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.
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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
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 cottonwick grunt
how to recognize it
Silvery, with a broad black area starting at the base of the dorsal fin and running along the back, the upper part of the tail stalk and both lobes of the tail. It has thin yellow stripes, the widest one in the middle of the body. The black patch on the back and tail is the easiest sign to recognize. The body is short and tall.
Also called: sapuruna-preta, sapuruna, sapurana-de-lista, mapurite, cottonwick grunt
don't confuse with:
We don't have tips on season, bait or technique for this species yet.
where found
open on the large mapWhere to look: Coastal and open-sea reefs and nearby seagrass banks, 3 to 50 m deep.
Western Atlantic, from Bermuda and southeastern Florida to Brazil, through the Bahamas and the Caribbean. In Brazil, there are records from Maranhão to Pernambuco.
coast
rules for the cottonwick grunt
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.
Conservation: Not on the Brazilian national list (Ministerial Ordinance GM/MMA No. 1.667/2026).
how much it weighs without taking it out of the water
estimated weight
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how we calculate
Length-weight relationship W = a·Lb (a = 0.01738, b = 3.0; FishBase (relação peso-comprimento bayesiana, estimativa da própria espécie)). It's an average: a fat or lean fish can vary by 10% to 20%.
more about the cottonwick grunt
Fish of the family Haemulidae, reaching 33 cm and weighing up to 550 g. It occurs in the western Atlantic, from Bermuda, southeastern Florida and the Bahamas to Brazil. It lives on coastal and open-sea reefs and nearby seagrass banks, in clear waters, 3 to 50 m deep. It forms schools and feeds on crustaceans. In fishing it has little commercial use: it is sold fresh, and there are reports of ciguatera.
Family: Haemulidae · predator
in the kitchen
Sold fresh. There are reports of ciguatera, so avoid eating reef fish of doubtful origin.
similar species
sources and references (3)
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: Haemulon melanurum (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Haemulon melanurumNames 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.
how we calculatewhere 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: