title: Philopatry and migration of Pacific white sharks.
abstract: Advances in electronic tagging and genetic research are making it possible to discern population structure for pelagic marine predators once thought to be panmictic. However, reconciling migration patterns and gene flow to define the resolution of discrete population management units remains a major challenge, and a vital conservation priority for threatened species such as oceanic sharks. Many such species have been flagged for international protection, yet effective population assessments and management actions are hindered by lack of knowledge about the geographical extent and size of distinct populations. Combining satellite tagging, passive acoustic monitoring and genetics, we reveal how eastern Pacific white sharks (Carcharodon carcharias) adhere to a highly predictable migratory cycle. Individuals persistently return to the same network of coastal hotspots following distant oceanic migrations and comprise a population genetically distinct from previously identified phylogenetic clades. We hypothesize that this strong homing behaviour has maintained the separation of a northeastern Pacific population following a historical introduction from Australia/New Zealand migrants during the Late Pleistocene. Concordance between contemporary movement and genetic divergence based on mitochondrial DNA demonstrates a demographically independent management unit not previously recognized. This population's fidelity to discrete and predictable locations offers clear population assessment, monitoring and management options.
authors.affiliation: Department of Biology, Stanford University, Pacific Grove, CA 93950, USA. salvo@stanford.edu
authors.forename: Salvador J
authors.initials: SJ
authors.lastname: Jorgensen
authors.forename: Carol A
authors.initials: CA
authors.lastname: Reeb
authors.forename: Taylor K
authors.initials: TK
authors.lastname: Chapple
authors.forename: Scot
authors.initials: S
authors.lastname: Anderson
authors.forename: Christopher
authors.initials: C
authors.lastname: Perle
authors.forename: Sean R
authors.initials: SR
authors.lastname: Van Sommeran
authors.forename: Callaghan
authors.initials: C
authors.lastname: Fritz-Cope
authors.forename: Adam C
authors.initials: AC
authors.lastname: Brown
authors.forename: A Peter
authors.initials: AP
authors.lastname: Klimley
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Block
mesh_terms: D000823:Animal Identification Systems; D025041:Animal Migration; D000818:Animals; D001522:Behavior, Animal; D003247:Conservation of Natural Resources; D004272:DNA, Mitochondrial / Q000235:genetics; D017753:Ecosystem; D005260:Female; D051456:Gene Flow; D005828:Genetics, Population; D006702:Homing Behavior; D010140:Pacific Ocean; D011157:Population Dynamics; D017215:Satellite Communications; D012754:Sharks / Q000145:classification / Q000235:genetics / Q000502:physiology*
chemical_list: D004272:DNA, Mitochondrial