jenny mojarra
Eucinostomus gula · Gerreidae · omnivore
Small fish of lagoons and mangroves, relative of the carapicus, which lives in groups and is used as bait. It has little commercial importance and is almost never caught on a rod.
Also called: primituma, carapicu, mojarra, silver jenny
- maximum
- 26 cm
- depth
- 0–55 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
tap or drag on the chart to read each hour · on a keyboard, arrow keyssee 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 jenny mojarra
who is the jenny mojarra
Fish of the family Gerreidae, the mojarras (carapicus and carapebas). It reaches 25.5 cm and lives in shallow waters, 0 to 55 m, mainly on mud bottoms in lagoons and mangrove-lined channels. It may form groups and probably eats small bottom invertebrates. It occurs from the North American Atlantic and Bermuda to Argentina, including Brazil, the Gulf of Mexico and the Caribbean. In fishing it is used as bait and has little commercial importance.
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 jenny mojarra; in the meantime, see the similar species.
fun facts
- Enters fresh water in regions of limestone rock.
identification
Spindle-shaped, silvery body, with the dorsal fin in two parts, one of spines and one of soft rays, a family trait. It looks like the carapicu (Eucinostomus argenteus), the carapeba (Diapterus rhombeus) and the carapicu-bandeira (Eucinostomus melanopterus), which live in the same region. The primituma is more abundant in mud lagoons lined with mangroves, and that habitat helps identify it.
where found
In Latin America it occurs from Mexico and the Caribbean to Argentina, including Brazil.
Habitat: Shallow waters of lagoons, mangroves and mud bottoms, 0 to 55 m; sometimes on sand with marine vegetation.
coast
rules for the jenny mojarra
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: Not on the Brazilian national list (Ministerial Ordinance GM/MMA No. 1.667/2026).
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.
Not dangerous to people. If used as bait, it must be kept alive in clean water.
in the kitchen
Sold fresh, but not very prized.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.01122, b = 3.07; 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: Eucinostomus gula (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Eucinostomus gulaNames by country and language.
- official Portaria GM/MMA nº 1.667, de 27 de abril de 2026: Lista Nacional Oficial de Espécies da Fauna Ameaçadas de Extinção (peixes e invertebrados aquáticos)The species is not on the list. Checked in the DOU of April 28, 2026.
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: