The Australian coral reef famous for the world’s largest documented whale-shark aggregation is Ningaloo Reef.
Ningaloo Reef lies off Western Australia’s northwest coast and forms part of the Ningaloo Coast World Heritage Area. Each year, whale sharks gather there after the reef’s mass coral spawning, when seasonal nutrient upwelling helps produce abundant plankton and fish eggs. These seasonal food pulses make the reef a predictable feeding ground for the world’s largest fish.
The aggregation commonly includes roughly 300 to 500 whale sharks, although numbers vary from year to year. Whale sharks are filter feeders, not hunting predators: they swim with their huge mouths open, filtering plankton, krill, fish eggs, and small schooling fish from the water. Their gentle behaviour has made Ningaloo a major site for regulated wildlife tourism.
Ningaloo is sometimes confused with the Great Barrier Reef because both are Australian reef systems. The Great Barrier Reef is far larger overall, but Ningaloo is especially renowned for whale sharks. The reef also supports more than 300 coral species, over 700 reef-fish species, and seasonal gatherings of manta rays and humpback whales.