Slender shark with a whip-like tail as long as the rest of its body and a white patch above the pectoral fins. Considered a sport fish in other countries, but Critically Endangered (CR) in Brazil: capture banned.
Also called: tubarão-raposa, cação-raposa, cação-pena, rabilongo
The common thresher is the largest of the threshers and lives in tropical and temperate seas around the world, on the shelf and in open sea, more abundant near land; the pups stay in shallow waters and bays. The upper lobe of the tail, as long as the rest of the body, serves as a whip to round up and stun schools of mackerel, sardines, squid and other pelagic fish. It has 2 to 4 pups per litter (usually 2), born at 114 to 150 cm, and maturity comes at about 3.5 m. It is caught by commercial fishing, which uses the meat, liver, leather and fins. It is Critically Endangered (CR) on the national list; globally, Vulnerable (VU) according to the IUCN. Do not seek out the species.
fun facts
Uses its tail as a whip to round up and stun schools before eating them (FishBase).
Some attacks on boats have been attributed to the species, but FishBase considers them doubtful; the size of adults, however, calls for respect. It can also damage fishing gear.
Pups stay near the coast, in shallow bays; adults travel in open sea.
The three thresher sharks were listed in Appendix II of CITES in 2016, with trade controls in force since October 2017.
how to recognize it
identification
Upper tail lobe ribbon-shaped, as long as the rest of the body. Relatively small eyes, curved pectoral fins with narrow tips and, at the base of the pectorals, a clear white patch: the white belly extends onto them. Back brown, grey, blue-grey or nearly black, paler on the flanks and abruptly white below. The second dorsal fin starts well behind the tips of the pelvic fins. The bigeye thresher has huge eyes and no white patch; the pelagic thresher is smaller, dark blue and also lacks the patch.
how thresher fishing looks
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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.
Cosmopolitan in tropical and temperate seas (FishBase: 74°N to 58°S). In Brazil, open sea and shelf along the coast, with juveniles closer to land. In Latin America FishBase records it from Mexico and the Caribbean to Argentina and Chile; in Uruguay it is known as azotador.
Habitat: Continental shelf and open sea, from the surface to more than 600 m; juveniles in bays and shallow waters near the coast.
coast
North CoastNortheast CoastSoutheast CoastSouth Coastshelfoceanic
calendar and clock
when to fish
best season
time of year
JanFebSeaAprMayJunJulAugSepOctNovDec
Estimate: no well-documented season in Brazil; the weights are neutral. Capture is banned all year.
best time of day
Any time. Hunts schools by day and by night; there is no reliable local data on timing in Brazil.
weather, water and behavior
what affects the thresher
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
cold and cold fronts
Prefers temperate to lukewarm water; the exact range varies by region.
atmospheric pressure
Little known effect.
moon
No known effect.
rain
Not very relevant.
water level
Not applicable at sea.
noise
Not well known.
wind
Rough seas end trips offshore.
tide
No relevant tide in the ocean; currents and forage fish schools matter.
depth
From the surface to more than 600 m; it usually stays shallow.
technique, gear and bait
how to fish
rod
Catch banned in Brazil; there is no recommended gear for targeting the species.
spinning / baitcasting reel
Not applicable.
line
Not applicable.
leader
Not applicable. If a shark takes the steel leader, cut close to the mouth when releasing it.
hook
Barbless circle hook (or one with the barb flattened) for any open-sea fishing: it comes out more easily and causes less injury.
accessories
cutting pliers
long-handled hook remover
thick gloves
tip from an angler
If a thresher shark bites by accident, release it beside the boat, in the water, cutting the line flush with the hook. Watch out for the tail whip and the animal's weight: it is a large shark.
what the law says
rules for the thresher
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: Vulnerable (VU, assessed 06/11/2018 by the IUCN). Since 2017 all thresher sharks have been in Appendix II of CITES.
Threatened species in Brazil: catch banned
full protection
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.
Finning prohibited: shark only whole, with its fins
fins naturally attached to the body
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.
1 specimen per angler per day (counts as 5 against the quota of 10)
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.
Colombia: marine sharks and rays are not fishery resources
commercial or sport extraction not permittedconfirm with the agency
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.
Argentina: directed fishing for sharks and rays banned for the federal fleet; incidental sharks returned to the sea
directed fishing for chondrichthyans banned; return live sharks without gaff; finning bannedconfirm with the agency
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.
Panama: shark finning banned in its jurisdictional waters
banned: cutting off the fins and throwing the body back into the sea
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.
Chile: finning of sharks banned on board and at landing
landing with fins fully or partially attached to the body
Law 20.525 (2011) added art. 5 bis to the General Law on Fisheries and Aquaculture: it is forbidden to cut the fins of any shark on board fishing vessels or during transshipment, and landing must be done with the fins fully or partially attached to the body. A loose fin without the corresponding trunk on board is presumed to be an offense. The fine for the vessel owner ranges from 50 to 500 UTM. We did not verify a specific Chilean rule on shark retention in marine recreational fishing.
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.
This is not catch and release: it is release of accidental catch. Do not bring the shark aboard; keep it beside the boat, in the water, and cut the line as close to the hook as possible. Watch the tail and do not take photos.
in the kitchen
Capture and trade banned in Brazil. In other countries the meat, liver, leather and fins are used (FishBase), but the species is threatened: release it.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00832, b = 2.86; 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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sources and references
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.
scientificFishBase: Alopias vulpinus (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology and IUCN status. Page checked on 13/10/2026. The common size range runs from the average size at maturity (351 cm) to the common length (450 cm) reported by FishBase. We do not give a common weight: the length-weight relationship uses total length, which includes the long tail, and would come out far above the maximum recorded weight.