blackfin tuna
Thunnus atlanticus · Scombridae · predator
The smallest tuna of the genus, found only in the western Atlantic. Common near islands and the shelf edge in the Northeast; fights hard on light tackle.
Also called: albacorinha, albacora-preta, atum-preto, albacora, blackfin
- common size
- 45–72 cm
- maximum
- 108 cm
- common weight
- 2–6 kg
- record/max.
- 20.6 kg
- depth
- 0–100 m
- ideal water
- 23–28 °C
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 blackfin tuna
who is the blackfin tuna
The blackfin tuna is the smallest tuna of the genus Thunnus and occurs only in the western Atlantic, from the United States to southern Brazil. It lives in warm oceanic waters, sometimes not far from shore, in schools, often mixed with skipjack tuna. It eats surface and deep fish, squid, shrimp, and crustacean larvae. In Brazil it is most common in the Northeast, at the oceanic islands and the shelf edge, and is caught on line. For the sport angler it is one of the best fighting fish on light and medium tackle, on jigging, popping, and trolling with small baits. The flesh is dark and tasty.
fun facts
- It is the smallest of the tunas in the genus Thunnus.
- It occurs only in the western Atlantic.
identification
Small tuna, dark metallic blue back and silvery flanks with a bronze band along the body in live fish; dark fins, dark finlets with a slight yellowish tint and a white tip. Differs from the young yellowfin tuna by its dark finlets, not bright yellow, and from the bonito-pintado by the lack of spots and wavy stripes on the back.
where found
From the Northeast to the Southeast, mainly at the oceanic islands and the shelf edge; there are records in the South.
Habitat: Warm, clear oceanic waters, shelf edges, islands, and oceanic banks; schools at the surface.
coast
states
Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, Espírito Santo, Rio de Janeiro, São Paulo
famous destinations
when to fish
best season
In the Northeast and at the islands it appears all year; in the Southeast, in the months of blue, warm water.
best time of day
Daytime, with peaks at dawn and dusk. Hunts by day, peaking at dawn and dusk.
what affects the blackfin tuna
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
cold and cold fronts
Water below 20 °C drives it away.
atmospheric pressure
A cold front brings rough seas.
moon
Small effect.
rain
Not very sensitive.
water level
Prefers blue, clear water.
noise
A feeding school tolerates the boat; a motor overhead scares it off.
wind
Moderate choppy sea is no problem; rough seas prevent going out.
tide
Current at the edges and islands concentrates bait.
depth
Surface to 50 m for most catches.
how to fish
- rod
- jigging PE 2 to 4; popping 7'0" to 7'6" PE 3 to 5
- spinning / baitcasting reel
- 5000 to 10000 spinning reel
- line
- braided PE 2 to 5 (30 to 65 lb)
- leader
- fluorocarbon 40 to 60 lb, 2 m
- hook
- assist hooks 3/0 to 5/0; reinforced single hooks
lures
- 60 to 150 g jigs
- 10 to 16 cm stickbaits and poppers
- small trolling plugs
natural baits
- live sardine
- lula
accessories
- luvas
- alicate
- small gaff
tip from an angler
When the school rises with birds, cast ahead and retrieve quickly.
rules for the blackfin tuna
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 national list (Portaria GM/MMA 1.667/2026). We found no specific federal rule for this species.
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.
If you are going to release it, keep the fight short, without lifting it out of the water, and return it with the boat moving slowly.
in the kitchen
Dark, tasty flesh; good grilled and raw, if bled and chilled quickly.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.01148, b = 3.05; FishBase (estimativa bayesiana por forma do corpo no gênero, comprimento total)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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sources and references
The season weights (months), the time of day and the sensitivities (cold, pressure, moon, wind, rain, tide, strong light, murky water and noise) are the app's editorial estimates, based on the literature below and on the field experience of anglers and guides. They are not official data nor a measurement made for this species, and they may vary by region and year. Closed seasons and legal rules appear in the rules section, with the norm and a link.
- scientific FishBase — Thunnus atlanticus (ficha da espécie)Names, distribution, biology, length-weight relationship and references. Page checked on October 13, 2026.
- 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)Most recent national list. The species is not on it (search by scientific name in the text published in the DOU, checked on October 13, 2026).
- official ICMBio/SALVE — Ficha de Thunnus atlanticus (avaliação nacional do risco de extinção)ICMBio national assessment, published in 2026. DOI checked on Crossref.
- scientific IUCN Red List — Thunnus atlanticus (avaliação global: Pouco Preocupante, LC, 01/07/2021)Global assessment. Link given on the FishBase entry (Red List, version 2025-2).
- scientific Collette, B. B.; Nauen, C. E. (1983). FAO species catalogue. Vol. 2. Scombrids of the world. FAO Fisheries Synopsis 125(2). Roma: FAO.
- technical ICCAT Manual, cap. 2.1.10.7 — Blackfin tuna (Thunnus atlanticus). International Commission for the Conservation of Atlantic Tunas.Chapter by Hazin, F. H. V.; Bezerra, N. P. A.; Viana, D. L. (UFRPE), updated in 2021.
- scientific Carpenter, K. E. (org.) (2002). The living marine resources of the Western Central Atlantic. Vol. 3: Bony fishes part 2 (Opistognathidae to Molidae). FAO Species Identification Guide for Fishery Purposes. Roma: FAO.Scombridae chapter (Collette, B. B.), cited by FishBase for the species.
- scientific Figueiredo, J. L.; Menezes, N. A. (2000). Manual de peixes marinhos do sudeste do Brasil. VI. Teleostei (5). São Paulo: Museu de Zoologia da USP. 116 p.Printed work; the URL is the bibliographic record on FishBase, which cites this work for the species.
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: