Triaenodon obesus · Carcharhinidae · predator
Small, slender reef shark that spends the day resting in caves and hunts at night. Vulnerable worldwide and seen more by divers than by anglers.
Also called: tubarão-ponta-branca-de-recife, whitetip reef shark, tiburón punta blanca de arrecife, cazón coralero trompacorta, tiburón aliblanco
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 whitetip reef shark is a small, slender shark of up to 2.1 m and about 18 kg. It lives in lagoons and on reefs exposed to the sea, usually at 8 to 40 m. It spends the day resting in caves, under coral ledges, on a sandbank or in a channel, and is more active at night or at slack tide, in places with strong current. It eats bottom fish, octopus, lobsters and crabs. Each female has 1 to 5 pups, usually 2 or 3. It travels short distances, 0.3 to 3 km over up to a year, and tends to stay in the same stretch of reef. Attacks on people are rarely reported, but FishBase considers it potentially dangerous, especially near speared fish. It is Vulnerable according to the IUCN.
Grey on the back, paler below and sometimes with dark spots on the flanks. Extremely short, broad snout, oval eyes and spiracles in most individuals. The first dorsal fin and the upper tail lobe have a well-marked white tip, sometimes the second dorsal and the lower tail lobe as well. The second dorsal is almost as large as the first, and there is no ridge between the dorsal fins. It differs from the silvertip shark by its smaller size, lack of a ridge and very short snout.
Indo-Pacific, from the Red Sea and the eastern coast of Africa to Indonesia and the Arafura Sea, north to the Ryukyu and Ogasawara islands and south to New South Wales (Australia), New Caledonia and the Austral and Pitcairn islands, with all of Micronesia. In the eastern Pacific: Cocos and Galapagos, from Panama to Costa Rica. Does not occur in Brazil.
Habitat: Lagoons and reefs exposed to the sea; by day in caves and under coral ledges or on a sandbank, and at night hunting.
Estimate: present year-round on reefs; no known fishing season.
Nighttime. Spends the day resting in holes and under coral ledges. It is more active at night or at slack tide, in places with strong current.
Not very sensitive on the tropical reefs where it lives; water below about 22 °C keeps it away.
Little known direct effect.
Little known effect.
Little effect on the reef.
Not applicable at sea.
Not very sensitive to noise, but it sleeps in caves and does not like being disturbed.
Little effect on the reef.
It is more active at slack tide and in the strong currents of channels.
Usually 8 to 40 m; recorded down to 330 m.
natural baits
accessories
Fish at night or at slack tide, near channels and reef edges. Do not disturb holes and caves by day: it shelters there. Release it in the water, without handling speared fish near it.
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: IUCN global assessment: VU (A2bcd, 16/07/2020). Does not occur in Brazil according to the FishBase country list; Brazilian rules apply if it is hooked in Brazilian waters.
In Brazil, finning is banned: catching sharks and rays and keeping only the fins, discarding the body (art. 3). Sharks and rays landed must arrive with all fins naturally attached to the body; carrying an animal aboard without fins or with loose fins, and transferring sharks and rays between fishing vessels, is prohibited. This applies to any species that may be retained.
In recreational sport fishing in Mexican marine waters, the limit for sharks is one fish per angler per day, which counts as five toward the total limit of ten fish (item 4.9.1 b). Fish over the limit must be returned alive to the water (item 4.9.5), and recreational catch may not be sold (item 4.11). Fish that are released do not count toward the limit: prefer to release it.
In 2021 Colombia stopped treating marine sharks and rays as fishery resources and began treating them as hydrobiological resources. The recitals of Decree 281/2021 state that they may not be extracted for commercial or sport purposes, and the decree created an environmental protection plan. Later AUNAP rules addressed incidental catch in artisanal fishing; we did not check the consolidated text. When in doubt, release them into the water.
Executive Decree 9/2026 (art. 19) bans, throughout the national territory and in sport, recreational, or tourism fishing, the catch, retention, handling for recreational purposes, use, and landing of sharks and rays (subclass Elasmobranchii). If one is hooked by accident, it must be released immediately, without taking it fully out of the water and without unnecessary handling. It is also prohibited to promote them as targets in tournaments (art. 19) and to sell the catch (art. 20). The decree takes effect six months after its promulgation on June 10, 2026 (art. 40), around Dec 10, 2026, and repeals Resuelto ADM/ARAP 002/2012 (art. 39). Confirm the date with ARAP.
Executive Decree 43477-MINAE (20/04/2022) designated the marine protected area of Isla del Coco National Park as a Shark Natural Sanctuary. The considerations recall that fishing is already banned in the park (National Parks Service Law 6084 and Decree 37023-MINAE) and list the whitetip reef shark, the silky shark and the silvertip shark among the park's 15 sharks. Outside the park, check the INCOPESCA rules.
Keep the fight short and release with the shark in the water. Cut the line flush with the mouth if the hook is deep, and revive it facing into the current. Do not hold it by the tail or gills; the liver of this species has been reported as toxic, one more reason not to keep it.
The meat and liver are used fresh where it is caught, but the liver has been reported as toxic (FishBase). Vulnerable worldwide: prefer to release it.
Length-weight relationship W = a·Lb (a = 0.00355, b = 3.12; 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
—
The season factors (months), the time of day, and the sensitivities (cold, pressure, moon, wind, rain, tide, strong light, murky water, and noise) are editorial estimates by the app, based on the literature cited below and on field experience of 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 standard and link. The months indicate when anglers usually find the species near the coast, not a catch season.
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.
