Scientific Name: Rhincodon typus
Common Name (UK, FR, PT, ES, DE): Whale shark, Requin-Baleine, Tubarão baleia, Tiburón ballena, Walhai
Short Species description: The world’s largest living shark and largest living fish. It is easily distinguishable from other sharks by its enormous size, unique ‘checkerboard’ pattern of spots and stripes on its back, three prominent longitudinal ridges along its upper flanks, and its characteristic head and mouth. They are popular with snorkelers and divers at sites where they aggregate off the coast.
The maximum size of these animals is not known, but accounts of individuals of up to 18 meters have been recorded. It is a pelagic and highly migratory species, that travel large distances to find enough food to sustain their huge size, and to reproduce. The shark is among the latest maturing and longest-lived of all fish, reaching sexual maturity at around 30 years of age and reaching ages of up to 70 to 100 years old. They spend most of their time close to the surface, and also have been known to occur at depths at around 700 meters. As a filter feeder, its prey consists predominantly of small planktonic and nektonic animals.
Population status: Endangered by the IUCN Status.
Threats: The species is caught commercially at some locations but not in the Atlantic. There are several reports of harassment by tourism operators. The AtlanticNaturalist.org has adopted a Code of conduct for whale shark tourism interactions in Portuguese waters.
Occurrence in the Azores (including season): In the Azores they can be found during the summer and autumn months when water temperatures are at their highest, particularly in Santa Maria Island, and in offshore banks. In 2020 they were seen regularly south of Pico Island from September to early November.
Habitat Use: The whale shark occupies a circumglobal distribution, occurring in all tropical, subtropical and warm temperate seas (apart from the Mediterranean) between 30°N and 35°S.
Pod Size: These gentle marine giants roam the oceans around the globe, generally alone as they are solitary fishes. However, large numbers of whale sharks often gather in areas with abundant plankton food, making them prime tourist attractions. It is presumed that when prey availability subsides, the sharks disperse to forage elsewhere.
Typical Behaviour: Whale sharks are generally associated with environmental factors that drive their movements to specific locations where food availability is high. Consequently, foraging is believed to be the main reason for the formation of whale shark aggregations. Feeding aggregations occur mainly in nearshore areas and are composed primarily of immature individuals. Conversely, aggregations of mature adults are rarely observed, and their occurrence is correlated with oceanic environments.
References
Macena, B. C., & Hazin, F. H. (2016). Whale shark (Rhincodon typus) seasonal occurrence, abundance and demographic structure in the mid-equatorial Atlantic Ocean. PloS one, 11(10), e0164440.
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