The whale shark, Rhincodon typus, is the largest fish species known, with individuals reaching over 60 feet in length. This filter feeder uses its massive, nearly five-foot-wide mouth to strain plankton, small fish, and fish eggs from the water column. Despite its size, the whale shark is docile and poses no threat to humans. It is one of only three known filter-feeding shark species, relying on the productivity of the open ocean.
Global Range and Preferred Waters
Whale sharks are a migratory, pelagic species inhabiting the open waters of the world’s oceans. Their distribution is cosmopolitan, spanning all tropical and warm temperate seas globally. They are most commonly found between 30° North and 35° South latitude, though individuals are occasionally sighted further poleward.
Their presence is closely linked to specific thermal conditions. Whale sharks are rarely found in surface waters below 21°C, preferring a range between 21°C and 25°C, sometimes tolerating up to 30°C. They inhabit the Atlantic, Pacific, and Indian Oceans. They are notably absent from polar regions and the cooler, enclosed waters of the Mediterranean Sea.
Key Aggregation Hotspots
Whale sharks reliably aggregate seasonally in specific locations, providing predictable feeding opportunities.
Major Aggregation Sites
The Yucatán Peninsula in Mexico, near Isla Holbox and Isla Mujeres, hosts one of the world’s largest gatherings between May and September. Hundreds of sharks congregate here to feed primarily on fish eggs.
Ningaloo Reef in Western Australia is a famous hotspot, where sharks gather annually from March to July, coinciding with the mass coral spawning event.
The Maldives, specifically around South Ari Atoll, is a well-documented site known for the long residency time of individuals.
Gladden Spit in Belize sees predictable seasonal appearances, where the sharks are drawn by the spawning of snappers.
Wreck Bay, along the northern Great Barrier Reef in Australia, shows consistent seasonal gatherings, mainly in late November and December.
Environmental Drivers of Location
The presence of whale sharks in specific locations is driven by the biological and physical conditions supporting their filter-feeding diet. The primary environmental factor is the availability of food, linking their location to dense concentrations of plankton and fish spawn. Oceanic processes, such as upwelling zones, play a substantial role in fueling this food chain.
Upwelling occurs when nutrient-rich, cooler water rises from the deep ocean to the surface, creating high primary productivity. This influx supports massive phytoplankton blooms, which feed the zooplankton and small organisms constituting the whale shark’s diet. Foraging behavior is associated with areas of high chlorophyll concentration, a proxy for phytoplankton abundance. Warm, tropical surface water temperature is also necessary to facilitate these blooms and spawning events.
Seasonal Migration Patterns
Whale sharks undertake movements driven primarily by the search for temporary, rich food sources. Researchers use satellite tags attached to dorsal fins to map these long-distance journeys across ocean basins. Tracking studies show that sharks in the Eastern Pacific can travel thousands of kilometers, with one individual completing a transpacific journey of over 20,000 km.
Migration routes often follow nutrient-rich currents, ranging from local movements along coastlines to vast oceanic routes between aggregation spots. While arrival timing at feeding grounds is predictable, their oceanic travel remains less understood. These movements are also likely influenced by the search for suitable, largely undiscovered breeding and birthing locations.