02 January 2009
Gulf of Tadjoura, Djibouti
A large group of whale sharks feeds in the Gulf of Tadjoura, off the coast of the Horn of Africa.
Although whale sharks are normally solitary creatures, large numbers are attracted to the Gulf of Tadjoura between November and February each year, when southwesterly winds churn the ocean. The swirling currents stimulate plankton blooms—rapid explosions of the plankton population, a whale shark’s chief diet.
Whale sharks (Rhincodon typus) are slow-moving, filter-feeding sharks found in tropical and warm oceans, and are the largest non-mammalian vertebrates on the planet. The species originated some 60 million years ago, and individuals normally have a lifespan of around 70 years.
Currently, however, whale sharks are listed as a vulnerable species. They come under particular threat from pollution and strikes by boat propellers, and are also hunted for their fins and flesh.
The sharks feed by drifting with their capacious mouths open, drawing in plankton, fish, and small crustaceans. Foreign objects, such as plastic, can also be drawn into the shark’s digestive system, causing harm.