the right time
to be on the water
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.
Loading the forecast…
—
hour by hour
slide your finger or mouse over the chart to see each hoursee hour-by-hour table
why this index at —?
choose the day
the fishing month at a glance
what's the best window for the crew?
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.
trend for the coming weeks
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.
everything about the freshwater drum
how to recognize it
Large, fusiform fish that lives on the bottom of rivers and lakes. It produces sounds, which helps identify the group. To tell it apart from other sciaenids, look at the habitat: this species is freshwater and occurs in North America, Mexico and Guatemala, while most relatives in the family are marine.
Also called: roncador-de-água-doce, roncador de agua dulce, freshwater drum
We don't have tips on season, bait or technique for this species yet.
where found
open on the large mapWhere to look: Bottom of medium and large rivers and of lakes.
Native to North America, from Canada to the Gulf, and to Central America, in Mexico and Guatemala. Not recorded in Brazil.
rules for the freshwater drum
Rules change; before keeping or transporting fish, check with the state environmental agency.
We found no species-specific rule beyond the region's general rules.
how much it weighs without taking it out of the water
estimated weight
—
how we calculate
Length-weight relationship W = a·Lb (a = 0.00933, b = 3.18; FishBase (relação peso-comprimento bayesiana, estimativa da própria espécie)). It's an average: a fat or lean fish can vary by 10% to 20%.
more about the freshwater drum
The freshwater drum is a fish of the family Sciaenidae, freshwater, reaching 95 cm and weighing up to 24.7 kg. It lives on the bottom of medium and large rivers and in lakes. Adults eat mayfly larvae, amphipods, fish, crayfish and mollusks; young ones eat zooplankton. It produces sounds, which explains the name drum. It has sport value and is caught commercially on a small scale. It occurs from Canada to the Gulf of the United States, and in Mexico and Guatemala.
Family: Sciaenidae · predator
fun facts
- The otoliths (ear stones) are L-shaped and are collected as lucky stones.
in the kitchen
It can be eaten fresh, fried or grilled.
sources and references (2)
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.
- scientific FishBase: Aplodinotus grunniens (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Aplodinotus grunniensNames by country and language.
how we calculatewhere each number comes from
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.
sources for this lookup
how accurate the forecast is
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: