Abstract

Fitzpatrick, B., Meekan, M., et al. Shark attacks on a whale shark (Rhincodon typus) at Ningaloo Reef, western Australia, Bulletin of Marine Science 78(2): 397-402 (2006)

The planktivorous whale shark, reputed to attain lengths of up to 18 m, is the world’s largest fish (Coleman, 1997). The immense size of whale sharks may offer a refuge from predation (Peters, 1983) by large sharks and killer whales, Orcinus orca (Linnaeus, 1758), similar to other marine megafauna such as cetaceans (Pitman et al., 2001). At present, there is only one published observation that suggests that whale sharks might be susceptible to any top order predator other than man (Fertle et al., 1996). However, very little is known of the biology and ecology of these animals, and the lack of predation records on whale sharks may simply reflect the fact that they usually inhabit tropical oceanic waters, far from coastal regions where predation is likely to be observed. Ningaloo Reef in Western Australia hosts an aggregation of whale sharks in coastal waters from March to June. The predictable arrival of whale sharks has led to the development of a lucrative ecotourism industry that allows divers to observe sharks in shallow waters on the seaward edges of the fringing coral reef. During these whale shark encounters, attacks by a predator, possibly a tiger shark, Galeocerdo cuvier (Péron and Lesueur in Lesueur, 1822), or great white shark, Carcharodon carcharias (Linnaeus, 1758), and ectoparasitic sharks (Isistius spp.) were documented. Encounters with the same whale shark 3 mo and then 1 yr later recorded wound healing.

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