whitetongue jack
Uraspis helvola · Carangidae · predator
Jack of sandy bottoms between 50 and 300 m, mainly nocturnal in habit. It occurs in the eastern Pacific, in Mexico and Ecuador, and is used in sport fishing.
Also called: xaréu-língua-branca, jurel lengua blanca, caramelo, whitetongue jack
- maximum
- 58 cm
- depth
- 50–300 m
the right time
to be on the water
Choose the place and the species. The index, from 0 to 100, combines weather, sun, moon and tide with each fish's habits. Up to 28 days, with each day's confidence.
Reading the weather across 3 global models and 31 simulations…
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hour by hour
slide your finger or mouse over the chart to see each hoursee hour-by-hour table
why this index at —?
choose the day
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.
the fishing month at a glance
what's the best window for the crew?
Choose how many fishing days. We compare each stretch by its average index, discount days with a warning or closed season, and show the 3 best.
trend for the coming weeks
Line: the middle value of 31 simulations of the American GEFS model. Band: where 8 out of 10 fall. Narrow, firm trend; wide, high uncertainty.
everything about the whitetongue jack
who is the whitetongue jack
The whitetongue jack belongs to the family Carangidae, with a spindle-shaped body compressed from the sides. It reaches 58 cm, and its common size is 35 cm. It lives on sandy bottoms at the base of outer reef edges, near islands and continental coasts, between 50 and 300 m deep. It is usually solitary or forms small schools, and is mainly nocturnal. It occurs in the eastern Pacific, in Mexico and Ecuador, and also in other tropical regions. It has small commercial fishing, is sold fresh, salted or dried, and is also a sport fish.
Essential profile. Identification, where it occurs and rules, with data from FishBase and the cited regulations. Season, time of day, technique and bait are added once we have a good source for the whitetongue jack; in the meantime, see the similar species.
identification
Spindle-shaped body, compressed from the sides, with the profile of a jack. Recognition relies on habitat: sandy bottoms at 50 to 300 m, where the species is mainly nocturnal. The Spanish name, jurel lengua blanca (white-tongue jack), points to a mouth trait. To tell it apart from other jacks, depth helps, because this one lives deeper than beach and estuary jacks.
where found
Eastern Pacific of Latin America, in Mexico and Ecuador, on sandy bottoms from 50 to 300 m.
Habitat: Sandy bottoms at the edge of outer reefs and on the shelf, 50 to 300 m.
when to fish
best time of day
Nighttime. The source notes a mainly nocturnal habit.
rules for the whitetongue 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.
We found no species-specific rule beyond the region's general rules.
catch and release
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.
No recorded danger to anglers. Since it lives on bottoms of 50 to 300 m, it can suffer barotrauma if brought up fast; if possible, release it carefully.
in the kitchen
Often sold fresh, salted or dried.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.01413, b = 2.95; 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
Essential profile: size, length-weight, depth, countries and conservation come from FishBase and the cited regulations, and the texts were written from those sources. Season, time of day, sensitivities, technique and baits and lures are not included yet, because we did not find a good source for this species.
- scientific FishBase: Uraspis helvola (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Uraspis helvolaNames by country and language.
similar species
where each number comes from
The weather comes from three independent global models, cross-checked hour by hour: when they agree, confidence goes up; when they diverge, the band between them shows on the chart. Beyond 16 days, we use the GEFS ensemble of 31 simulations: if 20 of the 31 predict rain, the chance of rain is 65%. Sun and moon are calculated astronomically, with no uncertainty.
The index adds up, weighted for each species: time of day (species curve anchored to real sunrise and sunset), moon (transits, rise and set, phase), pressure (3 h trend and 24 h swing), water temperature (in rivers, estimated from air temperature; at sea, estimated by an ocean model), wind, rain, clouds, tide and the month in the species' cycle.
sources for this lookup
how accurate the forecast is
Accuracy measured in the reference project (4 regions, 93 days, forecast vs. observed): maximum temperature is off by 0.6 °C on average the next day and 1.7 °C at 7 days; rain of 5 mm or more is detected 76% of the time the next day and 57% at 7 days. Detection isn't everything: the false alarm rate isn't published here yet, and 93 days in 4 regions is still a small sample. We now also measure every day, at the app's destinations: