Rioraja agassizii · Arhynchobatidae · predator
Coastal ray from the coast of Espírito Santo to Argentina, threatened in Brazil. Catching it is prohibited in the country: if you hook one by accident, release it right away.
Also called: raia-santa, emplastro, raya lisa, rio skate
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 santa skate is a skate of the family Arhynchobatidae, with a flattened body and a disc formed by the pectoral fins. It reaches 33 cm in disc width. It is a coastal species, living on sand, mud or gravel bottoms down to 130 m deep, from Espírito Santo to Argentina. It feeds on crustaceans, mollusks and fish. It is oviparous, and the egg cases have horn-like projections. It turns up in commercial fishing and is listed on the national list of threatened species as vulnerable, with catching prohibited in Brazil.
Essential profile. Identification, where it occurs and rules, with data from FishBase and the cited regulations. Season, time of day, technique and bait are added once we have a good source for the rio skate; in the meantime, see the similar species.
Small, flattened skate with a rounded disc, smooth back (raya lisa, in Spanish) and thin tail set apart from the disc. It is much smaller than the circle skate (Atlantoraja cyclophora), which has circles on its back and reaches 78.9 cm. It also shares the southeast and south coast with the emplastro skate (Sympterygia acuta), which has a larger snout.
Southwest Atlantic, from Espírito Santo to Argentina. In Brazil it lives on the southeast and south coast.
Habitat: Sand, mud or gravel bottom of the coast, down to 130 meters deep.
coast
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. IUCN global assessment: VU.
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
Threatened species with capture prohibited in Brazil. If it comes on the line, keep the skate in the water whenever you can, remove the hook with long-nose pliers or cut the line close and release it right away. Avoid lifting it by the tail and watch the spines on the back and tail.
Length-weight relationship W = a·Lb (a = 0.0049, b = 3.02; 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
—
Essential profile: size, length-weight, depth, countries and conservation come from FishBase and the cited regulations, and the texts were written from those sources. Season, time of day, sensitivities, technique and baits and lures are not included yet, because we did not find a good source for this species.
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.
