Steindachneridion scriptum
Large leather catfish of the rapids of the upper Uruguay and upper Paraná, threatened by dams. It is on the national list as Vulnerable: catching, transporting and selling wild specimens are banned.
Also called: suruvi, bocudo
The suruvi is a large catfish of the family Pimelodidae, up to about 1 m, restricted to the upper Uruguay and upper Paraná basins. It is potamodromous, that is, it migrates within the river itself, and like the large Steindachneridion it tends to frequent clearwater rivers with current, over stony beds. The genus review includes specimens from the Uruguay River at Itaqui and Barracão (RS) and Itá (SC), and from the Grande, Paranapanema and Pardo rivers in São Paulo. It was an important resource for riverside fishers, and dams, illegal fishing and industrial waste are named as the main threats in the Uruguay. IUCN rates it Endangered (2023), and ICMBio listed it as Endangered in 2014; the 2026 national list has it as Vulnerable, which gives full protection. If it takes the hook, release it right away.
Large catfish with smooth, scaleless skin and an elongated body, light gray with a whitish belly. The head, trunk and fins have irregular black blotches, some elongated, and scattered dark spots. Large mouth, small eyes, long maxillary barbel that reaches past the tip of the pectoral fin, and a deeply notched tail with a larger upper lobe. The Iguazu surubim (Steindachneridion melanodermatum) lives in another basin, above the Iguazu Falls, and the pintados and cacharas (Pseudoplatystoma) have stripes or spots in rows and a flatter head. When in doubt, treat any large rapids catfish from this region as protected.
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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.
Upper stretches of the Uruguay and Paraná basins, in Brazil, Argentina and Uruguay (Uruguay River). The material examined in the genus review comes from Itaqui and Barracão (RS), Itá (SC) and from the Grande, Paranapanema and Pardo rivers (SP), several specimens from stretches just below dams.
Habitat: Channel of clearwater rivers with current, preferably in pools near rapids, over a stony bottom; it also uses stretches below dams.
native to the basins
states
Rio Grande do Sul, Santa Catarina, São Paulo, Minas Gerais
There is no season: fishing for the species is banned. The weights are only there to warn bottom anglers that it may turn up in the upper Uruguay and upper Paraná.
Night and twilight. There are few studies on timing. Like other large bottom catfish, it should be more active at night (estimate).
Cold reduces activity (estimate).
Little known effect.
Little known effect.
Little known effect.
Floods and dam releases change the current and where it stays; no specific data.
No data; a bottom fish in pools.
Little effect.
Bottom of pools and channels, 1 to 15 m (estimate).
accessories
When bottom fishing with natural bait in the upper Uruguay or upper Paraná, it may bite. Keep the fish in the water, cut the line close to the hook if it has swallowed it deep, and let it go.
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 VU (Portaria GM/MMA nº 1.667/2026). IUCN global assessment: EN (B2ab(iii,v), June 5, 2023). In 2014, ICMBio had already classed it as Endangered.
The national list (Portaria GM/MMA nº 1.667/2026) classifies the species as VU. Under Portaria GM/MMA nº 1.666/2026 (art. 3º), VU, EN and CR species have full protection: catch, transport, storage, processing and sale are banned. If you hook one by accident, release it at once, handling it as little as possible.
Source: Portaria GM/MMA nº 1.666/2026, art. 3º, and Portaria GM/MMA nº 1.667/2026
Possession, killing and transport of these species are prohibited in Paraná's inland waters (Paraná and Atlantic Southeast basins, except the Iguaçu River and the coast). Catch and release only, with immediate release at the same spot.
Allowed: Recreational fishing only for non-native species and hybrids (peacock bass, tilapia, black bass, carp, croaker, etc.; piauçu remains prohibited), with handline, simple pole, or rod with spinning or baitcasting reel, up to 10 kg + 1 fish. In rivers, from shore only; in reservoirs, from a boat or from shore. Prohibited: floodplain lakes, aquatic-animal bait, within 1,500 m of dams and waterfalls, and within 500 m of confluences. Tournaments only in reservoirs and only with non-native species.
Source: IN IBAMA nº 25/2009
Allowed: Only exotic or hybrid species, 3 kg + 1 fish per day, with handline, rod, simple pole, or spinning or baitcasting reel. Nets prohibited. Keep the minimum distances from dams and reservoirs.
Source: Portarias IEF nº 154/2011 (São Francisco), 155/2011 (East) and 156/2011 (Grande/Paranaíba)
Allowed: Sport and guided fishing only in reservoirs, catch and release with barbless hooks (no keeping, transporting or eating). Subsistence: up to 5 kg per day, for household consumption only.
Allowed: Recreational fishing from shore, or from a boat without motor. Only handline or rod, line and hook, one gear per angler, up to 5 kg. Prohibited in floodplain lakes, within 1,500 m of dams, within 500 m of confluences, and in stretches listed in the rule (e.g., Turvo River).
Source: IN IBAMA nº 193/2008
Mandatory. Do not take the fish out of the water or lift it by the head: cut the line close to the hook or use long-nose pliers, and return it to the current, facing the flow, until it regains its strength.
Does not apply: catch in the wild is banned. FishBase records use of the species in aquaculture, and licensed farmed fish are not covered by the ban.
Length-weight relationship W = a·Lb (a = 0.00589, b = 3.1; FishBase (relação peso-comprimento bayesiana, estimativa)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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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.
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