FN Archimer Export Format
PT C
TI Otolith microchemistry suggests probable population structuring in the Indian Ocean for the broadbill swordfish Xiphias gladius
BT 
AF Darnaude, Audrey M
   Labonne, Maylis
   Petit, Cécile
   Médieu, Anais
   PERNAK, Marianne
   NIKOLIC, Natacha
   Artetxe-Arrate, Iraide
   Clear, Naomi
   Farley, Jessica
   Eveson, Paige
   lozano-Montes, Hector
   Davies, Campbell
   MARSAC, Francis
AS 1:1;2:1;3:1;4:2;5:2;6:3;7:4;8:5;9:5;10:5;11:6;12:5;13:7;
FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;11:;12:;13:;
C1 Marbec, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
   Marbec, Univ Montpellier, CNRS, Ifremer, IRD, Victoria, Seychelles
   Marbec, Univ Montpellier, CNRS, Ifremer, IRD, La Réunion
   AZTI, San Sebastian, Spain
   CSIRO Oceans and Atmosphere, Hobart, Australia
   CSIRO Oceans and Atmosphere, Crawley, Australia
   Marbec, Univ Montpellier, CNRS, Ifremer, IRD, Sète, France
C2 IRD, FRANCE
   IRD, SEYCHELLES
   IRD, LA RÉUNION
   AZTI, SPAIN
   CSIRO OCEANS AND ATMOSPHERE, AUSTRALIA
   CSIRO OCEANS AND ATMOSPHERE, AUSTRALIA
   IRD, FRANCE
SI SETE
SE IRD
UM MARBEC
UR https://archimer.ifremer.fr/doc/00652/76400/77439.pdf
LA English
DT Proceedings paper
AB Variation in otolith elemental fingerprints was investigated in the broadbill swordfish (Xiphias gladius) to complement genetic data obtained by next generation sequencing in the framework of a collaborative project on population stock structure of tuna, billfish and sharks of the Indian Ocean (PSTBS-IO). Swordfish specimens for this work were sampled in the southwest (SWI), west central (WCI) and southeast (SEI) regions of the Indian Ocean. A total of 70 otoliths (30 from SWI and 20 from each WCI and SEI) were selected and the elemental signatures of their cores were analysed by LA-ICP-MS to investigate potential differences in spawning origin among regions. Among the 15 chemical elements analysed, only Mg, P, Sr, Ba and B were above detection limits and significantly contributed to the variation in otolith core composition. Based on differences in these five elements, three groups of distinct multi-elemental signatures, denoting potentially discrete spawning origins (SpO), were identified using hierarchical clustering based on Euclidian distances. All SpO identified apparently contributed to the swordfish stocks of the three regions sampled, but in different proportions. SpO-1 was the most common spawning source among the fish sampled (49%); it probably corresponds to the swordfish spawning ground located between northeast Australia and Indonesia. SpO-3 was found to provide 34% of the total fish analysed, but mainly in SWI (53%) and WCI (35%). It could correspond to the spawning grounds reported for the species in the central and southwestern Indian Ocean. Lastly, SpO-2, which contributed to only 17% of the total fish analysed (mainly in SEI and WCI), may correspond to the spawning ground previously reported in the northwestern Indian Ocean, off the Somalian coast. Although our results show mixed origins in the fish sampled at each sampling location, the contrast in otolith core fingerprints between SWI and SEI otoliths suggests differences in main spawning origin, at least for the swordfish captured in these two regions of the Indian Ocean. Additional analyses are needed to consolidate these results, as well as information on the spatiotemporal distribution of chemical tracers in the water masses of the Indian Ocean to assign regions to otolith elemental signatures. 
PY 2020
CT 18th Working Party on Billfish (WPB). 02/09/2020 - 04/09/2020. Online, virtual. meeting Documents. IOTC-2020-WPB18-10_Rev1, 12p.
ID 76400
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