squaretail duckbill
Bembrops heterurus · Bembropidae · predator
Elongated fish of shelf mud bottoms, from Rio de Janeiro to Uruguay. It has commercial use and is not dangerous.
Also called: peixe-pau-comum, peixe-pau, pez palo común, squaretail duckbill
- maximum
- 28 cm
- depth
- 80–200 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 squaretail duckbill
who is the squaretail duckbill
The peixe-pau-comum belongs to the family Bembropidae, with a common size near 20 cm and reaching 28 cm. It has an elongated body and lives on soft shelf bottoms, mainly between 80 and 200 m deep, close to the bottom. It feeds on crustaceans and other fish. In Brazil, it occurs from the coast of Rio de Janeiro southward to Uruguay, and it is caught by commercial fishing. It is not dangerous and is not a target of sport fishing. The Atlantic eastern form may be a different species.
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 squaretail duckbill.
fun facts
- The eastern Atlantic form may be another species, which still needs to be studied.
identification
Elongated body with a flattened head and short snout, covered in scales up to in front of the eye, typical of the family. The caudal fin has an elongated upper lobe ending in a point, and the lateral line descends gradually along the upper edge of the pectoral fin. The color is yellowish to yellow-brown on the back and lighter on the belly. It lives on the shelf bottom, between 80 and 200 m.
where found
In Latin America it occurs from the coast of Rio de Janeiro to Uruguay, on soft shelf bottoms.
Habitat: Soft bottoms of the continental shelf, usually between 80 and 200 m.
coast
rules for the squaretail duckbill
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, but since it comes from 80 m or deeper it can suffer barotrauma when brought up. Handle it carefully and release it quickly.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00447, b = 3.08; 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: Bembrops heterurus (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Bembrops heterurusNames 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.
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: