Otolith ?18O Composition as a Tracer of Yellowfin Tuna (Thunnus albacares) Origin in the Indian Ocean

Yellowfin tuna of the Indian Ocean is overfished, and a better understanding stock structure needed to enable sustainable management. Here, otolith ?18O values young-of-the-year fish from known nursery areas equatorial (West, Central East) were used establish reference isotopic signature predict origin sub-adult adult individuals. Sub-adult Reunion Island similar West signature, but sub-adults Pakistan unlike any nurseries sampled. Therefore, area samples considered an additional source for predicting tuna, using multinomial logistic regression classification method. The western was most productive three fishing grounds sampled, with minor contribution Pakistan-like fish. Contribution or East population negligible. One analysed by secondary ion mass spectrometry along growth transect results compared isoscape approach infer lifetime movements. This study important first step towards spatial connectivity species.