chapter  19
20 Pages

Assessing Habitat Use and Movement

ByColin A. Simpfendorfer, Michelle R. Heupel

CONTENTS 19.1 Introduction .................................................................................................................................. 553 19.2 Measuring Habitat Use and Habitat Preference .......................................................................... 555

19.2.1 Habitat Use...................................................................................................................... 555 19.2.2 Habitat Preference........................................................................................................... 555

19.3 Approaches to Assessing Habitat Use and Habitat Preferences ................................................. 556 19.3.1 Direct Observation .......................................................................................................... 556 19.3.2 Relative Catch Rates ....................................................................................................... 556 19.3.3 Acoustic Tracking ........................................................................................................... 556 19.3.4 Acoustic Monitoring ....................................................................................................... 559 19.3.5 Satellite Telemetry........................................................................................................... 561 19.3.6 Archival Tags................................................................................................................... 562 19.3.7 Animal-Borne Video Systems......................................................................................... 565

19.4 The Importance of Scale in Habitat Use Studies ........................................................................ 565 19.4.1 Temporal Factors............................................................................................................. 566

19.4.1.1 Diel Effects ...................................................................................................... 566 19.4.1.2 Longer-Term Effects ........................................................................................ 567

19.4.2 Spatial Factors ................................................................................................................. 568 19.5 Factors Influencing Habitat Selection by Sharks ........................................................................ 569

19.5.1 Physical Factors .............................................................................................................. 569 19.5.2 Biotic Factors .................................................................................................................. 569

19.6 The Future of Habitat Use Studies on Sharks, Skates, and Rays............................................... 570 References .............................................................................................................................................. 570

19.1 Introduction Sharks occur in all of the world’s oceans and in waters that include the deep-sea, oceanic, neritic, and estuarine habitats. In addition, a few specialized species also occur in rivers and lakes connected to the ocean. The occurrence of sharks within these broad regions is well understood for most species. For example, the gummy shark, Mustelus antarcticus, is known to occur in the neritic waters of southern Australia, or the salmon shark, Lamna ditropis, is known to inhabit the boreal waters of the north Pacific. (Chapter 2 provides a detailed consideration of the zoogeography of the sharks, skates, and rays.) However, a shark will not occur in all of the habitats within its range; instead, it is more likely to have specific habitats in which it spends most of its time. It is this detailed analysis of the habitats that a species uses that is discussed here.