Carcharhinus brachyurus · Carcharhinidae · predator
A large temperate-water shark, bronze in color, the king of release-based shark fishing in northern Argentine Patagonia. It is not on the threatened list in Brazil, but it is Vulnerable worldwide and resembles protected species.
Also called: tubarão-bronze, bacota, tubarão-cobre, cação
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…
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.
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.
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 bronze whaler, the bacota of Argentines and Uruguayans, is the only Carcharhinus that prefers temperate waters. It lives in beaches, bays and on the continental shelf, and makes migrations tied to water temperature. In Argentina it appears from October to late March and enters Anegada Bay, near San Blas, from December, leaving by April; there most are large juveniles and subadults. It grows slowly and only matures beyond 2 m. In Brazil it occurs from the Southeast to the South, and it is not a threatened species on the national list. In Argentina it is the great trophy of beach and boat shark fishing at San Blas, Bahía Creek and San Matías Gulf, always with mandatory release.
Large, relatively slender body, bronze to olive-gray back with a metallic sheen, white belly and a faint pale band on the flank. Moderately long snout, rounded at the tip. Upper teeth narrow and curved, like hooks. First dorsal fin medium, with no ridge between the dorsals (the dusky shark, fidalgo, C. obscurus, Endangered, has a ridge). Fin tips dark, without distinct black spots. The bull shark has a much shorter snout.
In Brazil, from the Southeast to the South. In the southwestern South Atlantic it ranges from Brazil to Argentina, notably Anegada Bay and San Blas (Buenos Aires) and San Matías Gulf (Río Negro). Also in the Pacific, from California to Peru.
Habitat: Beaches, bays, tidal channels, estuary mouths and the continental shelf.
coast
states
Rio de Janeiro, São Paulo, Paraná, Santa Catarina, Rio Grande do Sul
In Argentina, the bacota appears from October to late March and stays in Anegada Bay from December to April, according to a study of the species. In Brazil, there is no defined season for anglers (estimate).
Daytime, with peaks at dawn and dusk. Feeds by day in channels with the tide running; from the beach, late afternoon and early evening usually produce more.
Its movements follow water temperature: it arrives with the warm water of summer and leaves in autumn.
Cold fronts lower the temperature of the shallow bays.
Spring tides move the channels.
Not very relevant.
Not applicable at sea.
It is wary of boats with engines running over the shallow channels.
Strong wind and rough seas prevent fishing from the beach.
The tide running through the channels is the bacota's hour.
From the shallows of the beaches to tens of meters out on the shelf.
natural baits
accessories
In Argentina release is mandatory; in Brazil, release it too: it is easily confused with the dusky shark and the sandbar shark, which are protected. Don't let it swallow the bait, keep the fight short, and release it in the water.
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 (Ministerial Ordinance GM/MMA 1.667/2026). Global assessment: Vulnerable (IUCN, April 6, 2020). Listed in CITES Appendix II.
The bronze whaler is not on the national list, but it looks very much like the dusky shark (C. obscurus, Endangered), the sandbar shark (C. plumbeus, Critically Endangered) and the bull shark (C. leucas, Vulnerable from late October 2026), all protected. If you're not sure of the species, release it.
Source: Portaria GM/MMA nº 1.667/2026 (national list: C. obscurus EN, C. plumbeus CR, C. leucas VU)
In Brazil, finning is prohibited (cutting off the fins and discarding the body). Every shark or ray landed must arrive with its fins attached to the body; it is prohibited to carry on board an animal without fins or with loose fins, and to transfer sharks between vessels. It applies to any shark that may be kept.
On the Buenos Aires Province coast (and in the Plata, Bahía Blanca and Mar Chiquita estuaries), escalandrún, bacota, gatopardo, cazón and hammerheads are "reserved directed fishing": release is mandatory, and killing is prohibited even for incidental catch. Gear rules: one rod per angler on a boat and two from shore; single-hook rigs only (tandem rigs prohibited); circle or biodegradable hook 12/0 to 14/0 with the barb flattened; a stopper float 25 cm above the hook is recommended on bottom lines, along with nylon line of at least 0.70 mm. Gaffs are prohibited. Remove the hook only if there is no risk; otherwise cut the line close to the hook, avoiding lifting the shark out of the water. From Pehuén-Có to the mouth of the Río Negro (including the Bahía Blanca estuary, Anegada Bay and San Blas), a permanent closed season also applies to artisanal and commercial fishing for escalandrún, bacota, gatopardo and cazón (Disposition 55/2008).
In Río Negro Province marine sport fishing (San Matías Gulf, El Cóndor, Bahía Creek), the bacota (Carcharhinus brachyurus) is under a special protection regime: killing during capture is prohibited and release is mandatory. In boat fishing targeting sharks: one hook per line (tandem rigs and tartuna-type galvanized hooks prohibited), a "J" hook with the barb filed or flattened, or a circle hook. A specimen on board only with scientific authorization.
In recreational sport fishing in Mexican saltwaters, the limit for sharks is one specimen per angler per day, which counts as five toward the total limit of ten fish. Fish caught in sport fishing may not be sold. Catch and release does not count toward the limit: prefer releasing.
Leave it in the water or at the shore, head facing the sea, without dragging it across the sand. Remove the hook with a dehooker or cut the line close to the mouth. Revive it until it swims off strongly.
In Brazil it may be kept under the general rules, but release is best practice: it is Vulnerable worldwide and resembles protected species. In Argentina, killing is prohibited. Sharks accumulate mercury.
Length-weight relationship W = a·Lb (a = 0.00501, b = 3.07; FishBase (estimativa bayesiana para a espécie e o gênero, comprimento total)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
—
The seasonal weights (months), time of day and 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 field experience of anglers and guides. The months indicate the time of year when the angler usually finds the species near the coast, not a catch season. They are not official data or measurements made for this species and may vary by region and year. Legal rules appear in the rules section, with the regulation and link.
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.
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:
Your location is saved only on this device and feeds the forecast, the map and the "today" on the home page.
