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.
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hour by hour
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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 nassau grouper
how to recognize it
Background color beige to gray, with five dark vertical bars; the third and fourth branch and form a W on the flank. A large black saddle mark at the top of the tail peduncle, black spots below and behind the eye, and a dark tuning-fork-shaped band on top of the head. It changes color within minutes. The rock hind (garoupa-gato) has red spots; the red grouper (garoupa-são-tomé) is reddish and lacks the saddle on the peduncle.
Also called: garoupa-de-nassau, garoupa-de-trindade, Nassau grouper
don't confuse with:
where found
open on the large mapWhere to look: Coral and rock reefs with hiding places, from the shore to about 90 m; juveniles in seagrass beds.
Bermuda, Florida, the Bahamas, the Yucatán Peninsula and the whole Caribbean; in the Gulf of Mexico, only on the Campeche Bank, the Dry Tortugas and Key West. FishBase lists Brazil based on the FAO catalog, but we found no confirmed recent record or national ICMBio assessment: treat the species as absent or extremely rare on the Brazilian coast.
when to fish
best season
Not a fish to target. Caribbean closed seasons cover the spawning period, from December to March depending on the country.
best time of day
Daytime. Mainly active by day, near its hiding places.
what affects the nassau grouper
cold and cold fronts
A tropical reef fish; cold water reduces its activity.
atmospheric pressure
Little direct effect.
moon
Spawning aggregations occur on moon-linked nights in the Northern Hemisphere winter; this is the most protected period.
rain
Little effect.
water level
Not applicable at sea.
noise
It is the least wary of the groupers, which left it exposed to fishing.
wind
No significant effect on release.
tide
Little studied.
depth
From the shore to about 90 m.
how to fish
tip from an angler
Fishing on a Caribbean reef: if you hook a Nassau grouper, don't keep it on board. Remove the hook with the fish in the water, or release it with a descender.
- rod
- the bottom-fishing rod you are using; it is not a target species
- spinning / baitcasting reel
- any reel, with a drag that lets you bring the fish up quickly
- line
- braided line 40 to 65 lb (a short fight helps release)
- leader
- fluorocarbon 60 to 80 lb
- hook
- barbless circle hook, which catches at the corner of the mouth
accessories
- descender (fish descender)
- long-nose pliers
- wet towel
catch and release
If you hook one, keep the fish in the water, remove the hook with pliers and release it. If it came up from depth with barotrauma, use a descender. No long photos out of the water.
rules for the nassau grouper
Rules change; before keeping or transporting fish, check with the state environmental agency.
Puerto Rico: fishing prohibited
fishing, possession and sale prohibited details
In Puerto Rico it is prohibited to fish for, possess, sell or offer for sale the Nassau grouper (cherna criolla), which must go back to the sea, alive or dead. In federal waters around the island, beyond 9 miles, fishing and possession are also prohibited, and a hooked fish must be released immediately with minimal harm.
Belize: closed season Dec 1 to Mar 31
catch prohibited Dec 1 to Mar 3101/12 to 31/03 details
In Belize, Nassau grouper may not be fished from December 1 to March 31.
Source: Belize Fisheries Department — fishing regulations (Nassau grouper)
Belize: only between 20 and 30 inches
50.8 cm (20 inches, TL) details
Outside the closed season, no one may catch, buy, sell or possess Nassau grouper under 20 inches (50.8 cm) total length.
Source: Belize Fisheries Department — fishing regulations (Nassau grouper)
Belize: maximum of 30 inches
76.2 cm (30 inches, TL) details
Nassau grouper over 30 inches (76.2 cm) total length may not be kept either: these are the large breeders.
Source: Belize Fisheries Department — fishing regulations (Nassau grouper)
Bahamas: closed season Dec 1 to Feb 28
catch and sale prohibited Dec 1 to Feb 2801/12 to 28/02confirm with the agency details
In the Bahamas, from December 1 to February 28, no one may catch, land, process, sell or offer for sale Nassau grouper, except with written authorization for research. Groupers landed during the period must have their head, tail and skin intact. The closed season was set in law in 2015. The text of the regulation was not checked: the rules come from official notices and news reports. Confirm with the Department of Marine Resources.
Mexico: grouper closed season from Feb 1 to Mar 31
catch prohibited from Feb 1 to Mar 3101/02 to 31/03 details
In Mexico, catching all grouper species, a group in which the official standard includes the Nassau grouper (cherna criolla), is prohibited from February 1 to March 31 in federal waters of the Gulf of Mexico and the Caribbean off Tabasco, Campeche, Yucatán and Quintana Roo, up to the Belize border. Bottom longlines are also prohibited during the period.
