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Marine Biology

, Volume 141, Issue 1, pp 131–143 | Cite as

Identification of Illex coindetii, I. illecebrosus and I. argentinus (Cephalopoda: Ommastrephidae) throughout the Atlantic Ocean; by body and beak characters

  •  P. Martínez
  •  A. Sanjuan
  •  A. Guerra

Abstract.

Shortfinned squid species of the genus Illex support commercial fisheries throughout the Atlantic Ocean and Mediterranean Sea. Previous identification of interspecific and intraspecific populations by morphological and size-at-maturity studies have not provided conclusive results. We analysed morphometric body and beak variables (24 characters) in three species of the genus (I. coindetii, I. illecebrosus and I. argentinus), using a geographic and seasonal series of 33 populations for 1,500 specimens of I. coindetii, I. illecebrosus and I. argentinus. Residuals of the regression between each morphometric body and beak variable and mantle length were used as input in a stepwise discriminant analysis. Species discrimination by body and hectocotylus characters required at least eight variables and resulted in high correct-classification percentages for I. coindetii and I. argentinus (75% and 90%, respectively), whereas the best identification resulted from beak characters (83% correctly classified). Size of the suckerless basal arm, sucker-bearing length and beak lateral wall discriminated best among I. coindetii from northern Iberia, northwest Iberia (year-1996) and Ireland in the Atlantic and western Mediterranean versus middle and eastern Mediterranean samples. Canadian shelf and American samples were discriminated from Canadian slope I. illecebrosus. Winter/shelf and winter/slope samples of I. argentinus seemed to form a single biological group separated from Falkland Island, 46°S/autumn spawners and 46°S/1996 specimens along the Patagonian Shelf. No significant sexual or maturity polymorphism was obtained. Discriminant analysis optimised population diagnosis on a morphometric basis of interest in fisheries strategies. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00227-002-0796-7.

Keywords

Discriminant Analysis Mantle Length Stepwise Discriminant Analysis Species Discrimination Link Server 
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.

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  •  P. Martínez
    • 1
  •  A. Sanjuan
    • 2
  •  A. Guerra
    • 3
  1. 1.Museo Nacional de Ciencias Naturales MNCN, CSIC, José Gutierrez Abascal 2, Madrid 28006, Spain
  2. 2.Xenética Evolutiva Molecular, Facultade de Ciencias-Bioloxía, Universidade de Vigo, Vigo 36200, Spain
  3. 3.Ecobiomar, Instituto de Investigaciones Marinas IIM, CSIC, Eduardo Cabello 6, Vigo 36208, Spain

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