In June of 2016, I got the chance to swim with the whale sharks in Coral Bay, Western Australia. Coral Bay is the definition of a small town; it’s literally only one road, on the edge of the Outback. To get there, you have to take a small plane from Perth to Exmouth, then it’s about a 3 hour drive down to Coral Bay, but it’s worth it. Coral Bay sits on the Ningaloo Reef, where whale sharks play during the winter months. Until my Tahiti trip in 2019, this was my most magical underwater moment.
Whale sharks were first discovered in South Africa in 1828 by Andrew Smith. They can grow up to 20 meters long and live to be 100 years old; they’re the largest fish in the sea and the largest shark in existence. Yes, whale sharks are sharks, not whales. Their scientific name is rhincodon typus and they’re part of the carpet shark order.
Whale sharks inhabit warm waters and are found all over the world in tropical and subtropical waters, so about 20-30 degrees Celsius, roughly 68-90 degrees Fahrenheit. The one place they’re not found? The Meditteranean Sea. Whale sharks are a highly migratory species, being driven by food and plankton blooms and fish spawning events. The longest recorded journey took over 3 years and spanned over 13,000 kilometers or over 8,000 miles, from California to Tonga! In terms of depth, they can be found anywhere from the surface, all the way to 1000 meters deep, making them a pelagic species. Their pups are normally dropped in waters surrounding Taiwan, the Philippines, and India.
Whale sharks tend to stay pretty segregated, and males and females only really mix when mating. Speaking of mating, whale sharks have 300 rows of teeth in each jaw, but they don’t use them for feeding! They do assist in the mating process. Males mature at about 17 years old or 9 meters long, and females mature at 20 years old or 10 meters long. They have the largest litter size of all sharks. One pregnant female was recorded with 300 pups! They’re born around 40-90 centimeters long, about 15 to 35 inches. They’ll then grow at a rate of .5 centimeters per day until they reach maturity!
So, if they don’t use their teeth for eating, how do they eat? They’re filter feeders! They feed on zooplankton, phytoplankton, and small, free swimming prey, such as bait balls. They can feed in a vertical position or by using suction filter-feeding, which enables them to draw in water at higher velocities than other filter feeders. Their dense gill rakers then retain all organisms above 2-3 millimeters in diameter and push the rest of the water out.
Orcas and other large sharks, such as tiger sharks and great white sharks, will sometimes attack the whale shark! Normally this happens with sick and injured individuals or at night, when the whale shark is ambushed. Humans are also a major predator for whale sharks, and an unknown number are killed each year, mostly in poor, seaside communities, for their meat, fins, and liver oil. Whale shark fins are regarded as trophy fins and can bring in thousands of dollars each. They’re currently listed as endangered, meaning they're at high risk of extinction, on the International Union for Conservation of Nature Red List.
If you come into contact with a whale shark, just relax! They tend to swim slowly near the surface and filter feed with their mouth open. Swim in a controlled, slow manner. Be sure to give the shark plenty of room to turn; don’t swim in front of the shark, behind the shark, or above the shark. Stay at least 3 meters to the side of the shark, and don’t chase it if it swims away. Keep your fins underwater so you minimize splashes that could scare the shark, and don’t over crowd the shark - there should only be a maximum of 4 divers around the shark at once. Keep that 3 meter buffer zone at all times, and don’t touch the shark! Report any sightings at whaleshark.org when you get back on land, and enjoy the magical experience of swimming with such a gentle giant!