A slim, small-headed shark of 1.6 m (5 ft) with white tips on the first dorsal and upper tail fins, tube-shaped flaps beside the nostrils, and oval eyes with vertical pupils. By day it lies still under a ledge or inside a cave, often several animals stacked together, which is where nearly every diver here has seen one.
Lying still is the trick. Most requiem sharks have to swim to breathe, forcing water over the gills by moving; this one can pump water through its mouth while stationary, so it can spend the entire day motionless on the bottom without suffocating. That single physiological difference is what makes it the shark you can watch at rest rather than in passing.
At night the same reef becomes a coordinated hunt. Whitetips work a coral head as a group, pushing thin bodies into holes and flushing sleeping fish toward the others - not cooperation with shared spoils, but a crowd whose combined pressure leaves the prey nowhere to go. A hunting group can dismantle a bommie over an hour, and the noise is audible from a distance.
They are strongly site-faithful, returning to the same cave for years, and they are unbothered by divers who leave them alone. Bites are rare and follow speared fish. The species is Vulnerable.
Habitat shifting & alteration · Temperature extremes
The Whitetip Reef Shark is caught throughout its range in industrial and small-scale longline, gillnet, trawl and handline fisheries that occur in the waters around coral reefs. Most is taken as incidental catch in general reef fisheries targeting teleost fishes. The species is often retained for its meat, fins, and liver. The species is also taken in small amounts by recreational fishers in some countries. In many parts of east Africa, and south and east Asian, there are large amounts of fishing effort targeted at carcharhinid sharks in continental shelf waters, and it continues to increase. For example, in the waters of Indonesia effort by small-scale fisheries has tripled when taking population into account (Ramenzoni 2017); and in Myanmar the International Labour Organisation (2015) estimated the number of vessels participating in the small scale inshore fishery to be about 26,000 in 2013, and the number of locally operated larger offshore vessels numbered 2,846 in 2013, having increased nearly 30% since 2009. Only in locations where fisheries are strictly regulated (e.g. Australia) (Espinoza et al. 2014), where human population densities are low (Nadon et al. 2009), or where dive-based tourism supports protection (Sutcliffe and Barnes 2018) are there low levels of threat that enable this species to remain common.
The reliance of this species on coral reefs makes it susceptible to declines in habitat quality. Global climate change has already resulted in large-scale coral bleaching events with increasing frequency causing worldwide reef degradation since 1997. Almost all warm-water coral reefs are projected to suffer significant losses of area and local extinctions, even if global warming is limited to 1.5ºC (IPCC Report, 2019). Destructive fishing practices in some nations (e.g. dynamite fishing) (McManus 1997) and declining water quality (MacNeil et al. 2019) have also led to the decline in coral reef habitat.
Threat classification from the IUCN Red List.
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