title: Biocomplexity in a highly migratory pelagic marine fish, Atlantic herring.
abstract: The existence of biologically differentiated populations has been credited with a major role in conferring sustainability and in buffering overall productivity of anadromous fish population complexes where evidence for spatial structure is uncontroversial. Here, we describe evidence of correlated genetic and life history (spawning season linked to spawning location) differentiation in an abundant and highly migratory pelagic fish, Atlantic herring, Clupea harengus, in the North Sea (NS) and adjacent areas. The existence of genetically and phenotypically diverse stocks in this region despite intense seasonal mixing strongly implicates natal homing in this species. Based on information from genetic markers and otolith morphology, we estimate the proportional contribution by NS, Skagerrak (SKG) and Kattegat and western Baltic (WBS) fish to mixed aggregations targeted by the NS fishery. We use these estimates to identify spatial and temporal differences in life history (migratory behaviour) and habitat use among genetically differentiated migratory populations that mix seasonally. Our study suggests the existence of more complex patterns of intraspecific diversity than was previously recognized. Sustainability may be compromised if such complex patterns are reduced through generalized management (e.g. area closures) that overlooks population differences in spatial use throughout the life cycle.
authors.affiliation: Dalhousie University, Department of Biology, Halifax, NS B3H 4J1, Canada. daniel.ruzzante@dal.ca
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Ruzzante
authors.forename: Stefano
authors.initials: S
authors.lastname: Mariani
authors.forename: Dorte
authors.initials: D
authors.lastname: Bekkevold
authors.forename: Carl
authors.initials: C
authors.lastname: André
authors.forename: Henrik
authors.initials: H
authors.lastname: Mosegaard
authors.forename: Lotte A W
authors.initials: LA
authors.lastname: Clausen
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Dahlgren
authors.forename: William F
authors.initials: WF
authors.lastname: Hutchinson
authors.forename: Emma M C
authors.initials: EM
authors.lastname: Hatfield
authors.forename: Else
authors.initials: E
authors.lastname: Torstensen
authors.forename: Jennifer
authors.initials: J
authors.lastname: Brigham
authors.forename: E John
authors.initials: EJ
authors.lastname: Simmonds
authors.forename: Linda
authors.initials: L
authors.lastname: Laikre
authors.forename: Lena C
authors.initials: LC
authors.lastname: Larsson
authors.forename: René J M
authors.initials: RJ
authors.lastname: Stet
authors.forename: Nils
authors.initials: N
authors.lastname: Ryman
authors.forename: Gary R
authors.initials: GR
authors.lastname: Carvalho
mesh_terms: D025041:Animal Migration; D000818:Animals; D005260:Female; D005398:Fisheries; D005399:Fishes / Q000235:genetics* / Q000502:physiology; D014644:Genetic Variation; D005843:Geography; D006702:Homing Behavior; D008297:Male; D009659:North Sea; D012621:Seasons; D012726:Sexual Behavior, Animal