Conservation: Critically Endangered (CR) in the global assessment. In the US, including Puerto Rico, it is listed as threatened under the Endangered Species Act, and all catch is prohibited. We found no confirmed record or national assessment in Brazil. IUCN global: CR · critically endangered.
how much it weighs without taking it out of the water
estimated weight
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how we calculate
Length-weight relationship W = a·Lb (a = 0.01148, b = 3.05; FishBase (estimativa bayesiana, comprimento total)). It's an average: a fat or lean fish can vary by 10% to 20%.
more about the nassau grouper
The Nassau grouper is the best-known grouper in the Caribbean and was once the most important species in the commercial fishery of the Antilles. It lives on coral and rock reefs, from the shoreline to about 90 m, almost always near hiding places; juveniles stay in seagrass beds. It eats fish and crabs. On a few winter nights of the Northern Hemisphere, tied to the moon, it travels to fixed spawning sites, where up to 30,000 fish have gathered. Fishing on these aggregations collapsed populations, and many disappeared. The IUCN rates it Critically Endangered, the US prohibits all catch, including in Puerto Rico, and several Caribbean countries close fishing during spawning. In Brazil its presence is not confirmed. If you hook one, release it quickly and carefully.
Family: Epinephelidae · predator
fun facts
- It is considered the tamest and most curious of the groupers, which left it exposed to fishing.
- Up to 30,000 fish have gathered at a single spot in spawning aggregations.
in the kitchen
It should not be eaten: catch is prohibited or limited over much of its range.
similar species
sources and references (11)
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 the field experience of anglers and guides. They are not official data nor a measurement made for this species, and they may vary by region and year. Closed seasons and legal rules appear in the rules section, with the norm and a link.
- scientific FishBase — Epinephelus striatus (ficha da espécie)Names, distribution, biology, length-weight relationship, country list and references. Page checked October 13, 2026. The country list includes Brazil based on Heemstra and Randall (1993); since we found no recent Brazilian record, the profile does not mark Brazil.
- scientific IUCN Red List — Epinephelus striatus (avaliação global: Criticamente em Perigo, CR, 18/11/2016)Global assessment. Link given on the FishBase entry (Red List, version 2025-2).
- official NOAA Fisheries — Nassau grouper (ficha da espécie)Listed as threatened under the US Endangered Species Act; all catch is prohibited in the country. Checked October 13, 2026.
- official Reglamento de Pesca de Puerto Rico, nº 7949 (Departamento de Recursos Naturales y Ambientales, 2010)Copy of the regulation published by the Caribbean Fishery Management Council; it applies in Puerto Rico waters up to 9 miles. Art. 8 (general limitations) checked October 13, 2026.
- official Code of Federal Regulations, 50 CFR Part 622, Subpart S — Regulations specific to the Puerto Rico Management Area (NOAA Fisheries, EUA)Consolidated text in the eCFR, checked October 13, 2026: §622.438 (prohibited species), §622.439 (area and time closures) and §622.444 (quotas). It applies in federal waters, beyond 9 miles from the coast.
- official Belize Fisheries Department — Fisheries RegulationsNassau grouper: prohibited to catch, buy, sell or possess fish under 20 inches or over 30 inches; closed season Dec 1 to Mar 31. Checked October 13, 2026.
- official Bahamas — Department of Marine Resources: aviso de fechamento da temporada da garoupa-de-nassau (1º/12/2021 a 28/02/2022)Official notice from the Bahamas government for the 2021-2022 season. Dates and prohibitions also confirmed in local news reports.
- press The Tribune (Nassau) — Grouper season has now closed (01/12/2017)December to February closed season in the Bahamas, and BREEF's call to respect it.
- official México — NOM-065-SAG/PESC-2014, para regular o aproveitamento das espécies de mero e espécies associadas no Golfo do México e no Mar do Caribe (DOF de 03/07/2015)Text published in the Official Journal of the Federation, in a copy from the Secretaría de Economía. Item 4.1 (list of grouper species), 4.8 (minimum size of red grouper) and 4.13 (fishing for domestic consumption).
- official México — Acordo que modifica a veda de todas as espécies de mero no Golfo do México e no Caribe (DOF de 03/03/2017; acordo original de 14/02/2007)Sets the closed season from February 1 to March 31, since 2018, in federal waters off Tabasco, Campeche, Yucatán and Quintana Roo. We found no later amendment; confirm each season with Conapesca.
- 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.
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: