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 marbled grouper
how to recognize it
Tall, strongly compressed body, black with many large white spots; the fins are also black and spotted, and the pectoral fin is large. The scales are smooth. Body depth fits 2.2 to 2.5 times into standard length. The preopercle is rounded and finely serrated. No other Atlantic grouper has this pattern of black with large white spots. Cabrillas (Mycteroperca) are much more elongated.
Also called: garoupa-gostosa, marbled grouper, mutton hamlet
don't confuse with:
where found
open on the large mapWhere to look: Deep reef ledges and edges, in caves and crevices, usually from 3 to 35 m (down to 213 m).
In Brazil, FishBase gives the species down to Rio de Janeiro, on reefs and deep edges; we found no survey that says where it is most common. Outside Brazil, it ranges from North Carolina to the Gulf of Mexico and the Caribbean, and to the Guianas and Venezuela.
coast
when to fish
best season
No set season, as it is a little-known tropical reef fish. There is no specific closed season in Brazil.
best time of day
Any time. Lives hidden in crevices and caves; we found no data on the best time of day. When in doubt, fish at light transitions.
what affects the marbled grouper
cold and cold fronts
A tropical reef fish; cold fronts reduce its activity.
atmospheric pressure
A churned sea after a cold front shuts down bottom fishing.
moon
Effect poorly known; spring tides move more bait on the reef.
rain
Little effect at depth.
water level
Not applicable at sea.
noise
Anchor and hull knocking on the reef scare fish.
wind
Strong wind makes it hard to hold position over the spot.
tide
Moderate current activates feeding at the reef edge.
depth
Usually 3 to 35 m.
how to fish
lures
- jig 80 to 200 g
natural baits
- small live fish
- lula
tip from an angler
Hole fish: when you feel the bite next to the rock, lift quickly, or it dives into the crevice and cuts the line.
- rod
- 6' to 7', 30 to 60 lb
- spinning / baitcasting reel
- baitcasting reel 300 to 400 or spinning reel 6000 to 8000, with strong drag
- line
- braided line 50 to 65 lb
- leader
- fluorocarbon 60 to 100 lb, 1.5 m
- hook
- circle 5/0 to 8/0
accessories
- descender (fish descender)
- long-nose pliers
- luvas
catch and release
Coming from more than 15 to 20 m, use a descender. Support the belly, wet your hands and release quickly. Because it is little known and rare, it is worth releasing the big ones.
rules for the marbled grouper
Rules change; before keeping or transporting fish, check with the state environmental agency.
Puerto Rico (federal waters): up to 5 per person per day
5 per person per day; 15 per boat with 3 or more people details
In federal waters around Puerto Rico, beyond 9 miles from the coast, the recreational angler may keep a maximum of 5 fish per day from groupers, snappers and parrotfish combined (up to 15 per boat when there are 3 or more people aboard). The limit does not apply to anyone with a commercial license from Puerto Rico or the U.S. Virgin Islands.
Conservation: Not on the Brazilian national list (Ministerial Ordinance GM/MMA No. 1.667/2026).
how much it weighs without taking it out of the water
estimated weight
—
how we calculate
Length-weight relationship W = a·Lb (a = 0.00955, b = 3.11; 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 marbled grouper
The marbled grouper (garoupa-gostosa) lives in the western Atlantic, from North Carolina to Rio de Janeiro, including the Gulf of Mexico and the Caribbean. It is a reef fish that stays on ledges and deep edges, usually in caves or crevices, from 3 to 35 m, but reaches 213 m. It is solitary and shy, and darts away when startled. It reaches 91 cm and 10 kg, and FishBase gives 50 cm as the common length. It is rarely seen in markets, and FishBase points to fishing pressure as the main threat. The IUCN classifies it as Data Deficient (2018); it is not on the Brazilian national list and not on the NOM-065 grouper list in Mexico. FishBase considers it a gamefish.
Family: Epinephelidae · predator
fun facts
- Darts away when startled and hides in crevices.
- FishBase points to fishing pressure as the main threat, despite being rare in markets.
- The Spanish name used in Puerto Rico is boricua.
in the kitchen
Rarely seen in markets, according to FishBase. No reliable data on flavor or ciguatera risk; follow local health guidance.
similar species
sources and references (5)
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 field experience from 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 rule and link. The common size and weight ranges, water temperature and typical depth are also editorial estimates, anchored in FishBase data.
- scientific FishBase: Dermatolepis inermis (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology and IUCN status. Page checked on 13/10/2026. Common size and weight ranges, water temperatures and typical depths are editorial estimates anchored in FishBase data. Entry name: 'garoupa-gostosa' is the Brazilian Portuguese name listed by FishBase; we did not find it in any other source, so please confirm local usage.
- scientific FishBase: nomes populares de Dermatolepis inermisNames by country and language.
- official Portaria GM/MMA nº 1.667, de 27 de abril de 2026: Lista Nacional Oficial de Espécies da Fauna Ameaçadas de Extinção (peixes e invertebrados aquáticos)The species is not on the list. Checked in the DOU of April 28, 2026.
- official 50 CFR § 622.444: cotas de pesca recreativa nas águas federais de Porto Rico (NOAA Fisheries, EUA)Consolidated text of the Code of Federal Regulations, checked Oct 13, 2026: paragraph (a)(1), combined quota for groupers, snappers and wrasses.
- scientific Heemstra, P. C.; Randall, J. E. (1993). FAO species catalogue. Vol. 16. Groupers of the world (family Serranidae, subfamily Epinephelinae). FAO Fisheries Synopsis 125(16). Roma: FAO.General reference for identifying groupers worldwide.
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: