ABSTRACT
Knowledge of the trophic and spatial ecology of elasmobranchs is widely recognized as a critical component of successful management and conservation programs (Mourier et al., 2016; Oh et al., 2017; White et al., 2017). Dietary biomarkers have emerged as an effective and affordable tool in the eld of foraging ecology (Graham et al., 2010; Newsome
et al., 2010; Peterson and Fry, 1987). Although shark research has been relatively slow to incorporate biomarker approaches, recent years have seen a substantial increase in the number of elasmobranch biomarker studies (Hussey et al., 2012). Examples can be found across the analytical spectrum, including dietary reconstructions (e.g., Stewart et al., 2017), resource partitioning (e.g., Kinney et al., 2011), and movement (e.g., Munroe et al., 2015). Biomarkers are now
CONTENTS
1.1 Introduction .................................................................................................................................................................... 1 1.2 Principles of Biomarker Ecology .................................................................................................................................... 2
1.2.1 Stable Isotope Analysis ....................................................................................................................................... 2 1.2.2 Fatty Acid Analysis ............................................................................................................................................ 3
1.3 Common Biomarkers in Shark Ecology ......................................................................................................................... 4 1.3.1 Stable Isotopes .................................................................................................................................................... 4 1.3.2 Fatty Acids .......................................................................................................................................................... 5
1.4 Sample Analysis ............................................................................................................................................................. 5 1.4.1 Tissues ................................................................................................................................................................ 5 1.4.2 Sample Collection and Preservation ................................................................................................................... 6 1.4.3 Urea Extraction ................................................................................................................................................... 6 1.4.4 Lipid Extraction .................................................................................................................................................. 7 1.4.5 Special Considerations for Calcied Structures ................................................................................................. 7
1.5 Ecological Applications .................................................................................................................................................. 7 1.5.1 Trophic Position .................................................................................................................................................. 7 1.5.2 Niche Breadth and Specialization ...................................................................................................................... 9 1.5.3 Diet Reconstruction and Mixing Models ..........................................................................................................11 1.5.4 Movement and Migration ..................................................................................................................................14 1.5.5 Compound-Specic Stable Isotope Analysis .....................................................................................................16
