CSIRO Marine Research, HOBART, AUSTRALIA
The movement patterns of white sharks in Australian waters were examined using a combination of satellite telemetry, archival and conventional tags. White sharks showed broad-scale movements consistent with mixing of the population across their entire Australian range and including across the Tasman Sea to New Zealand. Most movements were, however, confined to shelf waters, generally in areas of less than 100 m depth and in some cases into waters of less than 5 m depth. An archival-tagged white shark showed considerable plasticity in its vertical swimming behaviour with elements of most vertical swimming behaviours reported for a variety of sharks species tracked by acoustic methods. Common swimming behaviours occurred during different periods of the 74 day track and corresponded to the shark either moving into different habitats or travelling between them. The changes in swimming behaviour were abrupt and suggested switching of hunting strategies for different prey types in these habitats. Tracked sharks showed both prolonged periods of directional swimming in coastal waters at swimming speeds of 2-3 km h-1, as well as temporary residency in particular regions. Seasonal movements northward along the east coast of Australia during autumn-winter is supported by the movements of two satellite-tracked juvenile white sharks, by data from shark control programs and anecdotal observations. The consistency of paths taken by tagged and tracked white sharks in Australian waters, in general, suggests an ability to effectively navigate coastal waters and that they may follow common routes or 'highways' when travelling between regions hundreds of kilometres apart.