FN Archimer Export Format
PT J
TI Otolith shape as a valuable tool to evaluate the stock structure of swordfish   Xiphias gladius   in the Indian Ocean
BT 
AF MAHE, Kelig
   EVANO, Hugues
   MILLE, Tiphaine
   MUTHS, D.
   BOURJEA, Jerome
AS 1:1;2:2;3:1;4:3;5:4;
FF 1:PDG-RBE-HMMN-RHBL;2:PDG-RBE-DOI;3:PDG-RBE-HMMN-RHBL;4:;5:PDG-RBE-MARBEC-LHM;
C1 IFREMER, Lab Ressources Halieut, Boulogne Sur Mer, France.
   IFREMER, Delegat Ocean Indien, Le Port, Reunion.
   Univ Europeenne Bretagne, Rennes, France.
   IFREMER, UMR MARBEC 248, Sete, France.
C2 IFREMER, FRANCE
   IFREMER, FRANCE
   UNIV RENNES, FRANCE
   IFREMER, FRANCE
SI BOULOGNE
   LA REUNION
   SETE
SE PDG-RBE-HMMN-RHBL
   PDG-RBE-DOI
   PDG-RBE-MARBEC-LHM
UM MARBEC
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-univ-france
IF 1.229
TC 17
UR https://archimer.ifremer.fr/doc/00354/46527/46411.pdf
LA English
DT Article
DE ;connectivity;Fourier descriptors;morphometric markers;sagittal otoliths;stock discrimination
AB Swordfish Xiphias gladius is an oceanic-pelagic species. Its population structure in the Western Indian Ocean was studied from the shape of the sagittal otoliths of 391 individuals collected from 2009 to 2014. Normalised elliptical Fourier descriptors (EFDs) were extracted automatically using TNPC software. Principal components analysis (PCA) conducted on EFDs showed no significant effect of side (i.e. left or right otolith). Consequently, all 391 sagittal otoliths were used to identify stocks among six geographical areas: Reunion Island, Mozambique Channel, Rodrigues, South Africa, Madagascar South and Sri Lanka. To investigate the effects of sex, sampling year, sampling season, lower jaw fork length or geographical area on variations in otolith shape, redundancy analyses (RDAs) with permutation tests were conducted. The first four were non-significant (respectively, p = 0.124, p = 0.721, p = 0.197, p = 0.463), but geographical area appeared to discriminate groups significantly (p < 0.05). Furthermore, linear discriminant analysis (LDA) was performed and overall jackknife classification success reached 30%. Finally, a cluster analysis was conducted using Ward’s hierarchical algorithm, which discriminated three different groups. However, each group consisted of individual samples from all geographical areas. In conclusion, our results were unable to identify a clear geographical separation of swordfish at the Indian Ocean scale, corroborating recent genetic studies in this region.
PY 2016
SO African Journal Of Marine Science
SN 1814-232X
PU Natl Inquiry Services Centre Pty Ltd
VL 38
IS 4
UT 000391853200001
BP 457
EP 464
DI 10.2989/1814232X.2016.1224205
ID 46527
ER

EF