Endangered Species: The Gentle Giants of Our Oceans
What are they?
Whale sharks (Rhincodon typus) are the largest vertebrate fish in the world, with an average full size of between 18 and 32.8 feet long, some even reaching a length of up to 40 feet. Their average life span is around 70 years old, but they can live to be 100-150 years old. While they are similar to many whales due to their eating habits as filter feeders, whale sharks are in fact classified as sharks. To eat, whale sharks open their mouths around 1.2 meters wide while swimming, consuming plankton along with other small fish. Whale sharks will travel between 24 and 28 km per day to consume their necessary nutrition. These gentle giants like warmer waters, so they tend to stay in tropical oceans and migrate every spring to the western portions of Australia.
Whale sharks provide many different services to marine ecosystems. They help keep our oceans healthy by serving as vectors for nutrients to be transported from high-nutrient areas to those that lack proper nutrients. In addition to providing habitats for small marine organisms, whale sharks’ carcasses are also utilized to provide shelter and nutrients for a variety of benthic organisms, those of which are found on the bottom of the sea floor.
Why are they endangered?
Unfortunately, in the last 75 years, global whale shark populations have decreased by over 50 percent. There are many different reasons as to why these populations have declined dramatically in the last century. Like many other marine organisms, whale sharks have been captured through bycatch (accidental catch of species in fishing gear) because of unsafe fishing practices. Whale sharks have also been caught purposefully for their fins, meat, and oil in various international markets, especially in Asia. China and India continue to capture whale sharks for human uses even though they are both signatories of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Tourism can impact whale shark feeding patterns and boat traffic has led to more boat strikes as well. Other major threats to the global whale shark population include plastic and noise pollution, ocean warming, overfishing, and coastal development.
How are they being protected?
Consequently, whale sharks have become classified as endangered globally by the IUCN (International Union for Conservation of Nature) in 2016. Whale sharks have protection under other treaties as well, including Appendix I of the United Nations Convention on the Law of the Sea (UNCLOS), Appendix II of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), and the Convention of Migratory Species (CMS).
UNCLOS sets ocean jurisdictional boundaries, and for whale sharks specifically, it classifies them as a highly migratory species, which then requires specific assessment and management. The CITES treaty aims to regulate international trade of endangered species and prevent illegal wildlife trafficking through an import/export permitting system. Appendix II in particular, which the whale shark is classified, is for species that are not currently threatened with extinction, but trade needs to be controlled to avoid overutilization. CMS, a conservation and protection treaty for migratory wildlife species, classifies whale sharks in Appendix II which applies for species that require further international conservation efforts. However, there have been multiple proposals to move whale sharks into Appendix I since it is for endangered migratory species.
Furthermore, over 45 countries now have bans on shark fishing, and there are specific national regulations for whale shark fishing, including in the United States. Nevertheless, it is imperative to protect and improve the populations of these magnificent creatures in order to prevent them from becoming extinct.
Sources: American Oceans, Defenders of Wildlife, Earth.Org, Greenpeace, Humane Society International Live Science, National Geographic, World Wildlife Fund