american shad
Alosa sapidissima · Alosidae · forage fish
Shad that run up rivers to spawn and have highly prized roe. In Mexico it is an exotic species, introduced on the Pacific coast.
Also called: sável-americano, sábalo americano, american shad
- maximum
- 76 cm
- record/max.
- 5.5 kg
- depth
- 0–250 m
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.
Reading the weather across 3 global models and 31 simulations…
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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
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.
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 american shad
who is the american shad
Fish of the family Alosidae, up to 76 cm and 5.5 kg. It spends most of its life at sea, in schools near the surface over the continental shelf, and returns to freshwater rivers to spawn, sometimes running up to 630 km. Adults eat plankton, such as copepods and mysids, and occasionally small fish. It is a sport fish in angling, and has a commercial fishery in rivers and estuaries. Its roe is highly prized.
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 american shad.
fun facts
- Adults spend almost their whole lives at sea and return to freshwater rivers to spawn.
identification
Silvery body, laterally compressed, with a well-marked belly keel and blue or metallic green back. It has a dark spot on the shoulder, sometimes followed by others, or even by a second row. The lower jaw does not rise far inside the mouth, which separates it from other similar shads on the US east coast. It has no spines in the dorsal and anal fins.
where found
Native to the Atlantic coast of North America, from Labrador in Canada to Florida. In Mexico it is exotic: it was introduced to the Pacific and reached Todos Santos Bay.
Habitat: Coastal and continental-shelf waters, down to 250 m, and rivers and estuaries where it runs to spawn.
rules for the american shad
Summary of the regulations we found, with the source for each. 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.
catch and release
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.
No danger to anglers, as it has no dangerous spines or teeth. Handle with care so as not to injure the fish.
in the kitchen
Eaten fresh, salted or smoked, and the roe is highly prized.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00661, b = 3.08; 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
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sources and references
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: Alosa sapidissima (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Alosa sapidissimaNames by country and language.
where 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: