blunthead puffer
Sphoeroides pachygaster · Tetraodontidae · predator
Pufferfish with a flat head and a spineless body, living from 50 to 250 m on the shelf, often showing up in commercial fisheries.
Also called: baiacu-cabeça-chata, baiacu, botete chato, blunthead puffer
- maximum
- 40 cm
- depth
- 50–250 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 blunthead puffer
who is the blunthead puffer
Pufferfish of the family Tetraodontidae, reaching 40.5 cm. It lives on sand, mud and rock bottoms of the continental shelf, usually between 50 and 250 m. Juveniles are pelagic, and adults feed mainly on squid. In southeastern Brazil, the species was caught between 50 and 145 m. It occurs in tropical and temperate seas worldwide; in Latin America, along the Brazilian coast, Uruguay, Argentina, Chile and the Guianas. It shows up in commercial fisheries and is not a target of recreational fishing.
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 blunthead puffer; in the meantime, see the similar species.
identification
Short, deep body, brown on the back and white on the belly, sometimes with dark blotches on the flanks. The skin is smooth, without spines, and the tip of the caudal fin, or the whole lower part of it, is white. The smooth skin and the white tail tip are the marks that best help identify it among the bottom-dwelling pufferfishes.
where found
In Latin America it occurs along the Brazilian coast, Uruguay, Argentina, Chile and the Guianas, on sand, mud and rock bottoms.
Habitat: Sand, mud and rock bottoms of the shelf, usually 50 to 250 m.
coast
rules for the blunthead puffer
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.
It poses no danger to the angler. Like other pufferfish, it has strong teeth fused into plates; remove the hook carefully. Since it comes from depths of up to 250 m, it can suffer barotrauma, so release it carefully. Do not take it home to eat: pufferfish in general may contain toxin.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.02754, b = 2.84; 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: Sphoeroides pachygaster (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Sphoeroides pachygasterNames 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: