Marine Biology

, Volume 144, Issue 5, pp 961–970 | Cite as

DNA markers indicate that distinct spawning cohorts and aggregations of Patagonian squid, Loligo gahi, do not represent genetically discrete subpopulations

  • P. W. ShawEmail author
  • A. I. Arkhipkin
  • G. J. Adcock
  • W. J. Burnett
  • G. R. Carvalho
  • J. N. Scherbich
  • P. A. Villegas
Research Article


The Patagonian squid, Loligo gahi D’Orbigny, has been described as having temporally and spatially identifiable spawning aggregations. Variation at six microsatellite loci was used to assess whether seasonal and geographical spawning groups around the Falkland Islands represent distinct sub-populations. Genetic variation at these loci is high in this species (mean expected heterozygosity=0.87; mean number of alleles=14.7). No evidence of significantly different allele frequencies was found, either between samples from putative spawning cohorts or geographical areas, indicating that L.gahi around the Falkland Islands comprise a single genetically homogeneous population. Age structure analysis of samples (from statolith growth increments) indicated substantial spread in hatching dates among individuals of similar size and maturity status, suggesting the potential for extensive interbreeding between seasonal cohorts. A sample of L.gahi from the SE Pacific (Peru) displayed distinctly different gene frequencies (and allele size distribution at one locus) from SW Atlantic samples, supporting the suggestion that SE Pacific and SW Atlantic populations may represent distinct subspecies.


Genetic Differentiation Microsatellite Locus Life History Characteristic Falkland Island Mantle Length 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This study was funded by the Falkland Islands Government. We thank the FIFD observers for help in collecting samples, and Director of Fisheries, John Barton, for supporting this work. The work carried out during this study was conducted in compliance with UK and Falkland Islands law.


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • P. W. Shaw
    • 1
    Email author
  • A. I. Arkhipkin
    • 2
  • G. J. Adcock
    • 3
    • 4
  • W. J. Burnett
    • 1
  • G. R. Carvalho
    • 3
  • J. N. Scherbich
    • 2
  • P. A. Villegas
    • 2
  1. 1.School of Biological SciencesRoyal Holloway University of LondonEghamUK
  2. 2.Falkland Islands Government Fisheries DepartmentStanleyFalkland Islands
  3. 3.Department of Biological SciencesUniversity of HullHullUK
  4. 4.Department of ZoologyUniversity of MelbourneMelbourne 3010Australia

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