@inproceedings{fdi:010083430,
  title = {{O}tolith microchemistry suggests probable population structuring in the {I}ndian {O}cean for the broadbill swordfish {X}iphias gladius},
  author = {{D}arnaude, {A}.{M}. and {L}abonne, {M}aylis and {P}etit, {C}. and {M}{\'e}dieu, {A}. and {P}ernak, {M}. and {N}ikolic, {N}atacha and {A}rtetxe-{A}rrate, {I}. and {C}lear, {N}. and {F}arley, {J}. and {E}veson, {P}. and {L}ozano-{M}ontez, {H}. and {C}ampbell, {D}. and {M}arsac, {F}rancis},
  editor = {},
  language = {{ENG}},
  abstract = {{V}ariation in otolith elemental fingerprints was investigated in the broadbill swordfish ({X}iphias 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  {I}ndian  {O}cean  ({PSTBS}-{IO}).  {S}wordfish  specimens  for  this  work  were  sampled  in  the  southwest  ({SWI}),  west  central  ({WCI})  and  southeast ({SEI}) regions of the {I}ndian {O}cean. {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. {A}mong the 15 chemical elements analysed,  only {M}g,  {P},  {S}r,  {B}a  and  {B}  were  above  detection  limits  and  significantly  contributed  to  the  variation  in  otolith  core  composition.  {B}ased  on  differences  in  these  five  elements,  three  groups  of  distinct  multi-elemental signatures, denoting potentially discrete spawning origins ({S}p{O}), were  identified  using  hierarchical  clustering  based  on  {E}uclidian  distances.  {A}ll  {S}p{O}  identified  apparently  contributed to the swordfish stocks of the three regions sampled, but in different proportions. {S}p{O}-1 


was the most common spawning source among the fish sampled (49/100); it probably corresponds to the  swordfish  spawning  ground  located  between  northeast  {A}ustralia  and  {I}ndonesia.  {S}p{O}-3  was  found to  provide 34/100 of the total fish analysed, but mainly in {SWI} (53/100) and {WCI} (35/100). {I}t could correspond  to the spawning grounds reported for the species in the central and southwestern {I}ndian {O}cean. {L}astly,  {S}p{O}-2,  which  contributed  to  only  17/100 of  the  total  fish  analysed  (mainly  in  {SEI}  and  {WCI}),  may correspond  to  the  spawning  ground  previously  reported  in  the  northwestern  {I}ndian  {O}cean,  off  the  {S}omalian coast. {A}lthough 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 {I}ndian {O}cean. {A}dditional  analyses  are  needed  to  consolidate  these  results,  as  well  as  information  on  the  spatiotemporal  distribution  of  chemical  tracers  in  the  water masses  of  the  {I}ndian  {O}cean  to  assign  regions  to  otolith  elemental signatures.},
  keywords = {{OCEAN} {INDIEN} ; {AUSTRALIE} ; {INDONESIE} ; {REUNION} ; {SEYCHELLES}},
  numero = {{IOTC}-2020-{WPB}18-10},
  pages = {12  multigr.},
  booktitle = {},
  year = {2020},
  URL = {https://www.documentation.ird.fr/hor/fdi:010083430},
}