Inside The Mysterious World Of Whale Sharks
Whale sharks – animals so big they require two names. They’re the largest fish in the world, and also one of the most rare to swim with. Only one in three million people will ever do so. Despite being discovered in 1828 off the South African coast, there are still many misconceptions about whale sharks.
“Many people think that they’re whales,” says a spokesperson for Department of Biodiversity, Conservation and Attractions in Australia. “They are a true shark though, and not related to whales at all.”
In fact, the word was only added to their name because of their size – much like how tiger sharks were named because of their stripes.
Whale sharks congregate regularly in only 20-or-so places around the world. Specks in the vast sea, the hotspots include Mexico, Philippines, Maldives, Galapagos Islands and in our country’s very own Ningaloo Reef in Western Australia. Tours to swim with them leave from Exmouth and Coral Bay and run only between mid-March and mid-July. As you’d imagine, the experience is once-in-a-lifetime.
“Being in the water with such a large, slow-moving, majestic animal is a humbling experience,” says the DBCA spokesperson. “Sometimes they’re inquisitive and will be curious towards swimmers, which is magical.”
The gentle giants are often referred to as aquatic dinosaurs, and rightly so. They can grow up to 18m in length, weigh up to 11 tonnes and have mouths that can open to more than a metre wide. Suffice to say, swimming alongside them can be daunting. But there’s little reason to fear them. Whale sharks feed on plankton and are completely harmless.
Up until recently, why they assembled where they do was still a mystery – particularly baffling as, when swimming alone, they can travel all over the world. One whale shark was tracked making his way from Panama all the way to the Philippines.
This month however, research findings behind why their social spots – shallow areas next to steep slopes that quickly gave way to deeper water – are where they are were released.
Scientists discovered the deep water to be used for feeding and the steep slopes to help in bringing nutrients up to the surface. The shallow water also helps them to thermoregulate, warming themselves up again after deep dives. Their lifespan – up to 130 years – was also discovered.
Though they are continuously studied by scientists, there’s still plenty else to learn about them. “We don’t know where they breed or where they give birth, as nobody has seen this occur,” says the DBCA spokesperson.
“We also have limited understanding of their growth rates and how long they live. The juveniles aggregate in coastal waters so it is difficult to estimate the population size.”
Last year, a BBC film crew attempted to follow a pregnant female to watch where she gave birth, but had no luck. The secret is yet to be solved.
Published 26 July, 2018