Federal minimum size (70 cm) in the Southeast and South
70 cm (TL)ESRJSPPRSCRSSoutheast CoastSouth Coast
It is banned to fish for, keep on board or land largehead hairtail under 70 cm total length on the coast of ES, RJ, SP, PR, SC and RS.
fishing forecast
largehead hairtail
Trichiurus lepturus · Trichiuridae · predator
SeaEstuary
Silver ribbon with needle teeth. A classic night fishery from piers and bays, with sardine and jig.
Also called: espada, peixe-espada, catana
- common size
- 60–110 cm
- maximum
- 234 cm
- common weight
- 0.4–1.5 kg
- record/max.
- 5.0 kg
- depth
- 1–100 m
- ideal water
- 18–26 °C
fishing forecast
the right time
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…
0—
index Score from 0 to 100 for the fishing conditions of each hour. It reads weather, sun, moon, tide and the species' habits. It doesn't promise fish: it tells you when the water is on your side. 0–24 poor · 25–44 fair · 45–64 good · 65–84 very good · 85–100 excellent.
today
—
confidence —
confidence How much you can trust the weather forecast for the day. It drops with distance and when the models disagree. It is not the chance of catching fish.
models and trend Up to 16 days, three global weather models (the European ECMWF, the American GFS and a high-resolution blend) read hour by hour; when they disagree, the light band on the chart widens. Beyond that it's a trend: 31 runs of the American GEFS model. Confirm when it's 1 week out.
window Consecutive hours with the index near the day's peak and no danger alert. It is the time to have the bait in the water.
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 —?
next 7 days
chart: bar height = day's index · line = variation between models · striped = trend · fainter = less confidencechoose 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.
4-week calendar
the fishing month at a glance
plan a trip
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.
the species
everything about the largehead hairtail
overview
who is the largehead hairtail
The largehead hairtail is a silver ribbon up to 2 m long with needle teeth. It lives along the whole coast, from bays and estuaries to over 300 m deep, and makes daily migrations between the bottom and the water column to hunt. It eats sardines, manjubas, shrimp and squid, attacking from below. It is the classic night fishery from piers, bridges and anchored boats in Southeast bays, with sardine on a float or a metal jig, often near lights. Schools enter the bays most strongly in autumn and winter. White, tasty meat, good fried or stewed. Watch the teeth when removing the hook.
fun facts
- No tail fin or pelvic fins: it swims by undulating the long dorsal fin.
- It usually hangs vertically, head up, waiting for prey.
how to recognize it
identification
Ribbon-shaped body, very long and flattened, metallic silver, scaleless, ending in a fine point with no tail fin. Large mouth with long, fang-like teeth. Long dorsal fin along almost the entire body and no pelvic fins. Not confused with any other fish on the coast.
distribution
open on the large map where found
All along the coast, from estuaries and bays to the shelf and slope. Heavily fished in the bays of Guanabara, Santos, Paranaguá and Baía Norte de Florianópolis.
Habitat: Bays, estuaries, port channels, piers, bridges and mud bottoms of the shelf.
coast
North CoastNortheast CoastSoutheast CoastSouth Coastcoastalshelf
states
Amapá, Pará, Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, Santa Catarina, Rio Grande do Sul
when to fish
best season
time of yearbest: Apr–Aug
JanFebSeaAprMayJunJulAugSepOctNovDec
In bays and piers of the Southeast and South, the most cited season is April to August, when schools come in after sardines and shrimp. The rest of the year it appears irregularly.
best time of day
Night and twilight. Very productive at night on piers and bridges, especially near lights, and at dusk.
what affects the largehead hairtail
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
cold and cold fronts
Tolerates cold water; an autumn and winter fish in the bays.
atmospheric pressure
Not very sensitive.
moon
New moon nights and artificial light concentrate bait and hairtail.
rain
Light rain doesn't hurt.
water level
Very muddy water in the bay drives schools away.
noise
Not very sensitive; a school under the light tolerates movement on the pier.
wind
Strong wind disrupts the drift of the float.
tide
Prefers a moderate running tide: on the flood it enters the bays after bait; on the ebb it stays in the channels. At slack tide it keeps feeding at night near the light.
depth
Midwater to surface at night; near the bottom by day.
how to fish
- rod
- 7'0" to 9'0", 10 to 20 lb
- spinning / baitcasting reel
- spinning reel 3000 to 4000
- line
- braided 15 to 20 lb
- leader
- fine crimped wire or fluorocarbon 40 to 50 lb, 30 cm
- hook
- long-shank hook 1/0 to 3/0
lures
- metal jig 20 to 40 g
- silver spoon
- jig head with white shad
natural baits
- whole or filleted sardine
- manjuba
- mackerel fillet
- lula
accessories
- chemical light or lighted float
- long-nose pliers
- cloth to grip
tip from an angler
Sardine stretched on a long-shank hook, at midwater, under a lighted float. The hairtail nibbles the bait from behind: wait until the float goes fully under.
rules for the largehead hairtail
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 of threatened species.
Minimum size: 70 cm
ESRJSPPRSCRSSoutheast CoastSouth Coast
Source: IN MMA nº 53/2005 (coast from ES to RS; total length)
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.
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.
Hold it with cloth behind the head and use long pliers: the teeth pierce easily. Release it quickly.
in the kitchen
White, tender and tasty meat. In fried steaks, stew or breaded.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.000154367, b = 3.17; FishBase (estimativa bayesiana, comprimento total); coeficiente a ajustado ao porte máximo registrado). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
—
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 — Trichiurus lepturus (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 Trichiurus lepturus (avaliação nacional do risco de extinção)National assessment by ICMBio, published in 2021. DOI checked in Crossref.
- scientific IUCN Red List — Trichiurus lepturus (avaliação global: Pouco Preocupante, LC, 29/01/2013)Global assessment. Link given on the FishBase entry (Red List, version 2025-2).
- scientific Nakamura, I.; Parin, N. V. (1993). FAO species catalogue. Vol. 15. Snake mackerels and cutlassfishes of the world (families Gempylidae and Trichiuridae). FAO Fisheries Synopsis 125(15). Roma: FAO.
- 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.Trichiuridae chapter (Parin, N. V.; Nakamura, I.).
- scientific Menezes, N. A.; Buckup, P. A.; Figueiredo, J. L.; Moura, R. L. (orgs.) (2003). Catálogo das espécies de peixes marinhos do Brasil. São Paulo: Museu de Zoologia da USP. 160 p.List of the marine species recorded in Brazil. Printed work; the URL is the bibliographic record in FishBase, which cites the catalogue for the species.
how we calculate
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: