The whale shark is the largest shark or fish in the world, reaching up to 20 m or 60 ft. These giant sharks can live up to 100 years, reproducing for the first time at the age of 30. Pregnant whale sharks may have up to 300 infants that are carried in the mother’s uterus until the eggs hatch inside the mother. The eggs do not hatch at the same time but instead over a period of time that is still unknown.

The hatching babies are about 60–70 cm (24–28 inches) long. At this stage, baby whale sharks are vulnerable to attack; usually marlin or other species of shark so a large percentage never reach adulthood. They are one of the 3 filter feeding sharks that include the mega mouth and basking sharks. The principle diet of whale sharks is plankton, such as copepods, euphasids, also known as krill, fish eggs and fish larvae.

An adult whale shark has little to fear in the ocean other than fishing nets, harpoons and boat strikes. Natural predators include the orca as well as large sharks like the great white and tiger sharks.

The whale shark is epipelagic with circum-tropical distribution in tropical and warm temperatures seas. It is a highly migratory shark and suitable use of this threatened shark depends of international collaborations.

In the Indo-Pacific Ocean there still exists commercial fishing of the whale shark, however at the same time their attraction for eco- tourism has grown world wide.

At the end of the 90´s whale shark populations declined worldwide. In 2000 they were listed as a vulnerable on the World Conservation Union ¨Red List¨ and included on the Mexican Red List in 2001.In 2002 they were included on the appendix II of the Convention for International Trade in Endangered Species and in 2004 they were listed in Appendix II of the Convention for Migratory Species.

Our knowledge of its biology, ecology and behavior is limited and hampers our ability to implement appropriate protection for conservation. It is important to obtain greater understanding of whale shark population structure, dynamics and migration patterns in order to establish coherent whale shark conservation measures.

For the past several years, whale sharks have become a major interest of many marine biologists, governments, and tourist companies. This is due partly to the mystery of their life cycles and the challenge of making close observation of this charismatic shark. Scientists around the world are working to learn more details about these enigmatic animals and find ways to protect them.

In México the whale sharks aggregate in Holbox Island, a place between the Gulf of México and Caribbean Ocean and on the Pacific side of México they aggregate in Oaxaca, the Gulf of California and the Revillagigedo Islands.