However, researchers at Ningaloo have observed that the sharks usually feed by actively swimming through a mass of zooplankton or small fish with their mouths wide open. Whale sharks have also been observed to hang vertically in the water and feed by sucking water into their mouths. Very little is known about the reproduction of whale sharks, most information coming from a single egg found in the Gulf of Mexico. It is thought that the young develop in egg cases that are retained in the mother's body until hatching. Despite their large adult size, whale sharks are very small at birth, probably 40 to 50 centimetres.
Whale sharks occur world-wide in tropical and temperate seas and are thought to be highly migratory.
However, there is little information currently available on this aspect of their behaviour. If, and when, these tags are recovered, they will provide a insight into the migratory habits of this species. The data from these logbooks will be used to build up profiles of individual sharks and migratory habits. Tourism based on whale shark watching has increased dramatically in the last few years and Government agencies have taken steps to protect these magnificent animals. Fisheries Western Australia and CALM have combined to declare an indefinite closed season for this species under the Fish Resources Management Act and the Wildlife Conservation Act.