Bathytoshia centroura · Dasyatidae · predator
Large whiptail stingray of the western Atlantic, with a spiny tail. Critically Endangered in Brazil, with catch banned: if you hook one, release it carefully and away from the stinger.
Also called: raia-prego (nome usado na lista oficial divulgada pela Fiperj), raia-de-cauda-áspera, raia-chicote
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 roughtail stingray is one of the largest whiptail rays (family Dasyatidae) in the western Atlantic. It lives on sand and mud bottoms of the shelf, usually between 15 and 50 m, but has been recorded from 3 to 270 m, and visits the coast in the warm season, according to FishBase. It eats bottom invertebrates and fish. It is ovoviviparous: gestation lasts about 4 months and 2 to 4 pups are born. In the southwestern Atlantic it occurs from Brazil to Argentina; the eastern Atlantic populations, formerly treated as the same species, are now Bathytoshia lata. The national list (Portaria GM/MMA 1.667/2026) classifies it as Critically Endangered, a more serious category than the IUCN global assessment (Vulnerable): catch, transport and sale are banned. It turns up by chance in bottom and beach fishing, and its stinger is venomous.
Rhombus-shaped disc, wide, with a short snout, and a long whip-like tail with a stinger. Large adults have "spiny" tails and backs: large, well-spaced tubercles and plates along the middle of the back and at the disc edges; in juveniles these tubercles have not yet formed. According to FishBase, the tail has no skin fold on top (Hypanus say does) and the fold below is much narrower than that of the Caribbean stingray. FishBase gives 300 cm total length as the maximum and 125 cm disc width as the common size: these are different measures, so don't compare them directly.
In the southwestern Atlantic it ranges from Brazil to Argentina, passing through Uruguay; in Brazil, the most cited records are from the South and Southeast, and distribution along the Brazilian coast is poorly documented in the sources checked. In the northwestern Atlantic it occurs from the northeastern United States to the Gulf of Mexico. The eastern Atlantic populations are Bathytoshia lata.
Habitat: Sand and mud bottoms of the shelf, 3 to 270 m and usually between 15 and 50 m; enters brackish water and comes close to shore in the warm season.
coast
Estimate: FishBase describes it as a visitor to the coast in the warm season, so in the South and Southeast the chance of finding it near shore is higher from November to March. Catch is banned at any time; this information is for knowing when it may turn up by chance.
Any time. There is no time-of-day study for this species in the sources checked. Like other whiptail rays, it spends part of its time buried in sand (estimate).
Warm-season visitor: it moves away from the coast when the water is cold.
Little known effect.
Little known effect.
Little known effect.
Not applicable at sea.
Not very sensitive; it tends to stay buried or still on the bottom.
Little direct effect; rough seas make it hard to see the ray in shallow areas.
Enters shallow areas on the rising tide to look for food (estimate).
In most records, 15 to 50 m.
accessories
If a large ray hooks up while bottom or beach fishing, don't pull it onto dry sand or into the boat. Keep it in the water, away from the stinger, and cut the line close to the mouth if the hook won't come out easily.
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 banned throughout Brazil. Already on the previous list (Portaria MMA 148/2022) as CR. Global assessment: Vulnerable (IUCN, Jun 21, 2019). According to FishBase, the eastern Atlantic populations belong to Bathytoshia lata.
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 recreational sea fishing on the Buenos Aires province coast, chuchos (Myliobatis), "rayas en general", pez ángel, pez elefante and corvina negra form the "Mixed Fishing With Reserve" subcategory: up to two specimens per angler per day may be killed, counted within the 40-piece limit of mixed fishing, and all surplus must be released right away. The text says "rayas en general" and does not list species. We did not check whether a more recent provision replaces it; confirm with the province's Ministry of Agrarian Development.
This is not catch and release: it is release of an accidental catch. The tail stinger is serrated and venomous; a sting causes intense pain and a deep cut. Don't step on the ray or hold it by the tail. Keep it in the water, out of reach of the tail, remove the hook with long pliers or cut the line close to the mouth. If you are stung: wash the area, immerse it in very hot water (not so hot that it burns) and seek medical care.
Catch and trade banned in Brazil. FishBase records wings sold fresh, smoked or salted and dried. Don't buy it.
Length-weight relationship W = a·Lb (a = 0.00447, b = 3.12; 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 factors (months), the time of day, and the sensitivities (cold, pressure, moon, wind, rain, tide, strong light, murky water, and noise) are editorial estimates by the app, based on the literature cited below and on field experience of anglers and guides. They are not official data or measurements made for this species and may vary by region and year. Closed seasons and legal rules appear in the rules section, with the standard and link. The months indicate when the species is usually found near the coast or at the fishing spot, not a catch season. The water temperature range is also an editorial estimate, supported by FishBase values where they exist.
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.
