A small shark, found only in the South Atlantic, that eats crabs on the bottom. Critically Endangered in Brazil: catch prohibited. In Argentina, the gatuzo may be kept in mixed fishing, with a minimum size and a quota.
Also called: cação-malhado, cação-cola-fina, cação-canejo, canejo, gatuzo
The cação-malhado, the gatuzo of Argentines, exists only in the southwestern Atlantic, from southern Brazil to northern Patagonia. It is a small shark, at most 90 cm, that lives near the bottom on the shelf and comes into beaches and bays, where it hunts crabs, other crustaceans and small fish. It has 2 to 7 pups per pregnancy, born at about 26 cm. It is heavily exploited by commercial fishing in the region, and in Brazil it is Critically Endangered, with catch prohibited. In Buenos Aires Province it is a common species in beach and boat 'mixed fishing', with a minimum size and a daily limit.
fun facts
Found only in the southwestern Atlantic, from southern Brazil to Patagonia.
Its low, mosaic-like teeth work like a plate for crushing crabs.
It has 2 to 7 pups per pregnancy, born at about 26 cm.
how to recognize it
identification
A small, slender shark, gray to grayish brown on the back, usually with scattered white spots, pale belly. Short, pointed snout, oval eyes. The two dorsal fins are nearly the same size. Low, mosaic-like teeth for crushing. The cação-bico-doce is larger, without spots, with a much smaller second dorsal fin and a large lobe at the tip of the tail. Other coastal Mustelus (M. canis, EN; M. fasciatus, CR) are also protected.
how narrownose smooth-hound 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.
In Brazil, along the southern coast, especially in Rio Grande do Sul. Endemic to the southwestern Atlantic, from southern Brazil to northern Argentine Patagonia, including Uruguay and the Buenos Aires coast.
Habitat: Sandy and muddy bottoms of the continental shelf, beaches and bays.
coast
South Coastcoastalshelf
states
Santa Catarina, Rio Grande do Sul
calendar and clock
when to fish
best season
time of yearbest: Nov–Jan
JanFebSeaAprMayJunJulAugSepOctNovDec
Estimate: on the Buenos Aires coast the gatuzo comes close to beaches in spring and summer; in southern Brazil it also appears in the cold months. Biological information: in Brazil, catch is prohibited year-round.
best time of day
Any time. Feeds day and night, always on the bottom.
weather, water and behavior
what affects the narrownose smooth-hound
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
cold and cold fronts
A temperate-water species; tolerates cold water.
atmospheric pressure
Cold fronts bring rough seas.
moon
Little known effect.
rain
Not very relevant.
water level
Not applicable at sea.
noise
Not very sensitive.
wind
Rough seas prevent beach fishing.
tide
A rising tide brings crabs and small fish to the shore.
beach: 12' to 14' for a 100 to 150 g sinker; boat: 6' to 7', 15 to 30 lb
spinning / baitcasting reel
5000 to 7000 spinning reel
line
monofilament 0.35 to 0.45 mm
leader
0.60 mm monofilament, up to 3 single hooks per rod (mixed-fishing rule in Buenos Aires)
hook
circle hook 2/0 to 4/0
natural baits
shrimp
lula
fish fillet
caranguejo
accessories
alicate
desanzolador
measuring ruler (60 cm minimum in Buenos Aires)
tip from an angler
In Brazil catch is prohibited: release it in the water. In Argentina, measure before keeping it and respect the limit of 10 per day; those under 60 cm go back to the sea.
what the law says
rules for the narrownose smooth-hound
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: Catch prohibited throughout Brazil. Global: Critically Endangered (IUCN, July 1, 2019).
Threatened species (CR): catch prohibited in Brazil
catching, transport, holding and trade prohibited
The cação-malhado (Mustelus schmitti) is on the national list as Critically Endangered (CR) (it was already on the previous list, Portaria MMA 148/2022). Ministerial Ordinance GM/MMA 1.666/2026 (art. 3) prohibits catch, transport, storage, possession, processing and trade throughout Brazil. Anyone who hooks one by chance must release it alive immediately (art. 3, § 4). The rule does not authorize targeted fishing, even with release: in Brazil, do not seek this species.
Finning prohibited: shark only whole, with its fins
fins naturally attached to the body
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.
Buenos Aires (AR): gatuzo, 60 cm minimum size and up to 10 per day
60 cm minimum size; up to 10 killed per angler per day
In Buenos Aires Province marine sport fishing, the gatuzo is part of the 'mixed fishing' category. Minimum catch size of 60 cm; each angler may keep a maximum of 10 gatuzos per day, within the total of 40 pieces of mixed fishing; beyond that, release is mandatory. Maximum of three single hooks per rod. In Río Negro, Law 5.706/2023 allows the gatuzo to be added to mandatory release by resolution of the fishing authority (art. 22).
North CoastNortheast CoastSoutheast CoastSouth Coast
Many sharks and rays are on the national list (CR, EN or VU), with catching, keeping and transport prohibited, including those listed here. Species added to the list only in 2026 follow the 180-day deadline (until about Oct 25, 2026). If unsure of the species, release it.
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.
Remove the hook with a dehooker while it is still in the water or with the fish wet, holding it by the body, and release it right away. It is small and handles quick release well.
in the kitchen
Catch and trade prohibited in Brazil. In Argentina it is eaten, within the minimum size and quota.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00263, b = 3.1; 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
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sources and references
The seasonal weights (months), time of day and sensitivities (cold, pressure, moon, wind, rain, tide, bright 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 show when an 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 norm and link. The maximum weight (about 3.2 kg) was calculated from FishBase's length-weight relationship for the maximum length of 92 cm, because no maximum weight is published.
officialPortaria GM/MMA nº 1.666, de 27 de abril de 2026 — regras de proteção das espécies ameaçadas da lista nacionalArt. 3: full protection for VU, EN and CR species; § 4: incidental catch with immediate release of the live animal. The 180-day transition rule for species newly added to the list was verified from official summaries (Fiperj) and technical sources; the DOU (Brazil's Official Gazette) page did not open during verification.
