ABSTRACT
Although a species capable of long-distance dispersal, the Great White Shark, Carcharodon carcharias, exhibits philopatric behavior, with females known to return to natal sites in at least part of its range. However, intractability and rarity mean knowledge of its population dynamics remains limited. Direct observation, by tagging or photographic tracking, often lack, respectively, repeatability and objectivity, however, integrating these with advances in molecular genetics provides an indirect assessment of population connectivity, substructuring, and dispersal. Here we review the utility of population genetic structure inferred from molecular markers and discuss its application in the development and implementation of effective conservation strategies. Application of nuclear markers and population genetic analysis combined with published mitochondrial sequences afford the most highly resolved view of White Shark population structure to date, allowing further insight into the extent of sex-biased dispersal and the role of mating behavior in maintaining the observed population structure. The distribution of matrilineal clades across oceans gives cause for concern, emphasizing the existence of endangered populations in enclosed areas. Current genetic pro¢ling and species diagnostic techniques are reviewed, and their application in law enforcement is discussed. Although concordance of direct (photographic identi¢cation) and indirect (molecular tools) methods of individual identi¢cation has been used to validate proposed White Shark local movements, extensive sampling, new markers, and alternative DNA sources should also be considered. New methods and next generation DNA sequencing technologies may be developed to afford new insights into elasmobranch biology. Findings from these approaches are essential for formulation of White Shark population management plans in a species that is classi¢ed by the International Union for Conservation of Nature as “vulnerable.”
