bases of the second dorsal fin rays, which is the mark that separates it from the other jacks. The lobes of the second dorsal and anal fins are long, like filaments, and the pectoral fins are longer than the head. The chest has no scales up to the base of the pectoral fins. It looks very much like the African pompano (Alectis ciliaris), with a blunter snout and a body without visible scales.
how threadfin jack fishing looks
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Each card shows the day's index (0 to 100) and, below it, a strip with the index for each hour, from 0h to 23h. from poor to excellent.
Not found in Brazil. Eastern Pacific, from southern Baja California and the Gulf of California (Mexico) to Ecuador, including Revillagigedo, Galápagos and Malpelo. FishBase lists Mexico, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Colombia and Ecuador.
Habitat: Coastal and open-sea waters near the shore, over sand and rock bottoms, from the surface down to about 100 m; there is a report of a catch at the mouth of a river.
calendar and clock
when to fish
best season
time of yearbest: Jun–Sep
JanFebSeaAprMayJunJulAugSepOctNovDec
Occurs all year and there is no seasonal study. The app gives more weight to the warmer months, May to November.
best time of day
Daytime, with peaks at dawn and dusk. Studies on the species are lacking. The app's estimate follows the pattern of coastal jacks, with more activity at dawn and dusk.
weather, water and behavior
what affects the threadfin jack
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
cold and cold fronts
Cold water, as in winter upwellings, tends to keep jacks away from the shore.
atmospheric pressure
A front with strong wind stirs the sea and hinders; stable pressure helps.
moon
Small effect and no study for the species.
rain
Little effect; a thunderstorm with lightning: get out of the water.
water level
Not applicable at sea.
noise
A school passing along the shore spooks at a boat banging and a motor nearby.
wind
Strong wind hinders casting and controlling the drifting boat.
tide
Current at river mouths and points concentrates food and schools.
depth
From midwater down to about 100 m; the fishing records are from coastal waters.
circle 1/0 to 3/0 on natural bait; assist hooks on the jigs
lures
metal jig 20 to 60 g
silicone shad on a jig head
metal spoon
natural baits
live or dead sardine or anchovy
squid strips
shrimp
accessories
alicate
luvas
decompression device (descender) if you fish the bottom
tip from an angler
Like the coastal jacks, it strikes bait in motion: retrieve the jig with short pauses. If a thread-finned jack shows up, check the spot on the gill cover and the small spots at the base of the dorsal fin before deciding what to do.
what the law says
rules for the threadfin jack
Summary of the regulations we found, with the source for each. Rules change; before keeping or transporting fish, check with the state environmental agency. Conservation: Of little concern globally. Not listed in Mexico's NOM-059-SEMARNAT-2010.
Mexico: up to 5 per species and 10 saltwater fish per day
5 specimens of the species per angler per day, within the limit of 10 saltwater fish
In recreational sport fishing in Mexican federal waters, each angler may keep up to 10 marine fish per day, no more than 5 of the same species. The threadfin jack is not among the species reserved for sport fishing (marlin, sailfish, swordfish, "sábalo o chiro," roosterfish and dorado, up to 50 nautical miles from shore, item 0.3 of the standard) and has no quota of its own. Fish over the limit go back alive (item 4.9.5), and sport-caught fish may not be sold. Anglers fishing from a boat need the permits of the Federal Duties Law; anglers fishing from shore do not (item 4.3).
Personal Incopesca license, for people over 16confirm with the agency
In the regulation of the Fisheries and Aquaculture Law (Decree 36782, of May 24, 2011), art. 69, sport fishing is authorized only for natural persons over 16, with a license issued by Incopesca; tourists, whether national or foreign, also need the license. Art. 68 limits the landing of large pelagics to 5 per trip, and art. 66 promotes catch and release, but the rule sets no quota for this species. The decree was later amended (Decree 39458), so confirm the current rule with Incopesca.
Panama: new sport fishing decree in force from Dec 10, 2026
Executive Decree No. 9 (Jun 10, 2026), in force from Dec 10, 2026confirm with the agency
ARAP published Executive Decrees No. 9 and No. 10, of Jun 10, 2026, in the Official Gazette. The first regulates sport fishing throughout the territory; the second protects billfish (sailfish and marlins). Both take effect on Dec 10, 2026, after six months of adaptation. We did not verify the text: the press report gives no catch limits, sizes or license requirements. Before fishing in Panama, check with ARAP.
Colombia: AUNAP license and catch-and-release in sport fishing
Individual AUNAP license; catch-and-release guidanceconfirm with the agency
AUNAP Resolution 0549 of 2022 sets the guidelines for sport fishing for recreational purposes in Colombia. Anyone fishing needs a permit: for a natural person, Colombian or foreign, it is a personal, non-transferable license (art. 6). The rule uses "capture and release" as guidance. We did not verify the daily limit or the minimum sizes by species: check with AUNAP before keeping any fish.
catch and release Releasing the fish alive, quickly and with a wet hand. During a closed season it isn't always allowed: what the regulation says applies.
Hold it firmly by the jaw and support the body; avoid touching the gills. If it comes from depth, release it without delay. Release it facing the current and only when it swims on its own.
in the kitchen
Sold fresh, salted or dried in the region, according to FishBase. The author of a Mexican fish guide considers it good eating and says he has rarely seen it for sale.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.01445, b = 2.93; FishBase (relação peso-comprimento bayesiana, estimativa da própria espécie)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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sources and references
The season weights (months), time of day and sensitivities (cold, pressure, moon, wind, rain, tide, strong light, murky water and noise) are the app's editorial estimates, based on the literature below and on field experience of anglers and guides. They are not official data or measurements made for this species, and may vary by region and year. Closed seasons and legal rules appear in the rules section, with the standard and a link. The common size starts from FishBase's common length (30 cm), and the common weight is calculated from the length-weight relationship.
technicalMexican Fish (mexican-fish.com): ficha do Threadfin Jack (Euprepocaranx dorsalis)Independent guide to Mexican Pacific fishes, with photos of catches and the author's observations; not an official source. Page checked on 13/10/2026. It cites specimens up to 66 to 67 cm from the Los Cabos region (FishBase and STRI give 60 cm; we kept 60 cm), and says the species is rare, eats fish, squid and crustaceans, and is confused with Alectis ciliaris.
