acoupa weakfish
Cynoscion acoupa · Sciaenidae · predator
The largest weakfish on the coast, over 1 m. Hunts in murky water with the tide running, at dawn and at night.
Also called: pescada-amarela, pescada-verdadeira
- common size
- 40–80 cm
- maximum
- 110 cm
- common weight
- 1–6 kg
- record/max.
- 17.0 kg
- depth
- 1–25 m
- ideal water
- 24–29 °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 acoupa weakfish
who is the acoupa weakfish
The yellow weakfish (pescada-amarela) is the largest weakfish on the Brazilian coast, over 1 m and 15 kg. It lives in estuaries, bays, channels and murky inlets, from Amapá to Santa Catarina, with large populations along the coasts of Pará and Maranhão. It hunts fish and shrimp near the bottom, mainly with the tide running and in low light. Large ones gather in deep channels and at the mouths of the inlets. In the North it is a table and export fish: its dried swim bladder, the 'grude', is worth a lot in Asian markets, which greatly increased fishing pressure. For recreational anglers it is a hard fight and a prime fish on the table.
fun facts
- The 'grude' (dried swim bladder) is exported to Asia at a very high price.
- Like other drums, it makes sound by contracting muscles attached to the swim bladder.
identification
Elongated body, large oblique mouth with one or two large canine teeth at the tip of the upper jaw, mouth interior orange-yellow. Silvery grey back with golden sheen, yellowish fins, no spots and no barbels. Difference from the croaker: the croaker has chin barbels, a mouth under the snout and oblique stripes; the weakfish has no barbel and has canines.
where found
From Amapá to Santa Catarina. Very abundant on the Amazon coast (Pará and Maranhão); in the Southeast and South it appears in estuaries and bays such as Cananéia, Santos, Paranaguá and Babitonga.
Habitat: Murky-water estuaries and bays, deep channels, inlets, mangrove edges and beaches near rivers.
coast
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
when to fish
best season
In the Southeast and South the largest fish appear from spring to late summer, when they gather at inlets and channels. In the North and Northeast it is fished all year, with local variation linked to rainfall and salinity.
best time of day
Night and twilight. Most active at dawn, dusk and at night. By day it bites in murky water and deep channels with the tide running.
what affects the acoupa weakfish
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
cold and cold fronts
A cold front in the South pushes the weakfish out of the shallow areas; look for deep channels.
atmospheric pressure
Stable weather and falling pressure before the front usually give good strikes.
moon
Large-tide moons (full and new) concentrate the weakfish at channel mouths.
rain
Light drizzle doesn't bother it; it is a murky-water fish by nature.
water level
More salinity in the estuary draws the weakfish inward; a strong river flood pushes it toward the inlet.
noise
Moderately sensitive; anchor quietly and avoid bumping the hull.
wind
Wind against the tide makes waves at the inlets and makes it hard to keep the bait on the bottom.
tide
Very tide-dependent. The rising tide brings the bait school inside and the weakfish follows it through the channels; the falling tide is the time for the channel mouths and the inlet. Fish from mid-tide to near slack water; at slack the bite disappears.
depth
Bottom and mid-water between 3 and 15 m in the channels; shallower at night.
how to fish
- rod
- 6'6" to 7'0", medium action, 15 to 30 lb
- spinning / baitcasting reel
- spinning reel 4000 to 5000 or medium baitcasting reel
- line
- braided line 20 to 40 lb
- leader
- fluorocarbon 40 to 60 lb, 1 m
- hook
- circle or wide gap 2/0 to 5/0
lures
- jig head 1/2 to 1 oz with 4 to 5 inch shad
- sinking shrimp lure
- long-skirted mid-water lure
natural baits
- live shrimp
- live small mullet or parati
- manjuba
- sardinha
accessories
- olive sliding sinker
- large landing net
- alicate
tip from an angler
Use the sliding sinker only enough to keep the bait on the bottom with the tide. The weakfish bites and drops: wait a second before setting, or use a circle hook and just reel in.
snook in mangroves and estuaries
Boat or kayak fishing in mangroves, channels, brackish rivers and under bridges, with artificial lures and live shrimp, following the tide.
guidetides and moon in fishing
Spring and neap tides, high and low tide, slack water, rising and falling tide, tide tables and solunar theory: what really matters and how to use it without fanaticism.
guidefish preservation and cleaning
Quick killing, bleeding, the right amount of ice, a well-used cooler, filleting and transport within the law. Fish handled well on the boat is worth twice as much at the table.
rules for the acoupa weakfish
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 (Portaria GM/MMA nº 1.667/2026), but the global assessment indicates decline.
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.
Drums suffer from decompression when brought up from depth; reel in slowly over the last metres and release quickly. Don't squeeze the belly.
in the kitchen
White, soft meat with a mild flavour. Fried fillets, stewed, moqueca and fish stew (caldeirada).
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00759, b = 3.06; FishBase (estimativa bayesiana, 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 — Cynoscion acoupa (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 Cynoscion acoupa (avaliação nacional do risco de extinção)ICMBio national assessment, published in 2025. DOI checked on Crossref.
- scientific IUCN Red List — Cynoscion acoupa (avaliação global: Vulnerável, VU, 10/10/2019)Global assessment. Link given on the FishBase entry (Red List, version 2025-2).
- 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.Chapter Sciaenidae (Chao, N. L.).
- 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.
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: