Carcharhinus plumbeus · Carcharhinidae · predator
Robust, bronze-colored shark with a very tall, upright first dorsal fin that uses bays, river mouths and ports. Critically Endangered (CR) in Brazil and Endangered (EN) worldwide: catch banned.
Also called: tubarão-barriga-d'água, cação-barriga-d'água, barriga-de-água
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 sandbar shark (tubarão-barriga-d'água in Portuguese) is a robust shark of coastal and shelf waters worldwide, common in bays, river mouths and ports; it avoids surf beaches, coral reefs and uneven bottoms. It lives close to the bottom, between 1 and 280 m, and makes long seasonal migrations in part of its range. It eats mainly bony fish, along with small sharks, squid, shrimp and rays; juveniles prefer crustaceans. Each litter has 1 to 14 pups, and gestation lasts about 12 months. Populations separate by age. It is Critically Endangered (CR) on the national list and Endangered (EN) by IUCN (2020). Do not seek out this species.
Robust body, greyish-brown or bronze, unmarked, white below. Moderately long, rounded snout, tall triangular serrated upper teeth, and a ridge of skin between the two dorsal fins. The species' mark is a very large, upright first dorsal fin just behind the head, with large pectoral fins too; the fins are plain or slightly dark-tipped. The fidalgo and the Galápagos shark have a smaller first dorsal fin. If the shark has a ridge between the dorsals and you are unsure, release it.
Warm tropical and temperate waters worldwide (FishBase: 45°N to 41°S). In Brazil, it uses bays, estuaries and the shelf along the coast. In Latin America, FishBase records it from Mexico and the Caribbean to Argentina and Uruguay.
Habitat: Bays, river mouths, ports and shelf, near the bottom, from 1 to 280 m; avoids surf beaches, coral reefs and uneven bottoms.
coast
Estimate: FishBase cites long seasonal migrations, but with no local calendar; the weights are neutral. Catch is banned year-round.
Any time. There is no reliable data on the activity schedule in Brazil.
The 23 to 27 °C range is the one cited by FishBase; cold reduces activity.
Little known effect.
No known effect.
Heavy rain muddies river mouths; the animals tend to move.
Not applicable at sea.
Not well known.
Rough seas make any trip hard.
Uses bays and river mouths, where the tide moves food.
From 1 to 280 m; usually stays near the bottom.
accessories
If a sandbar shark is hooked by chance in a bay or river mouth, release it in the water, cutting the line close to the hook. Don't drag it onto the beach or leave it out of 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: On the national list of threatened species as CR (already on the previous list). Global: Endangered (EN, assessed by IUCN on Dec 3, 2020). The whole family Carcharhinidae has been in CITES Appendix II since Nov 25, 2023.
The national list (Portaria GM/MMA nº 1.667/2026) classifies the species as CR. Under Portaria GM/MMA nº 1.666/2026 (art. 3), VU, EN and CR species have full protection: catch, transport, storage, processing and trade are banned. If you hook one by accident, release it right away, with minimal handling.
Source: Portaria GM/MMA nº 1.666/2026, art. 3º, and Portaria GM/MMA nº 1.667/2026
In Brazil, finning is banned: cutting off the fins and discarding the rest of the body. The rule covers landing, transport, and trade by fishing vessels: every shark or ray must arrive whole, with its fins naturally attached to the body (partially folding them against the body is allowed); carrying an animal aboard without fins or with loose fins, and transferring sharks and rays between vessels, is prohibited. This does not authorize catching this species, which is banned.
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.
In 2021 Colombia stopped considering sharks and marine rays a fishery resource and began treating them as a hydrobiological resource; the recitals of Decree 281/2021 state that they may not be extracted for commercial or sport purposes, and the decree created an environmental protection plan. Later AUNAP rules dealt with incidental catch in artisanal fishing; we did not check the consolidated text. When in doubt, release it into the water.
Federal Fisheries Council Resolution 8/2021 (Consejo Federal Pesquero) bans directed fishing for chondrichthyans (sharks, rays and chimaeras), finning (cutting off the fins and discarding the body) and the use of gaffs to return live animals to the sea, and requires that sharks caught by chance be returned quickly and with minimal trauma, except cazón, gatuzo, pez ángel, espinoso and pintarroja. The text refers to trips and vessels, that is, the federal commercial fleet, and invites the provinces to adopt similar measures; we did not find a specific rule for sport fishing in Buenos Aires. For sport anglers, good practice is to release the shark in the water, without a gaff.
Law 9 of 2006 bans finning in Panama's jurisdictional waters. The law's definition of shark fishing covers directed or incidental catch by artisanal, commercial, industrial and sport vessels. The fine for artisanal fishing reaches 1,000 balboas, without prejudice to criminal liability. In the sources we checked, we did not find a specific Panamanian rule on retention or release for sport anglers.
This is not catch and release: it is release of an accidental catch. Keep the shark in the water and cut the line as close to the hook as possible. Don't drag it across the sand or lift it by the tail.
Catch and trade banned in Brazil. In other countries the meat is sold fresh, smoked, salted and frozen, and the fins have value (FishBase), but the species is threatened: release it.
Length-weight relationship W = a·Lb (a = 0.00479, b = 3.07; FishBase (relação peso-comprimento bayesiana, estimativa da própria espécie)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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The seasonal 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 field experience from anglers and guides. The water temperature range and the common size range are also editorial estimates, supported by FishBase. The months show when an angler usually finds the species, not a catch season. They are not official data or measurements made for this species, and they may vary by region and year. Legal rules appear in the rules section, with the norm and a 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.
