All About Whale Sharks!
It’s a whale, it’s a shark, well...it’s a whale shark! Yes, whale sharks are in fact SHARKS. They are one of my favorite (and Shira’s too) sharks, and they are incredible and interesting in many ways! Rhinocodon typus, the whale shark, is the BIGGEST FISH IN THE SEA. Let that “sink” in! These sharks can reach sizes of 8 feet to even 30+ feet in length. The World Wildlife Fund states that the longest recorded whale shark was about 40 feet long, but they could reach lengths of 65 feet. This is comparable to a school bus! They weigh up to 40,000 pounds; imagine coming across one of these beauties! They are found in offshore, tropical waters around the world.
Just like we have a unique and individual thumbprint, each whale shark has a different pattern of spots and markings on their body. Their skin can be up to 4 inches thick! Fun fact: whale sharks can live up to 70-100 years! However, only about 10% make it to adulthood (Padi Diving).
What Do They Do in the Big Blue?
Photo Source: Kevin Mantell at the Smithsonian Tropical Research Institute
These gorgeous sharks are huge, calm, and gentle. They are filter feeders and typically feed on plankton, small fishes, fish eggs, and copepods. Their mouths can be up to 4 feet across! Georgia Aquarium says, “A whale shark filters food from the water by ‘cross-flow filtration,’ which means the particle does not catch on the filter. Rather, water is directed away through the gills while particles carry on towards the back of the mouth in an ever more concentrated stream.” They can use suction feeding at the surface and grab concentrated food. Although solitary, whale sharks can be found in groups called shoals or shivers. They are found in shivers when food is plentiful, and then they separate. Whale sharks are known to have a few hundred rows of teeth, but these teeth do not aid them in hunting or eating.
As you may have read in other blog posts and sources, plankton is an amazing indicator of marine ecological health. The widespread distribution of whale sharks and their migration to find food can be an indicator of ecosystem health where they search for and feed on plankton.
Big Babies and Big Moves
Even their babies are big! A whale shark will have several offspring that are about 2 feet long when they are born. And when I say several, I mean up to 300 pups! Whale sharks are ovoviviparous. Ovovivipary is when eggs are formed internally inside of the mother and hatch out internally, in the uterus, and then they give birth to live babies. This is the same way boas give birth to “live” snakes versus laying eggs externally.
Being so large, they are slow-moving but migrate all around the world. They are not able to breach out of the water, and I don’t blame them! Their migration is still being studied, and there is a lot of missing information. From what we’ve seen and studied, these sharks are excellent migraters or travelers. Their nomadic nature distributes them all over the world, and they are often very solitary fish. The common reasons they migrate thousands and thousands of miles are climate change, temperature, diet, and reproduction. The longest documented migration for the whale shark was just over 12,000 miles. There is still so much to learn about the biggest fish in the world.
How Can I See Them? Help Them?
Photo Source: PADI Diving
Whale sharks are considered endangered by IUCN indications. They are at risk of going extinct in the wild. One main threat is hunting for meat, fins, and oil. Bycatch is another huge detriment to this species. Bycatch is when non-targeted species get injured, killed, or caught up by fishing lines. Additionally, some whale shark tourism can negatively affect their feeding and breeding behavior. There have been whale sharks known to be injured by boats bringing tourists to swim with them. They can also get frightened when tourists swimming with them get too close or try to ride and touch them. However, organizations like World Wildlife Fund (who Respect the Fin supports!) have worked for many years to ensure that these ecotourism activities can occur safely and respectfully. The World Wildlife Fund helps educate boaters and companies about whale shark behavior, patterns, safety, and the best ways to interact with these gentle giants. The congregation of whale sharks in Mexico brings thousands of tourists every year. The World Wildlife Fund conducts research in several different places and uses sonar technology, tagging, and cameras to study the elusive whale shark.
You can help whale sharks by reducing your plastic consumption, never purchasing shark products, participating in beach clean-ups, eating sustainably, and promoting and supporting ethical ecotourism for whale sharks. If you’re wondering where and when to see them, Padi has put together an online resource here to check out and research through.
To elaborate, from July to October, whale sharks gather in Mexico and diving or snorkeling with them is a huge tourist activity. Please do your research and find the most reputable and responsible company to support. You’ll want to look for marine biologists on board, ethical boating practices, and tourism based on education and conservation of the whale shark. The whale shark tourism industry is worth $100 million annually. Supporting whale shark tourism in an ethical way can maintain their importance and promote this species’ protection because they are such an iconic species to interact with. Check out Padi’s responsible marine life interaction guide here. Thanks for reading!
Written By: Bailey Higa